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By Andrea Estrada

Hydraulic Systems

Without its hydraulic systems, a piece of construction equipment could do little more than sit on the work site and gather dust. The pressure and flow of hydraulic fluid through the systems provide the muscle that lifts the bucket, moves the blade, and starts, stops, and steers the backhoe, bulldozer, or excavator.

Hydraulics, a science that dates back to the Middle Ages, is based on the idea that fluid cannot be compressed, no matter how much pressure is applied to it. Pour that fluid into a closed system, and when you apply a force at one end the pressure moves through the liquid to the other end. The magic of hydraulics, however, is that depending on the design of the system, the amount of force applied at one end of the system can increase—or decrease—the output at the other end.

Hydraulic components provide the big muscle in earthmoving equipment.

Take a simple piston pump, for example, in which two pistons sit in parallel cylinders. As pressure is applied to one piston and forces it downward, it pushes on the fluid beneath it, which, in turn, moves toward the second cylinder and piston. The fluid, under pressure from the force applied to the first piston, pushes the second piston upward. If the area of one piston is smaller than the area of the other, the output will vary. Here’s how it works. Pressure is applied in terms of square inches, or psi. Let’s say the area of the piston in the first cylinder is 2 square inches and the area of the piston in the second cylinder is 6 square inches. Let’s say, too, that we apply a force equal to 10 pounds to the first piston. That 10 pounds is affecting an area of 2 square inches. As the fluid moves to the second cylinder, however, where the area of the piston is 6 square inches, that same 10 pounds of force now affects three times as many square inches, so the output is three times greater, or 30 pounds of force. The same magic can also work in the reverse.

Every hydraulic system consists of five basic components: a motor, a pump, a series of directional control valves, a series of hoses and fluid supply lines, and an actuator. The motor powers the pump that moves the hydraulic fluid through the hoses and supply lines, as directed by the control valves, to the actuator. The actuator, in turn, converts the hydraulic energy into mechanical work, such as lifting a bucket or blade.

Without any one of these components, the hydraulic system grinds to a potentially costly halt.

In the next few Technology in Construction sections, we’ll take a detailed look at each of the components in the hydraulic system. Let’s start with the actuator.

As mentioned earlier, an actuator is a device that converts the energy produced by pressurized fluid into some form of mechanical work. That work can be linear, such as raising and lowering the arm on an excavator, or it can be rotary, as moving the treads forward or backward.

One of the most common actuators is the hydraulic cylinder, which is used for producing linear force. The hydraulic cylinder consists of a cylinder barrel—or body—the rod-end head, the cap-end head, the piston and piston rod, the piston seal, and rod seals. The piston, which fits into the cylinder barrel, is connected to a piston rod, which allows it to move back and forth or up and down. In addition, head- and cap-end ports allow for fluid to enter and exit the cylinder.

Take a look at the excavator and you’ll see at least four linear actuators, not including those that control the bucket. Two are attached to either side of the arm, one connects the arm to the boom, and the other helps direct the raising and lowering of the bucket. When the operator moves the lever accordingly, he increases the pressure of the hydraulic fluid on one side of the piston, which forces the piston and piston rod to move.

Hydraulic cylinders come in a variety of designs, each with its own particular use and advantages. Some of these include ram, single-acting, double-acting, telescopic, differential, cushioned, and lockout.

Just as linear actuators convert hydraulic energy to linear work, rotary actuators do the same for rotary work. Rotary actuators use pressurized fluid to rotate mechanical components. They operate with greater speed and power because they produce greater torque than, say, a pneumatic actuator, which relies on air pressure.

Rotary actuators feature two kinds of rotary elements: circular shafts and tables. Single-shaft actuators have an output on only one side of the device, while double-shaft actuators have outputs on both sides. Linear motion is converted into shaft rotation when helical teeth on the shaft connect with corresponding splines on the inside diameter of a piston. Hydraulic pressure causes the piston to be displaced within the housing, and at the same time, the splines cause the shaft to rotate. Turning the control valve to the closed position locks in place the hydraulic fluid inside the housing and the shaft.

Rotary actuators serve a variety of purposes in construction. On bulldozers, excavators, and other earthmoving equipment, for example, they can be used for extensive grading and sloping with different angles. They’re commonly used in steering systems, as well.

Management Software

You can’t cry over spilled milk, an old sage once proffered, nor should you throw good money after bad. If you’re using miscellaneous spreadsheets, handwritten notes, and old-fashioned payroll time cards to manage your grading and excavation jobs, however, you could be guilty of both—and paying the price with your bottom line.

Paper pushing isn’t the most interesting part of a general contractor’s or project manager’s job, but recordkeeping is a critical to business success. Without proper tracking of items such as labor, material, and equipment—not to mention productivity—neither the general contractor nor the project manager has any idea whether he’s making money, holding steady, or tossing it out like excess fill-dirt. Looking over his records at the end of a construction job, he could discover that he unknowingly overspent on materials and can’t recoup the loss because he didn’t renegotiate materials costs with his client (the spilled milk, so to speak). Likewise, his labor costs might have been higher than necessary because he continued paying one of his crews a premium rate but got less-than-premium work in return (throwing good money after bad). Tracking items by hand can be cumbersome and time-consuming, however, and that’s where project-management software comes in.

“It’s absolutely essential that someone managing a project is able to keep it on target in terms of expenses,” says Brad Matthews, vice president of marketing and sales for Houston, TX–based Dexter+Chaney. “If you run over budget, you lose money. It’s that simple.”

Dexter+Chaney produces Forefront Construction Suite, a software product designed for use by anyone involved with a construction job, from executives and financial managers in the office to project managers, superintendents, and foremen out in the field.

“If we know that we have a $100,000 budget and we’ve spent $50,000 of it, is that good news?” Matthews continues. “The answer is, we don’t have enough information to know. If we’re 60% complete with work, it would be good news because it would mean we’re under budget and making money.”

Project and construction managers need data in a timely manner, he adds. A manager needs to know his costs so far and whether he’s on target. With these two pieces of information, he’ll know whether he’s making money or losing it.

Say a contractor is partway through a job, does some calculations, and realizes he has some financial issues. He may discover that one or two phases of the job are costing more than they should. He doesn’t know why, so he gets together with his project manager and foreman, and together they go over the elements to figure out where the money is going. Maybe they aren’t using the right equipment; maybe the soil isn’t what they anticipated it would be when they bid on the job; maybe they don’t have the right amount or kind of labor. If they find out early on, they can make some adjustments and get back on financial track. If the contractor waits until after the job is finished to make these assessments, however, all he’ll know is why he lost money, but he won’t be able to do anything about it.

“Historically in business, job costing reports would come out of the final accounting system one to two weeks after the completion of that portion of the job,” says Steve McGough, chief operating officer of HCSS, a Houston-based company specializing in project management software such as Heavy Job. “By that time the individual foreman is already finished with that part of the job and has moved on to something else.”

With project management software, information flows into the office electronically. All the job information is aggregated, and everyone—project managers, superintendents, etc.—can look at daily results and see where money is being lost or gained and what adjustments need to be made.

“Say a foreman has to lay 100 feet of pipe. He has his crew, and as he works on a day he can put in hours for labor, hours for equipment, and the length of pipe he laid in the ground,” says McGough. “He can compare those figures to the original estimate and tell whether he’s making or losing money. Then he can make adjustments on a daily basis.”

It sounds pretty basic, but in reality the manager is juggling a variety of costs in a variety of areas—labor, equipment, and materials. He needs current figures for each cost within each area and then has to do the math to bring it all together.

“If you don’t have software to do it, you won’t get it done frequently enough because of the time factor involved in doing it,” Matthews says.

Another element of the job software helps manage is the contract itself. Many contracts are unit price rather than fixed bill, and that requires a variety of billing methods.

“From a cash-flow standpoint, you have to have good management,” he continues. “If you’ve done more work than you’ve charged the customer for, that means you’re funding the completion of the job, so to speak, and that negatively affects your cash flow.”

That can create a whole other level of complexity. Enough cash has to come in so you can pay your expenses. If it doesn’t, you’ll end up losing money.

“Actually, you want to be in a slightly overbilled position,” says Matthews, “and there are a number of strategies you can use to do that. But if you don’t have the information, you won’t be able to do it effectively.”

Software also helps accommodate changes to the contract, an element that often requires a lot of attention.

“That’s where costs leak into a project but revenues don’t,” explains Matthews. “When we do work that isn’t planned, the question is: Are we billing for changes, and are we billing in a timely fashion?”

It’s critical to know whether changes will have a positive or negative impact on revenue.

“It’s important that changes are managed early, not just for cash flow but also for your relationship with your customer,” he says. “If you talk about doing something differently and proceed along a new path but haven’t talked to the customer about costs related to it, when you get to the end of the job and add on the additional costs it can be problematic. Those collections are much more difficult when the change itself wasn’t managed effectively.”

Project management software can allow you to document any changes, even those that might be as informal as a scribble on a cocktail napkin. A digital photo of the napkin can be scanned into the software and become a record of a change request. Making a note on a spreadsheet or tossing a slip of paper in a file isn’t as formal—or as valuable—a record.

