Abstract of: Experimental investigation into the effects of membrane action for continuous reinforced glass beam systems

Abstract

In contemporary architecture, glass is more and more applied not only to make up the cladding of the building, but also for structural members such as beams and facade fins. The trend to increase the scale of these structural entities makes it increasingly structurally efficient to apply statically indeterminate beam systems. For these systems to be approved, contemporary building codes require them to provide structural safety on an element and system level. Therefore, a lot of hybrid glass beam concepts, in which glass is combined with another material that provides post-fracture capacity, were developed and investigated. Among others, reinforced glass beams have experimentally proven their feasibility for statically determinate (element safety) and indeterminate (system safety) support conditions by providing significant post-fracture capacity, ductility, plastic hinge formation and load redistribution capacity. However, system safety can also benefit from the effects of membrane action, which can result in yet higher post-fracture performance. Moreover, the latter can make a significant contribution to the robustness of a beam system when an accidental event occurs such as collapse of one of the supports. This paper presents experimental test results of statically indeterminate five-point bending tests with clamping end-supports on twelve 4.3 m long stainless steel reinforced beam specimens in which the horizontal membrane forces are assessed. Two series of tests were performed, with and without intermediate support, for two types of beams with varying reinforcement percentage (i.e. solid and hollow profile reinforcement). During the tests, significant compressive as well as tensile membrane action was observed. The effects of the latter on the loadcarrying behaviour is discussed by comparing the load-deflection diagrams with those of similar reinforced glass beam systems without clamped external supports. From this comparison, it is concluded that membrane action provides significant contribution to the load-carrying behaviour of such beam systems. Significantly higher post-fracture capacities can be achieved for both reinforcement sections and both types of tests. It is concluded that membrane action can be incorporated in design, which will lead to more economical, slender and more transparent reinforced glass beam systems.