基于轴向位移的钢支撑疲劳损伤评估方法

在罕遇地震下,框架-中心支撑结构中的钢支撑常因局部屈曲位置的低周疲劳开裂而过早退出工作。本文在焊接工字形钢支撑低周疲劳试验研究基础上,提出了一种可用于框架-中心支撑体系非线性动力时程分析中钢支撑疲劳损伤评估的经验方法,并给出了相关步骤的算法流程。研究结果表明:本文方法以钢支撑轴向位移为损伤参量,能实时估算在随机位移荷载下钢支撑的低周疲劳累积损伤发展,并与试验结果吻合较好。     

低周反复荷载作用下复合耗能支撑钢筋混凝土框架结构的 …

本文介绍了三榀钢支撑钢筋混凝土框架结构（包括两榀复合耗能支撑框架,一榀普通支撑框架）在低周反复荷载作用下的试验结果,对复合耗能支撑框架结构在低周反复荷载作用下的工作性能（包括受力性能,破坏形态,滞回曲线,骨架曲线,延性和耗能能力等）进行了探讨,揭示了复合耗能支撑框架结构良好的抗震性能。     

低周反复荷载作用下复合耗能支撑钢筋混凝土框架结构的抗震性能试验研究

本文介绍了三榀钢支撑钢筋混凝土框架结构（包括两榀复合耗能支撑框架、一榀普通支撑框架）在低周反复荷载作用下的试验结果。对复合耗能支撑框架结构在低周反复荷载作用下的工作性能（包括受力性能、破坏形态、滞回曲线、骨架曲线、延性和耗能能力等）进行了探讨,揭示了复合耗能支撑框架结构良好的抗震性能。     

腹板开孔形状影响耗能支撑滞回性能试验研究

腹板开孔耗能支撑有效地避免了传统中心支撑斜杆的失稳破坏,具有较强的耗能能力.为研究腹板开孔形状对支撑滞回性能的影响,对腹板开菱形孔、椭圆孔及长圆孔耗能支撑试件进行了低周往复加载试验,分析了试件在循环荷载作用下的破坏机理、滞回性能、承载能力、刚度退化及耗能能力.试验结果表明:耗能支撑试件滞回曲线饱满,耗能性能优越.耗能支...     

轴向布置金属阻尼器力学性能研究

基于当前金属屈服消能器的应用特点和使用限制,提出一种轴向布置的金属阻尼器,其主要构造特征为耗能钢板直接与连接钢支撑组合,使得支撑与阻尼器组合为单一减震构件,解决了金属阻尼器需要斜撑对称布置的技术问题。推导了轴向布置金属阻尼器的屈服承载力、刚度计算公式;进行了构件的低周往复荷载试验,得到了轴向布置金属阻尼器的滞回曲线和骨架曲线,试验结果验证了有限元分析结果的准确性。同时,试验结果表明:轴向布置的金属阻尼器具有良好的延性和稳定的滞回性能。采用ABAQUS有限元软件对12组不同参数的轴向布置金属阻尼器进行数值模拟,研究了耗能板的不同布置方式、数量、耗能形式对阻尼器力学性能的影响,结果表明,耗能板宽厚比是轴向布置金属阻尼器滞回性能的最主要影响因素。     

Y形偏心钢支撑RC框架结构滞回性能试验研究

为了研究耗能段与RC框架梁采用不同连接节点形式对Y形偏心钢支撑RC框架结构滞回性能的影响,进行了2榀1/3缩尺Y形偏心钢支撑RC框架的低周反复荷载试验。介绍了试验过程,分析了试件在循环荷载作用下的破坏机理、滞回性能、延性、刚度退化规律以及耗能能力。试验结果表明:应用Y形偏心钢支撑加固RC框架合理可行,Y形偏心钢支撑承担了结构80%以上的水平荷载;U型外包钢与框架横梁连接的试件连接节点承载能力较高,耗能段耗能充分,结构的滞回曲线饱满;钢板与框架横梁底部连接的试件滞回曲线捏缩,耗能段耗能不充分,结构整体耗能能力差;U形外包钢与框架横梁连接的试件,耗能段破坏导致结构失效;钢板与框架梁底部连接的试件,连接节点破坏导致结构失效。     

