08.23: Performance and design of shear‐keys in hybid RC beam and steel column systems

Abstract

This study describes experimental and numerical investigations into the inelastic performance of hybrid structural configurations consisting of reinforced concrete (RC) beams connected to steel columns by means of fully-embedded structural steel profiles (shear-keys). Experimental observations from a series of fourteen full-scale hybrid steel/RC specimens are presented. To provide further insights into the key response characteristics, detailed numerical analyses for the tested configurations are also carried out. The numerical studies are undertaken using nonlinear finite element procedures which are validated against the experimental results from the hybrid tests presented in this paper. The ability of the numerical models to provide faithful predictions, using a consistent set of material parameters, provides a high level of confidence in the reliability of the simulation techniques. Data from the numerical models are then sutilised to evaluate the shear-force distribution along the length of the shear-key. The contribution from the shear-key to the overall vertical force transferred to the column is comparatively assessed amongst the various configurations presented. For more simplified design considerations, an idealised distribution of the effective shear forces along the shear-key is also proposed in the current study. Bases on the findings, recommendations for the practical design of shear-keys in hybrid specimens are suggested and discussed.

Behaviour and design of hybrid RC beam-to-steel column connections

“…For all the material and geometrical characteristics examined in the experiments, the embedded shearkey was of sufficient strength, with no local failures in the steel insert taking place at ultimate. To better understand the shear force distribution and reactions at the shear-key, parametric investigations showed that for flexural reinforcement ratios (e.g ρl=0.3%), the shear-key takes a higher amount of force than in the case of relatively high reinforcement ratios (ρl=1.1-1.9%) [26,56]. In the former case, about 80% of the total force is transferred by the shear-key, whilst it varies in the second but can be as low as 40%.…”

Nonlinear numerical simulation of punching shear behavior of reinforced concrete flat slabs with shear-heads

“…To avoid previously mentioned mesh-dependency problems the crack band model with constant facture energy in which the tensile response is a function of the characteristic element length, may be considered. Models employing such approaches were able to predict the ultimate strength and deformational response of plain and reinforced concrete members (e.g., localized behavior under direct shear and tension [58,59], assessment of a long-term behavior [60], RC flat slabs with and without shear reinforcement under static loading [61][62][63], RC hybrid beams in shear and flexure [64][65][66][67]). However, detailed numerical studies on flat slabs with shear-heads are relatively limited and have typically focused on hybrid connections between steel columns and RC floors.…”