<p>This paper aims to investigate a precast concrete beam-to-column rigid connection under constant axial and reverse cyclic loads using mechanical reinforced couplers (MRCs) as well as propose a new MRC arrangement to improve the ductility and energy absorption of the connectors. Some advantages of using the MRCs are adequate space between reinforcements to have a proper bond with concrete, reduction in steel reinforcement, considerable reduction in congestion of reinforcements, ease of assembly, and increased construction speed. Seven half-scale concrete frame connections were constructed with different arrangements and locations of MRCs, and subjected to a given cyclic displacement simulating seismic load. One connection was cast monolithically using continuous overlapping reinforcement, and the rest were precast with MRC reinforcement. The finite element method (FEM) was utilized for simulating experimental results. For this purpose, the moment carrying capacity, energy dissipation, and ductility of connections were evaluated by analyzing the experimental and numerical results. The difference in failure modes of the monolithic and precast connections was investigated. The crack propagation pattern in the monolithic sample was similar to a smeared crack that started from the column face so that for precast MRC specimens there was a tip crack behind the column face and the smeared cracks shifted away approximately the effective beam depth from the column face. The precast specimen with MRCs closer to the column face showed higher strength about 15% more and ductility about 28% more in comparison to the monolithic and other precast specimens. The maximum normalized energy dissipation was 28% for the PCC2 sample. The numerical simulation predicted the general behavior of the precast connection zone satisfactorily despite disregarding the pinching effect in the cyclic loading.</p>

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Cyclic Behavior of Moment-Resisting Precast Concrete Beam–Column Connection Subjected to Mechanical Reinforced Couplers

  • Hossein Parastesh,
  • Ehsan Mobedi,
  • Reza Ashtarian

摘要

This paper aims to investigate a precast concrete beam-to-column rigid connection under constant axial and reverse cyclic loads using mechanical reinforced couplers (MRCs) as well as propose a new MRC arrangement to improve the ductility and energy absorption of the connectors. Some advantages of using the MRCs are adequate space between reinforcements to have a proper bond with concrete, reduction in steel reinforcement, considerable reduction in congestion of reinforcements, ease of assembly, and increased construction speed. Seven half-scale concrete frame connections were constructed with different arrangements and locations of MRCs, and subjected to a given cyclic displacement simulating seismic load. One connection was cast monolithically using continuous overlapping reinforcement, and the rest were precast with MRC reinforcement. The finite element method (FEM) was utilized for simulating experimental results. For this purpose, the moment carrying capacity, energy dissipation, and ductility of connections were evaluated by analyzing the experimental and numerical results. The difference in failure modes of the monolithic and precast connections was investigated. The crack propagation pattern in the monolithic sample was similar to a smeared crack that started from the column face so that for precast MRC specimens there was a tip crack behind the column face and the smeared cracks shifted away approximately the effective beam depth from the column face. The precast specimen with MRCs closer to the column face showed higher strength about 15% more and ductility about 28% more in comparison to the monolithic and other precast specimens. The maximum normalized energy dissipation was 28% for the PCC2 sample. The numerical simulation predicted the general behavior of the precast connection zone satisfactorily despite disregarding the pinching effect in the cyclic loading.