Delays, environmental concerns, historic site preservation, equipment scheduling, manpower, future projects, cost overruns, and public safety issues are just a few of the characters in the nightmare of inaccurate site maps and surveys.The importance of survey accuracy can’t be stressed enough, remarks A. Ryan Pollard, vice president of R.E. Cupp Construction in Fort Worth, TX. “Topographical accuracy is very important. We verify all of our topographies before breaking ground on a site and find, on average, that approximately 30% of the sites are not correct,” Pollard says. “And this percentage is even greater when aerial topographies are used.”Other contractors agree with Pollard on the problems of site inaccuracies and the importance of survey accuracy. “The first things I look at are available documents, plans, surveys—those kinds of things,” says Reuben M. Cansler, president of Cansler Construction Services Inc. in Tampa, FL. Cansler thinks the site generally determines the project, which includes zoning, size, location, road access, and availability of utilities. Because site surveys form the basis of most bids, it is imperative that the information be current and accurate. “Site surveys are only as good as their accuracy,” he says. “You must rely on site-survey accuracy for boundary information, elevation for grading, drainage, utilities, flood certification, and tree locations.”Because surveys are usually part of the contract specifications, one would think they provide all the information needed to make an accurate bid. Most contractors, however, say they could not depend on the accuracy of surveys and maps when bidding on projects. So what should contractors do to ensure accuracy? Dress in camouflage and sneak around in the dark of night? Look over the shoulder of the civil engineer while he works? Visit the archives at the county seat to find the historic use of the property?Take A Hike: Walking the Site Adds Info and Gives Insight
Taking the time to visit and walk the site can provide additional valuable insight for the project. It also gets you out of the office for a couple of hours.In addition to the studying the survey, Cansler believes in the importance of walking the site. “The survey will only show the site in question—not the surrounding sites,” he says. “The surrounding sites may have a great influence on the proposed project.” By walking the site, you can note things that have changed since the original survey was done and update your file on the project.Also by walking the site, you might encounter an “old-timer” who can fill you in on the history of the neighborhood—how it has changed over the years, what was on the lot years ago, where the riverbed was—and even about the 100-year flood.Hugh H. Willocks, president of Willocks Construction Corporation in Hilo, HI, agrees with Cansler about walking the property. “By observing the grass, the tree line, the natural water runoff, the past uses for the land, that kind of stuff, you can get a pretty good idea of the makeup of the land.” Grass and meadowland indicate soil, for example, while shrubs indicate rockier land. Not only does walking the site allow you to verify the accuracy of your information, but it also might uncover problems that can be addressed before they slow down the project.
Taking the time to visit and walk the site can provide additional valuable insight for the project. It also gets you out of the office for a couple of hours.In addition to the studying the survey, Cansler believes in the importance of walking the site. “The survey will only show the site in question—not the surrounding sites,” he says. “The surrounding sites may have a great influence on the proposed project.” By walking the site, you can note things that have changed since the original survey was done and update your file on the project.Also by walking the site, you might encounter an “old-timer” who can fill you in on the history of the neighborhood—how it has changed over the years, what was on the lot years ago, where the riverbed was—and even about the 100-year flood.Hugh H. Willocks, president of Willocks Construction Corporation in Hilo, HI, agrees with Cansler about walking the property. “By observing the grass, the tree line, the natural water runoff, the past uses for the land, that kind of stuff, you can get a pretty good idea of the makeup of the land.” Grass and meadowland indicate soil, for example, while shrubs indicate rockier land. Not only does walking the site allow you to verify the accuracy of your information, but it also might uncover problems that can be addressed before they slow down the project.
The bike system in action. You can see your site on-screen and deal with any issues or problems in real time.With caverns, underground lava tubes, ancient burial grounds, and hydroheads just waiting to be “discovered,” knowing the land and its previous uses might well dictate the type of project developed and how it is constructed. Willocks, who has been on the Big Island of Hawaii for 30 years, still gets surprises. Recently his crew encountered underground caverns during a public works project for a Hawaiian Homes subdivision. “We cracked into caves in about four places,” Willocks says. “We had to stop, cordon off the area, notify the owner, and get an archaeologist.”Hawaii’s underground network of lava tubes is laced with remains and artifacts of ancient Hawaiians. And sometimes—because of the cultural significance of a discovery—the project has to stop until an archaeologist can determine if there are ancestral remains or artifacts. “Even before ‘grubbing,’ you [must] have the historic officer come out, and there is only one on the entire island,” says Willocks. Finding something—anything—can stop the project, and stopping the project affects both the owner and the contractor.“We had to reengineer the project,” says Willocks. “We used concrete fill, incorporated a concrete cover, and lifted the roadway.” They worked in this case, but tons of concrete fill don’t always fix the problem. “In another area where we hit a cavern,” he says, “we couldn’t seal it because of endangered species [living in the cavern], so we designed a metal grate to secure entry yet allow access for environmentalists.”
