Improvement of shear capacity of composite structures

Many kinds of Arctic structures have been built during the past two decades to exploit the resources of the ice-infested waters of the Arctic region. The exterior walls of such offshore structures must be designed to resist the high external loads exerted by the moving ice floes and icebergs. Such structures, in addition to being economical, should be designed to possess a high degree of safety, durability and stability. Sandwich-type steel-concrete composite structures are a new concept designed to resist high external loads. The composite walls are found to be effective in transmitting large lateral forces due to ice or earth pressure to support bulkheads (Adams et al., 1988). The basic composite system consists of two thin continuous steel plates, placed concentrically with a filler material such as concrete between them. The other interesting types of steel-concrete composite structures are the double- skin sandwich structures, in which the two steel face plates are connected by studs with a concrete core between the steel plates. This paper presents the load-deformation behaviour of steel concrete composite members and their shear load-carrying capacity under static and cyclic loads. The new parameters included in this second test programme are steel fibre reinforcements, bar reinforcements, thin high-strength steel face plates and stainless steel face plates. The ultimate shear capacities of beam specimens are compared with the calculated values using empirical and upper- bound plasticity methods developed by the Centre for Frontier Engineering Research (C-FER). The test results presented in this paper are from the second phase of the experimental programme on composite members. The specimens in the first phase were all made from normal steel and ordinary concrete without adding any reinforcing materials, and were similar to specimen VTT-05 of the second phase of the test programme.