火灾下钢筋混凝土板温度场确定的有限元方法

利用有限元方法分析了火灾温度作用下钢筋混凝土板内部温度场的分布 ,用 FORTRAN语言编制了计算机程序。程序计算的结果与试验结果相吻合较好     

火灾下钢筋混凝土结构的温度场分析

利用有限元软件ABAQUS对高温下钢筋混凝土结构的温度场进行了计算和分析,计算结果和试验结果吻合较好,并为进一步认识钢筋混凝土结构的高温力学性能和耐火极限创造了条件。     

火灾高温作用下钢筋混凝土梁截面温度场的计算与分析

采用有限元—差分相结合的方法编制了钢筋混凝土梁构件截面内部瞬态温度场计算分析的程序,验证表明与精确解符合程度较好。并应用该分析程序进行了三面受火的混凝土矩形梁构件在不同时刻截面内部温度场的计算与分析,对计算结果也进行了对比验证,精确度较高,由此得到混凝土梁构件在各种情况下的截面温度场及其分布的特点与规律,为进一步研究钢筋混凝土梁构件的抗火性能提供了基础。     

火灾作用下钢筋混凝土梁温度场特征分析

基于Abaqus有限元软件,模拟钢筋混凝土梁三面受火作用下的温度场变化,分析了梁截面温度的分布规律,研究了混凝土保护层厚度、防火涂料厚度等关键因素对混凝土梁中受拉(压)钢筋、混凝土的温度场影响.研究表明,增加混凝土保护层厚度及防火涂料厚度均可有效提高梁的受火性能.保护层厚度增加一倍,受拉(压)钢筋温度分别下降52.5％...     

高温下钢筋混凝土梁的温度场分析

使用大型有限元分析软件ABAQUS对钢筋混凝土梁进行温度场分析,分析结果与试验结果吻合情况较好,为进一步深入研究钢筋混凝土梁在火灾下的力学性能和耐火极限创造了条件。     

钢筋混凝土的温度场有限元分析计算

钢和混凝土是现代建筑结构中的主要材料,而钢筋混凝土板则是其中最基本的结构形式。文章利用有限元软件ABAQUS对钢筋混凝土板进行了数值模拟分析,数值计算中采用二次实体传热单元对结构进行离散,比较了二维模型和三位模型的计算结果,计算中考虑了由于材料热工参数随温度的变化,计算结果与不同的试验结果进行了比较,分析了板内温度分布的特点和规律。有关分析方法和计算结果可为钢和混凝土结构进一步的抗火分析和设计提供一定的参考。     

火灾下钢筋混凝土剪力墙温度场数值模拟

为了研究配筋率、升温曲线、多面受火、传热系数等因素对钢筋混凝土剪力墙温度场的影响,利用COMSOL多物理场建模与仿真软件对火灾下钢筋混凝土剪力墙温度场进行模拟,并得到不同因素变化条件下的剪力墙的温度场分布规律,模拟结果与试验结果符合良好.对温度场模拟中各参数对温度场的影响进行了讨论,结果表明:受火时间越长,钢筋混凝土剪...     

火灾作用下钢筋混凝土简支梁温度场的非线性有限元分析

模拟火灾作用,采用大型结构分析程序ANSYS对钢筋混凝土简支梁的温度场进行了非限性有限元分析,得出了火灾作用下混凝土简支梁的温度场分布规律;并将计算结果与试验结果进行了比较,表明温度场的计算结果与实际结果符合良好,从而使火灾作用下钢筋混凝土简支梁的温度场分析从以往的定性分析上升到定量分析,为今后控制火灾作用对钢筋混凝土简支梁的影响提供了重要的计算依据和背景材料.     

火灾作用下钢筋混凝土梁温度场的有限元分析

以ABAQUS有限元分析软件为平台,建立了钢筋混凝土梁有限元模型,对其梁截面的进行了温度场分析。通过从三面受火及四面受火条件两个方面对钢筋混凝土梁进行了非线性数值分析,研究表明四面火灾条件下梁截面温度场呈现双轴对称性,而三面火灾下梁截面的温度场仅是单轴对称。     

某地下室钢筋混凝土顶板抗爆计算分析

本文从工程设计角度出发,通过具体的工程实例,介绍了两种不同的抗爆计算方法,即采用有限元软件ABAQUS对爆炸荷载作用下地下结构顶板进行了仿真模拟,同时利用规范简化算法对其进行了计算,并对二者的优缺点进行了分析,旨在为工程设计人员提供参考。     

