弱连体结构地震反应分析

采用随机振动、时程分析及振型分解反应谱方法,分别对多种隔震支座刚度情况下的高位隔震大跨连体结构地震响应进行分析,从而得出连体结构在不同频率比(塔楼基频/隔震装置固有频率)下的地震响应关系曲线;通过对曲线进行分析,得出当塔楼基频与隔震装置的固有频率比大于1.2~1.4时,连接体桁架地震响应就可产生减震效果的结论。通过对比三种方法计算结果发现,反应谱法计算出来的连体桁架位移与其他两种方法相比有明显误差,当隔震支座刚度较小时尤为明显。     

Simplified procedures for seismic design verification and evaluation of lead rubber bearing base‐isolated buildings based on free‐vibration response

Base isolation has seen widespread application to buildings and infrastructures over the past four decades. However, there is a lack of methods for assessing the performance of a base‐isolated structure at the end of construction and during its service life. To this end, simplified methods are developed for verifying isolation design and evaluating seismic demands of rubber‐bearing‐supported base‐isolated buildings based on their free‐vibration response, which could be obtained using field (on‐site) testing. The base isolation layer consists of lead rubber bearings (LRBs) and linear natural rubber (LNR) bearings. For design verification purposes, analytical solutions are provided to benchmark the free‐vibration response of base‐isolated buildings, considering the general case of a multilinear hysteretic isolation response representing multiple LRBs with distinct mechanical specifications. In seismic demand evaluation, seismic capacity of an isolation system is estimated using free‐vibration response of various amplitudes that cover a range of expected seismic intensity of interest. Seismic demands are obtained when capacity coincides with an earthquake response spectrum at a compatible damping level. Procedures are developed for the potential use of snap‐back tests and verified using experimental and numerical data.     

具有叠层橡胶基础隔震系统的多层建筑的动力响应

本文着重讨论具有叠层橡胶支座（ＬＲＢ）基础隔震系统的多层建筑的动力响应。文中采用常用的层间剪切模型，引入退化迟滞理论分析叠层橡胶隔震器的滞回特性曲线，进而分析了具有这种类型基础隔震系统的多层建筑的地震响应，探讨了隔震系统参数对结构响应的影响。     

橡胶垫基础隔震结构的减震性能分析

橡胶垫基础隔震技术作为一种有效的减震控制之一,在实际工程中得到了广泛的运用。对基础隔震结构非比例阻尼体系动力响应的时域解答进行了较详细推导,并用Matlab软件编制了相应的求解程序,最后以一栋5层剪切型结构为例进行仿真分析。分析结果表明,橡胶垫基础隔震能够显著降低结构的层间位移响应和加速度响应,提高结构的整体抗震性能。     

模块化钢框架变摩擦摆隔震结构抗震性能研究

模块化建筑具有整体装配率高,施工绿色环保、高效等优点,然而其抗震性能相对较差,震后修复成本高。将隔震技术应用到模块化建筑中,可在不改动上部结构的前提下,改善其整体抗震能力。相比传统橡胶隔震技术,摩擦摆隔震技术具有承载力大、工业化程度高、湿作业少等优势。为此,研发了一种自适应变摩擦摆隔震支座,分析了该支座力学特性,确定其有限元模拟方法。对变摩擦摆隔震支座进行不同工况下剪切性能试验,试验和有限元模拟结果相对误差均在10%以内,验证了有限元模拟方法的正确性。基于GB/T 51408—2021《建筑隔震设计标准》提出模块化钢框架变摩擦摆隔震结构一体化直接设计方法,以实际工程为背景,设计模块化钢框架摩擦摆和变摩擦摆隔震结构,并对非隔震结构和隔震结构的抗震性能进行对比分析。研究表明：相比摩擦摆隔震支座,所提出变摩擦方式可实现支座等效刚度增加11%左右,等效阻尼比增加18%左右;相比摩擦摆支座隔震结构,变摩擦摆支座隔震结构的楼板加速度、层间位移角、层间剪力和上部结构损伤程度略有增加,但隔震层位移明显减小,且这种特性随地震动强度的增加而愈明显,体现了变摩擦摆支座的自适应性。     

结构半主动变刚度控制的研究

尽管已有的研究证明传统的变刚度控制系统可以有效地抑制结构在地震激励下动力响应,但是现有的变刚度装置仅能在很小的范围内改变结构的周期,而且也不利于抑制结构的加速度反应。为了克服这一局限性,本文提出了一种新型的半主动变刚度(ISAVS)控制系统,兼具基础隔震和传统变刚度控制的优点。基于作者提出的离复位控制策略,本文针对ISAVS系统进行了地震作用下的数值模拟,验证了它的可行性和有效性。     