With software you can maintain all the documents relating to a project and have them in one place. Photos and other images, signatures, invoices from subcontractors or suppliers, and documents regarding changes to the contract can be attached to the original contract. Certainly, the software provides a system of tracking financial transactions and productivity numbers and quantities, but with the actual documents residing there as well you can have everything associated with a particular job residing in one place.

Another element software manages effectively is productivity. The software tracks costs for labor and equipment, but also the output of each. Say a contractor estimates a productivity rate of X/hour. For the entire job, however, the productivity rate is Y/hour. He needs to compare whether Y is better than X, and if so, why, and, if not, why not. Maybe he bid the job unrealistically and he needs to hone his estimating skills. Maybe his equipment costs are higher than he anticipated. Maybe he had to pay more for labor than he originally intended.

“A lot of this is information that’s already being gathered,” says Matthews. “Labor is being tracked because we have to pay people and expenses are being tracked because we have to pay our bills.”

By carrying information forward, the software also helps prevent errors and unnecessary work. Say, for example, a foreman is laying pipe for the next week. He might not know one of his laborers called in sick that morning because that information has been taken by someone in the dispatch office. If he copies the previous day’s time card, that laborer’s name will show up on it, which can result in a payroll problem down the road.

Project management software also provides a sense of ownership for everyone involved in a construction job.

“If you’re a foreman on the job and someone comes and says you’re going to enter your employees’ time electronically and send it in—and even enter equipment time and send it in electronically—you can see exactly what you’re doing. It allows you to manage the job,” says McGough.

Likewise, he continues, it brings functionality to the process: “It accommodates generic needs. If I say I need a dozer, backhoe, and three laborers tomorrow, I won’t know which equipment I’ll get or which laborers, but the dispatcher sends the information electronically and it shows up automatically on my computer.”

Project management software takes a load off any size firm, even a two-person operation. Most is designed to accommodate the user at any level, from the computer whiz to the person who has trouble finding the “on” switch. Some runs not only on a desk or laptop computer, but on a pocket PC and a PDA for field use.

Software systems can range in price from $4,000 to $20,000.         

Machine Control

In the grading and excavation business, time equals money. Spend less of one and you get more of the other. In the case of scrapers, dozers, and excavators, the means of accomplishing both can be summed up in two words: machine control.

With machine control, the equipment—not the operator—tracks the placement of the blade or bucket as it correlates to the design engineer’s plans and, depending on the parameters of the system, makes adjustments accordingly. Machine control allows levels of productivity, accuracy, and efficiency that can mean the difference between making money and losing it.

“I don’t think there are many contractors out there who aren’t using or haven’t used some kind of machine control,” says Fred Rogers, machine control national sales manager for Leica USA.

Adds Jason Killpack, product marketing manager for Topcon Positioning Systems, “In the past, the operator depended on stakes that would be updated on a daily or hourly basis to give accurate indications of where design grade was in relation to current grade. With machine control onboard, the operator has a virtual running grade indicator that shows exactly where the design grade is and the current position of the machine in relation to it.”

Design grade can be achieved the first time, eliminating the hours and associated expense of reworking areas.

Machine control systems on earthmoving and grading equipment use hydraulics to position the cutting edges and buckets in line with the design grades. The systems fall into two categories: indicate and automatic.

An indicate system provides the operator with visual grade information that appears on a display in the cab of his equipment. He monitors the information and manually adjusts the elevation of the blade or bucket accordingly.

With an automatic system, the operator receives the same visual grade information but has the option of directing it to the equipment’s hydraulic system, which will automatically adjust the blade to keep it on-grade.

“With automatics we’re talking about controlling elevation with laser control, sonic control, dual laser, or sonic slope,” says Rogers. “On a grader, for example, it’s controlled by a combination of three sensors—a blade tilt sensor, a rotation sensor, and a main fall sensor. They work in combination to equal the blade’s desired cross-slope.”

While machine control takes a lot of the guesswork out of grading and excavating (it virtually eliminates the need for grade checking) it doesn’t relieve the operator from important duty.

“He’s there to override and steer the machine. He has to know where to move the dirt and how to do it,” says Rogers. “The system will do the grade.”

To operate machine-controlled equipment, the operator needs to have a basic understanding of the kind of machine control that’s installed, notes Killpack. Different types of systems have varying degrees of complexity and some require a higher degree of user knowledge. A day or so of training, however, usually does the trick.

Many systems are designed to be user-friendly, whether the machine control takes its measurement data from a laser, sonar, or GPS satellites.

Machine control systems run anywhere from $1,800 or so for an indicate system up to $30,000 for a two-dimensional, dual-laser system.

“Contractors that want to step into machine control can do it with a 2-D system, and if they want to upgrade to a 3-D system they buy an upgrade package that contains all the necessary components,” says Rogers.

A two-dimensional machine control system for a dozer includes a laser and laser receiver, hydraulics that already exist on the machine, and a display screen. Most often, machine control systems are not original equipment but are added later on as the contractor takes the leap from manual to indicate to automatic. When earthmoving and grading equipment leaves the factory, however, it’s machine control ready.

“Think about the plumbing in your house,” says Reynolds. “Say you want to put a hot tub in your backyard. You have plumbing in your house but not in your yard. All you need, though, is a PVC pipe to connect the hot tub to the existing plumbing and you’re ready to go.”

What system you buy, however, depends on what Boyd Reynolds, machine automation product marketing manager for Leica USA, calls payback.

“A guy that’s out there digging a basement for a house doesn’t need a 3-D system. But a guy using a 2-D system for grading an area for a strip mall really needs 3-D,” he says. “Nobody wants to spend the kind of money we’re talking about if they’re not going to earn it back.”

Companies manufacturing machine control systems also provide a fair degree of technical support and assistance. Topcon, for example, trains its dealers to support customers, provides a hotline for technical support, and provides the Topcon Professional Services Group for site-specific support or specialized training. Similarly, the Leica USA Web site features videos that explain the nuts and bolts of machine control, and the company holds open houses in which contractors and operators are invited to run systems.  

Like our ancestors who looked to the sun, moon, and stars to guide their travels across land and sea, we in the 21st century still gaze upward for direction. However, our information derives not from the natural firmament but from the global positioning system (GPS), a collection of man-made satellites that orbit the Earth 24 hours a day. We use the data they provide not only to determine our precise location at any given time or in which direction we must proceed to reach our intended destination but also to identify where other things and people are situated on the planet.

On the construction site, GPS makes it possible for construction engineers to calculate the required position of equipment and survey lines to achieve unprecedented accuracy. Also, by combining GPS data with 3D site plans, a contractor can create an automatic grade control system in which the blades and buckets on his grading and excavating equipment adjust up and down automatically, without direction from the operator.

“You don’t need a surveyor checking grade or laying stakes,” says Kirk Shadel, head of 3D data preparation and support for Precision Laser & Instrument Inc. “All the information is there with the operator.”

Before exploring the benefits GPS brings to the job site, let’s take a look at how the technology works.
GPS is a worldwide radio-navigation system formed from a constellation of 24 satellites and their ground stations. This particular constellation, originally designated Navigation System with Timing and Ranging (NAVSTAR) was launched and is operated by the United States. Other constellations are orbiting roughly 12,000 miles up in space, including GLONASS, operated by Russia, and Galileo, launched by the European Space Agency.

The first GPS satellite was launched by the United States Department of Defense in 1978 as a tool for navigation and precise positioning. Its purpose in the early days was to help military personnel accurately determine the worldwide location of vehicles, planes, ships, and even soldiers. In the 1980s, however, the government made the system available for civilian use. GPS is now utilized in both commercial and scientific endeavors. Commercially, it is used for navigating airplanes, boats, and cars and by outdoor enthusiasts for activities such as hiking, fishing, and kayaking. On the construction site, GPS enables an equipment operator to pinpoint his exact location so he can position his bucket or blade precisely where the site plans indicate. Scientists, on the other hand, use GPS as a tool for studying earth sciences. The technology enables meteorologists to forecast the weather and study global climates, for example, while geologists use it in surveying and earthquake studies to measure tectonic motions during and between earthquakes.

Each GPS satellite circles the Earth twice a day in a very precise orbit. To make sure the satellites can be detected from anywhere on the Earth’s surface, they are divided into six groups of four. Each group follows a different path to create six orbital planes that completely surround the planet. The satellites are spaced so that from any point on the Earth, at least four can be detected at any given time. The satellites transmit information via radio signals.

