高温冻土地区高等级公路片块石路基降温效果分析     

王青志  房建宏  晁刚 《岩土力学》2020,41(1):305-314

基于长期、连续的地温观测数据,对位于共和至玉树高等级公路沿线、平均海拔为4 260 m且处于高温冻土区的片块石路基温度、热状态、冻融循环过程和冻土人为上限及变化速率等进行了分析,研究了沥青混凝土和水泥混凝土路面对片块石路基下伏多年冻土的影响,以期对其适用性进行评价。研究发现,沥青混凝土路面的铺设使路基吸收了较多的热量,促使下伏多年冻土升温,导致多年冻土快速退化。观测期内,高温冻土地区沥青混凝土路面下片块石路基中心冻土退化速率为33.5 cm/a,几乎是天然地基的5倍。而且路基阴阳坡效应严重,阳坡路肩冻土退化速率为33.0 cm/a,明显大于阴坡路肩 （22.0 cm/a）。与沥青混凝土路面相比,水泥混凝土路面较高的热反射率、较小的热辐射吸收率,有利于抬升冻土上限或减缓冻土退化速率。但在观测期间,发现处于高温冻土区的高等级公路片块石路基在沥青混凝土路面下融化盘面积增长速率为12.24 m2/a,而在水泥混凝土路面下为9.28 m2/a,即融化盘面积以不同程度的速率始终在增大。因此,单纯的片块石层的存在和路面类型的改变,并未彻底解决高温冻土区高等级公路路基热平衡问题,建议增加补强措施或采用复合路基结构来应对其热稳定性问题。  相似文献   

Correlation studies on an RC frame shaking-table specimen     

Angelo d'Ambrisi  Filip C. Filippou 《地震工程与结构动力学》1997,26(10):1021-1040

This paper presents the correlation of the results of a new model for the dynamic analysis of reinforced concrete (RC) frames with the experimental time history of a two storey RC frame shaking-table specimen. The frame member model consists of separate subelements that describe the deformations due to flexure, shear and bond slip in RC structural elements. The subelements are combined by superposition of flexibility matrices to form the frame element. A non-linear solution method which accounts for the unbalance of internal forces between different subelements during a given load increment is used with the model. The ability of the proposed model to describe the dynamic response of frame structures under earthquake excitations is evaluated by comparing the analytical results with experimental evidence from a two-storey, one bay reinforced concrete frame tested on the shaking-table. The model parameters for the shaking-table specimen are derived from available experimental evidence and first principles of reinforced concrete. The effect of reinforcing bar slip on the local and global dynamic response of the test structure is assessed. © 1997 John Wiley & Sons, Ltd.  相似文献   

基于振动台模型试验探讨HVSR方法对黄土场地效应适用性的研究进展          下载免费PDF全文

王会娟  王平  柴少峰  许书雅  严武建  刘琨  王丽丽 《世界地震工程》2018,34(1):144-151

黄土场地效应作为地震动影响的显著因素,相关机理得到各国学者的关注。从近年来的研究成果可知:经验谱比法（HVSR法）和传统谱比法（传递函数）是研究场地对地震动影响效应的常用方法,振动台模型试验和数值分析是研究的有效手段。阐述了HVSR方法和传递函数2种方法的应用现状,并就不同场地条件对地震动的放大影响效应的研究现状及数值分析理论在场地效应中的应用进行了归纳总结,基于振动台模型试验结合数值仿真模拟对HVSR方法用于描述黄土场地效应的适用性进行展望。  相似文献   

框架结构振动台试验分析及数值模拟          下载免费PDF全文

康帅  楼梦麟  殷琳 《世界地震工程》2018,34(2):112-122

设计了10层的框架结构模型,进行了单向及双向作用时不同频谱地震波输入下的振动台试验,对试验结果进行了对比分析,揭示了结构的动力特性及地震反应之间的联系。结果显示:加速度、层间位移和应变在地震波作用下的变化趋势是一致的,结构的层间位移和加速度沿层高的分布不一样;双向作用下结构的反应并不一定比单向作用时的反应大。并依据试验过程当中的测试数据,进行了相应的数值模拟,与实测结果进行了对比,吻合较好,可以为后续类似的研究工作提供借鉴。  相似文献   

管线系统抗震性能研究方法综述          下载免费PDF全文

尚庆学  李吉超  王涛 《世界地震工程》2018,34(4):174-181

现代公共建筑非结构构件的投资比远远大于结构构件的建造成本比例,非结构构件在地震中的破坏会造成巨大经济损失。作为一种典型的非结构构件,管线系统的破坏往往导致建筑丧失给水、排水以及消防等多重使用功能。从拟静力试验、动力试验、振动台试验、数值模拟及易损性分析等角度对管线系统抗震性能研究方法进行了系统总结,介绍各类研究方法的应用实例及其利弊,并对管线系统抗震性能研究方法的发展方向进行了展望。  相似文献   