Using orthogonal pairs of rollers on concave beds (OPRCB) as a base isolation system—part I: analytical,experimental and numerical studies of OPRCB isolators

A somehow new isolating system is introduced for short‐ to mid‐rise buildings. It does not need high technology for manufacturing and is not costly, contrary to other existing systems like lead‐rubber bearing or friction pendulum bearing systems. Each isolator of the proposed system consists of two Orthogonal Pairs of Rollers on Concave Beds (OPRCB). Rolling rods installed in two orthogonal directions make possible the movement of the superstructure in all horizontal directions. The concave beds, in addition to giving the system both restoring and re‐centring capabilities, make the force–displacement behaviour of the isolators to be of hardening type. The results of the studies on the specifications of the proposed isolating system and its application to buildings can be presented in two parts. Part I relates to the analytical formulations and the results of experimental and numerical studies of the system's mechanical feature, including its dynamical properties, and part II focuses on the effectiveness of the proposed isolation system in seismic response reduction of low‐ to mid‐rise buildings. In part I of the work, presented in this paper, at first general features of the OPRCB isolator are explained and the analytical formulation, governing its dynamic motion, is derived and discussed in detail. Then, the results of experimental and numerical investigations, including the lateral load displacement relationship of the OPRCB isolators under various vertical loads, obtained by both Finite Element Analyses (FEA) and laboratory tests are presented (FEA results have been verified by the laboratory tests). Finally, responses of some Single Degree of Freedom (SDOF) systems, isolated by OPRCB devices, subjected to simultaneous effect of horizontal and vertical ground motions, are presented and compared with responses of their fixed‐base counterparts. Based on the numerical calculations, it is observed that the oscillation period of the isolated SDOF system is independent of its mass, the initial amplitude of its free vibration response and the value of rolling resistance coefficient. With regard to seismic response reduction it is seen that the amount of absolute accelerations in the SDOF systems, isolated by OPRCB devices, can be reduced drastically in comparison with the fixed‐base systems. Results also show that if the rollers and cylindrical beds are made of high‐strength steel materials, the system can be used effectively under the vertical loads of about the axial forces of ground floor columns in ordinary buildings up to 14 storeys. Copyright © 2010 John Wiley & Sons, Ltd.     

网架屋盖考虑下部结构的摩擦摆隔震控制

摩擦摆(FPS)是一种具有球形滑动面的隔震装置,可用于保护大型工程结构免遭地震灾害的破坏。近年来,大空间建筑发展迅猛,为了提高其抗震性能,将FPS安装于网格屋盖与下部支承结构之间形成滑移隔震机制以降低结构的地震响应。针对某网架屋盖及其下部支承结构,开展了FPS滑移隔震研究。采用大型通用有限元软件ABAQUS,建立了整体结构的三维模型,模型中包括接触面单元和梁单元,能够反映结构的非线性行为。通过非线性时程分析,研究了考虑不同参数时FPS对于上述结构地震防护的可行性和有效性。     

隔震支座对空冷支架结构地震响应影响的研究

空冷凝汽器支架结构是一类特殊的工业建筑。主要针对该类建筑的结构形式,采用隔震技术,即在每个管柱的下方设置铅芯橡胶隔震支座,采用SAP 2000分析软件对原结构和隔震结构的地震响应进行比较分析。结果表明,隔震支座改善了结构的抗震性能,隔震技术对于这种结构体系具有很好的实际应用前景。     

宿迁某高层剪力墙住宅基础隔震设计方法研究

某高层剪力墙住宅位于地震高烈度区江苏省宿迁市,为了提高其抗震性能采用了基础隔震技术。由于我国规范对地震高烈度区建造高层隔震建筑还没有明确的设计依据。文中将组合隔震设计方法应用于该建筑的基础隔震设计中。为满足设定的抗震性能目标,隔震层采用了天然橡胶隔震支座和铅芯橡胶隔震支座的组合隔震形式。分析表明,地震作用下两种隔震支座充分发挥了其隔震性能,上部结构的地震响应明显降低,并且隔震层在罕遇地震下工作状态稳定,满足抗震规范要求。     

Effectiveness of sliding isolators with variable curvature in near‐fault ground motions