For that information to have any value, however, it must be captured by a ground station, which consists of a receiver and an antenna. Remember, the whole purpose of GPS is to determine the location of something, and the receiver accomplishes that task by locating three or more satellites (the more satellites, the greater the accuracy), figuring out the distance to each, and using that information to calculate its own location. This process is based on a mathematical principle called trilateration. Here’s how it works:

Let’s suppose you wake up one morning and find yourself completely lost somewhere in the United States. You have no idea whether you’re in California, North Carolina, or any state in between. You stop a passerby and ask about your location. You find out you’re 550 miles from Billings, MT. That’s some information, but not enough to tell you where you are. You could be standing anywhere within a 550-mile radius of Billings. So you ask someone else who tells you you’re 760 miles from Las Vegas, NV. If you combine the 550-mile radius around Billings with the 760-mile radius around Las Vegas you’ll find two points where they intersect. You have to be at one of those two points if you’re 550 miles from Billings and 760 miles from Las Vegas. The question remains, however, which one? You stop one more person who lets you know you’re 670 miles from Des Moines, IA. Aha! Include the 670-mile radius around Des Moines with the Billings and Las Vegas radii and you’ll find the spot where all three circles intersect—Denver, CO. And that’s where you are.

But once the receiver has located the satellites, how does it figure out their distance? When the receiver captures the signal from the satellite, it compares the time the signal was transmitted with the time it was received. The difference between the two tells the receiver how far away the satellite is. With distance measurements from a few satellites, the receiver can calculate its own position and display it on the unit’s electronic map.

Not only can the standard GPS receiver tell you exactly where you are at any given point, it also can trace your path as you move in one direction or another. If you keep the receiver in the “on” position, it will maintain constant communication with the GPS satellites and show how your location is changing. This information combined with the receiver’s built-in clock can tell you how far you’ve travelled, how long you’ve been traveling, your current speed, and your average speed. It can also leave a trail showing the course you have traveled and tell you at what time you can expect to arrive at your destination if you maintain your current speed.

In grading and excavating, GPS receivers are attached to construction machines. The receivers pass data to onboard computers that hold digitized site information. In real time, the information broadcasts from the satellite constellation to the receiver and on to the computer to guide the equipment’s movements.

In an indicate system, the data appear on a monitor inside the cab and the operator uses it to guide the machine. With an automatic system, the computer directs the movements of the machine, such as controlling its hydraulics and raising or lowering a blade or bucket automatically.

GPS is a pricey technology, although experts agree it can be a money-saver in the long run. An initial setup can run $100,000 or more depending on the type of machine, according to Shadel.

“But it’s an investment. You’re saving money by not having surveyors, which can be $30,000 per job,” he says. “You can eliminate a grade checker; you can eliminate someone standing there in front of the machine telling the operator to cut a tenth or fill a tenth. The operator has all the information.”

Hydraulic fluids work. Literally. Their pressure and flow provide the muscle behind the arms that lift buckets on a backhoe, lift a blade on a bulldozer, and keep all manner of construction machinery moving. When hydraulic fluid fails, work stops.

Hydraulic fluids are made from many different chemicals and perform a variety of tasks, all of which are critical to the life of hydraulic components. Among other duties, hydraulic fluids transmit power, provide a viscous seal, maintain system pressure, transfer heat to cool a system, prevent rust and corrosion, guard against foaming, separate water from oil for easy removal, and lubricate components. The three most common types of hydraulic fluids are mineral oil, organiphosphate ester, and polyalphaolefin. Others are made form glycol esters and ethers, castor oil, or silicone.

A host of liquids have been tested for use in hydraulic systems, but currently those used most include mineral oil, water, phosphate ester, water-based ethylene glycol compounds, and silicone fluids. Hydraulic fluids fall into three main categories: petroleum-based, synthetic fire-resistant, and water-based fire-resistant. Some are produced from crude oil while others are manufactured. Trade name products include Durad, Fyrquel, Skydrol, Houghton-Safe, Pydraul, Reofos, Reolube, Hyrdaunycoil, and Quintlubric.

Biodegradiable or biobased fluids use vegetable oils such as canola, rapeseed, sunflower, or soybean as the base. These are a good choice for environmentally sensitive applications such as farming and marine dredging where a ruptured oil line or other hydraulic hose failure could be disastrous.

So how do you figure out what kind of hydraulic fluid will benefit your equipment? Consider the use. Would multigrade be best, or should you use monograde? Detergent or non-detergent?

The operating temperature range of your equipment determines whether you need multigrade or monograde hydraulic fluid. If you run your excavator in temperature extremes from a freezing winter to a better-than-balmy summer, you’ll need multigrade fluid to maintain viscosity across such a wide temperature range. Viscosity is the internal friction of a fluid, produced by the movement of its molecules. In other words, it’s a particular substance’s resistance to flow. Water, for example, flows more freely than molasses; water has a lower viscosity.

If a piece of equipment operates within a narrow temperature range and optimal viscosity can be maintained with a monograde fluid, a monograde is preferable because the viscosity index (VI) improvers used to make multigrade fluids can poorly affect the fluids’ air separation properations. The VI is a numerical value that indicates the effect temperature has on changes in viscosity. The viscosity of a fluid with a low VI changes significantly in response to temperature. The fluid becomes quite thin at high temperatures and extremely thick when it’s cold. Conversely, the viscosity of a fluid with a high VI does just the opposite. It shows little change across a wide temperature range.

The preferred fluid for most purposes is one whose viscosity remains constant despite termperature changes.

Some hydraulic fluids have detergent additives that enable them to emulsify water and get rid of other contaminants such as sludge. Keeping water in check is critical because water causes the fluid to age and lose its ability to act as a lubricant and filter. Water contamination also can decrease the filter time of a hydraulic fluid.

How much?

For a contractor, the answer to that question can mean the difference between a winning bid and thanks-but-no-thanks. His potential client wants to know how much a job is going to cost and how much time it’s going to take. To give an accurate and competitive answer to the former, however, the contractor must ask himself the same question but on different subjects; he won’t know how much the job will cost until he’s figured how much he’ll pay for materials, how much he’ll pay for equipment, and how much he’ll pay for labor. And he won’t know that until he calculates every aspect of the job.

Here’s the scenario: A new shopping center is going up in a previously undeveloped area and your company wants to put in the parking lot. It’s a complicated job that requires extensive excavation and grading. With curbs, sidewalks, and designated areas for shade trees, even the shape of the lot is a challenge. And that doesn’t take into consideration the slopes and storm drains that will be necessary to keep water from collecting in puddles.

Using plans provided by the project engineer, you can sit down with a calculator and a sharpened pencil and spend hours figuring out the various distances and elevations by hand to determine your material needs. Or you could boot up your computer, input the computer-aided design (CAD) file the project engineer gave you, and let your takeoff software do the work.

With takeoff software, your computer runs the numbers and lets you know how much of any material you’ll need for the job.

“A takeoff is an approximation of quantities required for a certain scope of work,” explains Marco Cecala, president of TakeOff Professionals, an Arizona-based company that not only prepares takeoffs but takes the information from the data, combines it with more complete data, and actually builds an electronic model of the completed construction site as it appears on paper. Then the engineer in charge of that particular project looks for problems or errors that might have been overlooked by the design engineers (perhaps a trench they’d have dug, say, a foot away from where it actually needs to be).

“In the earthmoving world, a takeoff is an estimate of how much dirt will be moved,” continues Cecala.

 “It cuts the takeoff time dramatically compared to doing it manually,” Mark Kusher of Roctek International says of the software. “It does the calculating that’s otherwise very tedious and if done manually won’t have the same degree of accuracy. The software calculates lengths, areas, and volumes, but also, materials amounts.” Roctek produces WinEx and WinEx Pro, a pair of Windows-based 3D graphical cut-and-fill takeoff programs for site work contractors. Like most takeoff software programs, WinEx and WinEx Pro have measurement tools that calculate volumes, tonnage, areas, footage, and other miscellaneous quantities. They generate color-coded cut-and-fill maps that illustrate the deep areas of cuts and fills, cross-sections between any two points on the site, and 3D displays of any surface.

“Once you have those quantities they can be transferred to estimating software.” Other Roctek takeoff software products include SOFTakeoff, a digitizerless Windows-based graphical screen program designed to handle buildings, structures, or 2D sitework.

Adds Harry Ward, director of training at Carlson Software, which manufactures TakeOff, a software program that works in AutoCAD, “Takeoff software has tools to let contractors digitize hard copy, read in design data, and reproduce a model so they can make sure it meets the specs and criteria they have to follow.” Carlson’s TakeOff calculates cut-and-fill material volumes and has 3D simulation. It also includes roadwork, trenching, drill-holes, and subgrade capabilities.

Takeoff software falls into two categories: structural, which calculates quantities from the ground up; and earthworks, which calculates them from the ground down. Structural takeoff software will calculate required quantities of, say, lumber, concrete, rebar, tile, carpet, and ceiling tiles. Earthworks software does the same for cut and fill, trenchwork, pipework, and flat elements such as a concrete pad or a roadway.

“The first thing you put in are existing and proposed elevations so you can level the ground and then do whatever you need to on the site, whether it’s a roadway, parking lot, or trenchwork for pipes,” continues Kushner.

Suppose the parking lot in the job you’re bidding requires 4 inches of sand as a bedding, 6 inches of crushed stone above that, and, finally, 4 inches of asphalt. Based on the area of the parking lot, which the software has already determined, the software will calculate the quantity of each of those materials you’ll require.

