Anchorage Port Access Bridge

Anchorage Port Access Bridge seismic assessment: experimental work and FEM modeling of steel connections

As part of my Ph.D. studies, me and the research team performed a project for the Alaska Department of Transportation (AKDOT&PW), that consisted in the seismic assessment of the Anchorage Port Access Bridge. This project pursued the following objectives:

  • Determine the main mode of failure of the cap beam to column connections

  • Establish the maximum ductility capacity for each of the connections

  • Propose the retrofitting objectives and possible retrofitting techniques

  • Determine the locations at which the retrofits are needed.

The Anchorage Port Access Bridge

Large Scale Testing

Two large scale tests were performed on a knee joint test set up as shown in below. The force displacement for two different test set up showed different behavior for large diameter to thickness ratio (D/t) the behavior of the connection was ductile however for low D/t the behavior was brittle.

Force Displacement Response of D/t=80

Force Displacement Response of D/t=44

Knee joint tes set up

FEM Modeling

In addition FEM modeling was used for columns D/t that are present in the bridge but were not tested in the laboratory. The results shown below helped establish the retrofitting technique for each of the D/t present in the bridge

Force Displacement Response of D/t=69

Force Displacement Response of D/t=96

Finite element modeling of connection

Outcomes of phase 1

The results of this project provided the Alaska DOT with information of the current seismic performance of the Anchorage Port Access Bridge, establish the need for a retrofit and set the objectives of the retrofitting techniques.

Phase 2

Site information

A visit to the Anchorage Port Access Bridge was performed. Several piers along the bridge were investigated to obtain information that was not present in the as built drawings. In addition, the connections were analyzed for any sign of deformations or damages to the area of interest. The data collected will be used in the update of the global modeling of the bridge, and considered in the proposal of the final retrofit.