Recent studies have revealed that a sliding isolator with variable curvature (SIVC) can mitigate the resonance phenomenon likely to occur in seismic response of a conventional friction pendulum system (FPS) isolator due to its constant isolation frequency. The present study simulates four SIVC isolators and an FPS to find the optimum range of initial isolation period and coefficient of friction and employ them in comparing the effectiveness of SIVC in different peak ground acceleration (PGA) scales of near‐fault earthquakes. Velocity‐dependent coefficient of friction and modified viscoplasticity model have been used to simulate nonlinear friction force of the isolators. Results indicate identical performance of all SIVC isolators in PGA scales up to 0.4 g. When subjected to PGA scales from 0.4 g to 1.0 g, polynomial friction pendulum isolator (PFPI) and variable curvature friction pendulum system (VCFPS) reduce base displacement greatly, while conical friction pendulum isolator (CFPI) and variable frequency pendulum isolator (VFPI) show amplified responses. However, in mitigating structural acceleration, performance of CFPI and VFPI, unlike PFPI and VCFPS, which perform poorly, is excellent. Thus, in a strong near‐fault earthquake, PFPI and VCFPS or CFPI and VFPI can be chosen based on whether reduction of base displacement or super‐structural acceleration is the main concern of designer, respectively. Copyright © 2015 John Wiley & Sons, Ltd.     

高阻尼橡胶隔震支座的力学性能及隔震效果研究

对新型高阻尼橡胶隔震支座的力学性能及此支座对桥梁的隔震性能进行了试验研究.通过输入正弦波研究其力学性能,试验结果表明:新型高阻尼橡胶隔震支座是速度相关型支座,加载频率的等效水平刚度有较大的影响,但对其等效阻尼系数影响不大.然而加载经历对新型高阻尼橡胶隔震支座的等效水平刚度与等效阻尼系数均有较大的影响.同时通过速度控制型实时子结构试验精确、定量地验证了新型高阻尼橡胶支座对桥梁的减隔震效果.     

组合隔震支座在大跨度连廊结构中的应用

以一连廊结构体系为研究对象,采用组合支座连接大跨度连廊和底部结构,实现释放温度应力和减小结构地震反应的目的。介绍了这种高位隔震方法的特点和减震原理,优化设计了隔震支座并分析了其特性,利用ANSYS程序对整体结构进行了非线性地震反应分析,最后对比分析了该隔震结构减震效果。结果表明,该连廊结构采用组合隔震支座后,不仅可以释放温度应力,而且可以显著减小结构地震反应。该方法可供连廊式结构隔震设计参考。     

铅芯橡胶支座隔震储罐地震响应特性分析

利用双线性恢复力模型模拟铅芯橡胶支座力学特性,探讨了不同类型场地上,隔震储罐在铅芯橡胶支座(LRB)与叠层橡胶支座(RB)两种隔震方式下的地震响应特点.研究表明:铅芯屈服力、场地类型和地震强度是影响LRB减震性能的主要因素.与RB隔震方式相比,LRB具有降低基底剪力、支座位移、晃动波高等优点,但减震效果并不总是好于RB方式,与场地类型和铅芯屈服力的选取有关.特别是Ⅳ类场地上RB支座更适合储罐隔震设计.支座最优屈服力参数选取需要根据储罐自振特点、场地类型和地震强度共同确定.LRB支座更适合在高烈度地区应用,减震效率高而且稳定.     

Seismic isolation design of the San Bernardino County Medical Center replacement project

The San Bernardino County Medical Center Replacement Project, located in Colton, California, consists of six separate building structures containing a total of approximately 920 000 ft² of floor space for hospital and support services. Five of the six buildings will be base isolated. Each of the five base isolated buildings is of different size and configuration, ranging from a six story, 360 000 ft² curved front Nursing Tower to a two story, 24 000 ft² rectangular shaped Central Plant building. The building structures will be framed with structural steel, utilizing concentric braced frames as the lateral force resisting system. The design ground motion for the site, which is located 3 km and 15 km from the San Jacinto and San Andreas faults respectively, is very severe. A base isolation system has been designed for this facility which will provide an essentially elastic building response to the design strong ground motion. The base isolation system is a hybrid passive energy dissipation system consisting of both linear and nonlinear and high damping rubber bearings along with viscous damping devices located at the base of the structure. The high damping rubber bearings provide both lateral stiffness which governs the fundamental period of vibration of the system, and hysteretic damping, while the viscous damping devices provide velocity dependent damping which serves to control overall building displacements. This will maximize the probability that this essential facility will remain fully operational after a major earthquake. Design criteria, structural analysis and design methodologies, and construction details are presented and discussed. The response of one of the base isolated structures is calculated utilizing actual recorded ground motions from the 1994 Northridge earthquake.     

