EVALUATION OF EFFECTIVE WIDTH AND DISTRIBUTION FACTORS FOR GFRP BRIDGE DECKS SUPPORTED ON STEEL GIRDERS

摘要

Glass fiber reinforced polymer (GFRP) bridge deck systems offer an attractive alternative to concrete decks, particularly for bridge rehabilitation projects. Current design practice treats GFRP deck systems in a manner similar to concrete decks. The results of this study, however, indicate that this may result in non-conservative design values for the bridge girders. Results from a number of in situ load tests of three steel girder bridges having the same (GFRP) deck system are used to determine the degree of composite action that may be developed and the transverse distribution of wheel loads that may be assumed for such structures. Results indicate that appropriately conservative design values may be found by assuming no composite action between GFRP deck and steel girder and using the lever rule to determine transverse load distribution. When used to replace an existing concrete deck, the lighter GFRP deck will result in lower total loads applied to the bridge structure, although, due to the decreased effective width and increased distribution factors, local flange stresses and particularly the live load-induced stress range is likely to be increased. Thus, existing fatigue-prone details may become a concern and require attention in design.