The behaviour of puzzle-shaped composite dowels - Part II: Theoretical investigations

Theoretical investigations of an innovative form of shear connection with puzzle-shaped composite dowels PZ300/100 are presented on the basis of the experimental study outlined in the companion paper - Part I: experimental study. Detailed FEM computations in ABAQUS were performed to analyse the behaviour of steel dowels under pressure in the entire loading range until failure. The contact behaviour between the steel and concrete part, the nonlinear material model curve for steel and the linear material model curve for concrete are assumed in the FE model. This virtual model is highly convergent with the experimental results in the entire loading range. The failure mechanism of steel dowels is explained and a standard nonlinear slip-force path for the PZ300/100 (Fig. 2) connector is proposed. A new model of the stress system in steel dowels at the stage of their ultimate limit is proposed. Although the tensile strength of the steel is a major factor influencing the ultimate bearing capacity of the dowel, it is suggested that the design approach based on yield strength is more adequate for steel dowels than the standard approach used for welded studs and based on the ultimate tensile strength. Finally a new connector characterization, consisting of three components: the slip-force dependence, a synthetic mechanical model and the stress system in the critical section of the connector was proposed. All the three components constitute a new approach. (C) 2014 Elsevier Ltd. All rights reserved.