共查询到12条相似文献，搜索用时 171 毫秒
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罕遇地震下石化钢结构减震的关键影响因素 总被引：2，自引：0，他引：2
在强烈地震作用下,炼油厂的石化钢结构可能发生破坏,导致较大的经济损失,并易引发严重的次生灾害。为降低石化钢结构的地震风险,结合石化钢结构的特点,以某大型炼油厂重整装置反应器为例,建立有限元分析模型,设置黏滞阻尼器进行罕遇地震下的减震设计,并分析了阻尼器的设置位置、数量和阻尼参数等影响因素。研究结果表明,黏滞阻尼器所在楼层的层间剪力和层间位移角显著减小,布置在结构底部的减震效果优于布置在中、上部;随着阻尼器数量的增加,层间剪力和层间位移角都会随之减小,但减少幅度逐渐降低;阻尼系数对石化钢结构减震效果的影响大于阻尼指数,减震设计中宜优先调整阻尼系数以获得较好的抗震性能。 相似文献
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基于对50根弯曲破坏钢筋混凝土圆柱低周反复试验结果的分析,建立了完整滞回环的数学表达式并推导得出等效阻尼比计算模型;以双柱墩桥梁为例,说明了建立桥梁整体结构等效阻尼比与墩柱端部塑性铰等效阻尼比关系的方法。研究表明,完整滞回环数学表达式较好地反映了弯曲破坏钢筋混凝土圆柱的滞回特性,得到的等效阻尼比模型计算结果与试验结果符合较好;采用建立的桥梁整体结构等效阻尼比与墩柱端部塑性铰等效阻尼比的关系进行pushover分析更能反映实际情况。采用等效阻尼比模型算得的目标位移与基于Rosenblueth模型和Kowalsky模型算得的位移之间存在较大差距。 相似文献
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According to our current bridge seismic design codes, the bridge tower is explicitly required to remain almost elastic even under the excitation of occasionally happened earthquake. To achieve this seismic performance objective, usually the steel ratios of tower base and strut are required to satisfy the static loading demand and increase by a large margin as well in most engineering practices which leads to engineering inefficiency as well as a rising seismic demand for the substructure. Therefore, the structural design parameters including the location, the stiffness and the constrain condition of the strut with respect to the tower column of H shape tower were studied to explore their effect on the transverse seismic responses of cable-stayed bridge tower, Moreover, the effect of yield intensity of the strut on the seismic responses of the tower column is also studied. The results show that the location and the stiffness of the strut have a slight effect on the seismic responses while the transverse seismic demands of the bridge tower decrease drastically when the constrain condition between the cross beam and the tower column changes. 相似文献
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The base isolation technique has been widely used in different countries to reduce seismic disasters during earthquakes. But most of these devices are effective only in horizontal earthquake responses and do not work well in vertical earthquake responses. We propose a vertical seismic isolation system composed of a dish spring and a visco-elastic damper. To study the stiffness and damping performance of this isolation system, a series of tests under static and dynamic loads were performed. The results show that this system is effective in solving problems related to strong vertical bearing capacity and vertical damping of vertical isolation. The system has not only appropriate vertical stiffness and damper performance, but also excellent mechanical performance. In addition, it is compact, easy to manufacture, and can serve as an ideal vertical damping device. 相似文献
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For a reinforce concrete frame structures which is not satisfied the standard for seismic appraiser of building, viscidity dampers are used to retrofit the structure. Four reinforce schemes are selected in which six same viscidity dampers are located at different position of the structure. Compared seismic performance of the retrofited structure with unretrofited one, an optimum scheme where viscidity dampers should better set is obtained. Then the number and technical parameter of viscidity dampers are adjusted, and seismic performance of the structure are calculated. The results are compared and a more economic scheme is obtained because the cost is lowest and the displacement of the structure under earthquakes is satisfied the standard for seismic appraiser of building. Several rules and advices are gotten about how to use the viscidity dampers to retrofit reinforce concrete frame structures. The conclusion about viscidity dampers are useful for similar actual engineering. 相似文献
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This paper proposes a new method of structure control that to set damping braces in a top - bear arch bridge. Lumped damping can be introduced to structures to reduce seismic response. The FEM analysis of Nimu bridge which is braced with viscoelastic dampers had done. The results show that the viscoelastic damping braces can remarkably decrease displacement within the arc plane, which is an efficient structure control method. 相似文献
