某空腹式双曲拱桥承载力现场测试与分析

为检验在役双曲拱桥的承载能力与动力特性,对某净跨为36 m空腹式双曲拱桥进行了静载试验、动载试验及空间有限元分析。测试结构的静态应变、动态应变、挠度、自振频率、振型及加速度等结构反应,计算得出冲击系数。将实测结果与有限元结果进行对比分析,结果表明:应变校验系数为0.5~0.9,结构具有较好承载力。实测的各阶频率及相应振型与有限元计算结果比较吻合,桥梁整体竖向刚度较好。     

桥梁荷载试验方案及承载能力评估

荷载试验是对桥梁结构进行直接加栽测试的一项必要的科学试验,是检验桥梁施工质量和安全状况的一项重要的工作。现根据对某大桥的荷栽试验过程以及承载力评估等方面内容的监测结果来为桥梁后期的养护以及长期监测提供参考数据。     

印度高等院校评估与鉴定新方法述评

印度国家评估与鉴定委员会2007年制定并实施了高等院校评估与鉴定新方法.本文分析了印度高等院校评估与鉴定新方法的内容和特点,并指出其评估程序及时间安排、具体的评估指标和按学校类型确定各个指标的不同权重等,以供我国参考.     

钢管混凝土拱桥施工工艺

某大桥为连续五孔无风撑、双承载面下承式的钢管混凝土系杆拱桥,以本桥为例,介绍钢管混凝土拱桥的施工工艺及要点。     

大跨度钢管混凝土拱桥的稳定与振动

通过理论研究和数值计算，详细分析了大跨径钢管混凝土双肋拱桥的侧倾稳定性和地震响应。首先，根据双肋拱桥结构在竖向均布荷栽作用下的侧倾稳定临界力的近似解析解，讨论了横撑设置、横撑刚度等因素对稳定性的影响。其次，基于多点激振理论和拟静力位移概念，介绍了拱桥结构的动力特点和地震动作用下的响应，并讨论了行波效应的影响。分析表明，地震行波作用对大跨度拱桥影响很大，横撑设置对稳定性敏感。     

大跨度钢管混凝土拱桥设计与施工综述

从设计、施工以及养护诸方面探讨了大跨径钢管混凝土拱桥建设中需注意的问题。设计方面包括拱轴线的选择、拱脚段负弯矩的处理、横撑设置与稳定性、桥道系的选择等；施工养护方面包括钢管焊接、缆索吊装与斜拉扣挂、泵送混凝土与灌注次序、施工控制与检测、防腐与换索等。     

项目教学法在二手车鉴定与评估课程教学中的研究

依据笔者在教学一线的经验,就高职院校汽车电子技术专业二手车鉴定与评估课程性质及相关岗位职业能力的要求,对该课程教学内容与教学方法的选取及实验实训等进行了研究,工学结合,课程教学重点放在了学生综合职业能力的培养上,使学生所学知识适应企业岗位需求。     

大跨度钢管混凝土拱桥的模态分析

模态分析是结构动力分析的基础。目前对大跨度钢管混凝土拱桥进行模态分析主要采用非线性有限元法,本文介绍了这种方法采用的单元类型和建模方法,以丫髻沙大桥为研究对象,针对桥梁结构的实际情况进行模态分析。     

倮裹钢管混凝土拱桥施工控制

结合钢管混凝土拱桥施工控制的实例,探讨钢管混凝土拱桥施工控制的主要内容与控制方法,对监控结果进行分析,并对施工中需注意的事项提出几点建议。     

钢管混凝土拱桥下部施工技术探究

钢管混凝土拱桥在当今桥梁建设中发挥着重要的作用,从钢管混凝土拱桥结构特点入手,分析拱桥下部结构施工技术对当今路桥事业的发展有重要作用.     

Strengthening an in-service reinforcement concrete bridge with prestressed CFRP bars

Carbon fiber reinforced polymer(CFRP)bars were prestressed for the structural strengthening of 8 T-shaped rein-forced concrete (RC)beams of a 21-year-old bridge in China.The ultimate bearing capacity of the existing bridge after retrofit was discussed on the basis of concrete structures theory.The flexural strengths of RC beams strengthened with CFRP bars were controlled by the failure of concrete in compression and a prestressing method was applied in the retrofit.The field construction processes of strengthening with CFRP bars-including grouting cracks,cutting groove,grouting epoxy and embedding CFRP bars,surface treating,banding with the U-type CFRP sheets,releasing external prestressed steel tendons-were introduced in detail.In order to evaluate the effectiveness of this strengthening method,field tests using vehicles as live load were applied before and after the retrofit.The test results of deflection and concrete strain of the T-shaped beams with and without strengthening show that the capacity of the repaired bridge,including the bending strength and stiffness,is enhanced.The measurements of crack width also indicate that this strengthening method can enhance the durability of bridges.Therefore,the proposed strengthening technology is feasible and effective.     

