I-90 to I-5 Ramp – Seattle, WA
Highway Ramp Formwork Collapse Study
During the construction phase of the seismic upgrades to the ramp connecting I-90 westbound to I-5 southbound, a partial failure of the concrete formwork occurred. We were retained by Zurich North America to determine the cause of the formwork failure and to review the repair recommendations provided by WSDOT. Our investigation indicated that two of the anchors installed in the existing concrete to retain the lower form ties failed (pulled out) allowing concrete to spill from the forms. Based upon our review, we determined that the anchors were improperly installed.