Experimental Study of Increasing Earth Pressure on Integral Bridges Subjected to Reciprocal Loads

Integral bridges can eliminate economic and structural weaknesses by integrating reinforced concrete abutments and girders. However, owing to thermal expansion and compression of the girders under changing atmospheric temperatures, a bridge can be damaged from increased backfill earth pressure resulting from repeated horizontal displacement of abutments. Therefore, the thermal expansion and compression of bridge girders must be considered when designing integral bridges. Climate change associated with global warming may result in extreme temperature changes. Thus, bridge girders may have a higher thermal expansion and contraction compared to those in previous design assumptions. Therefore, we investigated the possibility of quantitatively evaluating the increasing earth pressure caused by the thermal expansion and contraction of bridge girders. This study entailed simulations of the repeated horizontal displacements of the bridge abutments using an aluminum bar laminate model. We obtained the results of 100 cyclic loading tests, which showed that the maximum value of the earth pressure at the end of the cyclic loading is minimally affected by the position of the amplitude center, and it can be predicted from the load–displacement relationship for non-repeated loading. Therefore, based on the results of the non-repeated load tests, the maximum value of the earth pressure resulting from repeated horizontal displacement of abutment can potentially be incorporated into the design of integral bridges.