【作者】 季瑶；

【导师】 王新堂；

【作者基本信息】 西安建筑科技大学 ， 防灾减灾工程及防护工程， 2013， 博士

【摘要】 目前国内外对普通钢管混凝土柱的抗火性能开展了较多的研究，而对轻骨料钢管混凝土柱火灾行为的研究还比较少，尤其对自应力及钢纤维增强轻骨料钢管混凝土柱的火灾响应及火灾后力学性能的研究更加薄弱。本文以页岩陶粒做为粗骨料，通过在混凝土中分别掺入一定量的膨胀剂和钢纤维制作了两种不同性质的轻骨料钢管混凝土柱，并以此为对象开展了一系列轻骨料钢管混凝土柱的抗火性能研究。由于钢纤维的加入可有效抑制核心混凝土微裂缝的发展，改善轻骨料钢管混凝土的力学性能；而膨胀剂的加入可在一定程度上提高轻骨料混凝土刚度较低的问题。因此，对自应力及钢纤维增强轻骨料钢管混凝土力学性能的研究具有重要的理论意义和工程应用价值。本文首先以含钢率和膨胀剂掺量为变化参数对9组钢管约束下的自应力轻骨料混凝土的膨胀性能进行了试验研究。在此基础上，对6个自应力轻骨料钢管混凝土中长柱开展了承载下的火灾响应及火灾后轴压力学性能试验研究，并用Marc有限元软件对其火灾下的温度场进行了模拟。为了对比分析，制作了18个自应力轻骨料钢管混凝土短柱和24个钢纤维增强轻骨料钢管混凝土短柱，并分别开展了常温及火灾后轴压力学性能的试验研究。其中受火条件考虑了700℃受火（1.5h）和900℃受火（1.5h）两种情况。基于试验结果，对各组钢纤维轻骨料钢管混凝土柱及自应力轻骨料钢管混凝土柱的实验现象、破坏形态进行了观测与分析。得到了各组试件受火后的荷载-位移曲线及荷载-应变曲线，分析了各个参数对火灾后自应力轻骨料钢管混凝土柱及钢纤维轻骨料钢管混凝土柱的承载能力和变形能力的影响。同时对试件常温下的极限承载力及火灾后的剩余承载力进行了分析比较。试验结果表明，在轴压力作用下的自应力轻骨料钢管混凝土中长柱火灾后剩余承载力下降幅度与无荷载作用的轻骨料钢管混凝土短柱火灾后剩余承载力下降幅度相差不大。轻骨料钢管混凝土柱火灾后轴压破坏形态与常温下的情况基本一致。根据常温试件和火灾后试件的试验结果，钢纤维的掺量和膨胀剂的掺量对轻骨料钢管混凝土短柱承载力均有一定的影响。随着试件含钢率的增加，钢纤维和膨胀剂的增强效果逐渐减弱。初始自应力和钢纤维掺量对火灾后轻骨料钢管混凝土柱的承载力提高作用效果随火灾温度的升高而降低。根据试验结果，进一步分析了火灾温度对剩余承载力的影响规律，并基于普通钢管混凝土设计规程，提出了考虑自应力影响的轻骨料钢管混凝土短柱承载力计算方法。给出了考虑含钢率影响的钢纤维轻骨料钢管混凝土短柱承载力修正系数，经修正后的公式可用于常温下钢纤维轻骨料钢管混凝土柱承载力计算。更多还原

【Abstract】 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更多还原