Aseismic smart building isolation systems under multi-level earthquake excitations: Part I,conceptual design and nonlinear analysis

As a novel structural control strategy, tuned mass damper (TMD) inspired passive and semi-active smart building isolation systems are suggested to reduce structural response and thus mitigate structural damage due to earthquake excitations. The isolated structure’s upper stories can be utilized as a large scaled TMD, and the isolation layer, as a core design point, between the separated upper and lower stories entails the insertion of rubber bearings and (i) viscous dampers (passive) or (ii) resettable devices (semi-active). The seismic performance of the suggested isolation systems are investigated for 12-story reinforced concrete moment resisting frames modeled as “10+ 2” stories and “8+ 4” stories. Passive viscous damper or semi-active resettable devices are parametrically evaluated through the optimal design principle of a large mass ratio TMD. Statistical performance metrics are presented for 30 earthquake records from the three suites of the SAC project. Based on nonlinear structural models, including P-delta effects and modified Takeda hysteresis, the inelastic time history analyses are conducted to compute the seismic performances across a wide range of seismic hazard intensities. Results show that semi-active smart building isolation systems can effectively manage seismic response for multi-degree-of freedom (MDOF) systems across a broader range of ground motions in comparison to uncontrolled case and passive solution.     

基于ANSYS的LRB性能模拟验证分析

铅芯橡胶支座(LRB)是一种有效的隔震装置,它通过延长结构的周期、增加结构的阻尼来减小结构的地震反应.在结构隔震分析中,LRB扮演了一个很重要的角色,对其模拟程度的正确与否对整个结构的分析结果将产生很大影响.本文采用大型通用有限元程序ANSYS,对一个单自由度隔震体系进行了LRB性能模拟验证分析,分析表明:在合理确定输入地震动PGA临界点的前提下,采用ANSYS中的Combin40单元来模拟LRB的滞回性能,能获得较为满意的效果;同时通过与SAP2K时程分析比较,也验证了ANSYS分析结构隔震的可靠性.     

隔震与减震结构经济性的对比分析

隔震和减震技术作为目前新型的工程抗震技术,近年来得到了广泛的应用。先对比了隔震和减震结构与传统抗震结构在经济上的差别;然后再基于不同建筑结构在采用隔震还是减震技术谁更经济这一问题,详细考虑了上部结构的区别、混凝土用量、含钢量、隔震支座和减震阻尼器设备等方面的差异,结合某学校项目的 8个单体案例进行了详细的对比分析与研究。以期为今后的隔减震结构经济性对比分析提供参考。     

某多层“自定义”钢结构住宅隔震设计

结合某多层"自定义"钢结构住宅工程,采用基础隔震体系及非隔震体系,对结构抗震性能进行综合对比分析。分别以El centro波、天津波(南北向)、合成人工波为地震动输入求解结构的动力响应;对结构延性需求进行分析,用两个自由度的Bouc-Wen滞回模型进行非线性动力分析,对其生命周期成本进行简要分析。结果表明:渐于成熟的隔震技术同样适用于钢结构体系。该钢结构住宅考虑隔震设计后,在满足承载力要求的前提下,隔震层有效控制了上部结构振动,结构地震响应有效降低,层间加速度反应大大减小,建筑物的安全性能得到保证,满足了住宅结构对舒适性的更高要求。     

Probabilistic seismic risk assessment of modified pseudo-negative stiffness control of a base-isolated building

Pseudo-negative stiffness (PNS) control of a base-isolated structure, which has a large damping ratio at the isolation level, is used to suppress isolator displacement without large force transmission to the superstructure during extreme earthquakes. However, potential increases in floor acceleration in the superstructure are induced by the large damping ratio, especially for low-to-moderate seismic input level. In consideration of structural functionality and safety, a modified PNS (MPNS) control scheme based on the ‘ideal isolation control principle’ is proposed, considering different seismic intensity levels. The effect of the MPNS control is investigated from three aspects, namely floor acceleration, inter-storey drift and isolator displacement within a probabilistic performance-based seismic engineering framework. Comparisons are made between MPNS control, conventional PNS control and passive damping control. A benchmark base-isolated building is used as a case study. In the seismic performance evaluation, the seismic intensity measures for different response parameters are optimised. An extensive parametric study is also conducted to identify the optimal control parameter to conform to the ideal isolation control principle. Results demonstrated that the MPNS control is an effective solution to the challenging problem of improving structural functionality at low seismic intensity, as well as structural safety from collapse at extreme seismic intensity.