硬壳覆盖条件下土壤冻融期水盐运动规律研究   总被引：23，自引：4，他引：19  

李伟强  雷玉平  张秀梅  田魁祥 《冰川冻土》2001,23(3):251-257

采用大田试验,研究了水泥硬壳覆盖后冻融期土壤温度、水分、盐分的变化规律,采用室内土柱试验,研究了冻融交替时期土壤中的水盐运动规律,试验表明,土壤水泥硬壳覆盖后土壤的冻结时间减少,冻结深度变浅;明显抑制土壤水分的无效蒸发;明显抑制土壤在融冻时期的土壤返盐,同时由于“冻层滞水”在春季的融化,有淋洗表层土壤盐分的作用,使土壤表层脱盐,土柱脱融试验进一步说明,土壤经冻融过程后,土壤中的水盐发生了重新分布。  相似文献   

大跨预应力混凝土空间框架结构的地震振动台试验研究     

熊学玉  耿耀明  李春祥  黄鼎业 《地震工程与工程振动》2005,25(1):102-107

利用地震振动台对大跨预应力混凝土井式梁空间框架结构的抗震性能进行了实验研究。两个模型的实验结果表明：(1)大跨预应力井式梁空间框架结构可以提供大的楼层平面内刚度；(2)对称大跨预应力井式梁空间框架结构，可以不考虑耦合地震反应；(3)大跨预应力井式梁空间框架结构的竖向地震反应中心大而周边小；(4)在相同加速度但不同的地震波作用下，结构的竖向地震反应不同。  相似文献   

不同型式暗支撑短肢剪力墙抗震性能试验研究   总被引：6，自引：0，他引：6  

黄选明  曹万林  吕西林 《地震工程与工程振动》2005,25(3):60-66

本文选取短肢剪力墙结构体系中较为薄弱的抗震构件“一”形短肢剪力墙，采用不同的暗支撑型式进行了两个1／2缩尺的带暗支撑短肢剪力墙构件的低周反复荷载试验，比较分析了它们的承载力、刚度、延性、滞回特性、耗能能力及破坏机制，建立了其承载力计算模型与方法。计算结果与实测值符合较好。  相似文献   

半刚性连接钢管混凝土框架剪力墙结构的动力特性分析   总被引：1，自引：1，他引：1  

孙修礼  梁书亭  王群依  蒋永生  李玉莹 《地震工程与工程振动》2005,25(3):93-97

将钢管混凝土框架剪力墙结构作为连续弹性无限自由度结构，建立自由振动方程，分析了半刚性连接对结构自振周期和频率的影响，推导出半刚性连接框剪结构自振周期系数的计算公式。使用通用有限元程序ANSYS进行结构的模态分析，有限元分析结果和公式计算结果吻合良好。结果表明，半刚性连接使得结构自振周期增大，半刚性连接对高阶振型自振周期的影响很小。提出了地震区钢管混凝土框剪结构体系的设计建议，可供工程设计人员参考使用。  相似文献   

钢筋混凝土建筑抗倒塌设计   总被引：14，自引：2，他引：14  

于山苏幼坡  马东辉苏经宇 《地震工程与工程振动》2005,25(5):67-72

建筑抗倒塌问题近年来在欧美国家得到广泛关注，并颁布了相关的设计规范和标准。我国还没有制定有关建筑抗倒塌方面的规范和标准。本文提出一种基于建筑危险性的钢筋混凝土建筑抗倒塌设计方法。该方法将钢筋混凝土建筑分为四类，通过设置拉杆连接系统和Alternate Path设计提高建筑抗倒塌能力。  相似文献   

等幅侧向位移循环下柱混凝土纤维应变规律的试验研究     

傅剑平  李英民  王敏  陈小英  白绍良 《地震工程与工程振动》2005,25(6):88-95

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   

A contribution to seismic shear design of R/C walls in dual structures     

Andreas J. Kappos  P. Antoniadis 《Bulletin of Earthquake Engineering》2007,5(3):443-466

The paper focuses on the seismic response of walls in dual (frame + wall) structures, with particular emphasis on shear behaviour. Although dual structures are widely used in earthquake-resistant medium-rise and high-rise buildings, the provisions of modern seismic codes regarding design of walls for shear are not fully satisfactory, particularly in the (common) case that walls of substantially different length form part of the same structure. Relevant provisions of the leading seismic codes are first summarised and their limitations discussed. Then an extensive parametric study is presented, involving two multistorey dual systems, one with identical walls, and one with walls with unequal length, designed to the provisions of Eurocode 8 for two different ductility classes (H and M). The walls of the same structures are also designed to other methods such as those used in New Zealand and Greece. The resulting different designs are then assessed by subjecting the structures to a suite of strong ground motions, carrying out inelastic time history analysis, and comparing the results against design action effects. It is found that although modern code procedures generally lead to satisfactory performance (differences among them do exist), the design of walls seems to be less appropriate in the case of unequal length walls. For this case a modified procedure is proposed, consisting of an additional factor to account for the relative contribution of walls of the same length to the total base and an improved envelope of wall shears along the height; this improved method seems to work better than the other procedures evaluated herein, but further calibration is clearly required.  相似文献   

钢骨混凝土结构抗震研究综述     

吴平川  张令心  杨克勇 《世界地震工程》2007,23(4):13-18

介绍了钢骨混凝土结构的特点以及抗震研究发展现状，指出了这种结构在抗震研究中存在的主要问题和今后需要进一步研究的方向。  相似文献   

Towards error‐free hybrid simulation using mixed variables     

Tarek Elkhoraibi  Khalid M. Mosalam 《地震工程与结构动力学》2007,36(11):1497-1522

Two procedures are developed and implemented in a hybrid simulation system (HSS) with the aim of enhancing the accuracy and reliability of the online, i.e. pseudo‐dynamic, test results. The first procedure aims at correcting the experimental systematic error in executing the displacement command signal. The error is calculated as the difference between command and feedback signals and correlated to the actuator velocity using the least‐squares method. A feed‐forward error compensation scheme is devised leading to a more accurate execution of the test. The second procedure employs mixed variables with mode switching between displacement and force controls. The newly derived force control algorithm is evaluated using a parametric study to assess its stability and accuracy. The implementation of the mixed variables procedure is designed to adopt force control for high stiffness states of the structural response and displacement control otherwise, where the resolution of the involved instruments may favour this type of mixed control. A simple pseudo‐dynamic experiment of steel cantilever members is used to validate the HSS. Moreover, two experiments as application examples for the two developed procedures are presented. The two experiments focus on the seismic response of (a) timber shear walls and (b) reinforced concrete frames with and without unreinforced masonry infill wall. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

高耸钢筋砼结构日照变形监测与初步分析     

姜晨光  吕国栋  于绍峰  孙玲丽  黄家兴 《北京测绘》2002,(2):31-33,30

本文叙述了高耸钢筋砼结构日照变形的监测方法与监测过程，初步总结出了日照变形的基本规律。  相似文献