Numerical and experimental investigation of the behavior of extended end-plate connections in steel structures

Abstract

It is well known that one of the most popular methods of connecting members in structural steel work is the bolted end-plate connection. Bolted end-plates are simple in their use and construction. But they are extremely complex in term of analysis and behavior since the connection behavior significantly affects the structural frame response and therefore it has to be included to the global analysis and the design of frame. The present paper deals with the structural behavior of full-scale stiffened and un-stiffened cantilever connections of typical I sections. The connection between the extended end-plate to the column flange is achieved by means of high strength bolts in each case. In order to obtain experimentally the actual tension force induced within each bolt, strain gauges were installed inside each one of the top bolts. Thus, the connection behavior is characterized by the tension force in the bolt, the extended end-plate behavior, the moment-rotation relation and the beam and column strains. Thereby, it is important to predict the global behavior of column-beam connections by means of their geometrical and mechanical properties. The experimental test results are compared to those obtained by means of a numerical approach based on the finite element method and is coupled to the theory of non-smooth mechanics. All the arising non-linearities in the connection are described through a non-monotone multi-valued reaction-displacement law. Thus, the problem is formulated as a hemivariational inequality leading to a sub-stationarity problem of the potential or the complementary energy of the connection. This simulation problem is solved by applying a non-convex non-smooth optimization algorithm. The comparison of the results of the experimental testing program with the numerical simulation proves the effectiveness of the proposed numerical method.