The cross section of the Shenley Bridge suggests that it is simply a slab-on-girder bridge, even if the slab acts compositely with the three longitudinal girders. However the deck panels, with moderately sized but widely spaced edge stiffeners, span transversely between the girders and longitudinally the main girders act as deck stiffeners even though they are rather large and very widely spaced. [Different proportions of deck thicknesses and stiffeners could give an orthotropic bridge approaching more usual proportions.] The fundamental difference of the Shenley Bridge from the usual orthotropic bridge is that the deck plate is not a single steel plate stiffened with trough stiffeners but a steel Sandwich Plate System (SPS) that is stiff enough by itself, self stiffened if you will, to span many times the span of a single steel plate thus reducing the number of stiffeners markedly. A Sandwich Plate System unit consists of two steel faceplates bonded to an elastomer core. The design of the Shenley Bridge, erected in November 2003, to carry gravity loads, particularly as related to the SPS deck panels is discussed and the results of full scale static load tests are presented and analysed.
