Experimental Study On Mechanical Behaviors Of Planted Reinforcement Of Column Underpinning Joints

Existing building shift technical difficulty, comprehensive, along with the practical application and experimental study of a large number of practical engineering, underpinning technique as shift technique is one of the most important, it directly affects the stability and the safety of the structure in the shift process, obtained the very good development in practice, but still need to be further the perfection of the underpinning technology to meet the shift transformation project of increasing complexity and functional diversity.The present stage of our country overall mobile buildings, frame structure accounted for a large proportion of. With the increase of mobile homes number and spacing, frame column under vertical load increasing, the underpinning design also increased the difficulty of. In both the shift transformation engineering framework structure, there will be inevitable combination of new and old concrete surface, the actual engineering is often used to improve underpinning beam height, smear method interface agent, interface, and chiseling groove, combined with the arrangement of reinforcing to enhance the shear performance of the joint surface. In this paper, reinforcing this method in combination with surface arrangement, explore the reinforcing arrangement on the characteristics and impact force underpinning node.The experimental design of10groups of frame column underpin1:2scale model for node, considering the shear span ratio is the influence on decision factors for the bearing capacity of one of the two, the design of shear span ratio level, each of the5different reinforcing parameter level test; test, carried out the experimental phenomenon and crack record the whole test the acquisition process, reinforced, concrete strain, record the walking beam, beam deflection and beam column combined with the relative displacement.In this paper, through the experimental study on static underpinned joint10groups of columns, analysis of experimental results on10specimens and data, the layout can not inserted reinforcement improved support for the bearing capacity of the whole node, shear span ratio factor is still the main factors for the influence on the load-carrying capacity of the one; through the same shear span ratio levels on5specimens of phenomena and data were analyzed and compared some literature, the inserting tendon arrangement can be similar to that of "hoop" role, so that the combination of new and old concrete surface bonding firm, enhan-ced the underpinning node integrity, effectively reduce the beam-column combination of surface crack width; failure node the shear failure, change control section node layout inserted reinforcement, the original binding face control shear is insufficient, into the cantilever beam ends of the underpinning beam; finally, through the review of theoretical formula and the experimental results, good agreement, provide the basis for the practical engineering.