Tensile Reinforcement Effects on Bridge‐Approach Settlement

It had been reported, through observation of actual field installations, that the inclusion of tensile reinforcement in the approach fill behind bridge abutments can effectively reduce approach fill settlement, and hence reduce the “bump” that may otherwise be experienced at both ends of the bridge. This study was undertaken to investigate, by the finite element method, the effectiveness of placing both tensile‐reinforcement sheets in the approach fill, and a “collapsible” inclusion between the reinforced fill and abutment in reducing bridge‐approach settlement. Confidence in the finite element analysis procedure was gained by comparing analytical results with the measured response of two controlled full‐scale bridge‐approach settlement tests; one with a geogrid reinforcement and the other without any reinforcement. Two parametric studies were then conducted. The first study examined the mechanism of tensile reinforcement for alleviating bridge‐approach settlement under different backfill, foundation, and reinforcement conditions. The second study examined the effectiveness of using both tensile reinforcement and a collapsible inclusion to reduce approach‐fill settlement, under different reinforcement stiffnesses and surcharge pressures. The results of the two studies are discussed.