| At present, the mechanical property of ordinary concrete filled steel tubes after firehas been studied by many researchers, but the research on lightweight aggregateconcrete filled steel tube is less, Especially to after stress and fire response and fire ofsteel fiber enhancement lightweight aggregate steel pipe concrete column the researchof mechanical properties is weaker. This shale ceramsite as coarse aggregate, made upinto a certain amount of steel fiber reinforced or expansive agent in lightweightaggregate concrete filled steel tube, formed of two kind of lightweight aggregateconcrete filled steel tube column. And objects carried out a series of study on fireresistance of lightweight aggregate concrete filled steel tube column. Core concrete ofsteel fiber can restrained the development of micro-cracks, improving themechanicalproperties of lightweight aggregate concrete filled steel tube. Lower stiffness oflightweight aggregate concrete expansive agent added can be improved to some extentTherefore, self--stress and mechanical properties of steel fiber reinforced lightweightaggregate concrete filled steel tube research is of great theoretical significance andapplication value.This article first of steel ratio and expansion agent fly to change parameters on the9groups of steel pipe under constraint stress study on expansion properties oflightweight aggregate concrete. On this basis,6from the SLCFST Middle long columnsunder the host of fire response and fire rear axle experimental study on mechanicalproperties and.the temperaturfield is simulated and analyzed by FEM software Marc Forcomparison,18SLCFST short columns and24SFCFST short columns, and were conducted at room temperature and fire-axle experimental study of mechanicalperformance. Under fire conditions taking into account the700°c under fire (1.5h) and900°c under fire (1.5h) two situations. Based on the experimental results, the group ofSFCFST column and SLCFST columns phenomena, failure modes observation andanalysis. After obtaining the loads of various group of test samples by fire-positioncurve and load-strain curve, analyzed each parameter to get a light from another lightafter the disaster from the SLCFST column and SFCFST column the influence ofbearing capacity and deformability. Ultimate bearing capacity and the fire in the roomtemperature of the specimen, the remaining carrying capacity comparedExperimental results show that, under the top load fire testing of Middle longcolumns of SLCFST residual strength is close to the short columns of SLCFSTwithout loads of fire-residual strength. The axial compression damage form of SFCFSTand SLCFST after exposure to fire is in basic agreement with that of the columns atroom temperature, Based on specimens at room temperature and after fire test piece testresult, steel fiber volumn and expansive agent volumn had an impact on bearingcapacity of lightweight aggregate concrete filled steel tube Effect of steel fiber andexpansive agent volumn on the mechanical performance of SFCFST decreased withincrease of the steel ratio. The initial self-stress and steel fiber content is reduced toimprove bearing capacity of the column of CFST after the fire temperaturerising.The effect of fire temperature on the residual bearing capacity of the shortcolumns presented here was discussed based on the experimental results obtained here,and the method of calculation of axial compressive bearing capacity of SLCFST wasput forward based on the design guideline of ordinary concrete filled steel tubes, inwhich the effect of self-stress is especially considered. The revised formula can be usedfor calculation of axial compressive bearing capacity of SFCFST not subjected to fireload, Under the amended formula can be used for room temperature calculation ofbearing capacity of steel fiber reinforced lightweight aggregate concrete... |
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