Strengthening an in-service reinforcement concrete bridge with prestressed CFRP bar

Carbon fiber reinforced polymer （CFRP） bars were prestressed for the structural strengthening of 8 T-shaped reinforced concrete （RC） beams of a 21-year-old bridge in China. The ultimate bearing capacity of the existing bridge after retrofit was discussed on the basis of concrete structures theory. The flexural strengths of RC beams strengthened with CFRP bars were controlled by the failure of concrete in compression and a prestressing method was applied in the retrofit. The field construction processes of strengthening with CFRP bars including grouting cracks, cutting groove, grouting epoxy and embedding CFRP bars, surface treating, banding with the U-type CFRP sheets, releasing external prestressed steel tendons-were introduced in detail. In order to evaluate the effectiveness of this strengthening method, field tests using vehicles as live load were applied before and after the retrofit. The test results of deflection and concrete strain of the T-shaped beams with and without strengthening show that the capacity of the repaired bridge, including the bending strength and stiffness, is enhanced. The measurements of crack width also indicate that this strengthening method can enhance the durability of bridges. Therefore, the proposed strengthening technology is feasible and effective.     

新FRP技术加固钢筋混凝土矩形柱改善延性的试验研究

Reinforced concrete （RC） columns lacking adequately detailed transverse reinforcement do not possess the necessary ductility to dissipate seismic energy during a major earthquake without severe strength degradation. In this paper, a new retrofit method, which utilized fiber-reinforced plastics （FRP） confinement mechanism and anchorage of embedded bars, was developed aiming to retrofit non-ductile large RC rectangular columns to prevent the damage of the plastic hinges. Carbon FRP （CFRP） sheets and glass FRP （GFRP） bars were used in this test, and five scaled RC columns were tested to examine the function of this new method for improving the ductility of columns. Responses of columns were examined before and after being retrofitted. Test results indicate that this new composite method can be very effective to improve the anti-seismic behavior of non-ductile RC columns compared with normal CFRP sheets retrofitted column.     

玻璃纤维布加固的钢筋混凝土梁试验研究与抗弯承载力计算

对9根玻璃纤维布加固的钢筋混凝土梁和3根对比梁进行了抗弯性能试验研究. 试验中考虑了配筋率、加固量、剪跨比与混凝土强度等级4个参数. 试验结果表明, 经玻璃纤维布加固的钢筋混凝土梁抗弯承载力有显著提高; 混凝土强度、配筋率、加固量对极限荷载有显著影响; 剪跨比对加固梁的破坏形态有影响. 根据不同的破坏模式, 提出了抗弯承载力计算方法.     

混凝土梁抗扭性能分析及承载力修正公式

采用ABAQUS有限元软件对各种强度等级下各龄期钢筋混凝土梁的受扭性能进行分析。各龄期混凝土的本构关系采用塑性损伤模型,受拉指标采用断裂能。有限元分析结果表明:各龄期混凝土的抗扭承载力随龄期的增长而增长,开裂前早龄期混凝土梁的抗扭承载力主要由混凝土承担,钢筋的贡献很小;前3d是混凝土扭矩增长最快的主要时间段,开裂扭矩和极限扭矩达到28 d的60%左右。最后,根据有限元参数分析结果,在现行规范的基础上提出了早龄期混凝土梁开裂扭矩和极限扭矩的修正公式。     

钢管混凝土系杆拱桥空间效应分析

建立平面与空间有限元模型，对郑州黄河公路钢管混凝土系杆拱桥(二桥)的活载横向分布系数、横粱、拱肋和系梁的受力特点进行比较分析，重点考察结构的空间效应问题，并分析了结构第一类空间稳定系数及其主要影响因素。分析结果表明，活载横向分布系数采用杠杆法与空间分析结果相近，可用于设计计算之中；系梁承受有较大的扭矩；吊杆横梁的受力性质接近于简支梁，而端横梁的受力要进行空间分析，考虑系梁扭矩的作用；K撑中的斜撑和系梁安装支架对提高结构稳定系数贡献较大。     

基于状态方程法的钢筋混凝土梁桥随机地震反应概率分析

钢筋混凝土梁桥在地震作用下结构可简化为一多自由度体系，基于状态方程法的一般原理，推导了钢筋混凝土梁桥的自由振动解和强迫振动解，并对结构在平稳白噪声激励下进行了随机地震反应分析。     

内嵌碳纤维板条抗剪加固混凝土梁性能研究

通过9根表层嵌入碳纤维增强塑料板条抗剪加固的钢筋混凝土梁和4根对比梁的静载试验,分析了构件的破坏形态、斜截面纤维应变分布特征及加固后极限承载力的影响因素。研究结果表明：嵌入式加固与外贴加固相比,可以明显地提高钢筋混凝土梁的抗剪承载力,并改变构件的变形性能。最后,在国内外研究资料的基础上,提出了加固后混凝土梁的受剪承载力计算公式,并对计算值与试验值进行了比较,结果吻合较好。     

Shear capacity of reinforced concrete columns strengthened with CFRP sheet

INTRODUCTION There is increased need in recent years for strengthening or rehabilitation of existing reinforced concrete structures adversely affected by overloading, construction material deterioration, seismic loads, structural deformation, etc. An effective method for increasing the shear capacity of reinforced concrete columns is the use of externally bonded carbon fiber reinforced plastic (CFRP) systems (ACI, 2002). FRP systems were first applied to reinforced concrete col-umns i…