宿迁市文体馆基础隔震非线性时程分析研究

宿迁市文体馆4500座位，约13000m^2,位于8度抗震设防区，主体结构为钢筋混凝土结构空间框架，钢网壳屋盖。该工程采用基础隔震技术设计，在桩基顶面与上部结构之间设置架空层，用作安置设备管道及隔震层。隔震层由叠层橡胶隔震支座和粘滞阻尼器组成。对主体结构基础隔震采用空间模型非线性时程分析方法进行了详细分析，结果表明：采用基础隔震措施可显著降低结构地震作用，上部结构水平地震作用减震系数可按0．25采用；设置附加粘滞阻尼器能较好地解决降低地震作用和限制隔震层位移之间的矛盾，对提高隔震体系的性能具有重要作用。技术经济比较表明，本工程采用基础隔震措施，具有明显的社会、经济效益。     

不规则框架结构的组合隔震反应分析

为研究不规则框架隔震结构的地震反应,分别对一个传统抗震结构、一个铅芯叠层橡胶支座隔震结构和四个组合隔震结构(隔震层由铅芯支座和滑板支座组成)进行了弹塑性地震反应时程分析,研究隔震支座参数对隔震效果的影响。结果表明:采用组合隔震技术时,合理选择隔震层的铅芯支座布置位置、滑板支座的摩擦系数和铅芯叠层橡胶支座的型号,可以有效地降低上部结构的扭转效应;对于不规则的建筑隔震结构,为减小地面运动带来的扭转效应,建议采用由铅芯支座和滑板支座组合而成的隔震层,可对上部结构的扭转起到很好的抑制作用。     

SMA三维隔震复合支座单层柱面网壳结构的地震响应

大跨空间结构具有空间跨度大,结构整体刚度大、受力合理、耗材少、重量轻等优点,在世界各地应用前景非常广阔。但在强震作用下,此种结构破坏严重,经济损失惨重。震害经验与理论研究表明地震动是一种复杂的多维运动,只考虑单分量水平地震作用是不够的,还应考虑竖向地震分量对整体结构的影响。在作者研制的SMA-叠层橡胶支座的基础上,针对竖向刚度大、竖向隔震效果不明显的问题,研制一种在上部串联加入碟形弹簧的新型三维隔震支座,并建立一典型的单层柱面网壳结构模型,在输入不同峰值地震动情况下,通过时程反应分析可见,SMA三维隔震支座下结构位移、加速度峰值与普通橡胶支座对比明显降低,时程曲线趋于平缓,典型的杆件轴力也有明显降低,说明了SMA三维隔震复合支座隔震效果更好。     

隔震曲线梁桥不同等级地震的振动特性模拟分析

曲线桥梁抗震特性模拟分析对于曲线桥梁隔震、减震有着重要意义。基于隔震曲线桥梁设计过程中的特点,通过非线性水平弹簧单元对铅芯橡胶支座双向非线性的能力进行模拟,根据SAP2000科学选择强震观测地震波,并考量曲线桥梁本身存在的特性对桥梁振动特性产生的影响,针对隔震曲线桥梁在不同等级地震下振动特征进行模拟分析,其中,通过隔震曲线桥梁铅芯橡胶支座模型的构建和梁桥不同等级地震计算模型、输入地震波与传感器量测等步骤得到的模拟结果为:不同地震波与加速度峰值输入过程中,地震动较小下的支座水平刚度比较大,且结构相对稳定;地震幅值增大时,桥梁支座水平刚度减小,且支座的恢复力位移滞回变化曲线面积比较大,能够更多地将地震输入能量消散掉,减小能量不断向曲线桥梁上方传递的速度,可有效减轻地震反应,起到隔震的效果。     

单层工业厂房-TMD减震控制系统研究

提出了采用质量调谐减震控制技术对厂房结构进行减震控制的方法。利用屋盖系统作为附加质量,屋盖支座采用夹层橡胶隔震垫,建立了厂房-TMD系统模型,并用非线性时程分析法对其进行了多种地震动激励下的计算分析,探讨了厂房-TMD减震体系减震效果的参数影响及减震机理。结果表明,采用质量调谐减震技术对单层工业厂房进行减震是一种有效的方法。     

