碳纤维布加固钢筋混凝土柱的剪力-位移关系及其破坏位移增大系数分析     

吴波  王维俊  王帆 《地震工程与工程振动》2004,24(5):141-148

编制了碳纤维布加固钢筋混凝土柱的剪力-位移关系全过程分析程序,通过对多种工况下碳纤维布加固钢筋混凝土柱的剪力-位移关系进行大量计算分析,较全面地探讨了碳纤维布配箍特征值、轴压比、剪跨比、箍筋配箍特征值、纵筋配筋率、混凝土强度等参数对碳纤维布加固钢筋混凝土柱的剪力-位移关系及其破坏位移增大系数的影响。在此基础上,给出了碳纤维布加固钢筋混凝土柱破坏位移增大系数的回归计算公式,统计建立了碳纤维布加固钢筋混凝土柱的剪力-位移关系三折线模型中各无量纲特征参数的确定方法。  相似文献   

钢管约束混凝土压弯构件滞回性能的实验研究     

尧国皇  韩林海 《地震工程与工程振动》2004,24(6):89-96

进行了12个钢管约束混凝土压弯构件在往复荷载作用下的荷载-变形滞回性能的实验研究,包括6个圆试件和6个方试件。考察的主要参数是构件的轴压比。通过实验观察了这类构件在往复荷载作用下的破坏模态并分析了其荷载-变形滞回曲线的特点以及刚度退化规律,同时对钢管约束混凝土压弯构件极限承载力和抗弯刚度计算方法进行了初步探讨。  相似文献   

大跨预应力混凝土框架结构的静力弹塑性(pushover)分析   总被引：4，自引：1，他引：3  

熊学玉  李春祥  耿耀明  黄鼎业 《地震工程与工程振动》2004,24(1):68-75

基于美国规范ATC-40和N2方法,建立了大跨预应力混凝土框架结构竖向地震反应的静力弹塑性(pushover)分析方法。编制了预应力混凝土构件截面弯矩-曲率的计算程序。这些为评价大跨预应力混凝土框架结构的竖向抗震能力提供了有益的参考。结合具体工程实例进一步说明了该方法的实施步骤。  相似文献   

普强高性能混凝土受压应力-应变全曲线试验研究     

曲艺 《海岸工程》2008,27(3):53-58

通过普强高性能混凝土和普通混凝土的应力-应变全曲线试验研究，得到一系列应力-应变曲线。对普强高性能混凝土和普通混凝土的立方体抗压强度与棱柱体抗压强度的关系、棱柱体抗压强度与峰值应力所对应应变的关系及棱柱体抗压强度与初始弹性模量的关系进行了分析。结果表明，虽然普强高性能混凝土的力学性能与普通混凝土的力学性能存在一定的差别，但主要力学性能还是相似的。说明在不改变混凝土的力学性能的基础上通过对普通强度混凝土原材料的优选和配合比的优化能够提高混凝土的耐久性能。  相似文献   

Feasibility of pre-earthquake strengthening of buildings based on cost-benefit and life-cycle cost analysis, with the aid of fragility curves   总被引：1，自引：1，他引：0  

Andreas J. Kappos  E. G. Dimitrakopoulos 《Natural Hazards》2008,45(1):33-54

There are two fundamental questions this article aims to deal with. First, whether a pre-earthquake strengthening of a large and heterogeneous building stock (the emphasis here is on building types common in S. Europe), is economically feasible or not, and second what is the optimal retrofit level for mitigating the seismic risk. To this purpose contemporary decision making tools, namely cost-benefit and life-cycle cost analyses, are tailored to the needs of the present study, and implemented with the aid of an ad-hoc developed new software application (COBE06). A method for estimating the reduction in structural vulnerability due to retrofit is proposed, as well as a methodology to determine the optimum retrofit level using the fragility curve approach. Finally, the proposed methodology is used in a pilot application that concerns the city of Thessaloniki, and results are drawn for the feasibility of strengthening the reinforced concrete building stock in this city.  相似文献   

Laboratory and field performance of recycled aggregate base in a seasonally cold region     

Tuncer B. Edil  Bora Cetin  Ali Soleimanbeigi 《寒旱区科学》2017,9(3):183-191

The objective of this project was to characterize the freeze-thaw properties of recycled concrete (RCA) and asphalt (RAP) as unbound base and to assess how they behaved in the field for nearly 8 years. This paper includes an examination of existing information, laboratory studies of freeze-thaw behavior, and evaluation of data from MnROAD field-test sections in a seasonally cold region, i.e., in Minnesota, USA. Test sections were constructed using recycled materials in the granular base layers at the MnROAD test facility. One test section included 100% RAP, another 100% RCA, a third one a 50/50 blend of RCA/natural aggregate, and a fourth one only natural aggregate (Class 5) as a control. The stiffness (i.e., elastic modulus) was monitored during construction and throughout the pavement life by the Minnesota Department of Transportation, along with the variation of temperatures and moisture regimes in the pavement to determine their effects on pavement performance. The resilient modulus of each material was determined by bench-scale testing in accordance with NCHRP 1-28a, as well as by field-scale tests incorporating a falling-weight deflectometer. Specimens were subjected to as many as 20 cycles of freeze-thaw in the laboratory, and the change in their resilient modulus was measured. In the field-test sections constructed with the same materials as the base course, temperature, moisture, and field modulus (from falling-weight deflectometer tests) were monitored seasonally for nearly 8 years. From the temperatures in the base course layer, the number of freeze-thaw cycles experienced in the field was determined for each test section. Inferences were made relative to modulus change versus freeze-thaw cycles. Conclusions were drawn for long-term field performances of the recycled base (RAB) in comparison to natural aggregate.  相似文献   

