Numerical analysis of frictional contact effects in push-out tests

Abstract

This paper proposes an accurate and efficient 2D nonlinear finite element model to investigate the mechanical behaviour of the shear connection between prefabricated concrete slab and steel girder in composite bridges. Beside material nonlinear constitutive laws and 4-noded plane elements, frictional contact finite elements are introduced in the model at the steelconcrete interface between the girder flange and the concrete slab, between the studs and the embedding concrete and at the base of the concrete slab. Numerical results are compared against experimental results of push-out tests. The tested specimens comprise 4 or 9 studs per slab. Firstly, it is shown that 2D numerical analysis may be accurately used for simulating the original truly 3D problem: a "layer-equivalence" methodology is proposed. A numerical investigation is then carried out to study the influence of the friction coefficient on the loadslip behaviour of the specimen and the distribution of internal deformations and forces in the specimen. A parametric study and some practical recommendations could follow this numerical approach for a better design of the connection.

A simplified 2D model to study the contact–friction at the interfaces of steel–concrete composite beam-to-beam joint

“…One observes that the shear force F is mostly supported by the bottom stud-rows. Referring to [15], the behavior of this located zone subjected to a shear force is similar to the case of a standard push-out test. One distinguishes 3 parts of the shear force transmitted by the joint: -First part supported by the horizontal stud-rows.…”

“…In previous companion papers [15,16] different configurations of push-out tests have been modeled using the 2D proposed model. For each test, comparisons between obtained numerical results and corresponding experimental results have showed a quite negligible contribution of the out-of-plane effects (along the axis perpendicular to the web surface of the steel section of the push-out specimen) showing the ability of the 2D proposed model to simulate correctly the behavior of composite sub-structure.…”

“…According to the results of the numerical calibration undertaken in [15,16] against experimental results of 20 push-out tests, the following values of friction coefficient have been selected; a value of l 1 = 0.3 between the top flanges of the girders and the slab and at the butt-plates/transverse concrete beam interfaces; a value of l 2 = 0.2 between the headed studs and the concrete. A perfect adherence between the rebars and the concrete of the slab has been considered.…”

“…This was done starting from a series of push-out tests carried out previously at the Laboratory and for which a 2D nonlinear finite element model was developed [15,16]. The push-out specimen was reduced to the reference plane of the steel beam web.…”

Experimental Study and Finite Element Modelling of Push-Out Tests on a New Shear Connector of I-Shape

“…Shear connectors were modelled by horizontal and vertical springs along the steel-concrete interface, and non-linear load-slippage curves representing realistic deformation characteristics were readily incorporated. Recently, Guezouli and Lachal [26] developed a new two-dimensional model to study the effect of steel-concrete contact and friction on the behaviour of stud shear connectors in push-out tests. It has been observed that the previous two-dimensional models with plane stress elements are able to predict satisfactorily the behaviour of the shear connectors both in terms of strength and ductility without any difficulty.…”