钢筋混凝土柱低周疲劳性能的试验研究

结构的地震破坏可看作是超过屈服后的非弹性阶段的低周疲劳问题,而单根柱的破坏分析是整个框架失效分析的基础,本文通过八根１／２比例的钢筋混凝土柱在不同位移幅值下的等幅低周疲劳试验和六根非对称位移循环下低疫疲劳试验,探讨了在不同位移幅值下降筋混凝土柱累积损伤的发展规划以及低周疲劳寿命的表达式,给出了低周疲劳寿命不同位移水平下正负位移幅值比之间关系的表达式。希望以此为基础,建立更为合理的结构抗震破坏准则。     

钢筋混凝土柱考虑损伤累积的反复荷载-位移关系分析

为能在反复荷载作用下钢筋混凝土柱的荷载-位移关系分析中考虑柱低周疲劳性能,提出了一损伤模型,对柱中纵向受力钢筋和混凝土的损伤状态作评估与记录。将这一记录材料性能信息的损伤指标带入材料各自的恢复力模型以考虑产生损伤后材料的强度和刚度退化。基于多弹簧模型对不同变幅加载路径下及等幅低周疲劳加载下钢筋混凝土柱的空间反应进行了数值计算模拟。与已有试验结果比较表明,所提材料层次上的损伤累积模型以及考虑损伤累积效应的柱构件空间荷载-位移关系分析方法具有一定的精度,为钢筋混凝土柱的抗震性能分析提供了一个辅助工具。     

两种摩擦耗能器的比较试验研究

对两种不同形式的摩擦耗能器进行了低周反复荷载试验。工其工作性能和耗能性能，并进行了带有不同摩擦片和不带摩擦片的对比试验，分析了影响耗能器性能的因素，试验结果表明，摩擦耗能支撑具有稳定的滞回性能和极好的耗能能力，摩擦片的类型与性能对摩擦耗能支撑的性能有较大的影响。     

耗能段腹板高厚比对Y型偏心支撑钢框架滞回性能影响的试验研究

Y型偏心支撑钢框架是偏心支撑结构中抗震耗能的结构形式之一,为了研究Y型偏心支撑钢框架中耗能梁段腹板高厚比对结构滞回性能的影响,进行了2榀1/3缩尺Y型偏心支撑钢框架的低周反复荷载试验.本文主要介绍了试验过程,分析了Y型偏心支撑钢框架在循环荷载作用下的破坏机理、滞回性能、延性、刚度退化规律以及耗能能力.试验结果表明:Y型偏心支撑钢框架延性好、耗能能力强,耗能梁段腹板高厚比的改变对Y型偏心支撑钢框架强度、刚度以及耗能能力具有较大的影响.耗能梁段腹板高厚比设计得合理,Y型偏心支撑钢框架侧向刚度较大,可以满足在小震或中震作用下的结构变形要求,在大震作用下提供良好的变形能力和耗散地震能量的功能.     

Seismic energy dissipation under variable amplitude loading for rectangular RC members in flexure

The energy dissipation characteristics of reinforced concrete members that exhibit both strength and stiffness deterioration under imposed displacement reversals were investigated. To do this, 24 symmetrically reinforced concrete rectangular specimens were tested under stable variable and random variable amplitude inelastic displacement cycles. Stable variable amplitude tests were employed to determine the low‐cycle fatigue behavior of specimens where the loading sequence was the major variable. A 2‐parameter fatigue model was developed in order to express the variation of the dissipated energy in displacement cycles with the cumulative hysteretic energy. This model was then used to predict the energy dissipation of test specimens subjected to random variable amplitude displacement cycles simulating severe seismic excitations. It has been demonstrated that the remaining energy dissipation capacity for the next displacement cycle was dependent on the relative relationship between the maximal displacement cycle and the energy dissipated along the completed displacement path. The plastic energy dissipation capacity of reinforced concrete members is both displacement path dependent and cumulative hysteretic energy dependent.     

