酸性大气环境下多龄期钢框架结构抗震性能及优化设计方法研究

发布时间：2018-03-18 09:00

本文选题：多龄期钢框架结构　切入点：拟静力试验　出处：《西安建筑科技大学》2015年博士论文　论文类型：学位论文

【摘要】：近年来,地震频发,钢结构因其抗震性能优良有被广泛应用于民用住宅的趋势。在钢结构广泛应用的背景下,由锈蚀带来的耐久性问题也变得愈发严重,锈蚀将造成钢构件截面削弱、钢材力学性能降低,进而影响钢结构的抗震性能。针对上述问题,本文从材性、构件、结构三个方面分别研究了锈蚀对钢材力学性能、钢框架柱抗震性能、钢框架结构抗震性能的影响,并在试验结果的基础上建立锈蚀钢框架结构地震损伤模型、恢复力模型及概率地震易损性模型。考虑到钢框架结构在整个使用寿命年限内将遭受腐蚀及地震的影响,对钢框架结构进行基于损伤可靠度的全寿命优化设计,实现了钢框架结构设计的最优化。本文主要研究工作及研究成果包括:(1)采用户外自然加速暴露试验方法对城市酸性大气环境进行模拟,对63个标准钢材材性试件及空间钢框架结构进行酸性大气腐蚀,得到具有不同锈蚀程度的钢材材性试件及锈蚀空间钢框架结构;对具有不同锈蚀程度的钢材材性试件进行拉伸试验,拟合试验数据建立了钢材力学性能(包括屈服强度、极限强度、弹性模量及伸长率)与失重率之间的数学关系。在上述材性试验结果及结构力学理论的基础上,对欧进萍等人提出的钢结构地震损伤模型进行改造,建立了在役钢框架时变地震损伤模型;对时变损伤模型进行算例应用,结果表明,本文建立的时变损伤模型可以很好的体现锈蚀损伤对钢框架抗震性能的影响。(2)利用气雾腐蚀箱对城市酸性大气环境进行模拟,对6榀钢框架柱进行酸性大气腐蚀;通过改变锈蚀程度、轴压比,对6榀钢框架柱试件进行了低周反复加载试验,考察了锈蚀钢框架柱的破坏过程与特征,研究了不同锈蚀程度、轴压比对钢框架柱的荷载-位移滞回曲线、骨架曲线、强度和刚度退化、变形能力、滞回耗能等力学性能的影响。基于上述试验的结果,建立了基于损伤的锈蚀钢框架柱恢复力模型。(3)对2榀锈蚀程度不同(分别为未锈蚀、严重锈蚀)的空间钢框架结构模型进行地震模拟振动台试验,测定了2榀钢框架结构模型的动力特性及不同烈度下的地震反应,对比分析了锈蚀损伤对结构自振频率、振型形态、位移反应、加速度反应、应变反应及破坏情况的影响;根据相似关系推算出原型结构在不同水准地震作用下的自振频率、振动形态、加速度反应、位移反应及剪力分布。(4)基于时变地震损伤模型提出了酸性大气环境作用下多龄期钢框架结构概率地震易损性分析方法及步骤;考虑服役龄期对钢框架结构抗震性能的影响,分别建立时变概率地震需求模型、时变概率抗震能力模型及时变易损性模型;在概率地震需求分析及概率抗震能力分析的基础上,得到多龄期(20年、30年、40年、50年)钢框架结构的易损性模型及易损性曲线。(5)基于“投资-效益”准则,建立钢框架结构全寿命抗震优化设计数学模型;在优化设计模型中引入加权系数,用于调整结构初始造价和损失期望在目标函数中的相对重要性;将损伤可靠度分析理论应用到钢框架结构全寿命抗震优化设计中,利用钢框架结构时变地震损伤模型计算结构整体损伤,用于评价结构是否可靠及计算结构在各性能状态下的失效概率;利用MATLAB软件平台进行编程,实现了钢框架结构基于损伤可靠度的全寿命抗震优化设计。
[Abstract]:In recent years, frequent earthquake, the steel structure because of its excellent seismic performance has been widely used in residential trend. Widely used in steel structure under the background of durability by corrosion brought is becoming increasingly serious, will cause the corrosion of steel member section steel weakened, mechanical properties could be reduced, thereby affecting the seismic performance of steel structure. To solve these problems, this paper from the material, component, structure three aspects were studied on mechanical properties of corrosion, the seismic performance of steel frame column, seismic performance of steel frame structure, and based on the test results of the corrosion of steel frame structure seismic damage model, restoring force model and the probability of seismic vulnerability model. Considering the steel frame structure will be affected by corrosion and earthquake in the whole life period and damage the reliability of whole life optimization design based on steel frame structure, the steel The optimization design of the frame structure. The main research work and result in this paper includes: (1) the outdoor accelerated natural exposure test method for city acidic atmospheric environment is simulated by acid on atmospheric corrosion of steel frame structure and the space of 63 standard steel material specimens with steel material with different corrosion degree of steel frame test structure and corrosion; tensile test of steel material with different corrosion degree of specimen, fitting the test data to establish the mechanical properties of steel (including yield strength, ultimate strength, elastic modulus and elongation) and the mathematical relationship between the rate of weight loss. Based on the above material test results and structural mechanics theory on the seismic damage model of steel structure of Ou Jinping's transformation, the variable seismic damage model of existing steel frame building; time-varying damage model example, node The results show that the time-varying damage model can well reflect the effect of corrosion damage on aseismic performance of steel frame. (2) the city atmospheric environment was simulated by acidic corrosion of acidic aerosol box, atmospheric corrosion resistance of 6 steel frame column; by changing the corrosion degree, axial compression ratio, low cyclic the loading test of 6 steel frame column specimens were studied, the failure process of the corrosion of steel frame columns and features of different degree of corrosion, the axial compression ratio of steel frame column load displacement hysteretic curve, skeleton curve, stiffness degradation, deformation ability, influence of hysteretic properties. Based on above experimental results, the damage corrosion of steel frame column based on the restoring force model. (3) of 2 specimens of different corrosion degrees (respectively, without corrosion, serious corrosion) of space steel frame structure model of seismic simulation shaking table test, determination The seismic response of the dynamic characteristics of 2 steel frame structure model and different intensity, comparison and analysis of the corrosion damage on the natural vibration frequency, vibration mode shape, displacement response, acceleration response, strain response and failure situation; according to the similarity relationship to calculate the prototype structure self vibration frequency, vibration shape, acceleration response under different level of earthquake, displacement and shear distribution. (4) based on the time-varying seismic damage model is proposed for probabilistic seismic fragility of steel frame structure of multi age acidic atmospheric environment under the action of analysis methods and steps; considering the influence of service duration on the seismic property of steel frame are established, time-varying probability of earthquake the demand model, time-varying probabilistic seismic capacity model and variation loss model; based on the analysis of probabilistic seismic demand analysis and probabilistic seismic capacity, by age (20 years, 30 years, 40 years, 50 years) steel The frame structure of the vulnerability model and fragility curves. (5) investment benefit criterion based on a steel frame structure of whole life seismic optimal design mathematical model; weighted coefficient in the optimization model, the relative importance of structural adjustment for the initial cost and the expected loss in the objective function of the damage; reliability analysis theory is applied to the steel frame structure of whole life seismic optimization design of steel frame structure, using time-varying seismic damage model to calculate the overall structural damage, is used to evaluate the structure reliability and structure calculation in the properties of the probability of failure; the use of MATLAB programming software platform, the realization of steel frame structure based on reliability optimization design of whole life injury seismic reliability.

【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TU391;TU352.11

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