多点激励下LRB隔震桥梁地震反应分析

研究了地震地面运动多点激励，即空间变化效应对装有铅芯橡胶支座（Lead Rubber Bearing）的连续梁桥地震反应的影响。首先，利用三角级数法生成了拟合规范反应谱的多点人工地震动时程；然后利用非线性时程分析法数值仿真并比较了某五跨LRB隔震连续梁桥在一致激励、仅考虑地震动行波效应、仅考虑地震动部分相干效应、同时考虑行波和部分相干效应以及同时考虑行波、部分相干和局部场地土效应等七种工况下结构的减震效果。行波效应和部分相干效应对铅芯橡胶支座隔震桥梁影响不大，而局部场地土效应对该类桥梁的地震反应分析影响很大，应该引起重视。     

平扭耦联隔震体系隔震支座阻尼分布影响分析

为了研究铅芯橡胶隔震支座的阻尼分布对平扭耦联隔震体系隔震效果的影响,本文对一个三层两跨钢框架,通过调整上部结构负重块位置及下部铅芯橡胶隔震支座的分布位置,进行不同偏心工况下平扭耦联隔震体系地震模拟振动台试验,获得了不同偏心工况、不同阻尼分布情况下结构位移和加速度的时程曲线。试验和分析表明:隔震层阻尼中心与上部结构的质心位置接近,或者增大隔震层的阻尼半径,可显著地降低上部结构的扭转反应。     

基于系统地震易损性的桥梁隔震支座优化设计

隔震支座对桥梁抗震有重要意义,优化支座的参数可有效提升隔震效率。以一座三跨连续梁桥为例,建立了考虑桩-土-结构相互作用的有限元模型。将铅芯橡胶支座的特征强度及初始刚度视为优化变量,以最小化桥梁结构的系统地震易损性为目标。通过动力时程分析,得到支座参数对桥梁系统地震易损性的影响规律,确定支座参数的合理区间。高斯过程模型用来取代耗时的动力时程分析,降低隔震支座优化设计的计算成本。分析结果表明:铅芯橡胶支座的特征强度和初始刚度对桥梁系统地震易损性有明显影响;支座优化设计有效降低了桥梁系统地震易损性,大幅减小支座的剪切应变,提高了支座的隔震效率。     

基础隔震房屋模型振动台试验研究

本文结合日本在建的基础隔震实际工程,采用中国有关工厂生产的铅芯橡胶支座的作为基础隔震支座,进行了基础隔震房屋模型和基础固家房屋模型模拟地震动台试验,并引入能量分析方法对两种试验结果进行了分析比较。结果表明,基础隔震模型隔震效果明显,隔震层滞回变能有效吸收地震动入能量,减小模型结构的塑性变形和累积损伤。     

多层建筑结构水平剪扭-竖向地震反应的智能复合隔震控制

本文在提出了“碟形弹簧-橡胶隔震垫”和MR阻尼器组合而成的智能复合隔震系统的基础上，建立了智能复合隔震系统对多层建筑结构“水平剪扭-竖向”地震反应控制的设计计算方法。提出了智能复合隔震系统对建筑结构水平地震反应的模糊半主动控制策略和对建筑结构竖向地震反应的被动控制方法。以一个五层框架结构为例进行了仿真分析。分析结果表明，本文提出的智能复合隔震系统是一种十分简单和有效的隔震系统。它可克服建筑结构常规隔震系统的两个主要缺点，有效地抑制多层建筑结构的多维地震反应。     

Lead-rubber hysteretic bearings suitable for protecting structures during earthquakes

Lead-rubber hysteretic bearings provide in a single unit the combined features of vertical load support, horizontal flexibility and energy absorbing capacity required for the base isolation of structures from earthquake attack. The lead-rubber hysteretic bearing is a laminated elastomeric bearing of the type used in bridge structures, with a lead plug down its centre. Since the invention of the lead-rubber bearing, a total of eleven bearings up to a diameter of 650mm, with lead plugs ranging from 50 to 170mm in diameter, have been tested under various conditions, including vertical loads to 3·15 MN, strokes to ρ 110 mm, rates from 1 mm/h to 100 mm/s, and temperatures of ?35°C to + 45°C. In all of these tests, the lead-rubber bearings behaved satisfactorily and the hysteresis loops could be described reasonably well by assuming that the lead behaved as an elastic-plastic solid with a yield stress in shear of 10·55 MPa. The bearings showed little rate dependence at ～100 mm/s, though at creep rates of ～1 mm/h the force due to the lead dropped to 30 per cent of that at typical earthquake frequencies. The effect of many small displacements has been tested with 11000 cycles at ±3 mm. A total of 92 lead-rubber bearings have been used in New Zealand to base isolate one building and three bridges. They have yet to be used overseas. This paper describes the tests on the lead-rubber bearings, the results and a design procedure for selecting the size of the lead plug.     

