Firstly, the method of influence coefficients is applied to the analysis of any number of parallel arches, identical in their centre lines and having any number of transversals connected across them, with normal and tangential reactions occurring at each intersection. Next, it is proved that any loaded, symmetrical arch can be replaced by an equivalent straight beam with a certain modified loading. It is then explained how an interconnected encastré arch system can be solved by using this theory together with a quasi-slab analysis or by the ‘continuous-strip transversals’ method. Finally, results from this approach (most of which is already familiar to beam and slab bridge designers) are compared with those from influence coefficients and from experiments on a model arch system.
E. Lightfoot and V.K. Datta