【作者】 李海旺；

【导师】 树学峰；

【作者基本信息】 太原理工大学 ， 结构工程， 2013， 博士

【摘要】 应对地震灾难是人类在地球生存和可持续发展的一个永恒主题。时至今日依然不断有城市、乡村遭到毁灭,继续给人类留下巨大生命与财产损失和难于愈合的心灵创伤。由此可见,在城镇膨胀发展的今天,如何构建城镇甚至乡村的抗震减灾体系依然是人类急待解决的重要课题。本文根据中国抗震减灾体系的现状,从灾难性地震的调查分析开始,提出构建“灾难性地震避难与救灾据点系统”的抗震减灾体系,并重点开展了大跨网格结构作为灾难性地震避难与救灾据点的抗震性能设计方法与应用研究。研究的主要内容与获得的主要结论如下：(1)首先对中国1920年以来发生的灾难性地震的地震参数进行了统计分析,结果表明在我国现行设防烈度为6～9度地区,历史上发生的灾难性地震的烈度均在9度以上,有的甚至达到了12度,其对应地震动峰值均在620gal～3200gal之间；高于设防地震水平的灾难地震随时可能在人口集中的城镇发生。为应对未来灾难地震发生后城镇应急救灾和避难问题,本文提出了对地震避难与救灾据点的建筑实施“灾难性地震设防”的构想,并针对设防烈度给出了一套灾难地震动设计参数取值。然后根据避难与救灾据点建筑功能的要求,将该类建筑功能的抗震设防性能目标调整为：“设防地震充分运行、罕遇地震运行、灾难性地震基本运行”。(2)通过对国内外灾难地震后应急救援实践的分析,大跨公共建筑宜作为救灾据点和避难场所的建设载体,在满足其公共建筑功能的基础上,易同时赋予其“避难与救灾”的功能。针对该类公共建筑一般采用单层大跨钢网格结构体系的特点,重点讨论了该类建筑结构赋予“避难与救灾”功能后抗震性能化设计的内容和方法,特别是灾难地震下该类结构整体(包括上部和下部结构)失效的判定准则和失效承载力的评定方法。该类设计计算方法的关键在于建立合适的地震波集以及计算分析结构体系整体的失效破坏形态。(3)为讨论大跨钢网格结构体系在地震作用下的失效破坏形态,选取常用的立体拱桁架结构为研究对象,通过对3个立体拱桁架模型进行跨中往复集中加载下的试验和计算机模拟分析,研究了其在地震作用下的失效破坏机理,获得的主要研究结果为：①拱桁架模型在跨中集中往复荷载作用下的破坏失效过程为：受力最大节问(薄弱节间)首先进入弹塑性状态,继而在节间内最大受拉腹杆端部出现细微裂纹,最后将该腹杆与下弦杆撕裂,导致逐步形成机构而破坏。②在跨中往复荷载作用下的塑性发展仅限于局部受力较大的区域、破坏时其整体塑性变形不大；整体滞回曲线扭捏、细长、不饱满,耗能性能一般；但受力较大的关键杆件滞回曲线饱满,耗能性能良好。③进入弹塑性状态后,往复荷载作用将产生塑性累积损伤,导致低周疲劳破坏；相贯线焊缝、4根腹杆在弦杆处的密集交汇导致的应力集中、三向拉伸应力、焊缝缺陷等影响因素将加速节点域低周疲劳破坏的历程。④三个矢跨比不同的模型试验结果没有表现出矢跨比不同对结构性能影响的规律性,主要原因为该三个模型的薄弱部位均位于相贯节点域内；同其他学者独立相贯节点试验的对比发现,结构体系中相贯节点与独立相贯节点试验的破坏形态基本相同,但前者反应的结构破坏形态更为全面。⑤试验与模拟获得的整体塑性发展过程、开裂位置、整体滞回曲线类型与性态、杆件的骨架曲线等基本一致,表明模拟中采用的集中塑性铰模型基本描述了试验模型中杆件塑性发展的情况。(4)利用本文提出的设计方法对某大跨度立体拱桁架结构体系、某体育练习馆网架结构体系进行了抗震性能设计案例分析,结果表明：采用基于失效性态的抗震设计方法利用集中塑性铰时程分析法、地震波作用下失效承载力平均系数评定法等对大跨度网格钢结构体系进行灾难地震设防的性能设计较为简单,容易被工程师掌握；利用基于失效形态的抗震性能设计方法,易发现结构体系的“薄弱部位”。通过对“薄弱部位”的加强与优化设计,可以较高的的性价比提高其抗震承载力,达到对其实行“灾难地震设防”的要求。更多还原