双向地震激励下储罐隔震计算模型对比分析

铅芯橡胶垫基础隔震浮顶储罐在双向地震激励下,采用不同的隔震层恢复力计算模型计算所得的地震响应存在差异.不同工况下,若不加区别地选取将给储罐设计带来不利影响.通过分析高径比、阻尼比、隔震周期以及屈服强度参数对计算结果的影响得出,特定高径比时等效线性模型计算所得波高偏小,基底剪力和位移偏大,因此设计时应综合权衡各模型的计算...     

Three-dimensional seismic isolation bearing and its application in long span hangars

Based on the seismic response characteristics of space frame structures,a new type of seismic isolation bearing defined as a three-dimensional seismic isolation bearing(3DSIB) is developed in this paper.The bearing offers excellent properties such as multi-dimensional seismic isolation,reasonable rotation capability,good ability to resist lifting load,uncoupled stiffness in horizontal and vertical directions,etc.In the 3DSIB,the horizontal dimension is designed by combining the Teflon sliding device and helical spring,while the vertical dimension is developed by introducing disk springs or helical springs.The mathematical model of the 3DSIB was established and its performance with the critical parameters was tested on a shaking table.Furthermore,the 3DSIB was applied in a 120 m span hangar structure and simulated using SAP2000 software to evaluate its performance in practical structures.The performance of the structures with and without 3DSIB was compared.It is shown that the hangar structure with 3D bearings achieves a better performance.The axial force and acceleration response of the structures with 3DSIB are effectively reduced,while the displacement response of the bearing is within the predetermined range.     

新型组合隔震支座设计与性能研究

在已有研究基础上,为提高摩擦型组合隔震支座变形能力、改进各摩擦组件位移协调性,建立实体化和参数化计算模型,对新型三段两级摩擦组合隔震支座进行构造及内力分析研究,使用ABAQUS软件对摩擦阻尼器和组合隔震支座进行实体有限元模拟。针对设置常规隔震支座和新型组合隔震支座的某隔震结构案例进行建模及非线性时程地震响应分析,推导组合隔震支座出力和构造参数的关系。研究结果表明,文章所采用的摩擦阻尼器参数化建模方法是准确的,新型组合支座可明显降低支座拉应力,减小隔震层位移,提高结构抗倾覆能力。文章提出的针对摩擦阻尼器的简化单元可大幅提高有限元模型的计算效率。     

Reduced order observer based identification of base isolated buildings

The objective of this study is to identify system parameters from the recorded response of base isolated buildings, such as USC hospital building, during the 1994 Northridge earthquake. Full state measurements are not available for identification. Additionally, the response is nonlinear due to the yielding of the lead-rubber bearings. Two new approaches are presented in this paper to solve the aforementioned problems. First, a reduced order observer is used to estimate the unmeasured states. Second, a least squares technique with time segments is developed to identify the piece-wise linear system properties. The observer is used to estimate the initial conditions needed for the time segmented identification. A series of equivalent linear system parameters are identified in different time segments. It is shown that the change in system parameters, such as frequencies and damping ratios, due to nonlinear behavior of the lead-rubber bearings, are reliably estimated using the presented technique. It is shown that the response was reduced due to yielding of the lead-rubber bearings and period lengthening.     

