Nonlinear Finite Element Analysis of R.C Beam-Column Joints

Abstract

Understanding behaviour of structural elements subjected to various types of actions is essential for efficient design of structure. For any RCC and steel structures, connections are the most critical elements, because in past major collapse of structures took place because of connection failure. Connections plays a vital role in transferring forces from one element to another element. Therefore, it is very important to understand behaviour of connections in structure. Experiments can be conducted to investigate actual behavior of any structural element. Experimental studies are costly and time consuming. Many times, it is difficult to conduct experiments on full scale test specimen, as handling and testing specimen is quite difficult and requires utmost care. With advances in computa- tional methods and availability of effective computational tools, numerical methods are widely used by the researchers to validate experimental studies. Finite Element (FE) analysis is an effective numerical tool as it is frequently used to overcome experimental limitations in understanding the performance of structures and structural components. In present study, performance of RCC elements, PCC elements and Reinforced Concrete beam column connections are evaluated through Finite Element Analysis(FEA). Modeling and analysis are carried out using FEA based software ABAQUS. Material non linearity are considered by using concrete damage plasticity model to represent the response of concrete under compression and tension. Validation of modeling procedure and analysis results is carried out by considering problems reported in literature. Concrete is modeled using 8 node 3D solid brick elements with reduced integration(C3D8R) and steel rein- forcements are modeled as 2 node 3D truss element (T3D2). Effect of descritization on results is also investigated. Analysis results in terms of deformation, stress and strain, obtained through numerical simulation are compared with that reported in experimental studies. Numerical analysis is performed to predict the load deformation behavior of circular PCC and RCC columns strengthened by Steel Fiber Reinforced Polymer (SFRP) confinement. Plasticity and elasticity models are used for steel reinforcing bars and Steel fiber rein- forced polymers respectively. The finite element analysis results are compared with that of experimental investigation of columns subjected to axial compression, to validate the proposed finite element model. From the FE analysis of PCC and RCC column with and without strengthening for 400 mm, 800 mm and 1200 mm height, the difference between experimental and numerical FE results in terms of ultimate load varies between 2% to 17%. RCC beam column joints under column removal scenario with different type of connections i.e. monolithic joint, dry connections or bolted connections and wet connections are analyzed using finite element software ABAQUS. For validation, results in terms of load v/s de ection obtained from the finite element analysis are compared with that obtained from experimental study. From the comparison of results of finite element analysis and experimental investigation, difference of 5% to 33% is observed in ultimate load and difference of 2% to 63% is observed in maximum de ection.