共查询到18条相似文献，搜索用时 171 毫秒
1.
通过14根铰支焊接工字形支撑在不同特征的循环轴向位移荷载下的低周疲劳试验，研究了循环轴向位移荷载的位移幅值、平均位移幅值及加载次序等因素对钢支撑低周疲劳及耗能性能的影响。研究发现，对称循环荷载中幅值越小，支撑翼缘局部屈曲发展越晚，其耗能及承载力退化也越平缓。文中提出了支撑在幅值6δ≤Δδ≤12δy的对称循环荷载下的疲劳寿命经验公式。试验表明，循环荷载的位移幅值是支撑疲劳损伤及耗能退化的最主要影响因素，过载峰效应及适当的平均压位移幅值改善了钢支撑低周疲劳及耗能性能。 相似文献
2.
钢筋混凝土柱考虑损伤累积的反复荷载-位移关系分析 总被引：7，自引：0，他引：7
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。 相似文献
3.
抗震结构的等效延性破坏准则及其子结构试验验证 总被引：6，自引：0，他引：6
基于试验结果与分析，本文提出了反映结构低周疲劳特性的“等效延性破坏准则”。将由结构非线性动力反应分析求得的、预计按本文所提破坏准则能引起柱破坏的三种不同位移反应时程，施加于三个柱试件，以验证所提准则的有效性与实用性。 相似文献
4.
5.
6.
分析钢筋混凝土(RC)梁与柱基于不同地震作用下的变形限值,对钢筋混凝土梁与柱进行低周往复循环加载拟静力试验。然后对试验进行仿真模拟,将试验结果与仿真模拟结果进行对比分析,发现二者结果相近,从而验证仿真模拟的可行性。在构件的荷载-位移曲线上获取屈服点、峰值点和极限点,分别计算这3个状态点对应的侧向位移值与构件计算长度的比值,则可得出构件在小震、中震和大震时对应的位移角值。改变梁、柱构件的剪跨比、配筋形式以及柱构件的轴压比等,来得到更多构件的荷载-位移曲线,将所有结果进行统计分析,得到钢筋混凝土构件在不同地震作用下的位移角限值。 相似文献
7.
为量化地震作用下钢筋混凝土（RC）柱损伤情况和变形,并将不同地震破坏状态下RC柱损伤和变形进行分析。从太平洋地震工程研究中心（PEER）数据库中收集91组RC柱抗震试验数据,选取4种广泛应用的构件损伤模型进行计算,将损伤发展曲线与层间位移角发展曲线进行对比分析。对RC柱损伤指标限值进行归一化处理,统计分析后得到不同破坏等级下的位移角限值,并给出了RC柱各破坏等级下的位移角限值与损伤指标限值对应关系。研究结果表明,牛荻涛损伤模型可更准确地评价地震作用下结构构件损伤程度,且与层间位移角发展曲线均呈近似线性增长趋势;不同破坏等级下的位移角限值验算保证率均＞80%,表明本文提出的位移角限值具有一定合理性。 相似文献
8.
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%。 相似文献
9.
考虑结构低周疲劳特性的地震反应谱 总被引：1，自引：3，他引：1
本文将钢筋混凝土框架和钢框架的低周疲劳性能引入地震反应谱的计算中,以地震反应累积损伤系数的形式考察了结构低周疲劳性能对地震破坏反应的影响。分析结果表明:1.结构破坏同时受结构本身强度及地震强烈强度的影响,普通结构在地震作用下有所损伤是难免的,但并不一定导致完全丧失抵抗外荷载能力的那种倒塌;2.结构强度和结构周期是引起地震作用下结构破坏的主要因素,当这两者均为中等大小时,结构低周疲劳性能及地震动持续时间也会对结构破坏产生影响;3.地震动持续时间对结构物损伤的影响受结构低周疲劳性能决定,它随结构本身的性质,尤其是结构寿命曲线而有差异。 相似文献
10.