AN ANALYTICAL HYSTERESIS MODEL FOR ELASTOMERIC SEISMIC ISOLATION BEARINGS

For the purpose of accurately predicting the seismic response of base-isolated structures, an analytical hysteresis model for elastomeric seismic isolation bearings is proposed. An extensive series of experimental tests of four types of seismic isolation bearings—two types of high-damping rubber bearings, one type of lead-rubber bearing and one type of silicon rubber bearing—was carried out with the objective of fully identifying their mechanical characteristics. The proposed model is capable of well-predicting the mechanical properties of each type of elastomeric bearing into the large strain range. Earthquake simulator tests were also conducted after the loading tests of the individual bearings. In order to show the validity of the proposed model, non-linear dynamic analyses were conducted to simulate the earthquake simulator test results. Good agreement between the experimental and analytical results shows that the model can be an effective numerical tool to predict not only the peak response value but also the force–displacement relationship of the isolators and floor response spectra for isolated structures. © 1997 by John Wiley & Sons, Ltd.     

Improved numerical analysis for ultimate behavior of elastomeric seismic isolation bearings

Elastomeric isolation bearings consist of multiple rubber layers with their top and bottom surfaces bonded to steel plates to restrict compressive deformation. Deformation constraints result in a variation of elastic modulus over the cross section of the rubber layers. In this paper, we describe a normalized compression modulus distribution on a circular rubber pad. The compressive and bending moduli of the rubber pad can be reproduced by applying the distribution to a series of axial springs. We also present a mechanical model for predicting the behavior of elastomeric seismic isolation bearings subject to large shear deformation and high compressive load. The mechanical model consists of a series of multiple shear springs at midheight and a series of axial springs at the top and bottom interfaces of the bearing. Simulation analyses of bearing tests were conducted to validate the proposed model. The analyses demonstrated that a model for circular lead-rubber bearings can successfully capture the influence of the axial load magnitude on the bearing shear behavior. The new model can simulate much more realistic behavior than prior models based on a uniform modulus assumption.     

三维隔震系统振动台实验研究

针对目前隔震体系尚不能减小竖向地震反应的缺陷,提出并研制了采用碟形弹簧的竖向半主动隔震装置。竖向半主动隔震装置是由碟形弹簧和外套油缸组成的,且由电磁阀控制油缸内油体与外接蓄油箱内油体间的油路,可实现竖向半主动隔震控制,提出了竖向隔震控制的半主动策略,结合水平隔震支座可实现三维隔震。通过振动台地震模拟实验,验证了三维隔震体系的效能,该研究对高烈度地区隔震技术的改善具有应用参考价值。     

SRC框格复合墙抗剪承载力计算及影响因素分析

SRC框格复合墙是在普通RC密肋复合墙基础上结合型钢混凝土概念而提出来的一种复合墙板,以轻钢龙骨代替框格内原有纵向受力钢筋,通过焊接或螺栓连接在梁柱轻钢龙骨节点处实现刚性或半刚性连接.在SRC框格复合墙模型试验基的础上,利用ANSYS程序对墙体受力过程进行了非线性有限元分析,提出了SRC框格复合墙抗剪承载力的实用计算公式,并对框格含钢率、轻钢强度等影响因素进行了有限元分析.研究结果表明:所提出的SRC框格复合墙抗剪承载力计算公式,与非线性有限元计算结果吻合较好,能够适应框格含钢率等不同因素变化的计算精度要求;提高肋梁中轻钢强度或含钢率可以有效提高墙体抗剪承载力,而不宜单独采用提高混凝土强度的方法.     

钢桁架(ST)约束混凝土组合柱抗震性能研究

目前,组合柱在建筑结构中进行了广泛应用和研究,研究表明:截面形式对组合柱的抗震性能有很大影响。首先,对钢桁架(ST)约束混凝土组合柱进行了试验研究。并在此基础上,利用有限元软件ABAQUS建立了数值分析模型;其次,基于数值分析模型,分析了组合柱中各部件的应力应变状态,分别考察了轴压比、缀板排列方式、体积配箍率、角钢肢宽与肢厚等因素对柱抗震性能的影响;最后,给出了组合柱在不同抗震等级下轴压比限值的建议值,可为后续组合柱的研究提供参考。研究表明:随着轴压比的增大,组合柱的延性变差,承载力先增大后减小;合理的缀板排列方式可有效抑制角钢的局部屈曲;随着体积配箍率的增大,组合柱的承载力有一定提升,延性提高较为显著;随着角钢肢宽和肢厚的增加,组合柱的承载力和延性均有显著提升。