Chapter 7: Construction Surveying

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Section 1: Survey Checks

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Overview

It is not the intent of the Standing Committee on Surveying (SCOS) to develop a strict guideline of policy and procedures for project engineers, project managers, and construction inspectors to follow in the area of construction surveying. The SCOS is confident that each project (through the area engineer’s office) within each of the 25 districts is being thoroughly managed and the committee does not intend to interfere.

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Surveying Suggestions

The SCOS would like to offer a few suggestions that may aid a project manager/inspector in the management of his/her project, from a surveying perspective.

  • The horizontal and vertical control for ANY project should be established by TxDOT surveying personnel or consulting surveying contracts within an individual district. The surveyors working for the subsequent construction contractor should be required to utilize that control to establish his/her own baselines/secondary control for the particular project.
  • Periodic spot-checks of the contractor’s completed surveying should be maintained. This should be accomplished by TxDOT surveyors or by an independent existing consulting surveyor under contract with TxDOT in that particular area within the district. These spot-checks are an excellent method of checking the contractor’s work and alleviating undue pressure on the project manager/inspector.

The following checklist contains suggested checks to be utilized by the project manager to review a contractor’s work:

Anchor: #i999625Table 7.1 Checklist

Item

Minimum Frequency

Remarks

Bench Marks

All

Includes all BMs and TBMs set by contractor.

Culverts & Storm Sewers

 

 

Flow Lines

50%

Both U.S. and D.S. flow lines should be checked. This check should include two of the first three lines the contractor places. There should also be intermediate checks on long structures.

Alignment

25%

This includes station location and placement angle.

Inlets & Manholes

 

 

Grade

25%

This includes checking calculations at each end of curb inlet to assure proper alignment with curb. Top grades and flow lines of manholes and drop inlets should be checked.

Location

25%

Includes station and offset.

Bridges

 

 

Alignment

100%

Check Contractor’s control points.

Deck Grades

50%

At least ½ of the bridge overhangs should be checked at 50 ft. intervals.

Drilled Shafts and Piling

100%

Check distance between shafts or piling.

Columns

100%

Check plumb before placing concrete.

Caps (Bearing Seats)

50%

Check for location and elevation prior to placing concrete.

Caps (Dowel Bars)

100%

Visually check location and projection.

Roadway

 

 

Grade

10%

Independent check of blue tops on all sub-grade and base courses.

Width

1 per 2000’

Includes sub-grade, base course, and finished roadway

Retaining Walls

 

 

Height

1 per section

The first footing and wall the contractor forms should be checked.

Footing Elevations

1 per wall

 



Notes:

  • In all cases, a record should be made of the survey checks and the corrections made. A daily report form may be used.
  • If the contractor demonstrates a propensity for erroneous surveying, the frequency of checks should be inversely proportionate to the quality of the contractor’s work product so far.
  • Checks by state personnel are not intended to relieve the contractor of his/her responsibility for accuracy. All survey checks should be random and independent.
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