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采用消(耗)能元件的结构在遭受地震作用时,元件芯材首先屈服进入塑性阶段,利用其滞回变形消耗地震输入能量,保护主体结构,元件芯材本构关系的数值模拟是对采用消(耗)能元件结构进行抗震分析与设计的基础。为更真实地模拟结构消(耗)能元件芯材在单调和循环荷载下的本构响应,更准确地对采用消(耗)能元件结构进行结构弹塑性地震响应分析,对常用作消(耗)能元件芯材的日本高延性钢材SN490B的单调、循环加载本构及循环骨架曲线进行了数值模拟,包括：采用Esmaeily-Xiao二次流塑性模型模拟材料在单调荷载作用下弹性段、屈服段、强化段和二次流塑段4个阶段;采用混合强化模型模拟材料循环荷载作用下的本构响应,运用大型通用有限元软件ABAQUS结合数值模拟参数对16种不同循环加载制度下的循环加载试验进行模拟,并与试验结果进行对比;采用Ramberg-Osgood模型、无量纲化的Ramberg-Osgood模型及两段式模型模拟循环骨架曲线。研究结果表明：所采用数学模型可以较好地模拟SN490B钢材单调、循环加载本构响应及循环骨架曲线,数值模拟与试验结果拟合较好。 相似文献
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In order to investigate the conditions of damage and failure of concrete-filled steel tube(CFST) arch bridges, considering the structural and mechanical characteristics of CFST arch bridges, the dual damage criteria assessment models of the various components based on deformation or strength and energy were developed. The nonlinear seismic response of CFST arch bridges was analyzed by finite element method and the fuzzy evaluation method of seismic damage based on fuzzy theory and analytic hierarchy process was studied. Finally, taking a long-span CFST arch bridge as example, the damage index of the bridge was 0.150, 0.152, 0.172 and 0.318 respectively when the seismic peak acceleration was respectively 0.1g, 0.2g, 0.4g and 0.8g. The results show that the CFST arch bridge is slightly damaged under the earthquake when the seismic peak acceleration is 0.4g, and the bridge is damaged moderately when the peak acceleration is 0.8g. 相似文献
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考虑地震动的非平稳性,变化连体位置,对非对称双塔连体结构运用虚拟激励法进行非平稳随机激励下的动力可靠度研究。采用刚度退化的Bouc-Wen模型模拟塔楼各楼层的滞变特性,建立非线性化动力方程。运用混合精细积分法对每一时刻的响应进行求解,得到连体位置变化时非对称连体结构在非平稳随机激励下的时变方差。基于首次超越破坏准则与Markov假定,研究非平稳随机地震激励下连体结构的动力可靠度。运用上述理论,在8度罕遇地震作用下对某非对称双塔连体结构进行随机地震响应与动力可靠度分析。研究结果表明,地震作用下结构的层间位移响应呈现强烈的非平稳性,变化连体位置对连体结构的随机地震响应与动力可靠度将产生显著影响。 相似文献
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In order to accurately evaluate the aseismic behavior of the seismic damaged masonry pagodas destroyed by Wenchuan earthquake and strengthened after the earthquake, a test was conducted to acquire related parameters on seismic performance from the specimens made by masonry and retrofitted with grouting and steel hoops. Taking a seismic damaged ancient masonry pagoda in Sichuan as a case study, four kinds of primitive specimens are fabricated by simulating the conformation of the masonry pagoda. Then the primitive specimens are destroyed under cycle loads and the damaged specimens are repaired by grouting and steel hoops. Cycle controlling tests are conducted with the specimens and relevant data are acquired. Experimental results showed that grouting combined with steel hoops could improve the ductility and energy dissipation capacity of a seismic damage of brick masonry structure, but it do a little to improve the stiffness of a seismic damage structure. And the cracking load of the repaired masonry is much lower than the original undamaged structure. 相似文献
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Based on dynamic time history analysis, dynamic response behavior of an un supported tunnel through fault zone which was simulated by interface and solid elements was studied under uniform input earthquake wave excitation. The analyses of response behaviors, including displacement difference, acceleration magnification, and plastic zones and so on, were carried out when earthquake wave excitation was input along transverse, longitudinal and vertical of tunnel respectively. The results show that simulation method for fault zone is effective; the earthquake causes obvious displacement difference at fault zone and surrounding rock contacting part. The maximal displacement difference reaches to 51.8mm under transverse uniform input earthquake wave excitation. And the displacement difference under vertical and longitudinal is only 44.3% and 23.1% of the transverse value, respectively; the acceleration magnification in fault zone is significantly greater than that in surrounding rock. Shear failure zone appears at the fault zone and surrounding rock contacting part, and it is especially prominent under input longitudinal earthquake wave excitation. It is proposed that fault zone has significantly influence on the dynamic performance of tunnel. The fault zone and the transitional zones are the control zones of seismic design when tunnel passes through fault zone, thus, the study on the anti seismic measures should be further strengthened. 相似文献