Study On Failure Mechanism Of Exterior Beam-column-slab Joints Of Reinforced Concrete Frame Structures

Jionts in the core area of the frame structure destroyed a huge impact on the seismicperformance of existing multi-jionts does not consider the impact of research on the seismicbehavior of slab, floor slab experimental studies have shown that even change willsignificantly affect the failure mode of the frame jionts. Specification jionts using shearcapacity is calculated based on semi-empirical formula of a large number of experimentaldata, the lack of a theoretical basis and did not consider the role of floor slab, so that thereare significant security risks earthquake effect next jionts area. For the above, thecompletion of the experimental study on four reinforced concrete frame jionts to test therole of reinforced concrete frame joints under earthquake force performance study onreinforced concrete frame beam-column-slab failure mechanism slab exterior jionts.In this paper, three reinforced concrete frame with side panels and comparativeanalysis of the jiont without board exterior jionts from the bearing capacity, the boardlongitudinal reinforcement, shear and deformation jionts, stirrup reinforcement ratio andcolumn section dimensions and other aspects of strip study on seismic performance exteriorjionts. Select OPENSEES finite element program to establish a fiber element model andnumerical simulation analysis. The main draw the following conclusions.(1)through the band plate and the test piece without EBCSJ-1plate specimen EBCJ-1Comparative analysis can be obtained, the other conditions are the same, the jionts plateshear stress of the specimen with a positive (pushing damage jionts)0.87, minus1.25, withno plate specimen jionts shear stress is positive (push)1.05, minus0.91, which indicatesthe presence of board increased the incoming jionts negative shear.(2)On the slab with a core area of the jionts in the specimen stirrup ratio EBCSJ-1,EBCSJ-2was0.45%, EBCSJ-3was0.72%, cross-sectional dimensions EBCSJ-1, EBCSJ-2is250×250(mm), EBCSJ-3is280×280(mm), the specimen damage EBCSJ-1, cornerEBCSJ-2was3.0%, corner EBCSJ-3was4.0percent, energy consumption increased from13.64kN mm to24.48kN mm, joint core rate increased corner stirrup increased by1%,energy consumption increased by80%, which indicates that with reinforced concrete framewith slab exterior jiont column longitudinal reinforcement stirrup ratio increased energy component increased ductility changed for the better.(3)Slab reinforcement forces participating jionts, most structures along the lateral(perpendicular to the beam direction), midline beams from near to far, Slab strain fromabout600or so approaching50, as the uneven distribution of strain Slab cause the torqueexists, the last slab torsion damage.(4)Based on a reinforced concrete frame joints "diagonal strut mechanism""trussmechanism,""binding mechanism" three main mechanism of the force beam-column-slabexterior jionts failure mechanism analysis; finally come Beam-Column-slab exterior failuremechanism jionts is considered "diagonal strut mechanism" slab influence coefficients.