Ayres Knowledge Center Scour Evaluation: Bridges with Unknown Foundations
SCOUR EVALUATION FOR BRIDGES WITH UNKNOWN FOUNDATIONS
Each of the hundreds of bridges evaluated by the team went through different phases of
evaluation. Evaluation was terminated when a bridge was deemed low risk or stable;
otherwise subsequent phases of evaluation were conducted, culminating in a Plan of Action for
bridges deemed scour critical. Plans of action varied from monitoring using fixed or portable
instruments to installation of scour countermeasures.
The example below is picked up after the bridge went through a Phase 1 field review. The
bridge, Main Street Over Halifax River, Bridge No. 794004, had unknown pile tip elevations due
to missing historic records. The bridge went through a Phase 2 Hydraulic/ Scour Analysis using
complex Tidal regime modeling, followed by Parallel Seismic Non‐destructive Testing to
determine pile tip elevations, and a Structural and Geotechnical Evaluation using a three‐
dimensional finite element program.
The reports with appendixes can run hundreds of pages and we have redacted them for the
purposes of this submittal. Evaluations were carried out for all the bridges in District 5 as listed
in the “Bridges with Unknown Foundation Evaluation Status Report”. Similar effort was carried
out by the team in other FDOT districts as well.
SUPPLEMENTARY REPORT CONTENTS
Scour Evaluation Reports for Bridge #794004, Main Street Over Halifax River:
Redacted Phase 2 Report Summary of Hydraulic/ Scour Analysis SR‐2
Redacted Report of Non‐destructive testing to Determine Pile Tip Elevation SR‐25
Phase 3 Structural and Geotechnical Analysis SR‐32