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我国曾修建过一些无中横隔梁的装配式钢筋混凝土简支梁桥,随着时间的推移,重型车辆的不断增多,横向联系较弱的铰缝部位易出现开裂,桥梁产生了比较严重的损坏。以《装配式钢筋混凝土宽腹T梁桥上部构造》通用图中7.5,12,15 m桥梁为例,通过增设组合桥面及中横梁的加固方式,分别计算分析铰接变刚接前后各梁横向分布系数、荷载组合设计值及承载力的变化,论证在解决铰缝开裂、改善桥梁整体性方面铰接变刚接加固方法的理论可行性。 相似文献
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《土木建筑与环境工程》2021,(3)
为提高装配式钢筋混凝土框架结构的抗震性能,针对震后梁、柱构件损伤严重等问题,提出了一种新型框架梁端构造——人工消能塑性铰,即在框架梁端通过预埋机械铰实现梁、柱构件铰接,同时安装附加钢板承载并耗能。设计制作了8组不同截面形式和构造的附加钢板试件,并对装有不同附加钢板的人工消能塑性铰构造进行低周往复荷载试验,研究该构造的破坏模式,并通过滞回曲线、骨架曲线、等效粘滞阻尼系数、延性等研究其抗震性能。结果表明:塑性损伤可控制在附加钢板中间开缝段,有效利用钢板弯曲变形实现耗能,使该构造具有损伤可控和损伤构件可更换,其中,卷边槽型附加钢板可防止耗能段钢板过早屈曲并提高耗能能力。 相似文献
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提出一种基于冲击响应频响函数和模型修正理论的装配式板梁桥铰接缝病害动力评估方法。将铰接缝整体平均刚度作为待识别变量,以特定频率段内的频响函数相关性指数构造目标函数,改进既有的有限元模型修正技术,从而实现对病害铰接缝的定位以及损伤程度的定量识别。数值分析结果表明:利用文中所提方法可实现对全桥多个铰接缝不同程度病害的同步识别,且计算效率高;所提方法抗噪能力较强,可保证收敛到全局最优解;冲击荷载施加位置和测点布置位置对病害识别结果影响较小。对某装配式板梁桥进行现场动力试验,更新改造前后评估结果与桥梁实际状态相符,从而从实际应用角度证明所提方法的可靠性和实用性。 相似文献
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通过4个1/2比例装配式钢筋混凝土柱 钢梁框架节点低周往复荷载作用下的试验研究,分析了节点区加劲腹板厚度及开孔的影响,研究该新型节点连接构造的受力性能及装配式钢筋混凝土柱 钢梁框架单元的抗震性能。基于试验结果对试件的破坏特征、滞回性能及变形组成进行分析。研究结果表明:装配式钢筋混凝土柱 钢梁框架节点滞回曲线呈纺锤形,梁端塑性铰区充分耗散能量,具有良好的抗震性能;装配式螺栓连接钢筋混凝土柱 钢梁混合节点具有良好的连接质量;加劲腹板厚度的增加一定程度上减小了节点的剪切变形,加劲腹板开孔对节点受力性能影响不大;梁弯曲变形引起的层间侧移在强柱弱梁型钢筋混凝土柱-钢梁框架节点总侧移中所占比例最大,节点剪切变形所占比例较小。 相似文献
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分析了装配式空心板梁产生铰缝开裂、渗水、梁底板纵、横向裂缝的病害原因,从防水与铰缝两方面入手,阐述了各种病害的防治措施,从而提高了桥梁的结构安全性,延长了空心板梁的使用寿命。 相似文献
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在许多国家,预应力混凝土箱梁被认为是中等跨径(30~50m)混凝土梁最有效的结构形式。但是当混凝土梁的单跨长度超过50m时,相对钢梁,混凝土箱梁自重问题成为其最大约束。因此,在韩国,中等跨径桥梁主要采用钢箱梁。在20世纪,研究者们多次尝试提高预应力混凝土箱梁结构的有效性,最终采用混凝土-钢混合梁以减轻结构自重。但是,混合桥采用不同类型钢腹板及不同连接形式,会引起结构安全性能和使用性能的变化。为了全面了解钢腹板梁及钢腹板连接形式的性能,对5根带腹板的预应力混凝土梁进行静力荷载试验。这5根试件中,有2根混合梁采用波形钢腹板,而另3根采用桁架式钢腹板。结果显示:通过加强钢腹板与预应力筋的连接节点,可以改善使用性能相关问题(开裂荷载和挠度)及安全性能相关问题(刚度和极限承载力)。 相似文献
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由于在减小梁腹厚度和维修可行性方面的优势,在当代的建筑趋势中带体外预应力的预浇拼接式桥梁已很普遍了。连续梁可以减少伸缩缝数量,改善行车路况,但这种梁的内在结构特性很难分析(尤其在极限状态下)。本丈通过实验来检验比较带体外应力和带复合应力的两种跨连续梁在非对称载荷下的伸缩特性 相似文献
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The object of this study is to determine and propose a suitable joint type for spliced hybrid I-girder bridges consisting of steel girders at the mid-span and PSC (prestressed concrete) girders at the supports. Three joint types are experimentally tested on small-scale steel-PSC hybrid beams to determine the type offering the best combination of structural capacity and constructional convenience. One joint type, first suggested and trialed in the present study, is composed of multiple perfobond rib connectors attached in parallel to upper and lower plates located between the steel girder and the PSC girder. The two other types incorporate the stud connectors, which are widely used in connecting steel and concrete, but differ in the amount of reinforcement. The test results reveal that a joint consisting of parallel perfobond ribs and a joint consisting of studs with sufficient reinforcement show the similar beam strength and failure modes resulting from the failure of the PSC components. Notably, beams of the proposed joint type consisting of perfobond ribs, compared to those with studs, show higher stiffness and strength prior to reaching their ultimate strength, as well as lower strains in the joint. Indeed, with the parallel-perfobond-rib-type joint, advances in constructional convenience as well as structural capacity can be anticipated. Thus, it is concluded that the proposed joint type is a more suitable system for spliced steel-PSC hybrid girder bridges. 相似文献