纤维石膏板中不同间距灌注混凝土芯柱抗震性能试验研究 总被引：10，自引：0，他引：10
本文根据墙板承受竖向荷载的大小提出在空心石膏板中不同间距灌注混凝土芯柱方案,并对3组(12块)不同间距芯柱石膏板进行了低周反复荷载试验．探讨了构件的裂缝分布、破坏形态、极限承载能力、耗能能力、位移延性等受力特性。为此类板应用于多层住宅实际工程提供了试验依据。 相似文献
11.
Julian Carrillo 《地震工程与结构动力学》2015,44(6):831-848
Widely used damage indices, such as ductility and drift ratios, do not account for the influences of the duration of strong shaking, the cumulative inelastic deformation or energy dissipation in structures. In addition, the formulation and application of most damage indices have until now been based primarily on flexural modes of failure. However, evidence from earthquakes suggests that shear failure or combined shear‐flexure behavior is responsible for a large proportion of failures. Empirical considerations have been made in this paper for evaluating structural damage of low‐rise RC walls under earthquake ground motions by means of a new energy‐based low‐cycle fatigue damage index. The proposed empirical damage index is based on the results of an experimental program that comprised six shake table tests of RC solid walls and walls with openings; results of six companion walls tested under QS‐cyclic loading were used for comparison purposes. Variables studied were the wall geometry, type of concrete, web shear steel ratio, type of web shear reinforcement, and testing method. The index correlates the stiffness degradation and the destructiveness of the earthquake in terms of the duration and intensity of the ground motions. The stiffness degradation model considers simultaneously the increment of damage associated to the low‐cycle fatigue, energy dissipation, and the cumulative cyclic parameters, such as displacement demand and hysteretic energy dissipated. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
绝大多数针对极端作用下的结构连续倒塌分析,在分析过程中不能实时地根据构件的损伤状态对分析模型进行修改,也不能考虑连续倒塌过程中的各种碰撞问题。连续倒塌过程中发生的碰撞对结构响应预测有重大影响。本文依据钢筋混凝土框架结构发生梁-梁碰撞的机理,基于OpenSees平台建模,结合Matlab的混合编程计算碰撞力,通过添加碰撞时程力并对结构进行模型更新,合理地实现钢筋混凝土框架结构在强震作用下的连续倒塌过程中发生梁-梁碰撞的具体过程。将得到的结果和传统时程分析法的结果进行的对比表明,结合Matlab和OpenSees命令可以实时地计算碰撞力序列和对结构进行更新,梁-梁碰撞和构件的逐步失效使结构的水平位移和转角有一定的增大,竖向位移有一定减小。 相似文献
13.
结构地震损伤破坏,本质上是地震动输入能量超出结构或构件耗能能力所致。“能量”参数能够综合反映地震动强度、频谱特性以及强震持时对结构破坏的影响,本文基于能量耗散原理建立结构损伤模型,采用有限元软件ABAQUS对3榀单层单跨钢筋混凝土平面框架结构抗震性能进行数值模拟,通过损伤指数量化研究了地震作用下钢筋混凝土框架结构的损伤演化规律。研究表明:基于应变能耗储的结构损伤模型,能够合理有效地反映“位移首超破坏”与“累积损伤破坏”模式,且上、下界收敛;模拟分析得到的滞回曲线和骨架曲线与试验数据吻合较好,数值建模方法适用于以梁、柱构件为主的框架结构抗震性能分析;耗能构件框架梁能够对结构损伤破坏发展和抗震性能劣化起到一定延缓作用,承力构件框架柱的损伤加剧会加速结构抗震性能的劣化;加载幅值较小时,结构依靠混凝土裂缝闭合摩擦消耗能量,“位移首超破坏”所致损伤所占比例较大,随着位移幅值及循环次数的增加,“累积损伤破坏”所致损伤所占比例逐渐增大。 相似文献
14.
本文通过弹性和弹塑性时程分析,研究了水平地震作用下梁铰型屈服RC框架模型结构的楼层屈服剪力系数、基本自振周期、楼层数3个因素对弹塑性位移增大系数的影响,通过非线性回归分析给出了弹塑性层间位移增大系数经验公式;通过分析滞回耗能沿楼层高度的分布,初步确定了梁铰型屈服RC框架结构的薄弱楼层位置;基于结构损伤分析,讨论了抗震规范中RC框架结构弹塑性层间位移角限值的水准。 相似文献
15.