Cyclic behavior and failure mechanism of self‐centering energy dissipation braces with pre‐pressed combination disc springs

A new type of bracing system composed of friction energy dissipation devices for energy dissipation, pre‐pressed combination disc springs for self‐centering and tube members as guiding elements is developed and experimentally studied in this paper. The mechanics of this system are explained, the equations governing its hysteretic responses are outlined and large‐scale validation tests of two braces with different types of disc springs are conducted under the condition of low cyclic reversed loading. The experimental results demonstrate that the proposed bracing system exhibits a stable and repeatable flag‐shaped hysteretic response with an excellent self‐centering capability and effective energy dissipation throughout the loading protocol. Furthermore, the maximum bearing force and stiffness are predicted well by the equations governing its mechanical behavior. Fatigue and destructive test results demonstrate that the proposed bracing system can maintain stable energy dissipation and self‐centering capabilities under large deformation cyclic loading even when the tube members exceed the elastic limit and that a larger bearing capacity is achieved by the system that has disc springs without a bearing surface. Copyright © 2016 John Wiley & Sons, Ltd.     

新型黏弹性阻尼器足尺性能试验研究

黏弹性阻尼器是一种典型的被动控制装置,它可以通过黏弹性材料的剪切滞回耗能起到提高结构阻尼和减小结构地震或风振响应的作用。自主研发了损失系数不小于0.5的黏弹性材料,并基于此材料研发了新型国产黏弹性阻尼器。通过对黏弹性阻尼器足尺试件进行不同应变幅值、加载频率工况下的基本力学性能试验、以及低周疲劳性能试验,研究了不同工况下新型黏弹性阻尼器力学参数及其变化规律。试验结果表明:新型黏弹性阻尼器的损失系数在多数工况下处于0.3~0.4之间;其基本力学性能与加载频率相关性较小,随着应变幅值的增加表现出一定程度的软化特征,但在各应变幅值下均具有稳定的耗能能力;新型黏弹性阻尼器有良好的变形能力,在150%的应变下能保持稳定的基本力学性能,应变350%时仍未破坏;新型黏弹性阻尼器的疲劳性能较好,经低周疲劳加载后各项基本力学指标变化率均不超过25%。     

新型舌板黏滞阻尼器力学性能试验研究

本文提出了一种新型舌板黏滞阻尼器,通过对该黏滞阻尼器进行低周循环加载试验和抗低周疲劳性能试验,研究并验证了该阻尼器的耗能性能、抗低周疲劳性能及恢复力模型。研究结果表明:选取合适参数的舌板式黏滞阻尼器滞回曲线饱满,耗能性能与抗低周疲劳性能良好。Maxwell模型能够较好地描述该阻尼器力学行为,反映阻尼器在各种试验工况下的出力情况。该阻尼器设计与加工简单,对工程结构的耗能减震有着实际意义。     

低层装配式钢筋混凝土水平坐浆墙体抗震性能试验研究

为了研究低层装配式钢筋混凝土水平坐浆墙体的抗震性能,对3个不同剪跨比的低层装配式钢筋混凝土水平坐浆墙体进行了低周反复荷载试验。根据试验结果,分析了剪跨比对墙体的破坏形态、承载力、变形能力、刚度退化和耗能能力的影响。结果表明:随着剪跨比的减小,墙体的破坏形态由弯曲破坏转为剪切破坏;试件SW2和试件SW3的承载力相对于试件SW1分别提高68%和110%,延性分别降低21.8%和37.5%;试件SW1的耗能能力最好,刚度退化速度最缓慢;预制钢筋混凝土墙板与现浇边缘构件协同合作,连接处无竖向裂缝,墙体整体性较好,具有良好的抗震性能,可用于我国城镇建设中的低层住宅结构。     

