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1.
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. 相似文献
2.
The low‐cycle fatigue model presented in the companion paper is employed for developing hysteresis and damage models for deteriorating systems. The hysteresis model performs strength reduction at a current displacement cycle by evaluating the loss in the energy dissipation capacity along the completed displacement path. Hence it is completely memory dependent. Pinching is accounted for implicitly by a reduced energy dissipation capacity in a displacement cycle. The model predicts the experimental results obtained from variable‐amplitude tests reasonably well. Response analysis under earthquake excitations reveals that both the maximum displacements and the number of large‐amplitude displacement response cycles increase significantly with the reduction in energy dissipation capacity, resulting in higher damage. Damage is defined as the deterioration in the effective stiffness of a displacement cycle, which is in turn related to the reduction in the energy dissipation capacity. A simple damage function is developed accordingly, consisting of displacement and fatigue components. It is observed that the fatigue component of damage is more significant than the displacement component for deteriorating systems under ground motions with significant effective durations. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
3.
Experimental evidence supporting the fact that results from quasi‐static (QS) test of low‐rise reinforced concrete walls may be safely assumed as a lower limit of strength and displacement, and energy dissipation capacities are still scarce. The aim of this paper is to compare the seismic performance of 12 reinforced concrete walls for low‐rise housing: six prototype walls tested under QS‐cyclic loading and six models tested under shaking table excitations. Variables studied were wall geometry, type of concrete, web steel ratio, type of web reinforcement and testing method. Comparison of results from dynamic and QS‐cyclic tests indicated that stiffness and strength properties were dependent on the loading rate, the strength mechanisms associated with the failure mode, the low‐cycle fatigue, and the cumulative parameters, such as displacement demand and energy dissipated. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
4.
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
5.
The residual capability of a damaged structure to resist further load is essential in optimal seismic design and post-earthquake strengthening. An experimental study on the hysteretic characteristics of prestressed concrete frame beams under different loading histories was performed to explore the influence of load history on energy dissipation and failure characteristics of the member. Based on the test results, the failure of the beam is def ined, and the relationship between the failure moment under cyclic load and from the skeleton curve is formulated. Finally, based on displacement and energy dissipation, a model for prestressed concrete beam damage-failure evaluation is developed. In this model, the effect of deformation level, cumulative dissipated energy, and loading history on prestressed concrete beam damage–failure is incorporated, thus it is applicable to stochastic earthquake forces. 相似文献
6.
In order to enhance the durability of high‐performance buckling‐restrained braces (BRBs) used in bridge engineering, which are expected to withstand severe earthquakes three times without being replaced, aluminum alloys were employed to manufacture BRBs. A series of low‐cycle fatigue tests, including 18 specimens, were conducted to address the low‐cycle fatigue strength of the aluminum alloy BRB. Test results of all specimens show that stable hysteretic curves were obtained without overall buckling occurrence. Failure mode of the welded aluminum alloy BRB is obviously affected by the ribs' welding under the variable or constant strain amplitude condition. Therefore, another type of aluminum alloy BRB, the bolt‐assembled BRB with or without spot‐welded stoppers, is proposed and tested. Results showed that the low‐cycle fatigue performance of bolt‐assembled BRBs with stoppers improved four to five times compared with welded BRBs. However, the stoppers' spot welding has an adverse effect on the failure mode because the crack, which induced the specimen's failure, initiated from the spot weld toes of the stoppers. Both bolt‐assembled BRBs with and without stoppers can meet the cumulative inelastic deformation requirement proposed for high‐performance BRBs under the constant strain amplitude, not larger than 2%. In addition, under the variable strain amplitude condition, only the bolt‐assembled BRB without stoppers has an excellent cumulative inelastic deformation capacity and sustains two cycles of 2.5% strain amplitude. Finally, recommended Manson–Coffin equations and preliminary cumulative damage formulae for welded and bolt‐assembled BRBs are given as the references of the strain‐based damage evaluation. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
7.
Dynamic damaging potential of ground motions must be evaluated by the response behaviour of structures, and it is necessary to indicate what properties of ground motions are most appropriate for evaluation. For that purpose, the behaviour of energy input process and hysteretic energy dissipation are investigated in this study. It is found that the momentary input energy that is an index for the intensity of input energy is related to the characteristics of earthquakes such as cyclic or impulsive, and to the response displacement of structures immediately. On the basis of these results, a procedure is proposed to predict inelastic response displacement of structures by corresponding earthquake input energy to structural dissipated damping and hysteretic energy. In this procedure the earthquake response of structures is recognized as an input and dissipation process of energy, and therefore structural properties and damaging properties of ground motions can be taken into account more generally. Lastly, the studies of the pseudodynamic loading test of reinforced concrete structure specimens subjected to ground motions with different time duration are shown. The purpose of this test is to estimate the damaging properties of ground motions and the accuracy of the proposed prediction procedure. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
8.