Over the last two decades, the probabilistic assessment of reinforced concrete (RC) structures under seismic hazard has been developed rapidly. However, little attention has been devoted to the assessment of the seismic reliability of corroded structures. For the life‐cycle assessment of RC structures in a marine environment and earthquake‐prone regions, the effect of corrosion due to airborne chlorides on the seismic capacity needs to be taken into consideration. Also, the effect of the type of corrosive environment on the seismic capacity of RC structures has to be quantified. In this paper, the evaluation of the displacement ductility capacity based on the buckling model of longitudinal rebars in corroded RC bridge piers is established, and a novel computational procedure to integrate the probabilistic hazard associated with airborne chlorides into life‐cycle seismic reliability assessment of these piers is proposed. The seismic demand depends on the results of seismic hazard assessment, whereas the deterioration of seismic capacity depends on the hazard associated with airborne chlorides. In an illustrative example, an RC bridge pier was modeled as single degree of freedom (SDOF). The longitudinal rebars buckling of this pier was considered as the sole limit state when estimating its failure probability. The findings show that the life‐cycle reliability of RC bridge piers depends on both the seismic and airborne chloride hazards, and that the cumulative‐time failure probabilities of RC bridge piers located in seismic zones can be dramatically affected by the effect of airborne chlorides. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
16.
To meet the demand for an accurate and highly efficient damage model with a distinct physical meaning for performance-based earthquake engineering applications, a stiffness degradation-based damage model for reinforced concrete (RC) members and structures was developed using fiber beam-column elements. In this model, damage indices for concrete and steel fibers were defined by the degradation of the initial reloading modulus and the low-cycle fatigue law. Then, section, member, story and structure damage was evaluated by the degradation of the sectional bending stiffness, rod-end bending stiffness, story lateral stiffness and structure lateral stiffness, respectively. The damage model was realized in Matlab by reading in the outputs of OpenSees. The application of the damage model to RC columns and a RC frame indicates that the damage model is capable of accurately predicting the magnitude, position, and evolutionary process of damage, and estimating story damage more precisely than inter-story drift. Additionally, the damage model establishes a close connection between damage indices at various levels without introducing weighting coefficients or force-displacement relationships. The development of the model has perfected the damage assessment function of OpenSees, laying a solid foundation for damage estimation at various levels of a large-scale structure subjected to seismic loading. 相似文献
17.
Reinforced concrete (RC) structures in low to moderate seismic regions and many older RC structures in high seismic regions include columns with steel reinforcement details not meeting the requirements of modern seismic design codes. These columns typically fail in shear or in a brittle manner and their behavior must be accurately captured when RC structures are modeled and analyzed. The total lateral displacement of a low ductility or shear critical RC column can be represented as the sum of three displacement components: (1) flexural displacement, (2) displacement due to slippage of the reinforcing bars at column ends, and (3) shear displacement. In this study, these three displacement components are separately modeled and then combined together following a proposed procedure based on the expected overall behavior of the column and its failure mechanism. A simplified slip model is proposed. The main objective of this research is to develop an easy-to-apply method to model and capture the cyclic behavior of RC columns considering the shear failure mechanism. The proposed model is validated using the available data from RC column and frame experiments. 相似文献
18.
钢筋混凝土结构震后损伤鉴定中,最常见的方式是鉴定者观察房屋破坏现象,根据经验给出震损等级。该方法直观高效,但对鉴定者的专业经验要求较高,且鉴定结果的主观差异较大。对此以RC框架柱为对象,开展了基于震损现象的震损量化鉴定方法研究:在RC框架柱震损现象量化试验基础上给出基于构件骨架曲线特征阶段的震损分级方法;对7个RC框架柱试件进行了改进Park-Ang损伤指数分析,建立了RC框架柱损伤指数-震损分级-震损现象的对应关系;基于RC框架柱的试验结果及典型震害编制了RC框架柱震损图集,并给出了使用图集进行框架柱震损鉴定的流程及方法。使用该方法对2个实际震害中的RC框架柱进行了震损鉴定,可为更加客观以及准确地开展钢筋混凝土结构的震损鉴定提供参考。 相似文献