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利用有限元分析软件ANSYS对某正放四角锥网架进行结构静力分析、模态分析和时程分析,得到该网架的模态频率和振型,在此基础上对比分析了网架在不同地震波作用下的最大位移,并得出一些有益的结论。 相似文献
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基于一正放四角锥网架结构算例,通过对其多火源位置的计算分析表明,杆件通常会在几个时间段内失效,而其余时间段网架则出现暂时的稳定平衡状态,通常都是连续几个荷载步都出现杆件的集体失效,其中以开始阶段的失效最为明显,网架结构的中心部位为抗火的薄弱环节,首批失效的杆件大部分集中在中央上弦. 相似文献
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某展览厅屋盖为斜放四角锥焊接空心球节点网架,平面尺寸36m×40m,高3m。网架采用地面组焊小拼单元、高空滑移就位、总拼的施工方案,安装时搭设满堂脚手架。为确保焊接质量,采取了相应的技术措施,技术经济效果良好。 相似文献
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火灾均匀温度场中正放四角锥网架结构临界温度研究 总被引:1,自引:0,他引:1
随着温度的升高,钢材的力学性能将会发生较大的变化。钢结构在均匀温度场达到承载能力极限状态时的临界温度是钢结构抗火性能的重要特征,而网架结构的临界温度主要受网架的几何特征、荷载比、构件稳定应力的影响。本文通过对不同参数条件下正放四角锥网架结构在均匀温度场中结构反应全过程分析,得到不同参数条件下正放四角锥网架结构的临界温度,为大空间建筑网架结构抗火设计实用方法提供理论依据。 相似文献
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结合大庆老年大学雨棚的结构设计,系统介绍了扇形变高度四角锥网架结构的方案选取、材料选择与荷载的取值,采用有限元软件ANSYS进行了网架建模,获得内力和变形并进行了构件承载力和结构的变形验算,最后给出了杆件节点和结构构造的设计,可为同类工程的设计提供借鉴. 相似文献
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预应力组合网架是一种基于组合网架和预应力技术发展起来的由钢和钢筋混凝土组合而成的空间结构,它可以充分发挥钢材抗拉,混凝土抗压的特点。当采用分批张拉时,后批索张拉必然会造成前面所有批索实际张力发生改变。本文对一3m×3m(网格数为3×3)的试验模型的三根预应力下弦拉索,采用了三种张拉次序(依次张拉、先张拉两边索再张拉中间索和先张拉中间索后张拉两边索)进行张拉,测出了索内预应力及结构内力的变化,并与基于张力松弛法的索-杆-梁-板系有限元法分析结果进行对比,结果表明,采用张力松弛法可以考虑不同张拉次序对索内预应力的影响。 相似文献
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通过拉伸试验和剪切试验,得到了PVB胶片的材料性能参数,并通过受弯承载力试验,研究夹层玻璃的受力特点,进而分析PVB胶片的厚度、温度变化对其承载能力的影响。试验结果表明:胶片对夹层玻璃的受力性能有显著影响,且胶片的粘结作用不能忽略,随着温度的升高,其承载力降低。运用ANSYS有限元软件对试验模型的受力性能进行数值模拟,有限元计算结果与试验结果吻合较好。试验结果和有限元分析结果均表明:现行国家规范关于夹层玻璃位移的计算值大于试验值和有限元分析值,计算偏于保守。 相似文献
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为探究火灾后采用聚合物砂浆加固修复混凝土空心楼盖二次火灾下的抗火性能,对四边简支混凝土组合塑料模盒空心楼盖进行两次火灾试验。介绍了试验空心楼盖第一次受火试验及火灾后构件修复情况,重点介绍了加固修复后空心楼盖第二次火灾试验,描述了试验空心楼盖在两次受火下的破坏特征、变形和温度场分布规律,并进行分析和对比。研究结果表明:采用聚合物砂浆修复的空心楼盖在二次火灾作用下,第一次火灾受损较为严重的部位易产生爆裂脱落,从而降低了耐火极限;二次受火下楼盖内混凝土的温度峰值高于一次受火,且距离板底越近,两次火灾作用中温度峰值差值越大;试件在两次火灾作用下跨中处最大竖向位移基本相同,第二次受火作用后的残余位移小于第一次;采用聚合物砂浆对火灾后的空心楼盖进行修复,修复后的楼盖仍具有一定的抗火性能。 相似文献
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J. Jones C. Wu D.J. Oehlers A.S. Whittaker W. Sun S. Marks R. Coppola 《Engineering Structures》2009,31(12):2825-2832
A finite difference procedure that can account for strain-rate effects, both shear and flexural deformations, permits variations in cross-section geometry and strength and loading over the length of a component is proposed to accurately and efficiently analyze the dynamic response of a simply supported structural member under blast loads. A section-based layered analysis model that accommodates varying strain rates across a member’s cross-section is used to derive sectional moment–curvature relationships. A formula is derived to estimate the distribution of strain rate over the depth of a cross-section along the length of the member, and the corresponding strain rate effects are incorporated into the section-based layered analysis model. The Timoshenko beam equations that include both shear deformations and rotational inertia are solved numerically using an explicit finite difference scheme. The accuracy of the proposed finite difference analysis model is part validated using results of blast testing of reinforced concrete slabs with combinations of explosive weights and standoff distances. The results are also compared with those obtained by conventional single-degree-of-freedom (SDOF) analysis and finite element (FE) analysis using solid elements. The finite difference analysis procedure is both fast-running and accurate and most suitable for design office application, combining the speed of SDOF analysis and the detail and accuracy of FE analysis. 相似文献
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《Structure and Infrastructure Engineering》2013,9(7):719-732
There are two alternative strategies that a designer may adopt and combine when faced with the retrofitting of a bridge: (a) the increase in the capacity or (b) the reduction in the actions of the structure. In this article, a new scheme, based on the second strategy, is proposed for the retrofit of existing multi-span simply supported (MSSS) bridges. The reduction in the actions of the bridge was mainly achieved by utilising an external restraining system consisting of I-shaped steel piles driven in the backfill soil and a slab that is the pile-cap of the piles. The restraining system was preliminarily designed and assessed in an existing MSSS bridge system, whose deck slab was made continuous. The existing and the retrofitted bridge were analysed by means of non-linear dynamic time history analysis and their response was compared in terms of serviceability and earthquake resistance performance. The study showed that the retrofitting scheme enhanced effectively the earthquake resistance of the existing bridge. 相似文献
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利用空间句法理论对上海市长泰广场进行街区空间的视域分析,利用视域分析法对长泰广场的街区空间进行空间解读与分析,通过视线整合度、视线拓扑距离、视线集聚度、视线控制度以及视线连接度等指标加以研究,对高端商业街区的发展找出定量化依据,并通过研究所得到的相关结果给出相关发展建议,为其他高端商业街区的发展提供量化的参考依据。 相似文献