为研究远场长周期地震动作用下SRC柱的抗震性能,对5个不同含钢率和配箍率的SRC柱进行同级位移循环加载10次的拟静力试验,分析其抗震性能指标。结果表明:同级位移循环次数对SRC柱抗震性能的影响与循环位移幅值有关。位移角不大于1/50时,同级位移循环次数对SRC柱的裂缝发展、承载力退化和耗能能力的影响均很小;位移角1/40时,随着位移循环次数的增加,SRC柱的裂缝不断发展,角部混凝土逐渐掉落,承载力退化幅度开始加大,耗能能力逐渐增强,损伤程度增长较快;位移角1/33时,同级位移多次循环导致SRC柱的损伤急剧发展,承载力快速降低,耗能能力明显增强,破坏程度显著加重。提高含钢率和配箍率均可以改善SRC柱的抗震性能。 相似文献
9.
It is not common to purposely subject the web of wide‐flange or I‐sections to out‐of‐plane bending. However, yielding the web under this loading condition can be a stable source of energy dissipation as the transition at the corner from the web to the flanges is smooth and weld‐free; this prevents stress concentrations causing premature failure and eliminates uncertainties and imperfections associated with welding. Further, short segments of wide‐flange or I‐sections constitute a simple and inexpensive energy dissipating device as minimum manufacturing is required and leftovers not useful for other structural purposes can be re‐utilized. This paper proposes a new type of seismic damper in the form of braces based on yielding the web of short length segments of wide‐flange or I‐shaped steel sections under out‐of‐plane bending. The hysteretic behavior and ultimate energy dissipation capacity is investigated via component tests under cyclic loads. The experimental results indicate that the damping device has stable restoring force characteristics and a high energy dissipation capacity. Based on these results, a simple hysteretic model for predicting the load–displacement curve of the seismic damper is proposed, along with a procedure for predicting its ultimate energy dissipation capacity and anticipating its failure under arbitrarily applied cyclic loads. The procedure considers the influence of the loading path on the ultimate energy dissipation capacity. Finally, shaking table tests on half‐scale structures are conducted to further verify the feasibility and effectiveness of the new damper, and to assess the accuracy of the hysteretic model and the procedure for predicting its failure. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
10.
A new smooth hysteretic model for ductile flexural‐dominated reinforced concrete bridge columns 
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下载免费PDF全文 A new smooth hysteretic model is proposed for ductile, flexural‐dominated reinforced concrete bridge columns. Four columns designed per modern seismic codes were tested using monotonically increasing and variable‐amplitude cyclic loading protocols and ground motion loading to develop the model. Based on the test results, hysteretic rules for damage accumulation and path dependence of reloading were constructed. For damage accumulation, unloading stiffness degradation is correlated with the maximum displacement and hysteretic energy dissipation, while reloading stiffness degradation is set equal to the unloading stiffness degradation. Pinching severity is related to the residual displacement in the direction opposite to the loading direction. Strength deterioration is correlated with the damage index and does not occur until the damage index reaches a threshold, after which the deterioration is proportional to the increase of the damage index. For path dependence of reloading, reloading paths are classified into primary paths and associate paths. The primary paths are those that start from a residual displacement that is equal to or larger than the previous maximum one. The associate paths are those that do not belong to primary paths and tend to be directed towards certain points. Reloading without load reversal is assumed to be linear. Comparison with the results of pseudo‐dynamic tests using three consecutive ground motions showed that the proposed model closely matched the test results. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
11.