Doing some trenchwork or pipework? Key in the depth of the trench, the slope (if one is required), the size and diameter of the pipe, and whether you’ll use backfill material to fill in the trench after you lay the pipework and the software will let you know in terms of volume and weight how much you’ll have to excavate to make a space for the pipework and how much backfill material you’ll need.

“The program will give you a total cut and a total fill,” says Kushner. “If you have excess, you’ll have to truck it away. If you don’t have enough, you’ll have to bring it onto the site.”

Takeoff software comes with a veritable symphony of bells and whistles, so a contractor has to do some research before choosing a program. It might include a digitizer board that allows you to turn paper plans into a digital file by tracing the lines and inputing some of the pertinent figures.

“To do the takeoff efficiently, you need electronic CAD files and paper plans,” says Cecala. “CAD files make the job go faster and more accurately.”

When takeoff software first came out, it did basic counts of lengths and areas. As the technology progressed, however, the software was developed to calculate different quantities of materials.
Some programs are more user-friendly than others, notes Kushner, with some manufacturers placing greatest emphasis on the efficiency of the software and the calculations.

“Others may have a priority on being user-friendly but aren’t as powerful,” he says. “Many fall in the middle—they’re powerful and user-friendly. That’s an important factor. You want to find a software package that doesn’t require you to sacrifice too much of one to get the other.”

The purpose of the software is to save you time and make your job easier, he adds. That’s not happening if you have to spend two months learning how to use it.

Imagine completing a day’s work in under an hour. Now that’s productivity. Contractors can become just that efficient when they take advantage of the estimating and job software currently on the market. For specialists in grading and excavation, the software can mean the difference between black on the bottom line and bright red.

“Site work is the biggest risk on any job,” says Michael Gillum, director of research and development for Quest Solutions. His company produces six different software packages. “If you screw up on your bid and there are 10,000 more yards [of dirt] that have to be hauled off, you have to pay for it. A lot of companies go bankrupt making that mistake.”

Software designed especially for bidding, estimating, and project management can streamline the process, although the contractor has to provide key information. Products from companies such as Bid2Win, Constructw@re, Hard Dollar, and Corecon feature databases with general information particular to different areas of the country, but only the contractor knows exactly what equipment he’ll have to use for a job, how many people he’ll have to employ and what special materials he’ll have to procure, and how much dirt he’ll have to import and export. The software can’t calculate anything until all the variables have been plugged in.

To begin inputting information, the contractor needs a set of plans. It can be in the form of blueprints or an electronic document, in which case it would be a computer-aided design (CAD) or portable document format (PDF) file, or even a Joint Photographic Experts Group (JPEG), Bitmap (BMP), or Tagged Image File Format (TIFF) image. Typically onsite work will come from AutoCAD, which uses DWG, DWF, and DXF formats.

“Once a contractor has a copy of the blueprints, he knows what he has to bid on,” continues Gillum. “If he’s doing it by hand, he’ll lay out the blueprint and measure with a calculator and scale or guesstimate. And, unfortunately, that’s what a lot of contractors do and have cost overruns and more.”

Producing an accurate bid that will win the job and still keep the contractor in the black requires that he do what industry experts call a takeoff and an estimate.

“The takeoff function is critical to successful business,” explains Erich Schoenkopf, founder and president of Vertigraph Inc., maker of BidPoint, BidScreen, SiteWorx, and BidWorx. “Takeoff is coming up with the quantities. Estimating is putting the price to the quantities. You have a lot more variables with the takeoff.”

If that same contractor is using bidding and job control software, he’ll enter the requisite information and the computer will do the rest. Using a digitizer board and paper blueprints or his computer mouse and digital blueprints, he’ll input the existing ground elevations and details about the worksite, all of which should be part of the blueprints. Does something already exist on that area? Is half a parking lot there that has to be demolished and the old materials hauled away?

“A digitizer board is accurate to an eighth of an inch versus using a ruler or calculator, in which case you can be off by feet,” Gillum says.

Doing it manually, with a pad of paper and a pencil, would take eight hours to calculate all the variables to complete a simple rectangular parking lot, he continues. “Estimating software can do it in less than an hour,” he says.

After the data are entered, the software spits out a grid report, also known as a staking report, which shows where the stakes are situated to give the bulldozer operator important elevation information.

“You can also get a three-dimensional view so you can look at the parking lot in three dimensions and see where it drains,” says Gillum. “It lets you see where you might have made a mistake. If you’re doing it by hand and don’t have a visual representation, you’re not going to catch that mistake. And that’s huge.”

Vertigraph’s SiteWorx can create a topographical image of a job site using information digitized into the software. Enter existing and proposed contour lines, spot elevations and areas, project boundaries, and topsoil strip and respread areas. With the blueprint digitized into the software, just click your mouse and SiteWorx will accurately calculate cut and fill volumes. It even lets you know how to adjust proposed elevations to create a balanced site.

Finally, construction software will provide a summary page with detailed information such as how much dirt needs to be imported or exported, how many square tons of asphalt you’ll need, how much bedding material.

“It will give you everything you need to accurately bid materials,” continues Gillum. All you have to do is plug in the specifics—how much, exactly, a square ton of asphalt costs, for example, and what you’ll pay to haul 20 truckloads of fill dirt away from the site.

But just where do you find those specifics? That information comes from a variety of sources. One is a price book such as that built into Vertigraph’s BidWorx software, which offers construction cost information on certain products, services, and materials in different parts of the country. Vertigraph’s starter price book is included at no charge. Other price book files, including R.S. Means and Richard Engineering Services, are also available. Armed with these data, a contractor in Chicago who’s bidding on a job in Florida can refer to the price book, which will indicate how material and labor costs differ in that part of the country. The price books contain nationally averaged low bid award costs.

Another source of information is the contractor himself—what he has in his head, on a spreadsheet, or in a bunch of past bids. “The database is nothing more than a history of cost information,” says Gillum. The contractor should know from previous bids and equipment maintenance reports, for example, what it costs him to run his bulldozer for an hour—including gasoline, wear and tear, and other associated expenses—and how many bulldozers he’ll need to get the job done on schedule.

To estimate a job accurately, a contractor has to know first what it consists of and how much time he has to complete it. From there he’ll break the work into a handful of categories: labor; equipment; materials; subcontractor costs, if any; and any miscellaneous costs associated with that particular job such as dump fees for disposing of extra fill dirt that exists on the site.

Let’s take a look at them individually.

Labor

• How many people will you need and in what capacity to complete the job within the time allotted?
• What does it cost you to employ each worker, including his or her wages, requisite payroll taxes, workman’s compensation insurance, and perhaps health insurance?

Much of this information is listed on previous bids or somewhere in payroll records.

Equipment

• What equipment will be required for the job? Three bulldozers? A backhoe? A truck for hauling dirt away from the job site?
• What is each piece of equipment’s cost of operation? For that, consider purchase price; payments; depreciation; scheduled maintenance (cost and frequency of oil changes, for example); unscheduled repairs (replacing a fuel pump or filter, perhaps); and consumable items such as fuel, hydraulic fluid, oil, and even tires (how much do they cost and how often do you have to replace them?).

Materials

• Twenty truckloads of fill dirt to achieve the elevation levels indicated on the site plan. Where are you going to get it? What will it cost? Where is it, and how far do you have to haul it? According to Schoenkopf, this is where a contractor benefits from experience and contacts in the field. How are you going to get the dirt to the site? Will you use your own truck and do it yourself (which will impact your labor and equipment expenses), or will you hire a trucking company to do it? To decide that, you have to compare what it will cost for you to do it yourself to what the trucking company will charge. It may be that when you consider wear and tear on your own equipment and the labor involved, going with the trucking company turns out to be more cost-effective. Otherwise, you’ll have to do the research yourself. Sources for importing dirt differ from one geographical area to another. It may also be the case that the elevations on the plans can be adjusted to accommodate the amount of dirt already and create what is referred to as a balanced site. Advising the client that doing a balanced site will reduce costs significantly could help you win the contract.

Subcontractor

• What are you going to pay the trucking company you’ve decided to hire to import dirt onto the site?

Other

• Say you have to export 20 truckloads of dirt off the site. Where are you going to dispose of it? How much will it cost? Do you know of another contractor who can use it? Again, contacts in the field and experience will be invaluable to the contractor in making this cost assumption.

A Construction Laser Tutorial

So you’ve stepped into the 21st century and added a construction laser to your box of grading and excavating tools. The next step is to put it to use on your job site. Whether you have chosen a total package laser—one that includes the laser, laser detector, and grade rod to which you clamp the laser detector—or a handheld model, the technology will help you move quickly and accurately through your grading and excavating work.

Almost any grading or excavation job will benefit from the presence of a construction laser onsite, according to Paul Adkins of Laser Technology Inc. With its precise measurements, accurate to a millimeter on many models, the laser allows equipment operators to move dirt and smooth an area in one effort rather than doing the work, taking measurements to determine where the grade does or doesn’t match the job specifications, and then adding or removing it as necessary. Its precision also can save the contractor money on material and equipment over-runs by allowing him to match the construction engineer’s blueprints as closely as possible.

