Structural response of RC wide beams under low-rate and impact loading

摘要

This paper summarises the test data obtained from an experimental investigation of reinforced concrete (RC) wide beams, which can also be described as one-way slabs, under low-rate (static) and high-rate (impact) concentrated loading applied at their mid-span. The aim of the work was to investigate key aspects of structural response such as the load-deformation behaviour, crack patterns, strength and failure modes of these basic structural elements under varying levels of loading rate. Three 125 mm thick specimens were studied and they measured 1800 mm long and 360 mm wide. They were simply supported at a span of 1600 mm. One specimen was tested under static loading, and the other two were subjected to impact loading using a drop weight. For both load rates investigated, measurements included strains, deflections and support reactions. Additional measurements for the impact test included accelerations and the use of a high-speed, high-resolution video camera to record the whole test. Digital photography was also used for the low-rate test. The use of digital photography and video recording has proved to be a valuable source of data to validate the readings of the more conventional instrumentation and also to give insight into transient features of the impact test such as crack patterns, particularly those which opened and closed during the test. The comparison between the low-rate and impact behaviour has helped further the understanding of the structural response of RC structures under varying rates of loading.