采用有限元软件ABAQUS,以锈蚀率（0%、5%、10%、15%和20%）为变量,对5根钢筋混凝土柱的力学性能进行了数值模拟,研究各试件的滞回性能、骨架曲线、延性及耗能能力,分析钢筋锈蚀率对承载力、延性、耗能和塑性铰转动能力的影响。研究结果表明:模拟分析得到的锈蚀钢筋混凝土柱的强度和变形与试验结果吻合较好,建立的有限元模型可用于锈蚀钢筋混凝土柱的力学性能分析;混凝土开裂前,锈蚀构件的力学性能基本与未锈蚀构件相同,混凝土开裂后,构件的承载力、屈服荷载、极限位移、延性等均随钢筋锈蚀率的增大而降低;轻度锈蚀构件的滞回性能和破坏形式与未锈蚀构件类似,随着钢筋锈蚀率逐渐增大,滞回环的饱满程度降低,“捏拢”现象严重,滞回曲线由“弓形”逐渐发展成“反S形”,耗能能力降低,破坏形式趋于脆性破坏,位移延性系数、平均耗能系数等指标逐渐下降。 相似文献
12.
为探究局部锈蚀矩形截面钢筋混凝土（RC）桥墩重度震损加固后的抗震性能,本文对拟静力破坏后的6个矩形截面RC桥墩试件进行扩大截面加固。通过加载试验,对加固桥墩试件从破坏形态、滞回特性、水平承载力、位移延性、侧向刚度以及耗能等方面进行了系统分析。结果表明:相比于普通箍筋,横向施加预应力的改进扩大截面加固方式对破坏后桥墩试件的抗震性能修复成效更佳;在同等位移幅值下,锈蚀率不断增大,桥墩试件抗震性能呈现逐渐降低的趋势;钢筋锈蚀位置上移,加固后桥墩试件的抗震性能提升;轴压比加大,加固后桥墩试件承载力和侧向刚度增大,但延性降低。 相似文献
13.
改进的钢筋混凝土结构双参数地震破坏模型 总被引：34，自引：4，他引：34
本文在分析现有结构地震破坏模型的基础下，提出了一种改进掇参数地震破坏模型。文中采用三线退化型恢复力模型对实际钢筋混凝土结构在实际地震作用下的变形与累积耗能，极限变形与极限滞回耗能进行了分析，通过模型计算的破损结果与实际在结果的对比，研究了模型参数，从而建立了钢筋混凝土结构的双参数地震破坏模型。 相似文献
14.
Non-linear seismic behavior of structures with limited hysteretic energy dissipation capacity 总被引：1，自引：0，他引：1
Pierino Lestuzzi Youssef Belmouden Martin Trueb 《Bulletin of Earthquake Engineering》2007,5(4):549-569
This paper investigates the non-linear seismic behavior of structures such as slender unreinforced masonry shear walls or
precast post-tensioned reinforced concrete elements, which have little hysteretic energy dissipation capacity. Even if this
type of seismic response may be associated with significant deformation capacity, it is usually not considered as an efficient
mechanism to withstand strong earthquakes. The objective of the investigations is to propose values of strength reduction
factors for seismic analysis of such structures. The first part of the study is focused on non-linear single-degree-of-freedom
(SDOF) systems. A parametric study is performed by computing the displacement ductility demand of non-linear SDOF systems
for a set of 164 recorded ground motions selected from the European Strong Motion Database. The parameters investigated are
the natural frequency, the strength reduction factor, the post-yield stiffness ratio, the hysteretic energy dissipation capacity
and the hysteretic behavior model (four different hysteretic models: bilinear self-centring, with limited or without energy
dissipation capacity, modified Takeda and Elastoplastic). Results confirm that the natural frequency has little influence
on the displacement ductility demand if it is below a frequency limit and vice versa. The frequency limit is found to be around
2 Hz for all hysteretic models. Moreover, they show that the other parameters, especially the hysteretic behavior model, have
little influence on the displacement ductility demand. New relationships between the displacement ductility demand and the
strength reduction factor for structures having little hysteretic energy dissipation capacity are proposed. These relationships
are an improvement of the equal displacement rule for the considered hysteretic models. In the second part of the investigation,
the parametric study is extended to multi-degree-of-freedom (MDOF) systems. The investigation shows that the results obtained
for SDOF systems are also valid for MDOF systems. However, the SDOF system overestimates the displacement ductility demand
in comparison to the corresponding MDOF system by approximately 15%. 相似文献
15.
钢混凝土组合截面外包薄钢组合管具有良好的防腐蚀性能和力学性能,可用于海洋、水下以及具有腐蚀性环境中的管道运输或结构受力构件中。利用截面分层法设计加工满足受弯承载能力的试验试件,并对其进行拟静力抗震性能试验,研究分析构件几何特征和填充混凝土强度对其耗能减震能力的影响。结果表明:各试验试件的荷载-位移滞回曲线图形均比较饱满,钢混凝土组合截面外包薄钢组合管具有良好的耗能减震能力。通过提高构件"约束效应系数"的方法可优化构件的截面设计。试件几何特征及填充混凝土的强度对试件的力学性能有较大影响,长细比较大的试件在往复加载制度下屈服位移明显减小。 相似文献
16.
