【作者】 张大山；

【导师】 董毓利；

【作者基本信息】 哈尔滨工业大学 ， 结构工程， 2013， 博士

【摘要】 钢筋混凝土板在遭遇火灾、爆炸和冲击等极端荷载作用下，通常会处于大挠度状态。由于受拉薄膜效应的存在，使得钢筋混凝土板在发生较大挠度时仍能保持稳定，不发生坍塌。因此，受拉薄膜效应对维持结构的整体性起到了重要作用，进而保证了受灾结构内人员逃生和重要物资的抢救具有较为充足的时间。薄膜效应分为受压薄膜效应和受拉薄膜效应两种。其中，受压薄膜效应通常对应钢筋混凝土板的小挠度状态，而受拉薄膜效应则对应钢筋混凝土板发生较大挠度的情况。在已有的研究中，受压薄膜效应得到了广泛的关注，而受拉薄膜效应并没有得到足够的重视。基于上述原因，本文以钢筋混凝土板受拉薄膜效应为研究对象，从理论和试验两个角度进行了常温和火灾作用下考虑受拉薄膜效应的钢筋混凝土板大挠度下承载力的研究，主要研究内容如下：（1）由于经典屈服线理论无法考虑受拉薄膜效应对钢筋混凝土板大挠度下承载力的影响，本文基于经典屈服线理论的基本假定及其板块平衡法和机动法计算原理，认为受拉薄膜效应是由塑性铰线截面处钢筋合力的竖向分量或钢筋伸长做功所引起，提出了钢筋混凝土单向板和双向板在常温下的大挠度承载力计算模型，并利用已有的国内外缩尺混凝土板的常温静力加载试验数据，与国内外已有的受拉薄膜效应计算模型进行对比。对比结果表明：本文提出的模型在计算钢筋混凝土板大挠度下承载力时具有较好的精度。（2）为进一步验证本文提出的受拉薄膜效应计算模型的合理性，本文开展了10块足尺钢筋混凝土板在大挠度下的常温静力加载试验，包括：简支、固支、和一边简支一边固支等三种边界条件的6块单向板，和四边简支矩形和四边简支方形两种条件的4块双向板。根据试验现象验证了受拉薄膜效应是由塑性铰线截面上钢筋合力的竖向分量或者钢筋伸长做功引起的这一假设的合理性。根据试验数据的分析，本文对提出的钢筋混凝土受拉薄膜效应计算模型中的挠度特征值计算公式进行了修正，并验证了本文提出模型的合理性和有效性。利用本文提出模型的计算公式开展参数分析，对受拉薄膜效应的主要影响因素进行了探讨。（3）本文归纳并总结了国内外不同工况的足尺钢筋混凝土板的火灾试验，包括：简支双向板、固支双向板、简支单向板以及多跨连续板。通过对上述试验现象的理解，归纳了火灾下钢筋混凝土板的破坏模式，并证实了钢筋混凝土板在火灾作用下发生大挠度时受拉薄膜效应的存在及其产生的原因。进一步基于本文提出的常温下考虑受拉薄膜效应的钢筋混凝土板的承载力计算模型，考虑了火灾时的高温效应，提出了火灾下考虑受拉薄膜效应的钢筋混凝土板的承载力计算模型。并利用已归纳的试验数据，验证了本文模型在预测火灾下钢筋混凝土板的大挠度下承载力的准确性。更多还原

【Abstract】 In general, reinforced concrete (RC) slabs undergo large deflections when they aresubjected to extreme loads, e.g. fire, blast and impact. Due to tensile membrane action,RC slabs can still keep steady even under quite large deflections. Therefore, tensilemembrane action plays an important role in maintaining the integrity of structures. Inaddition, it provides highly probability that the persons and important properties in theattacked buildings can be rescued and saved with adequate time.Membrane action involves compressive membrane action corresponding to lowdeflections, and tensile membrane action to larger deflections. During the past years,compressive membrane action was widely studied, while less attention was paid ontensile membrane action. Based on the above consideration, tensile membrane action ofRC slabs subjected to large deflections is taken as the research objective of this thesis.Considering the influence of tensile membrane action, the load-carrying capacity of RCslabs, at ambient and elevated temperature, is studied from both theoretical andexperimental aspects. The main contents are summarized as follows:1) The influence of tensile membrane action on the load-carrying capacity of RCslabs is not incorporated in the conventional yield line theory. In this thesis, the tensilemembrane action is assumed to be provided by the vertical component of the steelforces at the section of yield lines or the plastic energy dissipation due to the extensionof reinforcements along yield lines after the formation of mechanism of plastic hingeline. Then, a new model is proposed to estimate the load-carrying capacity consideringthe influence of tensile membrane action. The new model is validated and comparedwith other similar models proposed by others using the small-scale experimental resultshome and abroad. It is illustrated that the new model has adequate accuracy to estimatethe load-carrying capacity of RC slabs subjected to large deflections.2) In order to examine the performance of the new model, a serial full-scaleconcrete slabs tests were carried out at ambient temperature. All the slabs were tested tolarge deflections, and six one-way concrete slabs, two rectangular and two square slabswere contained. The one-way concrete slabs had three different edge conditions, i.e. twoedges simply supported, two edges clamped, one edge simply supported and one edgeclamped. The edges of all the two-way concrete slabs were all simply supported. According to the after-test observations, the assumptions used in the model arereasonable. That is to say that tensile membrane action is do provided by the verticalcomponent of the steel forces at the section of yield lines or the plastic energydissipation due to the extension of reinforcements along yield lines. Through studyingthe test data, the proposed model is proved to be effect. Additionally, the formula usedin the proposed model, to calculate the deflections for the characteristic points, ismodified. Using the proposed model, main factors having influences on the tensilemembrane action are examined.3) Several fire tests of full-scale concrete slabs are summarized, including two-wayslabs with four edges simply supported and four edges clamped respectively, one-wayslabs with two opposite edges simply supported, and multi-bay continuous concreteslabs. Through interpreting the test observations, failure modes of the test slabs aresummarized. Besides, tensile membrane action of RC slabs is proved to occur in fire,and its mechanism is explained. Incorporating the high-temperature effects, a newcalculation model is further presented to calculate the load-carrying capacity of concreteslabs in fire. Through studying the fire test results, the new presented model is proved toexactly predict the load-carrying capacity of RC slabs.更多还原