STRENGTHENING MASONRY ARCH BRIDGES THROUGH BACKFILL REPLACEMENT BY CONCRETE

In the presented case history, a radical method is proposed to strengthen a two span masonry arch bridge, where considerable differential settlement of the central pier had extensively fractured the arch body. The adopted remedy consisted of replacing the existing backfill by a reinforced concrete slab taking up most of the loads and an underlying multi-layered ordinary concrete mass, or cement-bound graded aggregates, filling in the remaining space. While keeping the architectural aspect and value of the bridge almost intact, the proposed technique relieves the loading on the often fragile old masonry arches and eliminates horizontal thrusts and pressures on piers, abutments and spandrel walls. (A) For the covering abstract, see IRRD E100543.