钢筋混凝土双向板火灾试验研究

进行了一块四边简支与一块四边固支钢筋混凝土双向板足尺试件在恒载-升温工况下的火灾试验。介绍了试件的设计、试验方案以及观测内容和方法。主要研究了双向板在受火过程中沿板厚混凝土的温度场分布规律、钢筋的温度变化、板平面内外的变形、板边转角随温度的改变情况以及固支板支座反力随火灾作用的变化。试验结果表明,在荷载和温度的耦合作用下,沿板厚存在非线性温度场,固支板的支座反力有显著的重分布,板的面外变形比常温下显著增加;四边简支与四边固支钢筋混凝土双向板具有与常温下不同的破坏模式,四边简支板破坏主要出现在长向跨中以及吊装阶段配置在板顶的负弯矩钢筋截断处;四边固支板在板顶出现椭圆型盆状塑性铰线。     

The behaviour of reinforced concrete slabs in fire

In this paper a robust model is presented based on the previous layer procedure developed by the author to also take into account the effects of concrete spalling on the behaviour of concrete slabs under fire conditions. In this study, a detailed analysis of a uniformly loaded reinforced concrete slab subject to different degrees of concrete spalling under a standard fire regime is first carried out. Further, a series of analysis of floor slabs with different degrees of concrete spalling is also performed on a generic reinforced concrete building. A total of 16 cases have been analysed using different degrees of spalling on the slabs, with different extents and positions of localised fire compartments. It is clear that adjacent cool structures provide considerable thermal restraint to the floor slabs within the fire compartment. And it is evident that the compressive membrane force within the slabs is a major player in reducing the impact of concrete spalling on the structural behaviour of floor slabs in fire.     

基于ABAQUS的火灾下楼板的温度场研究

利用有限元分析软件ABAQUS对火灾情况下楼板的温度场进行了分析,获得了楼板截面温度场的分布规律,计算结果与试验结果吻合良好,从而为进一步深入认识钢筋混凝土楼板的高温下力学性能创造了条件.     

Reliability analysis of reinforced concrete slabs under explosive loading

Inherent in every material is the uncertainty of strength parameters, be it uncertainty in distribution type or distribution variables. In the case of structures subjected to explosive loading, the load itself is very much uncertain, as it is widely accepted that explosive experiment is difficult to predict. With these random effects associated with material, geometry and loading, it is necessary to incorporate them into the analysis in order to have a more realistic estimation of the structural response. This paper presents results from a parametric investigation of the reliability of reinforced concrete slabs under blast loading. Performance functions are set up based on displacement ductility and maximum strain limit-states for reliability estimation. Monte Carlo simulation is used to verify the adequacy of the SDOF representation of the structural slab.     

高温下钢筋混凝土内部温度场数值模拟

针对高温下钢筋混凝土构件导热的非线性瞬态特点,全面考虑其热工参数和质量热容参数的变化时序性,把传热学理论与计算机数值模拟技术相结合,利用ANSYS热分析功能,模拟高温(火灾)作用下混凝土构件内部温度场的变化,应用瞬态温度场仿真程序对四面受火矩形截面柱和T形截面梁温度场进行了数值模拟,模拟结果较试验结果偏大的原为模拟未考虑结构构件实际火灾环境的散热。算例模拟表明,模拟结果与文献给出的试验结果图形曲线走向一致,验证了计算机数值模拟结果分析的适用性与正确性,为混凝土结构构件抗火分析提供了计算辅助手段与理论依据。     

Modelling of unbonded post-tensioned concrete slabs under fire conditions

This paper investigates the structural behaviour of unbonded post-tensioned one-way spanning concrete slabs in fire conditions. The slabs were simply supported and reinforced with 15.7 mm nominal diameter seven-wire mono-strand tendons. A nonlinear finite element model for the analysis of post-tensioned unbonded concrete slabs at elevated temperatures was developed. The mechanical and thermal material nonlinearities of the concrete, prestressing tendon and anchorages have been carefully inserted into the model. The interface between the tendon and surrounding concrete was also modelled, allowing the tendon to retain its profile shape during the deformation of the slab. The temperature distribution throughout the slab, time–deflection behaviour, time–longitudinal expansion, time–stress behaviour in the tendon, and the failure modes were predicted by the model and verified against test data. The study has shown that the coefficients of thermal expansion currently used in the European Code for calcareous and siliceous concrete can lead to inaccurate predictions of the structural behaviour. A parametric study was conducted to investigate the effects on the global structural behaviour due to the change in the aggregate type, load ratio and boundary conditions. It was shown that by varying the boundary conditions the fire resistance was greatly affected. Although changing the aggregate type and load ratio affected the time-displacement response, the fire resistance defined by failure of the slab was not affected due to the splitting mode of failure above the tendon locations not being affected by these parameters. Comparison with the codes shows that the UK code BS8110 is generally unconservative, whereas the Eurocode EN1992-1-2 provides reasonable design rules.