GFRP SEISMIC STRENGTHENING AND STRUCTURAL HEALTHMONITORING OF PORTAGE CREEK BRIDGE CONCRETE COLUMNS

摘要

Located in Victoria, BC, Canada, the Portage Creek Bridge is a 125m long, three-span structure with areinforced concrete deck supported on two reinforced concrete piers, and abutments on H piles. Thebridge was designed prior to the introduction of current bridge seismic design codes and constructionpractices. Therefore, it was not designed to resist the earthquake forces that are required by today'sstandards. The bridge is on a route classified as a Municipal Disaster Route scheduled to be retrofitted toprevent collapse during a design seismic event, with a return period of 475 years.Conventional materials and methods were used to retrofit most of the bridge. The dynamic analysis of thebridge predicted the two tall columns of Pier No. 1 will form plastic hinges under an earthquake resultingin additional shear to the short columns of Pier No. 2. A non-linear static pushover analysis indicated thatthe short columns will not be able to form plastic hinges prior to failure in shear. The innovative solutionof Fibre Reinforced Polymer Wraps (FRPs) was chosen to strengthen the short columns for shear withoutincreasing the moment capacity.The FRP Wraps and the bridge were instrumented as one of 36 demonstration projects across Canadasponsored by ISIS Canada to assess the performance of FRP and the use of FOS (Fibre Optic Sensors) forstructural health monitoring (SHM). The two columns of the bridge pier were strengthened with GFRP(Glass Fiber Reinforced Polymer) wraps with eight bi-directional rosette type strain gauges and four longgauge fibre optic sensors attached to the outer layer of the wraps. In addition, two 3-D Crossbowaccelerometers are installed on the pier cap above the columns and a traffic web-cam mounted above thedeck at the pier location.