Transportation Project Experience
IH 35 Yager Lane to Wells Branch Parkway
Low-Altitude Aerial Mapping & Design Survey
Loop 1604 / US 281
HDS Laser Scanning of Bridge Structures & DTM
State Highway 45 Southeast
SUE & Utility Coordination
American Disabilities Act (ADA) Ramp Location
GPS Data Collection & Mapping
IH 35 Yager Lane to Wells Branch Parkway
Low-Altitude Aerial Mapping & Design Survey
Low altitude aerial mapping and topographic/design surveying services to support the engineering design efforts for 3 miles of IH 35. Global Positioning System (GPS) primary control was established along the project followed by panels (secondary control) to control the aerial photography. Aerial mapping at 1" = 20' and a contour interval of 0.4 foot was provided. These mapping files were augmented by on-the-ground survey location of obscured areas, driveways, side streets, visible utilities, drainage structures and right-of-way location. Level C and D Subsurface Utility Engineering (SUE) was also provided. After completion of the field work and compilation of the data, the client was provided with digital files of the planimetrics and the digital terrain model (DTM). Also delivered were hard copies of the survey control for the project and ground survey data.
Loop 1604 / US 281
HDS Laser Scanning of Bridge Structures & DTM
HDS Laser Scanning - Bridges
A portion of this project included proposed widening and replacement of existing bridges. These included structures at cross streets along US 281 and Loop 1604 and the main lane and frontage road structures at the existing interchange. Survey information at the edge of and cross slope of bridge deck, face of abutment backwall, centerline of each bent, inside edge of top of deck at 1/5 point intervals on each span, bearing seat elevations and centerline of existing bridge columns was requested.
SAM, Inc. provided sub centimeter level accuracy for all requested information by capturing the data using HDS. Once captured, the hundreds of laser scanned data points that comprised the planar surfaces of the desired objects were modeled and intersected to create vertices at the requested location with a much higher level of accuracy and precision than if located by any other available means. Horizontal and vertical positions at these vertices were extracted; feature attributes were attached and exported as an ASCII point list. In addition to providing the requested survey information, the entire bridge structure at each location was scanned. This allowed the capture of additional survey data for later use without the need to revisit the site in the field, which would negatively impact the project schedule.
HDS Laser Scanning - DTM
Roadway DTM survey information was needed for the existing portion of the US 281 mainlanes at the tie in of the proposed direct connectors. Approximately 10,500 linear feet of northbound and southbound mainlanes and frontage road of US 281, and an additional bridge structure were captured using the Leica© HDS3000 laser scanner with no lane closures, disruption of normal traffic flow, or occupation of the roadway by survey personnel. Individual scans were registered together based on project control to create a georeferenced point cloud dataset. Using this dataset, breaklines and mass points were developed and exported. These features were imported into a Microstation DTM file from which a triangulated irregular network (TIN) was produced with sub centimeter level accuracy.
State Highway 45 Southeast
SUE & Utility Coordination
This project consisted of improving FM 1325 to expressway toll lanes from IH 35 to US 183 in south Austin, Texas . Over 98,300 linear feet of existing underground utilities were identified, located, and mapped within the project limits including the connections at IH 35 and US 183 for multi-level bridge configurations. These utilities consisted of underground water, wastewater, storm drainage, telecommunication, fiber optic, cable, TV, gas, and electrical systems. Identification of overhead utilities (i.e., electric, telecommunications, and cable TV) systems was also provided.
This information was used by the design team to identify potential utility conflicts with new improvements, prepared construction cost projections for relocating utilities in conflict and to ensure continuous construction operations for the project.
American Disabilities Act (ADA) Ramp Location
GPS Data Collection & Mapping
SAM, Inc. developed the project plan for a GPS field asset inventory of ADA ramps within the TxDOT right-of-ways within the Austin District, approximately 731 miles of roadway. This project plan included defining the scope of work, data capture procedures, equipment standards, training, and other requirements necessary to collect the required ADA ramp information within an 11 county area. SAM, Inc. also developed and tested the Data Dictionary used to collect up to 60 data features for each ramp.
SAM, Inc. served as the overall project coordinator directing the efforts of 7 additional survey consultants. With combined resources we were able to field 21 survey crews. This project required the collection of specific information for a district-wide inventory of intersections and ramps. This information allows TxDOT to assess and prioritize intersections and ramps that must be upgraded to be in compliance with the American Disabilities Act Pedestrian Accessibility Project.
As part of the data collection process SAM, Inc. established an FTP site. Each survey crew downloaded their daily data collection efforts to this site. SAM, Inc. technicians then processed and performed quality control of all data collected by the survey consultants to include Trimble Pathfinder Pro data dictionary .SSF data files and .JPEG format image files. SAM, Inc. performed QA/QC procedures and notified the survey consultants of any problems or necessary corrections. After the QA/QC was performed, the data was appended to a master set of files in ARCGIS 8. As part of this process the images were linked to the feature data using the hyperlink tool in ARCGIS 8.
SAM, Inc. also determined Texas Reference Marker and displacement information and added this to the feature data for all corners located. This data was determined using either digital or hardcopy RI-1 (Road Inventory) data provided by Austin District - TxDOT.