“Excavation is one of the most costly divisions within the entire building process,” says Pollard. “If the land requires a certain amount of cost to develop it, then that facility has to pay for and absorb the cost. Therefore the site cost determines which facilities can produce that kind of money.”Sometimes the project has to fit the site. “For example, if a developer has sold home sites based on the fact that a golf course is going to be built in a specific area, then the golf course developer’s challenge is to find a way to make a golf course fit and work in the area provided,” explains Mindy Bieging, sales and marketing manager for 3D Nature LLC in Arvada, CO. 3D develops software for landscaping.Boring Logs Aren’t Always Boring; It Matters Where Borings Are Taken
After you have checked the survey, walked the site, visualized the project, talked with the old timers, and reengineered the project to fit the site, how else can you avoid delays due to mapping or survey problems? Willocks says his company depends on the professionalism of the engineers. “On large projects we really look at the design civil engineers. We depend on input from the design engineers and on the boring log to give us enough information to make an accurate bid.” He adds that it is crucial to compare the boring logs to the plans and specifications. “It is important to see where the borings were taken. I need to know how far apart [the borings were and if] the samples [are] reflective of the total area of the project.” Generally the borings are the responsibility of the property owner, but for site work done in advance of building, Willocks notes, “it is important [that] the borings [be] taken right underneath the heaviest part of the project.” And the borings must be representative of the lay of the project.Willocks tells of a recent street project where workers encountered a huge deposit of ash. Because ash is unstable to build on, the project was stopped. This is not only important from a weight standard but also for water runoff. “It can be that there were borings taken, but they missed the ash deposit,” Willocks says. “Then the company has to go back to the order.” Had more bore samples been taken, Willocks Construction might have made a more comprehensive bid.Ash deposits presented another problem for the street project, involving dry wells. For this roadway, the dry wells were designed to be 6 ft. wide and 20 ft. deep. The design idea was to drain away water yet trap dirt and sediment above the drain holes. “We ran into ash about 6 to 7 feet down,” says Willocks. “After we sank our dry wells, we got rain. More water came in through the ash than drained away. The pressure from the water rushing into the dry wells caused the covers to shoot up into the air!”Willocks fixed the problem by designing a concrete liner with drain holes. Where the dry well encounters the ash area (from about the 7-ft. level to the 20-ft. level), the liner is solid concrete, which is intended to prevent incoming water. A 50-ft. plastic drain extends below the concrete to suck off the water, leaving the dirt and rock to settle inside a lip in the concrete.
“Excavation is one of the most costly divisions within the entire building process,” says Pollard. “If the land requires a certain amount of cost to develop it, then that facility has to pay for and absorb the cost. Therefore the site cost determines which facilities can produce that kind of money.”Sometimes the project has to fit the site. “For example, if a developer has sold home sites based on the fact that a golf course is going to be built in a specific area, then the golf course developer’s challenge is to find a way to make a golf course fit and work in the area provided,” explains Mindy Bieging, sales and marketing manager for 3D Nature LLC in Arvada, CO. 3D develops software for landscaping.Boring Logs Aren’t Always Boring; It Matters Where Borings Are Taken
After you have checked the survey, walked the site, visualized the project, talked with the old timers, and reengineered the project to fit the site, how else can you avoid delays due to mapping or survey problems? Willocks says his company depends on the professionalism of the engineers. “On large projects we really look at the design civil engineers. We depend on input from the design engineers and on the boring log to give us enough information to make an accurate bid.” He adds that it is crucial to compare the boring logs to the plans and specifications. “It is important to see where the borings were taken. I need to know how far apart [the borings were and if] the samples [are] reflective of the total area of the project.” Generally the borings are the responsibility of the property owner, but for site work done in advance of building, Willocks notes, “it is important [that] the borings [be] taken right underneath the heaviest part of the project.” And the borings must be representative of the lay of the project.Willocks tells of a recent street project where workers encountered a huge deposit of ash. Because ash is unstable to build on, the project was stopped. This is not only important from a weight standard but also for water runoff. “It can be that there were borings taken, but they missed the ash deposit,” Willocks says. “Then the company has to go back to the order.” Had more bore samples been taken, Willocks Construction might have made a more comprehensive bid.Ash deposits presented another problem for the street project, involving dry wells. For this roadway, the dry wells were designed to be 6 ft. wide and 20 ft. deep. The design idea was to drain away water yet trap dirt and sediment above the drain holes. “We ran into ash about 6 to 7 feet down,” says Willocks. “After we sank our dry wells, we got rain. More water came in through the ash than drained away. The pressure from the water rushing into the dry wells caused the covers to shoot up into the air!”Willocks fixed the problem by designing a concrete liner with drain holes. Where the dry well encounters the ash area (from about the 7-ft. level to the 20-ft. level), the liner is solid concrete, which is intended to prevent incoming water. A 50-ft. plastic drain extends below the concrete to suck off the water, leaving the dirt and rock to settle inside a lip in the concrete.
