Design Survey

Description

Design surveying is the collection of field data to identify and determine the spatial relationship of existing improvements, utilities and terrain surface features required by the engineer for the development of the proposed roadway improvements. The level of detail required for a design survey will depend on the project description. The level of detail for hydraulic/hydrologic analysis, schematic design, and PS&E can vary substantially. The project engineer will be the individual that decides the level of detail required for the project. The surveyor must work closely with the project engineer to ensure that the level of detail provided is commensurate with project requirements without expending resources unnecessarily. The surveyor should always keep in mind that he a member of a design team and may be first on the ground, and is in a unique position to act as an advisor to the project engineer regarding field conditions that could impact the project. RODS Surveying utilizes existing ground control provided by TxDOT or establishes a ground control network for the project using static GPS.

Although RODS Surveying has successfully established vertical ground control with static GPS for a number of years, project conditions may require the use of a digital level to differentially transfer elevations from one point to the next. Unless otherwise requested by TxDOT, ground control is established to first order NGS standards and referenced to NAD 83, 1993 ADJ, HARN and NGVD 88. Once ground control is established, field data will be collected using a total station and data collector, or GPS RTK methodology. Standards and specifications used for data collection are as described in Chapter 3 of the TxDOT Survey Guide and the TSPS Manual of Practice, for Category 6, Condition I or II, Topographic Survey. RODS Surveying utilizes several software packages for collection and processing of data to develop files compatible with Microstation 8 and Geopak 2004, including SDMS and CAICE.

Design Survey Task Sequence and Quality Control Measures

a. Field inspect project site and discuss proposed improvements with project engineer or designated TxDOT representative. Determine in detail the information required by the project engineer and the format of the deliverables. All design surveys performed by RODS Surveying are under the direct supervision of an RPLS who will coordinate directly with the project engineer or other TxDOT representative.

b. Secure copies of TxDOT plans and right-of-way maps of the existing facility. Existing plans and maps can serve as quality assurance documents that all existing utilities and improvements are included in the surveys.

c. Compile all plans, maps and ground control information and review scope and purpose of surveys with field crew (s) and lead technician selected for the project.

d. Recover existing ground control or establish ground control. All horizontal ground control is established with static GPS and supervised by an RPLS who is a full time GPS mission planning and post processing specialist. Vertical ground control may be established with static GPS or differentially with digital levels depending on the project circumstances and the requirements of the District.

e. Locate and describe improvements and utilities for planimetric mapping and take cross sections and/or map terrain break lines and spot elevations for digital terrain modeling. Drainage structures, safety end treatments, bridge details and signage may be photographed with a digital camera for clarification when preparing deliverables. All occupied and backsight station set ups and instrument heights are field checked by tying to a third control point before vacating the occupied station. Target poles are fixed-height poles to minimize target height errors.

f. Process data collection files and review for errors and conformance to standardized procedures and policies.

g. Import SDMS (.prj) files into SDMS Processor or CAICE for processing and review data for anomalies.

h. Field inspect improvements, utilities and digital terrain modeling. This task is performed by a technician after all data collection files are processed and improvements and utilities are plotted.

i. Prepare Microstation 8 and Geopak 2004 (2D.dgn, 3D.dgn., .dat, and .tin) files and CAICE (.arc) files.

j. Make final review of files. This review is made by the supervising RPLS in conjunction with the lead technician working on the project.

k. Submit deliverables to TxDOT for review.

l. Address any questions or concerns voiced by TxDOT personnel, supplement and edit files as necessary, and resubmit deliverables.

Design Survey Deliverables

Deliverables for design surveys will consist of paper plots of planimetric and topographic surveys as required, copies of field survey processing reports and point tabulations on bond paper, photostatic copies of utility research and field notes, Microstation 8 and Geopak 2004 (2D.dgn, 3D.dgn., .dat, .tin, and .gpk) files, SDMS (.ctl, .prj, .cal), and CAICE (.arc) files as requested. This listing is representative of design survey deliverables and may vary depending on the requirements of the individual District.