Experimental study of the effect of restraining rim design on the extreme behavior of pendulum sliding bearings          下载免费PDF全文

《地震工程与结构动力学》2018,47(4):906-924

While the performance of sliding isolators has been extensively validated under typical levels of ground motion, there have been very few experimental studies on the extreme behavior of sliding isolation bearings when the displacement limit is reached. However, to appropriately design isolated systems, from selecting the displacement capacity of the bearing to sizing the superstructure members, the behavior of the bearing as it reaches, and in some cases exceeds, the displacement limit should be well understood. A series of shake table tests to investigate the extreme behavior of double pendulum sliding bearings under strong ground motions were conducted at McMaster University. One major difference in sliding bearings around the world is how the motion of the bearing is restrained at the bearing's displacement capacity. Scaled bearings with four different types of restraining rim designs were included, representing typical sliding restraining rims found in Europe, Japan, and the United States. Experimental observation shows that the restraining rim has a significant influence on the extreme behavior of sliding isolation bearing. Key response parameters such as impact force and uplift are evaluated and compared between the different sliding bearing designs. While the bearing with no rim bearing imparts the lowest forces to the superstructure, it loses its functionality at a lower amplitude input than all the other rim types. For the other rim designs, the impact forces are significantly higher but they remained operational although damaged.  相似文献   

Is rocking motion predictable?          下载免费PDF全文

J. A. Bachmann  M. Strand  M. F. Vassiliou  M. Broccardo  B. Stojadinović 《地震工程与结构动力学》2018,47(2):535-552

An argument of engineers and researchers against the use of rocking as a seismic response modification technique is that the rocking motion of a structure is chaotic and the existing models are incapable of predicting it well. This argument is supported by the documented inability of rocking models to predict the motion of a specimen excited by a single ground motion. A statistical comparison of the experimental and the numerical responses of a rigid rocking oscillator not to a specific ground motion, but to ensembles of ground motions that have the same statistical properties, is presented. It is shown that the simple analytical model proposed by Housner in 1963 is capable of predicting the statistics of seismic response of a rigid rocking oscillator.  相似文献   

Shaking Table Test Study on Dynamic Characteristics of Bridge Foundation Reinforcement on Slopes   总被引：3，自引：3，他引：0  

Lei D  Qi Zhihui  Jiang Guanlu  Wang Zhimeng  Li Anhong 《中国地震研究》2017,31(3):403-413

With the fast development of bridge construction in mountainous and seismic areas, it is necessary to conduct related research. Based on the design of a shaking table model test, here are the following test results:the filtering effect exists in soil and is affected by the dynamic constraint conditions, the amplitude is strengthened around the natural frequency and weakened in other frequency bands in the Fourier spectrum. Since the acceleration scaling effect occurred on a sloped surface, the acceleration response decreases from the outside to the inside in soil. The dynamic response is relatively strong near the slip surface in bedrock due to the reflection of seismic waves. The failure mode of landslide is decided by the slope angle and slipping mass distribution, and the test shows the front row stabilizing piles should keep a proper distance from bridge foundation so that seismic resistance can be guaranteed for the bridge foundation.  相似文献   

跨越断层地震动对结构地震反应的研究进展          下载免费PDF全文

王文明  易思银  田利  王彦明 《地震工程学报》2017,39(3):578-586

地下管道、交通、电力系统等是重要的生命线工程,跨越断层的结构地震时具有较大的破坏风险,确保它们在地震时安全可靠的运行具有重要的意义。本文首先介绍了跨越断层地震动的基本特征,然后从跨越断层地震动模拟、跨越断层地震动对结构的影响以及振动台试验等几个方面进行论述,总结了跨越断层地震动对结构地震反应的研究现状和存在的问题。最后针对大跨空间结构需要研究的重点问题进行了展望。  相似文献   

Shake table testing on restoring capability of double concave friction pendulum seismic isolation systems          下载免费PDF全文

Felice Carlo Ponzo  Antonio Di Cesare  Gianmarco Leccese  Domenico Nigro 《地震工程与结构动力学》2017,46(14):2337-2353

After an earthquake, non‐negligible residual displacements may affect the serviceability of a base isolated structure, if the isolation system does not possess a good restoring capability. The permanent offset does not affect the performance unless the design is problematic for utilities, also considering possible concerns related to the maintenance of the devices. Starting from experimental and analytical results of previous studies, the restoring capability of Double Concave Friction Pendulum bearings is investigated in this paper. A simplified design suggestion for the estimation of maximum expected residual displacements for currently used friction pendulum systems is then validated. The study is based on controlled‐displacement and seismic input experiments, both performed under unidirectional motion. Several shaking table tests have been carried out on a three‐dimensional isolated specimen structure. The same sequence of seismic inputs was applied considering three different conditions of sliding surfaces corresponding to low, medium and high friction. The accumulation of residual displacements is also investigated by means of nonlinear dynamic analysis. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献