Survey Issues

Types of Bridge Survey

• Standard Bridge Survey

• Major Bridge Survey – Generally more extensive than std

survey– May require specialized equipment

such as boat and sounder– May require random survey data to

create accurate DEM

Common Misunderstandings

• Thalweg and stream bed only required in vicinity of bridge/culvert and any possible RPW

• Roadway survey needs to extend beyond valley crest. This allows comparison of various cut/fill and bridge height scenarios

• Accuracy can be critical to determining bridge parameters

Survey Issues• Geographic extent of data• Missing data• Density of data• Quality of data• Site conditions during field survey

• Accuracy of data processing/coding• Accuracy of drawings• Timeliness of survey drawings

Check for errors

Critically examine survey:– Look for consistency between

different views– Compare with site visit notes and

photos– Look for evidence of common errors– Assume that errors exist and then

look for evidence to disprove your assumption

Examples