But how, exactly, does the laser operate on the site? What’s involved in the setup, and how does a contractor use it to its fullest advantage?

By the time a contractor has actually traded cold hard cash for his laser equipment, he’s done a fair amount of research to determine the kind of laser he needs for his work purposes.

If most of his jobs involve grading, he’s probably opted for a rotating construction laser, which operates like a high-tech level that emits light beams to create a level reference plane. Within the rotating laser family, he will have chosen from a flat-plane laser, single slope, or dual slope, depending on the complexity of his jobs.

A flat-plane laser emits a single horizontal beam, which varies in distance from 500 to 1,500 feet. With a single-slope laser he can dial in one axis of a slope, and with a dual-slope laser he can dial in both vertical and horizontal axes. The distance range for a single-slope laser matches that of a flat-plane laser and for a dual-slope laser it’s anywhere from 1,000 to 2,500 feet.

The stationary, total-package laser consists of the laser beacon, which produces the light beam; the tripod on which the laser beacon sits  a detector that receives the beam  and the measuring rod on which the detector is clamped to determine the height of the beam.

Let’s say you have the winning bid for a job grading and paving a parking lot for a large shopping mall. To get started, you’ll pull your laser out of the box and check the batteries to make sure they’re charged properly. Before setting up the laser, however, you’ll take a look at the blueprints for the job and choose the area you want to work. A large parking lot generally will be separated into sections that correspond to the laser’s distance range, and the grading will be done one section at a time.

Once you’ve identified the section you’ll be working, you’ll find a known elevation point—generally a survey stake—and place your tripod over it. The elevation point will be situated probably 10 feet or so offset from the actual parking lot area. Then you’ll take the laser detector and measuring rod to a survey stake somewhere within the section you’re working but at a point that takes optimal advantage of the laser’s distance range. You’ll clamp the laser detector to the measuring rod and begin to set the benchmark.

The purpose of benchmarking is to align the laser beam correctly. If the alignment isn’t right, the entire grading job will be off and you, the contractor, will lose a lot of profit when you have to redo the job.

To set the benchmark, you’ll turn the laser on and input the slope indicated on the blueprints. Let’s say the blueprints call for a 3% fall on the x axis and a 2% fall on the y axis. The purpose of the slope in the parking lot is to direct water toward a designated catch basin so it doesn’t collect in puddles in the lot and drench shoppers’ shoes as they walk to and from their cars. Each area of the lot has a designated catch basin to which the slope dialed into the laser will correspond.

When you input the axis data and align them with the survey stakes, you adjust the laser receiver on the measuring rod until you hear the on-grade sound that means the laser on the tripod and laser receiver on the measuring rod are working in synch. Once alignment has been established, the contractor can walk anywhere in that section and see where he has to bring in dirt or take it away. The height of the laser doesn’t matter as long as it’s aligned perfectly with the appropriate survey stakes. It can be as high as 20 feet off the ground as long as it’s aligned correctly and the laser detector is set as high.

In general, the contractor or his crew will set up the laser in the morning and take it down at the end of the day. After the first setup, they’ll go back to the same point for alignment.

Elsewhere on the parking lot job the construction laser can be used to make sure the elevations are correct for curbs and islands. Setting curbs and gutters takes place before grading impacts the grading elevation. If, for example, the contractor takes a laser measurement that shows the curb is too high or too low, he takes that information back to the construction engineer. The contractor has to find out whether, under those circumstances, he should grade to the curb or to the specifications on the blueprint. Generally, the contractor would be instructed to match the level of the curb and then submit what’s called a ‘change order’ to the company paying for the work. If the contractor bids the job to the specifications on the blueprint but then has to pay, say, $30,000 for additional gravel, dirt, and asphalt to make up for the difference in curb elevation, he’s entitled to reimbursement for his extra expense. If he doesn’t do a laser measurement beforehand, however, he won’t know that the curb is the wrong height, won’t know to alert the construction engineer, and when he goes ahead and grades to match the curb he’ll end up losing money because he won’t know that someone else’s error is causing him to use more gravel, asphalt, and dirt than his original bid anticipated.

Whether the job at hand is a parking lot, a soccer field, or a running track, the setup for the laser is the same. The only difference with a running track is the placement of the laser. For grading a parking lot or ballfield the laser is placed outside the actual grading area; when working on a running track, the laser is placed within the space inside the track.

Suppose you have a job that requires some digging with a backhoe, say, a 10-foot hole. To accomplish that, you’ll pull out your flat-plane laser and set it up and turn it on. Then you’ll take your laser detector and put it on the grade rod, which you will have situated on an elevation hub nearby, and set the laser detector at 10 feet. Then you’ll go back to your laser and adjust it up and down until you hear the familiar on-grade beep.

Now the backhoe operator can start digging. The grade checker working with him will jump into the hole every so often and measure the depth until it hits the 10-foot mark.

When a contractor doesn’t require the kind of accuracy provided by a total package laser model he can save a little money by using a handheld laser. Handhelds can get measurement accurately to 3 to 5 centimeters at 1,800 feet. This is referred to as resource grade accuracy. The larger models offer survey grade accuracy.

“There’s only certain times where you need dead-on millimeter accuracy,” says Adkins, whose company manufactures handheld lasers. “There are preliminary phases to any job where resource grade accuracy is more than acceptable.”

Say, for example, you need to check the height of a bridge clearance or the distance from where you’re standing to a particular telephone pole. You can pull out your handheld, turn it on, push a menu button, and get the information you need without having to set up tripods and measuring rods.

The handheld also can be used to measure grades. “I mount my laser on a staff that represents a known height, let’s say 5 feet, 5 inches,” says Adkins. “I’m going to have another guy at the spot across the way and he has another pole marked with the same height. I point my laser at his pole and I’ll get the elevation. If it tells me my inclination is minus 2 degrees, I know it’s 2 degrees lower from where I am now.”

Using the handheld, the crew can do some grading, take a measurement, and do more grading. “It verifies that the grade is at the desired inclination,” Adkins says.

Variable-Displacement Pumps

The variable-displacement pump—also know as a piston pump—is a technological marvel that allows a machine to harness the power of fluid to do heavy work. It falls into the general area of science known as hydraulics, with credit going to Leonardo da Vinci who developed the basic concept of hydraulics back in the Middle Ages. Galileo continued the study with some of his own experiments.

The governing principle behind hydraulics is that fluid cannot be compressed, no matter how much pressure is applied to it. Put that fluid, whether it’s water or oil, into a closed system and push on it at one end. The pressure moves through the liquid at its original strength to the other end.

In a hydraulic system, force applied by the operator at one point is transmitted through valves, hoses, and tubes to other areas. Take, for example, the master cylinder in a car’s brake system. When the driver applies pressure to the brake pedal, he sends an equal amount of pressure through the system and out to all four wheels.

In a piece of construction equipment outfitted with a variable-displacement pump, hydraulic fluid at high pressure is distributed throughout the machine to operate its various systems—transmission, brake, and steering—and to raise and lower buckets and blades. Engines or electric motors power the pumps.

A very common variable-displacement pump is the axial piston pump, which consists of several pistons enclosed in cylinders arranged next to each other and rotating around a central shaft. At one end, a swash plate connects to the pistons, and as the pistons rotate, the angle of the plate causes them to move in and out of their cylinders. At the other end, a rotary valve alternately connects each cylinder to the fluid supply and delivery lines. By changing the angle of the swash plate, the stroke of the pistons can be varied continuously. When the swash plate is perpendicular to the axis of rotation, no fluid flows; when it’s at a sharp angle, a lot of fluid gets pumped.

Another common variable-displacement pump is the radial piston pump, which can change output by changing rotation speed.

“The reason to use a variable-displacement pump is that for any given range of speed you can obtain the same hydraulic flow,” says Joe Gimbel, product manager for Case Construction. “The variable-displacement pump has a whole range of settings, all of which put out the same amount of volume.” That means constant force.

“I first came into contact with them for motor graders,” he continues. “They were using them because the hydraulics would be lively at any RPM. With the old gear pumps, the operator would want to use gear ratios to adjust the speed of the machine and use engine RPM to keep the hydraulics working. Because of fuel prices, it’s more economical to use a system that give you proper flow at any given RPM.”

Because variable-displacement pumps have a lot of moving parts, they require more tender loving care than do their gear counterparts. “They’re a little more sensitive,” notes Gimbel. “Their tolerance to moisture and dirt is lower. Gear pumps are much more simple.”

Variable-displacement pumps come in different sizes for different applications.

Rather than consider the maximum effort a machine can produce, operators should pay attention to its range of power.

“It should do at low RPM exactly what it’s doing at high RPM. At high RPM the [fluid] displacement gets lower, and at low RPM it gets bigger so [the pump] can put out the same amount of flow,” Gimbel says.

Remembering hopping onto a machine and throwing the throttle forward and using gear ratios, he marvels at the ease and efficiency with which variable-displacement pumps operate. “They save on fuel and make all the systems better,” he says.