A typical bike package setupWillocks says this particular project has 38 dry wells. “It cost a lot to redesign the project when we hit the ash. The additional cost per dry well was between $10,000 and $15,000.” Those numbers would impact the bottom line on any project. “You can control surface runoff with ditches for diversion,” says Willocks. “But underground streams and hydroheads surface where they want.”Cansler also depends on soil-boring reports, which provide information on the type of soil below the grade, indicate the presence of any rock, and help determine what type of building foundation may be used. “I also depend on environmental reports to determine if any types of pollution are present,” he says.With public works projects, Willocks points out that the contract defines the specifications for cutting, fill, pipe size, and so on. Although one would like to think the information is inclusive, it is “not so,” says Willocks. Problems still develop during the course of the projects.Lasers Improve Mapping Accuracy; New Technology Nips at Lasers’ Heels
“Laser surveying has impacted excavation in a positive direction,” says Pollard. “It allows you to be extremely accurate in almost every given scenario. GPS [global positioning system] surveying has had even a larger positive impact than laser surveying. We utilize the [Trimble] SiteVision GPS devices, which give our operators real-time grades.”Cansler agrees, “Laser instruments have greatly impacted the surveying industry as well as the whole construction industry. But I think GPS has had a greater impact on surveying than the laser [has].”Even the latest laser technology, however, is losing out to advanced computer programming. “Laser surveying is fairly obsolete compared to modern [real-time kinetic] GPS and even robotic total stations,” says Alan Williams, vice president and head of software development at GeoLogic Computer Systems (GCS). “However, we have a way to work with rotating lasers in combination with GPS to still do 3D construction [with vertical curves].” GCS software is compatible with a variety of machinery and equipment.When the contractor wants to buy equipment to make his operation more efficient, he comes to GCS, notes Williams. The company works with project engineers, obtains data, and develops solutions. Using computers and software is one way to ensure accuracy and maintain control of mapping.“Many of our customers will make their own topography maps of a site before or after bidding on the project,” says Williams. “They can then easily compare that surface with the design surface to get an accurate volume and picture of the dirt to be moved. It is very cheap and quick today to just ‘re-topo’ the site, which probably is much more accurate than [what is] provided to the contractor.”Williams thinks surveyors are often responsible for today’s map errors. “On almost every demo we do, we find some problem in the surveyors’ stakes, the string line, or the plans,” he reports. “Once we found an error in the hubs that a surveyor put in for a new airport. The hubs had an error increasing from zero to 0.2-foot vertical error and then back to zero again [probably because the surveyor moved his total station]. The contractor says he was going with the hubs anyway.
