3-D LiDAR Scanning
ASE has two C-10 Leica ground-based 3-D LiDAR scanners in daily use. LiDAR scanning allows us to dramatically cut the time and expense of mapping, topographic and as-built surveys. We used scanning to survey pavement locations on the high-traffic freeways and sidestreets of the I-57/I-294 interchange project. This use allowed us to keep our crew members off the roadways, save traffic control costs and prevent traffic congestion, while improving the safety of our personnel and motorists. We have also used scanning on several other projects in order to collect accurate data in a fraction of the time that would have been needed for conventional methods. We are constantly finding new and innovative uses for this revolutionary surveying technology.
Our Staff has pioneered the latest techniques in obtaining topographic data. Our President/CEO, Coventine Fidis, currently is on the ASPRS committee for writing the specifications for terrestrial-based LiDAR scanning. We are at the forefront of the movement to apply GPS technology to topographic surveys. This new technology is extremely well suited for topographic surveys. Currently, we are one of the few firms in the Midwest to use ground-based 3-D LiDAR Scanners to get thousands of times the topographic data that could be obtained with conventional surveying methods and with greater accuracy than traditional topographic surveying techniques.
3-D LiDAR scanning can give extremely accurate results that save our clients time and money while providing a better finished product. We currently use scanning technology to perform work in areas where access to the survey area is dangerous, like lock and dam surfaces, toxic sites, rail surveys in close quarters, industrial sites, high traffic roadways, difficult to access structures on bridges and buildings, and areas of unsure footing, such as large stockpiles of loose materials. We also use scanning when extremely accurate survey data is required for close-tolerance engineering design and construction. In addition, scanning gives incredibly accurate results for quantity calculations due to the fact that conventional methods for quantity calculation surveys necessarily require approximations that are not used in the three-dimensional imaging provided with a scanner. We have had excellent results from using 3-D LiDAR scanning instead of conventional surveying techniques for traditional topographic surveys and we bill the costs for our scanning work at the same rate as we would for conventional methods, so that our clients save money due to our shorter time in the field. We give our clients the benefits of scanning with no additional costs to them and do not charge for the use of the equipment.
ASE has used scanning on the following projects:
· Michigan Avenue Bridge- Historic Northwest Plaza/Stairway Reconstruction/Restoration. ASE provided 3-D LiDAR scanning on the stone staircase on the Historic Michigan Avenue Bridge over the Chicago River for an as-built depiction to be used in a reconstruction of the historic structure. The original construction plans for this staircase varied from its actual construction. Due to the variations from original plans and the unique geometry of the structure, the masonry contractor determined that traditional measurements would not be able to provide enough data for an accurate reconstruction. Algozine contacted ASE to see if we would be able to provide them with a 3-D as-built drawing that they could use to cut the stone blocks to match the exact appearance of the hundred year-old bridge features. We worked with Algozine to determine the necessary data elements, scanned the staircase and processed the data. The bridge remained open to foot traffic during the entire duration of our scanning work. Algozine was able to use our scanning data for their computerized masonry fabrications to create blocks that were the exact duplicates of the original stones. The experimental method that we devised allowed the reconstruction to be an unqualified success, and the results exceeded the client’s expectations.
· Howard CTA Terminal Station Survey. Wight & Company enlisted the help of ASE’s 3-D LiDAR scanning on a Design Build project for the Chicago Transit Authority (CTA) Howard Street Red Line station. The design involved an intricate placement of a new roof overhang within the stations current design. The new roof required tie points to be welded into the existing overhead curved structural steel trusses. ASE scanned the structural steel, modeled the structure and exported a 3-D MicroStation drawing used to determine the location of the tie points and the distance to the proposed roof.
· Winnetka Road Bridge over the I-94. Wight & Company enlisted the help of ASE’s 3-D LiDAR scanning for design services on a removal and replacement of damaged bridge beams. The project consisted of a bridge substructure’s beams that were damaged as a result of an collision with a large truck. ASE scanned and modeled the beams in an afternoon. A report was then provided to the engineering staff that indicated the amount of deformation for each beam affected. To reduce to cost of the work, ASE provided deformation information in relation to the first beam not affected by the collision, thereby removing the requirement for control, or other conventional work.