Lasers
Once the stuff of science fiction and Star Wars movies, lasers have moved into the mainstream and taken their place in consumer electronics, in doctors’ offices, and even on construction sites. The same laser beam that causes a CD player to produce music and allows an eye surgeon to restore a patient’s 20-20 vision in a matter of moments can help a bulldozer operator make fast and accurate work of a grading or excavating assignment.

“If you’re trying to achieve a perfectly flat grade, a laser is absolutely best for that,” says Boyd Reynolds, product marketing manager for Leica Geosystems. “And if you’re trying to achieve a grade that’s sloped, a laser is perfect. It provides wonderful accuracy.”

Indeed, most lasers boast an accuracy to one-thirty-second of an inch.

“Professional construction lasers deliver very tight accuracy,” says Pat Bohle, division vice president of marketing for Trimble’s construction division. “That’s especially important for applications such as concrete pad work for large commercial buildings, which typically have very tight tolerances.” While general and concrete contractors commonly rely on construction lasers and receivers for elevation control, he continues, they’re also ideal for use on smaller machines such as backhoes, skid-steers, and mini excavators for site preparation applications.

“The use of lasers for these applications is less adopted,” he notes. “However, they do provide significant productivity improvements and tight accuracy control for a range of dirt-moving applications.”

But what is a laser and how does it work? The word laser is an acronym for “light amplification by stimulated emission of radiation.” A laser is a specific kind of light, the qualities of which make it ideal for construction purposes. Laser light, for example, is monochromatic. It contains one specific color that is easy to recognize. In addition, laser light is highly directional. Light from most sources spreads out as it travels, so as the distance from the source increases the amount of light hitting any given area actually decreases. Laser light, however, has a very tight beam that remains strong and concentrated over a distance as much as 2,500 feet long. Think about a flashlight, which releases light in many directions. The beam becomes weak and diffused. Laser light travels as a parallel beam and spreads very little.

For grading applications, the rotating construction laser is the tool of choice. Think of it as a high-tech level that emits one or more light beams through its apertures to create a level reference plane. The laser box, from which the beam originates, sits on a tripod, and as the beacon rotates, it expands the level plane to cover a 360-degree-diameter range.

Rotating lasers come in three basic types: flat plane, single slope (also called single grade), and dual slope (also called dual grade). Most are self-leveling, which means you take it out of the box and set it on a tripod and it automatically finds and maintains level within a specified range. Manual level lasers, which require the operator to adjust the unit by hand using thumb screws and bubble vials, also exist, but over the last five years most have given way to electronic models that require only rough leveling upon setup.

A flat-plane laser emits a single horizontal beam from its rotating beacon. The beam varies in distance, generally ranging from 500 to 1,500 feet. It is commonly used for checking elevation and setting foundations and concrete.

A single-slope laser allows the operator to dial in one axis of a slope. It might be used for any general construction application, including excavation and sloped pads. A farmer might use a single-slope laser, for example, to grade a hog pen in which he wants everything to fall to one corner. The distance range for single-slope laser beams is similar to that of flat-plane lasers.

With dual-slope lasers, the beacon emits simultaneous horizontal and vertical beams to establish both level and plumb reference lines. The surface can be flat or tilted with a grade. A dual-slope laser has a distance range of 1,000 to 2,500 feet.

So how, exactly, does a laser—whether flat plane, single slope, or dual slope—function on the construction site? A construction laser consists of the laser beacon itself, which produces the beam of light, and a receiver that registers the beam and lets the bulldozer operator know whether or not he’s on target. The laser beacon sits atop a tripod strategically located on the construction site. The receiver is attached to the appropriate part of the equipment—say, the blade of the bulldozer. It is situated on a measuring rod, which allows the operator to place the blade properly in relation to the site’s benchmark. The benchmark determined by the surveyor and project designer indicates the height, width, and length of the area being graded.

“All construction sites have a benchmark,” says Rob Roske, owner of Montana Lasers LLC, “and usually there are two of them.”

The laser is set at some number of feet above the benchmark, and as the beam hits the receiver, which is adjusted on the measuring rod to the same number of feet above the benchmark, the receiver lets out a beep indicating whether the blade is too high, too low, or just right. There is no need for reading grade stakes or having a work partner tell the operator where or how much to adjust the blade.

In the pre-laser era, such work would have been accomplished with automatic or manual levels with two people on the job—one to operate the equipment and another to point out where the grade was—say, a tenth of an inch too high or maybe two-tenths of an inch too low.

“Now the receiver will let you know if you need to move the blade up or down,” says Roske.

Adds Bohle, “By providing tight elevation control for a range of tasks, a contractor can work more productively.”

As the laser rotates, it creates a plane of light and will register on a receiver operating anywhere within the circle. Every laser is rated by the manufacturer for a certain distance range, and the keys to accuracy are staying within that range and making sure nothing interferes with the flow of the beam.

Although a laser rated at, say, 1,500 feet can be detected by a receiver as far as 2,500 feet away, it won’t provide an accurate reading at such a distance. As the beam extends beyond its established rating, two things happen. First, the light begins to diffuse slightly and in doing so becomes less precise, and second, the curvature of the earth actually impedes the beam as it heads toward the receiver.

Construction experts agree that in determining which type of construction laser—flat plane, single slope, or dual slope—will meet his needs, a contractor should consider what he wants to accomplish with it.

“You need to know the applications, what you want to do with it,” says Reynolds. “Some lasers are more accurate than others; some reach farther than others. If you’re doing a lot of sports fields, for example, you’ll want a single-grade laser. More complex jobs require dual grade.”

If the potential for machine control is a consideration, look for a unit with a laser beacon that rotates at least 600 revolutions per minute. Some go as high as 900 revolutions per minute, but 600 is the minimum for machine control. In some models, the laser rotates only 300 revolutions per minute and while that may be fine when the operator controls the blade or bucket, when a contractor decides to step up to the next level and let machine control run the show, his 300-revolutions-per-minute laser will be too slow.

“The laser market has become fairly homogenous, and there’s not a lot of difference between competitors,” continues Reynolds. “It’s important, though, to key in on a dealer that will provide service. The laser will get knocked over, so you need to find a reputable dealer with good service.”

Construction lasers range in price from $500 to $800 for a flat-plane model, $1,000 to $1,600 for the single slope, and $6,000 to $7,200 for the dual slope. A contractor prepared to spend $800 on a flat-plane laser might do well to consider springing an extra few hundred dollars for the single-slope variety. According to grading professionals, the more complicated jobs he’ll be able to take on will more than make up the difference.

Coming up: Construction lasers and machine display and control—letting the equipment do all the work.

Pumps: An Introduction
Simply defined, a pump is a machine or device used to raise, compress, or transfer fluids from one place to another. Pumps come in different shapes, sizes, and designs and thus serve a variety of purposes on a construction site.

When a backhoe rolls forward on its tracks and scoops up a bucket of dirt, for example, a complex set of hydraulic systems makes each movement possible. At the center of the action are hydraulic pumps, which, in this case, provide the flow of pressurized oil the various systems need in order to function.

Here are five types of pumps commonly used on construction sites and heavy equipment:

Gear Pumps. Gear pumps generally are used to pump thick fluids such as oil. They consist of a pair of meshing gears that rotate in a housing. As the fluid moves into the inlet region, it is trapped between the gear teeth and carried around to the outlet side. The pressure in the outlet region builds up until it is high enough to discharge the fluid.

Piston Pumps. The basic piston pump consists of some number of pistons housed within individual cylinder barrels. As the pistons are pulled upward within the cylinder barrel, a vacuum is created that sucks fluid through an intake valve into the open space. When the pistons are pushed downward, the fluid is expelled through exit valves. The pumping rate can be adjusted by altering the distance the pistons retract within the cylinders. Doing so controls the amount of liquid discharged by each stroke. Piston pumps are commonly used on excavators and other heavy construction equipment.

Vane Pumps. Rotary vane pumps use rotating assemblies to move fluid within the pumping chamber. The vanes are mounted to a circular rotor that sits within a circular cavity. The centers of the circles are offset, and when the rotor spins, vanes are pushed outward. As the vane rotates along the intake side of the pump, the volume area increases and fluid is drawn into the vane chambers. Along the discharge side, the volume area decreases and fluid is forced out of the pump. Vane pumps have common applications on scrapers, conveyer belts, power steering, and automatic transmission.

Centrifugal Pumps. Centrifugal pumps move fluid by means of centrifugal force. Several ribs or vanes are mounted on a revolving disk within the assembly, and as the disks turn, they create suction, which pulls fluid into the pump. The fluid occupies the space between the vanes, and as it rotates with the blades, it is forced out through an exit valve. Centrifugal pumps often are used for pumping liquids for water supply systems, mines, irrigation, dredging, and sewage disposal.

Progressive Cavity Pumps. With a progressive cavity pump, fluid moves within a cavity that progresses along the pump. A rotor fits into the pump body, and as it turns, the cavity moves and fluid is sucked in to fill it. With continued rotation, the fluid travels through the cavity and out through the discharge. Cavity pumps are often used for sewage and cement applications.

