Study on mechanical performance of old-to-new concrete connecting joints in renovation of existing and new metro stations
To further clarify the mechanical performance of the old-to-new concrete connecting joints used to link old and new structures during renovation,six old-to-new concrete connecting joint specimens were designed and their bending and shear-bending performance were tested.The effects of different post-installed rebar arrangement schemes and bending-shear conditions on the deformation performance,load-bearing capacity,cracking behavior and failure modes of the joints were analyzed.Based on the full-process mechanical behavior of the joints,the load-bearing mechanism of the joints was revealed and a method for calculating the load-bearing capacity of the joints under both bending and bending-shear coupled conditions was proposed.The results show that the old-to-new concrete connecting joints,primarily connected by embedded post-installed and reserved rebars in the existing structures,exhibit good integrated performance.Under both bending and bending-shear coupled conditions,the failure location of the joints is the preserved wall section in the existing structure.The bearing capacity of the joints is mainly provided by the tension and dowel action of the planted rebars in concert with the concrete in the compression zone.The proposed method for calculating the load-bearing capacity of the old-to-new concrete connecting joints,can be used to predict the joint load-bearing capacity under both bending and bending-shear coupled conditions.Under the premise of meeting the requirements of design codes,larger diameter post-installed rebars are recommended to reduce the number of rebars required.
metro stationrenovationold-to-new concrete connecting jointpost-installed rebarshear span ratiomechanical performance
NETL
NSTL
万方数据