Seismic energy dissipation in deteriorating systems through low‐cycle fatigue

Energy dissipation characteristics of structural members which exhibit both strength and stiffness deterioration under imposed displacement reversals are investigated. In the experimental part, 17 reinforced concrete beam specimens were tested under constant and variable amplitude inelastic displacement cycles. The constant‐amplitude tests were employed to determine the low‐cycle fatigue behaviour of specimens where the imposed displacement amplitude was the major variable. A two‐parameter fatigue model was developed in order to express the variation of dissipated energy with the number of displacement cycles. This model was then used to predict the energy dissipation of test specimens subjected to variable‐amplitude displacement cycles simulating severe seismic excitations. It has been demonstrated that the remaining energy dissipation capacity in a forthcoming displacement cycle is dependent on the energy dissipated along the completed displacement path. Moreover, it is observed that total energy dissipation is dependent on the length of the displacement path. Copyright © 2003 John Wiley & Sons, Ltd.     

Tensile strength equation for HSS bracing members having slotted end connections

In the previous study, the authors investigated the effect of w/t ratios on the behaviour of bracing members under symmetric cyclic loading in compression and tension. In this study, 11 bracing members with slotted end sections made of cold‐formed square hollow structural sections (HSS) were tested. The w/t ratios ranged from 8 to 28. Unlike the test results of other former studies obtained under compression‐oriented cyclic loading, the results of this study showed that bracing members having a smaller w/t ratio (<14) had less deformation and less energy dissipation capacity, and a shorter fracture life compared with other specimens. Such inferior behaviour resulted from early fracture at the slotted end section. This study compares tensile strength obtained from the design equations in the AISC LRFD manual and Eurocode 3 using the actual strengths of the tested specimens. This study found that for preventing early fracture in HSS bracing members, design fracture strength should be larger than design yield strength. Design strength equations are proposed for bracing members in special concentrically braced frames (SCBF). The proposed design equations are verified by experimental tests conducted under symmetric cyclic loading in tension and compression using two HSS bracing members designed according to the proposed equation. Copyright © 2007 John Wiley & Sons, Ltd.     

Conceptual study of X-braced frames with different steel grades using cyclic half-scale tests

In this paper,an experimental and analytical study of two half-scale steel X-braced frames with equal nominal shear strength under cyclic loading is described.In these tests,all members except the braces are similar.The braces are made of various steel grades to monitor the effects of seismic excitation.Internal stiffeners are employed to limit the local buckling and increase the fracture life of the steel bracing.A heavy central core is introduced at the intersection of the braces to decrease their effective length.Recent seismic specifications are considered in the design of the X-braced frame members to verify their efficiency.The failure modes of the X-braced frames are also illustrated.It is observed that the energy dissipation capacity,ultimate load capacity and ductility of the system increase considerably by using lower grade steel and proposed detailing.Analytical modeling of the specimens using nonlinear finite element software supports the experimental findings.     

变厚度钢板内芯防屈曲支撑试验研究

提出了一种变厚度钢板内芯防屈曲支撑（VTBRB）。设计了2个足尺变厚度钢板内芯防屈曲支撑试件,其中:1个试件在变厚度内芯端部设置加劲肋;另1个试件采用无肋式变厚度内芯。通过拟静力试验分析了2种内芯构造形式对变厚度钢板内芯防屈曲支撑的滞回性能、失效模式、受压承载力调整系数和累计塑性变形等的影响。研究表明:2个变厚度钢板内芯防屈曲支撑均表现较好的抗震耗能特性,其受压承载力调整系数均满足相关规范的限值要求。设置加劲肋可以减少变厚度内芯端部无粘结材料的磨损,并可以有效提高变厚度内芯防屈曲支撑的低周疲劳性能。