Bidding and Estimating Software
In the old days of bidding and estimating, a contractor might have pulled out a pad of paper, a ruler, and a planometer to calculate the cost of a proposed job. He’d sharpen his pencil and write out the details by hand. He’d compute, either manually or with a calculator, the number of people he’d need to get the job done, how many hours they’d put into it, how much materials would cost, and what equipment would be required. An experienced contractor carried a lot of the information in his head—he’d done enough work over the years to make pretty accurate estimates.

Except when he didn’t.

A miscalculation—inadvertently counting as square feet what should have been square yards, actual costs of materials exceeding estimates—or any of a host of other errors could cost him big time, especially if he didn’t become aware of it until he was well into the project. Now, many computer-literate contractors use Microsoft Excel to complete estimates and plan out projects on spreadsheets. The possibility for error, however, is still high. Plug an incorrect formula or figure into one cell and the entire bid can be off.

Enter software designed especially for bidding, estimating, and project management. With products from companies such as Bid2Win, Constructw@re, and Corecon, contractors can stay on track from initial estimates to project completion. The software also allows them to streamline design and project management among team members throughout the life of the project.

“Bidding and estimating software allows a contractor to put together quantities and prices for a particular bid,” says Michael Gillum, director of research and development for Quest Solutions. His company produces six different software packages. “It could be for a pool, a house, a building, or a septic tank. The software allows it to be done much faster and more accurately because the computer is doing the math for you.”

Any contractor doing more than $1 million of work annually can benefit from some variety of the software.

“If someone digs out septic tanks and that’s all they do, they don’t need it,” continues Gillum. “If they do $1 million a year, though, and they want to stay competitive, they do.”

Software for bidding, estimating, and project management ranges in price from $1,000 to $20,000. Typically, the low-end programs will do measurements but won’t assist with pricing or anything else. At the high end are programs equipped with a host of bells and whistles that accommodate multi-users.

“A majority of businesses out there are under 30 employees,” says Norm Wendl, founder of Huntington Beach–based Corecon Technologies Inc. “Those people using Excel or Word for estimating and project management aren’t systematizing their work and aren’t able to truly track if they’re making money on certain activities for a job.”

Bidding, estimating, and project management software address the specific needs of professionals in the construction industry. It gives them a degree of standardization, so they don’t have to rely on a mix of spreadsheets and word processing documents to track their information. In addition, specific information is often built in so the contractor doesn’t have to research it himself. It might include, for example, the cost of concrete or lumber in the user’s area or the going price for labor or equipment use. The information on the database is updated on a weekly, monthly, or annual basis and based on figures specific to the user’s geographic area. Database companies such as RS Means and Construction Estimating Institute make the updates available via fax or an electronic spreadsheet the contractor can import into his existing database.

“The software will come with an average number for his area,” notes Gillum. “[The contractor] will add in his profit, travel time, the things that no software can predict.”

“A lot of businesses use Excel for estimating and QuickBooks for managing,” continues Wendl. “They may have a good business and may be making money at the end of the month, but the problem is they don’t know where they’re making money. On some bid items they’re making a lot, and on others they’re losing. With QuickBooks they can do accounts payable, timecards, payroll, et cetera, but it doesn’t give an accurate picture of which bid items are making an actual profit.”

Some applications, such as Bid2Win and Bid2Win Enterprise, Constructw@re, and Quest, a product of Quest Solutions, are independent software programs that are loaded onto a user’s computer. Corecon Technologies’ Corecon 2006 is a Web-based operation, which means users pay a monthly subscription fee and can access the software from remote locations using a secure login ID and password. Depending on the size of the business and the number of users, it can be more cost-effective than a self-contained software program a business owner would purchase outright.

“Corecon 3, our last Windows-based product, was $2,000 per user with a $400 annual maintenance fee,” says Wendl. “Corecon 4 and the second-generation Corecon 2006 ranges from $40 to $60 per user per month for a one-year contract.”

Some contractors would prefer to own their software program and customize it for their use. They’d rather not pay a monthly fee or deal with passwords and user names.

“Most contractors aren’t computer savvy,” says Gillum. “Often, this is the first time they’re using computers. A contractor who’s been in the business for 10, 20, or 30 years hasn’t been working on a computer. He wants to turn it on, walk through a few steps, and turn out a bid. It has to be easy and intuitive.”

On the bidding and estimating side, the software allows for detailed line-item estimates using industry-standard databases such as RS Means. It can track labor and equipment items, crews, materials, work assemblies, and formulas. To manage subcontractors, the software makes it possible to send out multiple bid requests, either electronically or via fax, and have subs and suppliers respond with their prices via the Internet. It can transform estimates into detailed prime contracts and estimate line items into subcontracts and purchase orders. Document control allows a general contractor to track, send, create, and customize requests for information, submittal packages, daily logs, and more.

For project management, the software assists the contractor in practically every aspect of running a job. First, it can automatically transfer the successful bid information to a project management file so the contractor doesn’t have to input for a second time all the data associated with the project. For day-to-day management, the software handles, among other tasks, document control, quality control, scheduling, job cost control, contract administration, project analysis, budgets, and even e-mailing and faxing reports. It will keep daily logs; track permits, specifications, and miscellaneous tests and inspections; maintain a project calendar; track equipment; maintain labor timecards; and manage all the details associated with subcontractors.

Applications such as Corecon 2006 have interface links to Microsoft Office, Microsoft Small Business Accounting, and QuickBooks so it can transfer project financial information, including project bills, invoices, timecards, and accounts payable and receivable, from one program to another.

Although software for estimating and bidding and project management has existed for 20 years, research shows that a full 50% of industry professionals still have not incorporated it into their business operations. For those who made the leap, however, business on average has enhanced ten-fold.

“Ten times more productivity is huge,” declares Gillum. “A guy who runs a bulldozer all day, goes home to his family, and then has to do estimates until 2 a.m. isn’t happy. But with the software doing so much of the work for him he can put out more bids, increase his productivity, grow his business, and spend more time with his family.”

Likewise, equipment systems have taken a giant leap forward in recent years with electronically controlled fuel injection systems taking the place of carburetors, for example, and hydraulic valves operating by way of changes in electric current rather than a pushrod. And that’s just the beginning. The dozers of the future will resemble their predecessors about as much as a Ferrari does a Model A Ford.

Grading & Excavation Contractor is joining this 21st century construction revolution with a new regular section called Technology in Construction that will introduce, highlight, and examine the new technologies and systems. In these pages you’ll read about everything from equipment controls and systems that alter the way a backhoe or skip/load operator moves his machine to a host of software programs that help a contractor organize and manage all aspects of his business.

You’ll meet professionals in the field who share their experiences with the new technologies, explaining how they’ve incorporated them into their projects and how they’ve increased their productivity and improved their bottom lines. In the process, you’ll get ideas about how the new technology can help you improve and even expand your own business.

“We’re living history,” Topcon’s Richard Rybka says of the technology evolution. “You see people using it across the country from the Pacific Northwest to New England. It’s a massive progressive change.”

From lasers to construction management software, technology is creating a whole new world within the construction industry. New job opportunities are emerging for people ready catch this wave of the future. GPS specialists, for example, are finding themselves in high demand, as is the crew member who is well versed in data management, field operations, and how machinery works.

“It’s not only changing the way contractors do business but their responsibilities on the job site,” Rybka says of the technology that provides accurate, up-to-the-minute information that gives contractors a professional edge. “It’s really changing the contractor’s position on the ladder.”

There’s no doubt technology will continue to march forward and the construction professionals who take advantage of it will lead the industry. By featuring state-of-the-art machine controls, software programs, equipment systems, and more, Technology in Construction will help you stay at the head of the pack.

Machine Control
In the last few years a major change has swept over the world of construction equipment, and it can be summed up in two words: machine control. Machine control can take practically all of the guesswork out of grading and excavation by using laser, global positioning, and other advanced technology to set parameters and measurements otherwise done manually or with a trained eye.

Truly the wave of the future, machine control means as much to construction work now as the tractor did to farming almost 100 years ago.

Machine control consists mainly of laser and global positioning systems (GPS), machine interface systems, controls, and displays. To help acquaint readers with the technology that nearly all will encounter over the course of their professional lives, Technology in Construction will introduce the components, highlight their uses, and show how they come together in one piece of equipment. Descriptions and explanations will help readers build a basic understanding of how the elements work and how readers can incorporate them in their own construction jobs.

The goal of a grading and excavation job is to work a construction site with the appropriate equipment to achieve a design created by an engineer. Even if the job is a flat building pad, it usually has some slope. That slope can be created more efficiently and accurately than ever with the new technology. It might be a laser control system that provides two-dimensional control; it could be a robotic total station used for measuring angles and distances. Each of these, along with global positioning systems, calculate precise measurements and relay them to a display inside the cab.

Machine control systems fall into two categories: indicate and automatic. With an indicate system, the operator knows how to achieve the grade specified in the design requirements for his particular area by tracking information that appears on a display inside the cab. Indicate systems provide the operator with visual guidance so he can place the cutting edge or bucket properly, but he maintains control of the equipment. With an automatic system, the operator drives the machine, but the various systems—laser, GPS, etc.—control the movement of the blade or the bucket to achieve the same result. The operator doesn’t have to do anything but keep the machine moving in the right direction. The automatic system places the cutting edge appropriately on the design surface, and the machine does the rest.

