COMPUTER MODELLING OF THE CONSTRUCTION AND LOAD TESTING OF A MASONRY ARCH BRIDGE

Cambridgeshire County Council, England found it necessary to replace the previous Kimbolton Butts Bridge by a new masonry arch bridge in 1992. It decided that the new bridge would be an ideal test site to examine the behaviour of masonry arch bridges under increased loading. It is hoped that monitoring and research will contribute to a design guide which gives more confidence in the design of masonry arch bridges. The bridge has a brick arch barrel, with spandrel walls and reinforced brick parapets on concrete pad foundations. The Transport Research Laboratory (TRL) conducted a load test on it. The CRISP finite element analysis program was used to develop a finite element model of the bridge with the loading of a specific heavy vehicle. Reasonably good agreement was obtained between the finite element analysis and some of the data obtained from the load test. Comparisons with other finite element models suggests that numerical modelling of brick arches requires: (1) careful measurement of material parameters, especially stiffness; (2) parametric studies which investigate the sensitivity of the analysis results to specific input parameters; and (3) more comparisons with instrumented arches subject to field load tests.