“Laser surveying has impacted excavation in a positive direction,” says Pollard. “It allows you to be extremely accurate in almost every given scenario. GPS [global positioning system] surveying has had even a larger positive impact than laser surveying. We utilize the [Trimble] SiteVision GPS devices, which give our operators real-time grades.”Cansler agrees, “Laser instruments have greatly impacted the surveying industry as well as the whole construction industry. But I think GPS has had a greater impact on surveying than the laser [has].”Even the latest laser technology, however, is losing out to advanced computer programming. “Laser surveying is fairly obsolete compared to modern [real-time kinetic] GPS and even robotic total stations,” says Alan Williams, vice president and head of software development at GeoLogic Computer Systems (GCS). “However, we have a way to work with rotating lasers in combination with GPS to still do 3D construction [with vertical curves].” GCS software is compatible with a variety of machinery and equipment.When the contractor wants to buy equipment to make his operation more efficient, he comes to GCS, notes Williams. The company works with project engineers, obtains data, and develops solutions. Using computers and software is one way to ensure accuracy and maintain control of mapping.“Many of our customers will make their own topography maps of a site before or after bidding on the project,” says Williams. “They can then easily compare that surface with the design surface to get an accurate volume and picture of the dirt to be moved. It is very cheap and quick today to just ‘re-topo’ the site, which probably is much more accurate than [what is] provided to the contractor.”Williams thinks surveyors are often responsible for today’s map errors. “On almost every demo we do, we find some problem in the surveyors’ stakes, the string line, or the plans,” he reports. “Once we found an error in the hubs that a surveyor put in for a new airport. The hubs had an error increasing from zero to 0.2-foot vertical error and then back to zero again [probably because the surveyor moved his total station]. The contractor says he was going with the hubs anyway.
“We mentioned the error several times more, but the contractor only called the surveyor back when we said we needed a ‘Hold Harmless’ agreement or we would leave. The risk of a plane crash seemed too high if the airport didn’t demand that the job be done over. The surveyor corrected the hubs, thus saving himself from a huge lawsuit if the airport had been paved badly,” says Williams.Avoid Horror Stories by Investing in Better Software for Site Maps
Horror stories develop because most engineers do not produce 3D data in their electronic data files, suggests Pollard. “If they do claim to produce it, it is usually not accurate.”3D Nature’s Web site brags, “We are terrain fanatics with varied backgrounds in geology, object oriented programming and production animation who have come together to create an insanely great program.”“3D Nature is a software design company,” says Bieging. It develops software that can model, visualize, render, and animate terrain. “Many of the people who use our products have sites that they have to make a specific project work on,” she points out. “We feel site-map accuracy is vital. That is why many of our customers use our line of products. We provide World Construction Set [WCS] and Visual Nature Studio [VNS]. These are tools that allow companies to visualize their projects prior to actual groundbreaking and earthmoving. Both WCS and VNS can create very photorealistic and accurate site maps.“
Horror stories develop because most engineers do not produce 3D data in their electronic data files, suggests Pollard. “If they do claim to produce it, it is usually not accurate.”3D Nature’s Web site brags, “We are terrain fanatics with varied backgrounds in geology, object oriented programming and production animation who have come together to create an insanely great program.”“3D Nature is a software design company,” says Bieging. It develops software that can model, visualize, render, and animate terrain. “Many of the people who use our products have sites that they have to make a specific project work on,” she points out. “We feel site-map accuracy is vital. That is why many of our customers use our line of products. We provide World Construction Set [WCS] and Visual Nature Studio [VNS]. These are tools that allow companies to visualize their projects prior to actual groundbreaking and earthmoving. Both WCS and VNS can create very photorealistic and accurate site maps.“
Automated data capture screen: The boxes show your NEZ location, and the real-time display shows locations and the points already collected. Our products are directly impacted [by laser surveying] because with greater data detail and accuracy, our software products are able to produce much more accurate maps and plans,” Bieging says, stressing that it is very important for the industry to understand that new tools and technologies are available. “And although they may require a bit of investment up front [both financial and in time to learn to use the new tools], these new opportunities can pay for themselves many times over in a very short period of time.” And what kind of cost are we talking about? 3D’s WCS 6 is less than $1,000; VNS lists for $2,475.Williams agrees with Bieging about software being an investment rather than a cost. “When the contractor wants to buy equipment to make his operation more efficient,” says Williams, “that’s when we get involved. GCS sells software and hardware for running construction equipment, such as graders, dozers, trimmers, et cetera. We also sell equipment to put on an all-terrain vehicle [or pickup] for rapid surveying. We do not do the work ourselves anymore; we just sell and support the equipment.”
