Research On Bond-slip Behavior Between Shape Steel And Concrete In SRC Structures Under And After High Temperature

Based on the SRC push-out tests under and after high temperature, both the strength and theaverage bond-slip behavior, were analyzed and studied. The relationship between the bond strengthand the highest temperature or the highest temperature after natural cooling, which the specimenexperienced, was determined. According to the experimental results, a set of bond strengthcalculation formulae which considering temperature, and the bond-slip constitutive relations wereestablished. Finally, the experimental results provided conditions for the numerical simulationabout the SRC which not considered the bond-slip constitutive relations under and after hightemperature. The results could provide the conditions for the fire resistance of steel reinforcedconcrete study.Firstly, the former studies, including the bond-slip behavior in the RC and SRC, wereanalyzed, and then push-out test was determined to be used. Furthermore, a new type of fireheating furnace was manufactured, by which the temperature could be maintained at a constanttemperature for a long time.18standard push-out test specimens for under high temperature,18standard push-out testspecimens for after high temperature and3comparison specimens at room temperature weredesigned to study the influence of bond strength and the bond-slip constitutive relation. The fourmain factors, including the highest heating temperature, time maintained at the highest temperature,steel shape embedment length, and concrete cover thickness, were considered. Through thedisplacement sensor located in the loading position, the load-end slip could be measured well.In order to analyze the mechanism of bond-slip in the SRC, the whole test process wasobserved and recorded in detail. According to the test results, the bond-slip curves and theircorresponding characteristics were analyzed fully. By analyzing the bond-slip curves, twocharacteristic bond strength, including the maximum bond strength the residual bond strength, andtwo corresponding characteristic slip values were summed up to analyze the bond-slip constitutiverelation. Through the analysis of the relationship between the highest heating temperature and timemaintained at the highest temperature and the average maximum bond strength, the averageresidual bond strength, as well as their corresponding characteristic slip values, a series ofcalculation formula was derived. These formulas included the average maximum bond strength,the average residual bond strength, and their corresponding characteristic slip values. Ultimately,the curve expression on the bond-slip constitutive relations under and after high temperature in theSRC was put forward.