The effect of the overlying fill on stresses in a new arch bridge

Kimbolton Butts Bridge is an 8m single span brickwork arch bridge which was constructed in 1992 in Kimbolton, Cambridgeshire. Instrumentation of the structure was undertaken to assess the distribution of stresses in the fill and on the extrados, the strain and deflection of the arch barrel and the temperature in the fill. A series of load tests funded by the Highways Agency of UK, was carried out soon after construction, in which axle loads of up to 30 tonnes were applied at Im intervals along the length of the bridge. Following this, the University of Edinburgh is carrying out long term monitoring of the structure in an attempt to quantify the effect of both temperature and seasonal variation on both the stresses and strains in the fill. This paper initially describes the specification and installation of the instrumentation in the bridge, followed by an account of the selection of the long term data acquisition equipment and its subsequent installation. Results are presented from the load tests and compared to a finite element analysis of the structure. Finally, an example is given on the analysis of some of the preliminary results obtained from the long term monitoring, which shows the variation in stress with that of the air, soil and arch extrados temperatures.