肋柱式锚杆支挡结构的徐变次内力分析     

王后裕  刘志杰  言志信 《岩土工程技术》2008,22(3):127-130

采用老化徐变理论和等效弹性模量法,对肋柱式锚杆支挡结构的徐变影响提出了具体计算方法,并通过实例计算了支挡结构的徐变次内力。计算结果表明,在逆作法条件下,随着开挖深度的加大,岩土侧向压力也增大,使后期施工的混凝土构件产生的徐变次内力也随之增大;考虑徐变后使结构设计更加安全可靠,尤其坡脚处后期浇筑的混凝土构件,更要关注徐变的影响。  相似文献   

混凝土灌注桩桩头渗水的处理及预防措施          下载免费PDF全文

孙立宝 《探矿工程》2016,43(5):86-88

混凝土灌注桩桩头渗水对桩体混凝土受力和基底防水产生影响,对混凝土结构中的钢筋造成腐蚀。结合工程实例,对桩头渗水产生的原因进行分析,主要有操作经验不足、责任心不强,灌注器具不合格,混凝土质量指标不符合要求,灌注接近结束时拔管速度过快、灌注终了超灌高度测量不准,基土含水量高、水压大等;出现桩头渗水可采用人工剔除或注浆封堵处理;介绍了预防措施,包括加强作业人员培训,强化灌注器具检查,严控混凝土质量,重点监管终灌时的状态,做好基坑内降水工作等。  相似文献   

全珊瑚骨料海水混凝土力学性能试验研究   总被引：3，自引：1，他引：2       下载免费PDF全文

糜人杰  余红发  麻海燕  达波  袁银峰  张小平  朱海威  窦雪梅 《海洋工程》2016,34(4):47-54

为了探讨全珊瑚骨料海水混凝土的基本力学性能,并比较其与普通混凝土和轻集料混凝土的差异,通过实验系统测定了珊瑚混凝土的基本力学性能,建立了其轴心抗压强度(f_(c,m))、劈裂抗拉强度(f_(sp,m))、抗折强度(f_(t,m))与立方体抗压强度(f_(cu,m))之间的线性关系与计算公式。结果表明:在强度等级C20~C50的范围内,珊瑚混凝土的f_(c,m)和f_(sp,m)分别比普通混凝土的f_(c,m)和f_(sp,m)高出10%~48%和9%~33%,随着强度等级的提高,两种混凝土之间的差距在减小。珊瑚混凝土的f_(t,m)与普通混凝土的ft,m之间的差异规律与强度等级有关,较低强度等级的C30珊瑚混凝土ft,m比普通混凝土的f_(t,m)要高4%,而较高强度等级的C55珊瑚混凝土f_(t,m)比普通混凝土的f_(t,m)低13%。较高强度等级的C50珊瑚混凝土f_(c,m)、f_(sp,m)和f_(t,m)分别比页岩陶粒轻集料混凝土的f_(c,m)、f_(sp,m)和f_(t,m)低11%、0.9%和4%。  相似文献   

The Effect of Concrete Deformation on Displacement of an Axially Loaded Drilled Shaft     

Dongwook Kim  Hobi Kim  Kyung Joon Shin 《Marine Georesources & Geotechnology》2016,34(2):116-126

This article presents the settlement of drilled shafts resulting from their structural deformations. Although drilled shafts are widely used as foundations for settlement-sensitive structures such as bridges and high-rise buildings, the structural deformations of drilled shafts are not typically taken into account in the design process. However, if unexpected structural deformations of drilled shafts cause additional settlement to the foundation, the serviceability of the superstructure can be jeopardized. Unfortunately, very few research efforts have been made to quantify the structural deformation of drilled shafts; this needs to be addressed to accurately predict the settlement of drilled shafts. In this study, we investigate the effect of structural deformation on displacement of axially loaded drilled shafts. Finite element analyses were performed to quantify the structural deformation of drilled shafts. The analysis results indicated that the structural deformation of drilled shafts could be quite significant for long drilled shafts. The main factors that affected the structural deformation of drilled shafts were found to be pile length, the material properties of drilled shafts, and the relative humidity of surrounding soil. An approximate equation is proposed to estimate the long-term deformation of drilled shafts.  相似文献