【Abstract】 To deal with the earthquake disasters is an eternal theme of human survival and sustainable development on Earth. Today, disaster earthquakes still continue to destroy cities and villages, to leave a huge life lost and property damage and even trauma to humans. As the result, how to build earthquake resistance and disaster mitigation system in cities and towns and even rural area is still an important issue for human need to solve while the development of urban expansion can be seen anywhere. Based on the current situation of the earthquake resistance and disaster mitigation system in China, this paper from the beginning of investigation and analysis on catastrophic earthquake, proposes to build an earthquake resistance and disaster mitigation system of "catastrophic earthquake refuge and relief stronghold system", and focus on researching on the seismic performance design methods applied to the long-span grid structure buildings with the function of disaster earthquake refuge and relief stronghold. The main content of the study and the main conclusions obtained are as follows: First, the seismic parameters of the catastrophic earthquake in China since1920are been investigated statistically, the results showed that6to9degrees regions in our current fortification intensity, the intensity of the catastrophic earthquake in history was more than9degrees and some even reached12degrees, which corresponds to the peak of ground motion between620gal～3200gal, therefore the disaster earthquake that its intensity is higher than the level of fortification earthquake intensity may be occur at any time in cities and towns with large population. Response to future disaster earthquake the town emergency relief and refuge issues, the idea of the catastrophic earthquake fortification for the building with the function of earthquake refuge and relief stronghold is proposed in the paper. And a set of the disaster ground motion design parameters taken for current fortification intensity system in China is presented. Then the seismic fortification objective for the public building with earthquake refuge and relief stronghold function is adjusted to:"full operation under fortified earthquake, normal operation under rare earthquake, basic run under catastrophic earthquake", according to the requirements of these kinds of buildings.Through the analysis of the domestic and international disaster earthquake emergency rescue practices, large span public buildings are proposed to serve as the carrier as a relief stronghold and refuge shelter. It is easy for them to give the function of refuge and relief on the basis that meets their public serve function. According to the fact that public buildings generally use a large-span steel grid structure system, this paper focus on the study on the content and method of the seismic performance design of these building structures with the function of relief stronghold and refuge shelter, especially on failure criteria and failure bearing capacity assessment method for the structure as a whole (including the upper and lower part of the structure) under disaster earthquakes.To discuss the failure behaviors of the large-span steel grid structure system under earthquake, select spatial arch trusses, which commonly used in large-span public buildings, as the research object. Experimental and modeling investigation on three spatial arch truss models under cyclic loading vertically on the node of their middle span is carried out to study failure mechanism, the main findings are as follow:①Their failure process is that the weakest section firstly enter into the elastic-plastic state, then minor cracks appear on the end of the web bar with the maximum tensile force in their weakest section, last the web rods gradually tear from lower chord to lead for the truss to form geometrical mechanism and collapse.②the development of plasticity is limited to the local areas in which the inner forces of their bars are great, therefore their overall plastic deformation is generally small; The overall hysteresis curves are distorted, slender and not full, so their energy consumption performance is normal; but the hysteresis curves of the rods having entered into elastic-plastic state are full, their energy consumption performance is good.③After entering into the elastic-plastic state, reciprocating loading results in plastic cumulative damage, finally lead to low-cycle fatigue failure; the stress concentration, the three-way tensile stress state in the interfingering lines among the lower chord and4web rods, and weld defects will push the low cycle fatigue failure.④three different model test results did not show regularity with span ratio, its main reason is that the weak parts of the three models are all in the interfingering line joints in the loading area; The comparison finds that the failure patterns of the interfingering line joints in structural model tests here and independent interfingering line joint tests carried out by other scholars is basically the same, but the former is more comprehensive⑤The overall plastic development process, cracking location, the truss model’s overall hysteresis curve, hysteresis behaviors of the rods are generally consistent in their test and simulation, and it shows that rod’s centralized plastic hinge model used in simulation can bring the basic well description of plastic development of the rod in the test.The design cases of a large span public building of spatial arch truss structural system and a sports practice gymnasium of double-layer grids is carried out by the design method presented in this paper. The results show that structure system seismic performance design case studies, the results showed that:it is easy for engineers to understand and master the seismic performance design method based on failure modes under enough and suitable earthquake waves. It is easy to find the "weak part" of the structural system when the seismic design method above is applied. By strengthening the weak parts and optimize the design, it can be higher cost-effective to improve structural system seismic capacity to achieve its requirements of disaster earthquake fortification.更多还原