· Chicago Avenue Bridge over the Chicago River. Survey for integrated existing condition depiction of Bascule Bridge. Survey approach centered on 3-D LiDAR Scanning to depict structural elements, overall footprint, and aesthetic elements to design grade standards.
· I-90 ISTHA Predesign; Higgins Rd to Elgin Plaza. ASE performed 3-D LiDAR scanning on 11 bridges within a 7 mile stretch of I-90. The scanning located: bottom of beams at/near piers; measurements for the calculation of clearances; structural features (abutment walls, piers, sidewalks); bearing seat details and elevations.
· Weigh-In-Motion High Sensitivity Pavement Sensor Site Selection. At five test sites throughout the State of Illinois Tollway system, ASE provided the Toll Highway Authority with extraordinarily detailed pavement surface drawings to intricate tolerances. The level of detail and density of measurement of the pavement at these sites was required, so that the client could choose the precise location at each site that was most suitable for highly sensitive Weigh-In-Motion (WIM) sensors that would enable the state authorities to weigh trucks in live lanes of traffic at highway speed without interrupting the flow of traffic (or even notifying truckers that they were being weighed). The sensors were absolutely flat and required the pavement in the vicinity of the sensor to be ground flat. The density of our measurements was necessary to allow the Authority to pick a sensor location that would require the least amount of costly pavement grinding/milling to meet the approach and departure pavement planes. The pilot program sensors were located using our data and successfully installed.
· Interchange Improvements of IL 59 at I-88. ASE performed the existing condition survey of the interchange in an extremely congested area. Due to the fact that the Tollway Authority did not want to enforce lane closures at these vital transportation facilities, ASE was asked to obtain all 3-D pavement locations with 3-D LiDAR scanning. 3-D LiDAR scanning enabled ASE to remotely measure all pavement surfaces without the need to interrupt the normal flow of traffic. The client required all pavement marking and striping to be located, and these features were automatically acquired in the scanning process with no additional field effort. Part of one ramp had been originally built upon unsuitable soil and the pumping of the pavement was causing pavement failure. ASE was able to provide the client with extremely accurate scanning data to identify the area of failure and locate a prefabricated span to bridge the area of unsuitable subgrade.
· Tri-State Tollway; 82nd & 83rd Plaza, Cermak Plaza, Irving Park Plaza. Pavement elevation required for design of new plaza configuration. 3-D LiDAR scanning was done. Tasks included data compilation, horizontal control (scanning), vertical control (scanning), centerline alignment, and pavement scanning (LiDAR) to create “DTM” from scanned data. Draft planimetrics in Microstation using ISTHA CAD Standards.
· CTA Block 37 – Airport Express Tunnel Connections. Survey existing tunnel alignment and surface features, and existing commercial property lines, and right-of-way limits in the vicinity of the project. 3-D LiDAR scanning was used for safety, to verify and supplement as-built survey, produced by conventional survey techniques. Design documents submitted by AUTOCAD via project website.
· Vulcan McCook Reservoir – CUP. Survey mapping of the conveyor route, under Interstate 55, over Des Plaines River and through McCook Reservoir. 3-D LiDAR scanning was used for creating an accurate DTM on large, loose stock piles that were unsafe for walking on. Tasks included data compilation, horizontal control, vertical control, spot elevations, and topographic surveys. Draft planimetrics in 3d AutoCAD drawings submitted in IDOT CAD Standards.
· Northwest Tollway – IL Rte 31 to Randal Road Plaza 9. New plaza configuration needed for extra lane placement. 3-D LiDAR scanning used to eliminate lane closures for high traffic area, and for safety reasons. Tasks included data compilation, utility survey, topographic survey, and pavement scanning (LiDAR). Draft planimetrics in Microstation using ISTHA CAD Standard.
More information about our LiDAR scanning abilities are available upon request.