The GCS: Topo program is a rapid surveying system. With it, you can survey up to 200 ac. and collect as many as 20,000 points in one day. The system can even collect points as you drive. Think of the time and money you can save with software that accurately surveys in a fraction of the time required by conventional methods.Even Experience Can’t Help Avoid Pitfalls
Experience doesn’t always save a contractor from cost overruns. Even having worked a project in the same area doesn’t guarantee accurate bids. In fact, all of the contractors interviewed had a horror story to tell. “We got burned on a project in the home lots [the Hawaiian Homelands development],” says Willocks. “We made an assumption based on other work we’d done in the area. We assumed 50% of the structural base course. The problem was that it didn’t ‘screen out’ to the grade I needed.”Because the job was a county project, Willocks Construction couldn’t use it. “The county wouldn’t let us use it,” says Willocks, “so we had to go out and buy fill. There wasn’t a lot we could do; we can’t afford to do test borings. We depend on accurate information to help us make the right bid.” These things become another cost overrun to take to the accountant.Training, Experience, and Obeying the Law: Keys for Success
Accurate surveys, walking the site, laser technology, global positioning, specialized software, and years of experience in the field all can help avoid pitfalls on a project. Cansler adds one more: the importance of the engineer. “I have worked with a number of different civil engineers,” he says. “You select the one that has experience in the area and [with the] type of proposed project.”Pollard agrees with Cansler about the importance of the engineer in the equation. “We have working relationships with certain engineering firms. We rely very heavily on boring reports.”The accuracy of the site survey depends on the data available for the project area and the tools for creating maps, according to Bieging. The engineer also must help interpret the data and the information. “3D products are used by engineers all over the world,” Bieging says.Even with the best maps; the most accurate survey; and all of the experience, new computer technology, and luck in the world, there’s one more thing to consider for successful completion of a project.“We always do our projects in accordance with the law,” says Willocks. “We follow all federal, state, and local laws. And that includes OSHA [the Occupational Safety & Health Administration]. OSHA considers all rock in Hawaii to be fractured rock. Because OSHA believes fractured rock to be unstable, we must provide shoring and work at certain angles.” Only a contractor or an engineer familiar with the area would understand what Willocks means.“After all is said and done,” he maintains, “it still comes down to being responsible, resourceful, and ready to do your homework.” And perhaps good luck helps too.
Maybe next time Willocks cracks an underground cavern, he’ll uncover pirate treasure.
The GCS: Topo program is a rapid surveying system. With it, you can survey up to 200 ac. and collect as many as 20,000 points in one day. The system can even collect points as you drive. Think of the time and money you can save with software that accurately surveys in a fraction of the time required by conventional methods.Even Experience Can’t Help Avoid Pitfalls
Experience doesn’t always save a contractor from cost overruns. Even having worked a project in the same area doesn’t guarantee accurate bids. In fact, all of the contractors interviewed had a horror story to tell. “We got burned on a project in the home lots [the Hawaiian Homelands development],” says Willocks. “We made an assumption based on other work we’d done in the area. We assumed 50% of the structural base course. The problem was that it didn’t ‘screen out’ to the grade I needed.”Because the job was a county project, Willocks Construction couldn’t use it. “The county wouldn’t let us use it,” says Willocks, “so we had to go out and buy fill. There wasn’t a lot we could do; we can’t afford to do test borings. We depend on accurate information to help us make the right bid.” These things become another cost overrun to take to the accountant.Training, Experience, and Obeying the Law: Keys for Success
Accurate surveys, walking the site, laser technology, global positioning, specialized software, and years of experience in the field all can help avoid pitfalls on a project. Cansler adds one more: the importance of the engineer. “I have worked with a number of different civil engineers,” he says. “You select the one that has experience in the area and [with the] type of proposed project.”Pollard agrees with Cansler about the importance of the engineer in the equation. “We have working relationships with certain engineering firms. We rely very heavily on boring reports.”The accuracy of the site survey depends on the data available for the project area and the tools for creating maps, according to Bieging. The engineer also must help interpret the data and the information. “3D products are used by engineers all over the world,” Bieging says.Even with the best maps; the most accurate survey; and all of the experience, new computer technology, and luck in the world, there’s one more thing to consider for successful completion of a project.“We always do our projects in accordance with the law,” says Willocks. “We follow all federal, state, and local laws. And that includes OSHA [the Occupational Safety & Health Administration]. OSHA considers all rock in Hawaii to be fractured rock. Because OSHA believes fractured rock to be unstable, we must provide shoring and work at certain angles.” Only a contractor or an engineer familiar with the area would understand what Willocks means.“After all is said and done,” he maintains, “it still comes down to being responsible, resourceful, and ready to do your homework.” And perhaps good luck helps too.
Maybe next time Willocks cracks an underground cavern, he’ll uncover pirate treasure.
