The effects of various parameters in sensitivity analysis of plain concrete beam using rigid body spring model

The Rigid Body Spring Model (RBSM) is an alternative method to Finite Element Model (FEM) to solve continuum problems in civil engineering. The method has three main advantages, i.e., having a smaller local stiffness matrix, the ability to directly simulate cracks, and independent formulation of element types. Although the method has been extensively used in studying the behaviour of concrete structures, specific research on sensitivity analysis of this method has not been done nor published. In this research, sensitivity analysis of plain concrete beam using the model is performed. The parameters to be considered are boundary size, boundary element type, number of elements, crack mesh refinement, number of stages, and the effect of half modelling. Based on the sensitivity analysis, optimum parameters were selected to calibrate the model to three plain concrete samples. The result suggests that modulus elasticity of cylindrical concrete under compressive test is to be reduced around 0.2 times for simulating beam under third point loading.