Elastic behaviour of the steel part of a shear connection with MCL composite dowels

Abstract

Originally, the idea for determining the elastic resistance of a steel dowel based on the stress layout was described by Lorenc in [5]. A stress plot at the dowel root is the result of the superimposition of two effects; one of them is the result of global internal forces acting on a beam, i.e. global bending moment and/or axial force, and the second is an effect of local longitudinal shearing forces. The first effect, the global one, results in normal stresses at a dowel root which are increased by the effect of the geometrical notch. The second effect, the local one, results in a stress plot in and around the steel dowel caused by contact pressure at the steel-concrete interface (the steel dowel is then bent and sheared). For SLS, reduced stresses are considered, and for FLS, the first principal stresses. The first analyses were based on test results and numerical investigations, both for the PZ composite dowel shape. The analytical approach was omitted, the reason being the complexity of the problem, because of dowel geometry and, mainly, steel-concrete contact effects. Mathematical equations were adopted to describe variable stress values along the edge of the steel dowel as a function of the distance measured from its root. This approach led to two equations being derived, one describing the stress state in the dowel depending on a global stress value in a beam (M + N) at the level of the dowel root and the distance from dowel root to point considered, and a second one describing the stress state in the dowel depending on a longitudinal shear force value and the distance from dowel root to point considered. Adding these two equations linearly produces the stress state along the dowel edge. Appropriate mathematical operations made it possible to find the maximum stress as a function of the internal forces (M, N, VL) and, furthermore, to create a dimensionless envelope of connector resistance, already including stress concentration factors. Knowing the normal stress value at the point of the dowel root (without taking into account a notch concentration factor) and the value of the longitudinal shearing force, it is possible to check whether the maximum stresses in the dowel considered exceed a permissible stress value, e.g. yield strength of steel. The envelope presented in Fig. 1 was initially calculated only for the case of global normal stresses having the same sign as the maximum stresses re-

Steel failure mode of composite dowel shear connector with rectangular regular cutoff

“…The resultant force on each dowel is represented in terms of force F, which corresponds to the maximum force applied per dowel according to numerical simulation (qcn,Num) for X model. Kożuch and Rowiński [34] and Lechner [16] show in their works images similar to Fig. 13, where the position of the force F and the direction of the cracks in the steel dowels are highlighted for clothoidal connectors.…”

“…3 STUDY OF STRESS DISTRIBUTION FROM NUMERICAL ANALYSIS Kozuch and Lorenc [15] argue that the steel dowel behavior model presented by Feldman et al [31] does not fully represent the steel-concrete interaction in the composite connection, especially for the analysis of the steel failure strength. According to the analysis model proposed by Feldman et al [31] the failure in the steel dowel occurs following a horizontal plane that represents the critical section, but Kozuch and Lorenc [15], Lechner [16], Rowinski [33] and Kożuch and Rowiński [34] demonstrate in their works through experimental and numerical studies that failure in steel dowel does not occur in a horizontal plane. Furthermore, for Kozuch and Lorenc [15] the uniformly distributed loading along the steel dowel height is a simplification that does not correspond to the real situation, in the same way as the rectangular distribution of normal and shear stresses in the critical section (Fig.…”

Experimental study on the bearing capacity of PZ shape composite dowel shear connectors with elliptical holes

“…However, PZ shape composite dowel shear connectors are mainly used in prefabricated composite beams in some European countries 21 – 26 , and these research studies are also based on composite beams. The related research and practical applications of corrugated steel–concrete composite bridge decks have not well-documented.…”

The evolution of the shape of composite dowels

“…This shear connection is currently being proceeded to obtain European Technical Specification (consistent with rules of Eurocode 4), and appropriate rules have been proposed by the project team SC4.T1 [52], and for purposes of this work, a list of papers considered as "background documents" for the design procedure of composite dowels are investigated and referenced. The list contains publications that include design guides [8,16,23], practical applications (bridges) [2,18,[36][37][38][39][40][41][42], and research [5,6,7,9,13,14,17,20,21,22,[24][25][26][27][28][29][30][31][32][33][34][35]. One can compare this list, which was compiled from the point of view of the author from Poland, with the papers being referenced in German publications [3] to obtain a wide and objective point of view (the first bridges were designed in these two countries as a cooperation between the first two co-authors).…”