tailieunhanh - A 6DOF super element for nonlinear analysis of composite frames with partial interaction and semi-rigid connections

This paper presents a displacement - based finite element formulation for nonlinear analysis of steel - concrete composite planar frames subjected to combined action of gravity and lateral loads. A 6DOF super element is proposed for modelling composite beam, allowing for partial interaction between the steel beam and the concrete slab, semi - rigid nature of beam to column composite connection and material nonlinearity. | Vietnam Journal of Mechanics, VAST, Vol. 33, No. 1 (2011), pp. 13 – 26 A 6DOF SUPER ELEMENT FOR NONLINEAR ANALYSIS OF COMPOSITE FRAMES WITH PARTIAL INTERACTION AND SEMI-RIGID CONNECTIONS Le Luong Bao Nghi, Bui Cong Thanh University of Technology, VNU-HCMC Abstract. This paper presents a displacement - based finite element formulation for nonlinear analysis of steel - concrete composite planar frames subjected to combined action of gravity and lateral loads. A 6DOF super element is proposed for modelling composite beam, allowing for partial interaction between the steel beam and the concrete slab, semi - rigid nature of beam to column composite connection and material nonlinearity. The load control method and the displacement control method are utilized for tracing the structural equilibrium paths, and the direct method is utilized for solving the nonlinear problem. Numerical examples, concerning a two-span continuous composite beam, a portal composite frame and a six - storey composite frame, are performed. The results are compared with experience data or theoretical results from other studies and are discussed for influences of the factors mentioned above on behaviour of composite beams and composite frames. Key words: Super finite element, composite constructions, partial interaction, semi rigid composite connections, nonlinear analysis. 1. INTRODUCTION Steel - concrete composite constructions have been widely used in buildings as well as bridges thanks to their ability to combine the advantages of both steel and concrete. Therefore, the research into this type of construction to find out an efficient, robust and accurate method for analysis of this type has always been necessary. The relative longitudinal slip between the concrete slab and steel joist due to the deformability of the shear connectors is referred to as the partial interaction (PI) in composite beams. This nature has a significant influence on the behaviour of the composite beams and the .