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Richard Sause 《Structure and Infrastructure Engineering》2015,11(4):450-465
I-shaped steel girders with tubular flanges have been studied for application in highway bridges because of their large torsional stiffness compared to conventional I-shaped steel plate girders (I-girders). For straight girder bridges, the large torsional stiffness of a tubular flange girder (TFG) results in significantly greater lateral–torsional buckling strength compared to a corresponding I-girder. For horizontally curved girder bridges, the large torsional stiffness of a TFG results in much less normal stress, vertical displacement and cross-sectional rotation compared to a corresponding I-girder. The paper presents experimental and finite element analysis results for straight and horizontally curved TFG bridges. The results show the advantages of TFGs in comparison to conventional I-girders. A TFG demonstration bridge constructed in the USA is described. 相似文献
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进行了上弦杆为钢管混凝土、上下弦杆均为钢管混凝土的桁梁试件和空钢管桁梁试件的对比试验研究。研究结果表明,弦杆钢管内填充混凝土可提高弦杆的抗压、抗弯和径向刚度,改变节点失效模式,提高节点强度和刚度;弦杆为钢管混凝土的桁梁试件与空钢管桁梁试件一样,结构破坏均是因节点失效引起的;由于弦杆管内填充混凝土提高了节点的强度和刚度,不仅受压的上弦杆而且受拉的下弦杆管内填充混凝土,都会提高圆管截面桁梁试件的整体承载力。最后对管节点的承载力和桁梁试件整体承载力进行了讨论。 相似文献
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高墩桥在中国西部多山谷地区得到广泛的应用,然而对其抗震性能的研究并不充分,我国尚没有确立相关的分析设计方法与规范,因此对其进行非线性地震响应分析乃至倒塌分析以便研究其地震破坏模式是十分有意义的。本文以贵州省高速公路上跨越山谷的某大桥为例进行了研究。该桥是一座处于典型西部地区山地、桥体为双向分离的曲线T型刚构高墩混凝土桥。本文在对全桥进行动力特性分析的基础上,采用有限元软件LS-DYNA进行了全桥非线性时程响应分析,考虑桥体的碰撞,得到塑性铰形成与发展状况以及破坏模式,实现了对全桥倒塌过程的仿真。本研究结果对类似桥梁的抗震设计提供了有益的参考。 相似文献
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非规则梁桥纵向地震反应及碰撞效应 总被引:18,自引:0,他引:18
针对我国西部山区典型的非规则梁式桥梁 ,采用非线性时程地震反应分析方法 ,探讨了纵向地震作用下非规则梁桥相邻联的非同向振动特性和伸缩缝处的碰撞效应。结果表明 :当梁式桥相邻联周期相差较大时 ,纵向地震作用下 ,会导致伸缩缝处相邻梁体较大的相对位移和碰撞 ,碰撞导致低墩地震反应增大 ,对结构抗震不利。还提出了减小相邻联非同向振动和伸缩缝处碰撞效应的措施和方法 相似文献
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Longitudinal splicing of precast prestressed concrete (PSC) girders has recently gained increasing support as an effective method to accelerate bridge construction. The presence of the joints in the spliced girder may alter the dynamic properties of the system. In this study, a 20 m long full-scale spliced PSC girder was fabricated and tested to identify its dynamic characteristics against a monolithically fabricated girder (monolithic girder) with the same dimensions. The experimental program involved two phases. First, the dynamic properties of the test girders were identified from a modal test. Numerical modal analyses based on three-dimensional finite element models were also performed, and the calculated modal parameters were compared with the test results. The second phase involved a characteristic decrease of the natural frequency due to the damage to each girder after the load test. This study shows that the spliced girder provides a dynamic performance comparable to that of a monolithic girder in both the uncracked and cracked states. 相似文献