STRENGTHENING OF OFF-SYSTEM BRIDGES USING FRP COMPOSITES

ABSTRACT

A significant number of Bridges in the United Stated and all over the world need rehabilitation and strengthening. Due to budget constraints, many authorities are forced not to proceed with strengthening but to post load restrictions on their bridges as a temporary measure. Fiber reinforced polymers (FRP) provides an economical and practical solution for repair/strengthening of highway bridges. Three off-system bridges in Missouri that were constructed in the 1970’s had a constant increase in the traffic volume and the use of heavier trucks. Analysis of these bridges indicated that they are deficient in shear and flexure and demanded an upgrade to withstand the current (HS20) truck loading. Using FRP composites, an economical upgrade solution was achieved due to the speed and ease of their installation that involved minimum labor and traffic interruption. Load tests were conducted on two of these bridges before and after strengthening to evaluate their performance. This paper reports on the strengthening techniques, design approach, and testing of the bridges.