本文设计了1片普通混凝土剪力墙试件和5片混杂纤维混凝土剪力墙试件,进行低周往复加载试验,研究混杂纤维混凝土分布位置和高度对剪力墙抗震性能的影响。根据拟静力试验数据,分析了墙体试件的滞回曲线、骨架曲线及关键点、位移延性、刚度退化性能、耗能能力以及关键位置钢筋应力应变分布情况。结果表明:（1）剪力墙试件中采用混杂纤维混凝土的区域以均匀的水平裂缝为主,有效控制了剪力墙的斜裂缝的产生,最终表现出弯曲破坏模式。（2）相比混杂纤维混凝土分布在约束边缘区域,混杂纤维混凝土分布在底部的试件滞回曲线更加饱满,耗能能力更好。（3）混杂纤维混凝土分布高度越高,滞回曲线越饱满。当分布高度大于0.3h （h为全长）时,混杂纤维混凝土分布高度的提升对承载能力和变形能力的影响较小。（4）混杂纤维混凝土的掺入提高了剪力墙的抗剪性能,在一定程度上可替代水平分布筋。 相似文献
17.
A. Benavent‐Climent 《地震工程与结构动力学》2007,36(8):1049-1064
This paper proposes a new model for quantifying the damage in structural steel components subjected to randomly applied flexural/shear stress reversals, such those induced by earthquakes. In contrast to existing approaches that consider the damage as a combination of the global amount of dissipated energy and maximum displacement, the proposed model represents the damage by two parameters: (a) the total dissipated energy and (b) the portion of the energy consumed in the skeleton part of the load–displacement curve. These parameters are employed to define a single ‘damage index’, which measures the level between 0 (no damage) and 1 (failure). The proposed model takes into account that the ultimate energy dissipation capacity of the steel component is path‐dependent and can change throughout the entire response duration. The new model is derived from low‐cycle fatigue static tests of round steel rods and steel plates subjected to bending and shear. The accuracy of the model is verified experimentally through dynamic real‐time shaking table tests. From these tests, it is observed that the proposed model measures the level of damage at any stage of the loading process reasonably well and predicts the failure of the structural component accurately. The model can be easily implemented in a computer program to assess the level of seismic damage and the closeness to failure in new structures or to evaluate the safety of existing ones. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
18.
本文研究配有高强钢筋的高强混凝土框架结构的耗能性能与抗震能力.对2层2榀1/2比例的模型结构进行了拟动力试验,分析了高强钢筋的高强混凝土框架结构在地震作用下的滞回反应和耗能能力,探讨了结构在地震作用下的破坏机理,滞回特性及薄弱环节或部位.结构的延性系数达到4.0以上,等效阻尼系数达到0.055以上.试验结果表明,此类结... 相似文献
19.
在已完成的包括16个构件的等位移循环加载钢筋混凝土柱的系列试验中，通过在其中3根柱的塑性铰区沿混凝土受力方向安设位移计，较准确测定了混凝土测试标距内的平均应变在一个加载循环内的变化规律及其随周数增长的变化规律；发现了单周最大压应变随周数的增长而持续增大，单周最大名义拉应变随周数增长而持续减小的重要现象；并与柱顶水平力-水平位移滞回规律实测结果相对应，结合截面受力特征对所得单周和多周应变变化规律的成因作了分析。 相似文献
20.
提出一种组合型减震结构,由钢框架、节点阻尼器和原结构连接组成,外附钢框架将节点阻尼器连接在原混凝土框架结构上形成的增设节点阻尼器的外附钢框架结构,节点阻尼器的剪切滞回变形可以减小结构自身需要消耗的能量,从而提高原结构抗震性能。对原混凝土结构和增设节点阻尼器的组合型结构进行了的振动台试验。通过分析结构在不同地震波激励下的加速度和位移响应,得出楼层加速度和层位移的减震效果。研究结果表明:该结构体系在小震作用下通过提高结构刚度来增强其抗震性能;在大震作用下则可借助节点阻尼器的变形耗能来提升结构耗能能力,结构加速度减震系数达到53%,层间位移减震系数高达72%,验证了增设节点阻尼器的外附钢框架结构的减震效果。 相似文献