An indicate system still requires the operator to know where to fill, where to cut, and where to deposit dirt, but the automatic system allows him to achieve his specified grade more precisely and efficiently.

Machine control has revolutionized the construction industry by making it possible for jobs to be completed more quickly and with the highest degree of accuracy. With wireless technology, a contractor can match a design engineer’s specifications to within one-tenth of a foot. Also, the technology lets him work in real time so design changes can be made or incorporated into the job site in practically an instant. With a wireless computer in the cab of his pickup truck, a contractor can receive up-to-the-minute progress reports from his equipment, download design changes sent by the engineer, and blend the two seamlessly by programming the new design specs into, say, the GPS-controlled hydraulic system.

Machine control systems operate through microprocessors situated deep within the equipment, which monitor every aspect of a machine, including operating information such as engine temperature, fuel, and oil use. They also control the critical hydraulic system that allows a blade or bucket to move with ease and accuracy.

Whatever the job site, every project begins with plumb, level, and square reference points from which the rest of the construction grows. A laser is the tool of choice for bright, crisp two-dimensional reference points or for an accurate plumb layout. Contractors can choose from carpenter levels, laser levels, rotary levels, and hybrid laser products.

For the person who installs acoustic ceilings or cement flatwork, for example, a rotating laser with a detector is necessary. Rotating lasers provide a continuous plane, either vertical or horizontal.

Some lasers are ideally suited for large job sites and agricultural land leveling and feature an integrated radio remote controller capable of two-way communication up to 1,000 feet. Radio communications between the remote and the base laser allow the operator to verify adjustments right from the cab of a machine.

Still others provide complete visual grade control with up to nine channels of information and three on-grade positions. The operator can tell at a glance how much grade he needs to cut, which makes grade control a one-person job. The grade checker can turn his attention elsewhere.

A laser also can provide three-dimensional positioning information by way of a machine control system. A fan-beam laser communicates digital control data to a receiver attached to the machine. The receiver takes in elevation, design cross-slope, and steering information, which it sends on to the control box.

Another system looks to the sky for information about location, position, and direction. GPS is a worldwide radio-navigation system formed from a constellation of 24 satellites and their ground stations. This particular constellation was launched and is operated by the United States. Other constellations are orbiting some 11,000 miles up in space, including GLONASS, operated by Russia, and Galileo, launched by the European Space Agency. 

Global positioning allows construction engineers to take information broadcast by the satellites and use it to calculate the required position of equipment and survey lines to achieve accuracy to within one-tenth of a foot. Some operate in collaboration with laser systems for even greater precision. On the job site, GPS receivers are attached to machines, which pass data to an onboard computer that holds digitized site information. In real time, the information is broadcast from the satellite constellation to the receiver and on to the computer to guide the equipment’s movements. In an indicate system, the data appear on a monitor inside the cab, and the operator uses the data to guide the machine. With an automatic system, the computer directs the movements of the machine, such as controlling its hydraulics and raising or lowering a blade or bucket automatically.

Often a contractor will use an indicate system for the bulk of an earthmoving job and an automatic system for the fine grading.

With advances in machine control and the subsequent development of machine interface systems that keep a bulldozer and other construction equipment on the job, construction workers find themselves scaling a learning curve to become proficient in the new technologies. Clutch-and-brake and cable-control have given way to hydraulic systems that detect the slightest motion of a joystick and respond accordingly. It’s a new world for contractors and operators, and those who resist the new technology will likely find themselves left in the dust.

Equipment Systems
Exploring the various equipment systems that make backhoes, excavators, skip/loaders, and other construction beasts move with agility and relative ease, Grading & Excavation Contractor’s new Technology in Construction section will take a look at the new technology that is changing the way construction equipment works and operators do their jobs. The key components are hydraulics, mechanical systems, electrical systems, controls and instrumentation, power plants, transmissions, and components and accessories. In this first issue we offer an overview of each component and how together they make for a powerful piece of equipment. In subsequent issues we’ll examine each component separately and in greater detail.

Much has changed in the world of equipment systems, not the least of which is hydraulics. Hydraulic pressure gives construction equipment much of its power by making it possible for the individual components of a piece of construction equipment to move. A hydraulic system consists of hydraulic lines, a reservoir of hydraulic fluid, a pump, and a series of pistons. In the new hydraulic technology, electric current rather than a pushrod causes valves to open and close.

Mechanical systems also have undergone changes in recent years. Steering wheels, pedals, and levers are being eliminated in favor of joysticks that allow the operator to keep his hands on more than one control. With one stick he can move the backhoe forward or backward, and with the other he can control the dig of the bucket.

Similarly, advances in hydrostatic transmissions allow the operator to choose the appropriate travel speed for the job and enable him to shift back and forth from forward to reverse without using the clutch or brake. In the past, an operator had to pay attention to a host of factors while getting his grading or excavation job done. Now an on-board computer handles much of that. When the computer detects an unbalanced load on the blade, for instance, it makes the appropriate adjustment automatically.

With electrical systems, the significant change is the controller area network (CAN) serial bus, which serves as a communication system for the machine. With the new technology, electrical systems are more interrelated with the operation of the machine as a whole. With the CAN bus, for example, variations in current cause valves to open and close rather than the operator flipping a lever and doing it manually. A special feature of the CAN bus is that components can be plugged in modularly and don’t impact any existing wiring.

As technology has moved forward, so have instrumentation and control. The on-board computer allows for a continuous stream of information, all of which appears on a digital monitor system. The operator has quick access to the machine’s performance history and diagnostics, and for those machines equipped with after-market global positioning systems, the monitor system allows him to switch back and forth between machine function data and global positioning system (GPS) information.

While GPS is a popular addition to a machine’s standard features, a plethora of aftermarket components, accessories, and systems has been developed that allow machine operators to use their equipment in different ways. An excavator, for example, can become a rock cutter when the bucket is replaced by a hydraulic rock hammer.

The past two years have seen some tremendous changes in construction equipment and operation. In the old days, a backhoe ran pretty simply. A carburetor, generator, and battery and a fairly simple system of hydraulic valves kept it going. The operator controlled it with levers and did everything by eye because all the components functioned manually. Speed and accuracy depended on his skill. Not so today when equipment manufacturers follow a never-ending quest to improve the performance of their machines and outfit them with user-friendly controls that make grading and excavation work more science than art.

Software for Contractors
With the right software applications and systems, a contractor can keep track of every aspect of his business from managing his payroll to tracking maintenance and repair on his bulldozer.
Within their categories, the various software programs differ from one another in a few respects such as window design and individual features. A general overview of current software follows, and in subsequent issues Technology in Construction will take a closer look at individual applications and explore how professionals have applied them to their businesses.

Construction and project management software such as Smart Contractor allow a user to control practically all the administrative tasks associated with his business. Fully integrated with Quickbooks, the software can create job estimates; generate custom job proposals and contracts; create job activity schedules complete with employees and subcontractors; generate requests to vendors and subcontractors; create purchase orders; track change orders and allowance variances; print invoices or bank draw requests; track payment receipts and other accounts receivable; track job costs; print job recap reports and make final payment calculations; create a variety of cash flow reports; track customer contacts; and even store job-site photos.

With its Quickbooks integration, this type of software also allows a contractor to manage financial and accounting issues such as accounts payable and everything related to payroll.

Fleet management software enables a business owner to maintain complete records on all his equipment. The software generates reports that cover a range of topics including vehicle costs; a parts inventory; fueling; tire management; mechanical productivity; purchasing information; vendor information; driver interface and reporting; depreciation; and asset tracking.

Equipment and inventory management software such as that offered by Cheetah allows contractors to know at all times where their equipment is located and how it is being used. It also enables contractors to maintain service records, create repair and maintenance work orders, and even track warranties.

In addition to software applications specializing in construction business management, a variety of specialty software systems cover areas such as human resource management; education and training; civil engineering and surveying systems; computer-aided design (CAD); and geographical information systems and mapping.

Human resources software automates the process of employee management so contractors can tailor employee record-keeping to fit their needs. With the software they can track employment history, status changes such as pay rates or tax changes, 401(k) administration and eligibility, health benefit eligibility, and more.

Other innovative software applications assist with fieldwork by calculating cuts and fills, stripping, strata quantities, subgrade materials, topsoil re-spread, areas, lengths, trench excavation, and backfill from digitizer input or CAD import. These applications can automatically list the fill required under each subgrade as well as any subgrade material; calculate the water, storm, and sanitary sewer excavation by strata; and backfill quantities from traced profiles or from contours. They can assist with highway construction, site development, and general earthmoving projects. Special features of these include a built-on AutoCAD engine; digitizing, drillhole, trenching, and roads routines; calculating volumes and material quantities; cutting and filling color maps and labels; creating three-dimensional drive-over simulation; preparing files for stackout and machine control; and two-dimensional to three-dimensional conversion routines for linework and spot elevations.

GEC - September/October 2006

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