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上部结构刚度改变对桩-土-杆系结构动力相互作用的影响 总被引:4,自引:0,他引:4
采用改进的Penzien模型 ,利用研制开发的桩 -土 -杆系结构动力相互作用分析程序DIPSFSA ,对带支撑和不带支撑的钢框架均按刚性基础和考虑桩土参与作用两种情况进行地震反应分析 ,研究上部结构刚度改变对桩 -土 -结构动力相互作用的影响。结果表明 ,在Ⅲ、Ⅳ类场地土条件下 ,无论上部结构是否加设支撑 ,桩土参与共同工作对上部结构地震反应均有不容忽视的影响 ,且上部结构相对于地基的刚度越大 ,桩 -土 -上部结构之间的共同工作效果越明显。从而说明 ,软土地基上结构刚度越大 ,结构不一定越安全。 相似文献
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在桩 土 上部结构动力相互作用中 ,二阶效应及节点板域的剪切变形对于高层钢框架结构的地震反应内力、位移等均有不可忽视的影响。研制开发的桩 土 平面杆系结构动力相互作用分析程序DIPSFSA不仅可直接求解考虑共同工作后钢框架结构各杆件的内力和位移 ,而且还可以考虑节点剪切变形及轴力引起的二阶效应 ,更准确地模拟结构的实际受力与变形特征 ,便于Ⅲ ,Ⅳ类场地土上钢框架的实际设计与应用 相似文献
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考虑桩-土-桥梁结构相互作用振动台试验研究 总被引:22,自引:0,他引:22
实验室进行相互作用试验对进一步认识和完善桩 -土 -结构相互作用研究有十分重要的意义。本文设计实现了一个进行桩 -土 -结构相互作用试验研究的土箱模型 ,并在振动台上进行了自由场模型试验 ,通过自由场土层反应理论分析检验了土箱设计的合理性。在此基础上进行了单柱桩墩模型、单柱墩 2× 2模型、双柱墩 2× 2模型和双柱墩 3× 2模型的试验 ,探讨了不同桩基形式和桥墩结构在不同输入地震动下的地震反应规律及结构破坏特征 ,对比研究了单柱墩与双柱墩桥梁抗震性能 ,为进一步验证和研究相互作用理论分析提供了基础数据 相似文献
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地基-基础-支护结构-上部结构动力相互作用体系的计算分析研究 总被引:1,自引:0,他引:1
利用通用有限元程序ANSYS针对地基-基础-支护结构-上部结构动力相互作用体系进行了计算分析,探讨了支护结构的存在对高层建筑抗震性能的影响,计算中土体的本构模型采用等效线性模型,利用粘-弹性人工边界作为土体的侧向边界,并研究了支护排桩长度和刚度、上部结构刚度以及基础型式等参数对动力相互作用体系的动力特性及地震反应的影响。 相似文献
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基于桩-土-结构动力相互作用体系振动台模型试验的数据,研究了动力相互作用体系对上部结构的影响.研究结果表明:由于动力相互作用体系的影响,上部结构频率减小,阻尼增大;在输入地震波加速度峰值较小时,桩-土体系对地震波起放大作用,输入地震波加速度峰值较大时,桩-土体系起减震作用;在地震波由振动台台面传到土体表面的过程中,桩-土体系改变了地震波的频谱成份. 相似文献
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大跨斜拉桥的自振频率和阻尼低以及空间尺度大,其地震响应受桩基础、场地土特性和地震动空间效应的影响较大。然而,由于试验条件和技术所限,目前尚缺乏相关的全模型振动台试验研究。以一座试设计主跨1400m超大跨斜拉桥为原型,设计和制作了一座几何相似比为1/70且包括上部结构、桩基础和场地土等在内的试验模型,通过振动台试验研究了多点激励对桩-土-斜拉桥全模型地震响应的影响及其规律。试验结果表明:纵向多点激励使一侧主塔的纵向位移、一侧主塔和桥墩的纵向桩-土-结构相互作用效果以及主跨一侧竖向位移增大,而另一侧减小;横向多点激励使一侧主塔的横向位移和一侧桥墩的横向桩-土-结构相互作用效果增大,另一侧减小,但使两侧主塔的横向桩-土-结构相互作用效果和主跨两侧横向位移响应均增大;桩-土-结构相互作用对斜拉桥的加速度响应产生不利影响。基于上述结果,大跨斜拉桥的抗震设计或性能评估应考虑多点激励和桩-土-结构相互作用的影响。 相似文献
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桩-土-结构相互作用下的Pushover分析 总被引:1,自引:0,他引:1
利用SAP2000有限元软件,对考虑桩-土-结构相互作用的高层框架结构进行了Pushover分析。分析计算过程中建立了考虑桩-土-结构相互作用的有限元模型和文克尔梁模型。研究结果表明:考虑桩-土-结构相互作用的Pushover分析方法可以简便、有效地预测桩-土-结构体系的地震反应;文克尔梁模型更方便实际工程应用。 相似文献
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采用ANSYS软件分别就刚性地基假定下上海中心大厦Miranda模型、考虑桩-土-结构相互作用的上海中心大厦Miranda模型进行了动力时程分析,并对两者进行了比较,得出一些有益的结论.本文还提取了相互作用模型基底处的加速度耦合项,与原地震波叠加,形成修正地震波,将修正地震波输入到以刚性地基为假定的上部结构中以考虑相互作用带来的影响,为减小结构抗震计算规模提供了支撑. 相似文献
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The two large‐scale shaking table tests of tall buildings on soft soils in pile group foundations are performed to capture the effect of the seismic pile‐soil‐structure interaction (PSSI) on the dynamic responses of the pile, soil, and structure. The two different model conditions are observed, including a fixed‐base structure and a structure supported by 3‐by‐3 pile group foundation in soft soil, representing the situations excluding the soil‐structure interaction (SSI) and considering the SSI, respectively. In the tests, the superstructure is a tall building with 12‐story reinforced concrete frame. The pile‐soil‐structure system rests in a shear laminar soil container, which is designed to minimize the boundary effects during shaking table tests. The two models are subjected to various intensity seismic excitations of Shanghai bedrock waves, 1995 Kobe earthquake, and 1999 Chi‐Chi earthquake events. According to the experimental and analytical results, SSI systems have longer natural periods than the fixed‐base structure. In addition, soft soil has amplification effect under smaller seismic excitations and isolation effects under larger earthquake intensities. The strain amplitude at the top of pile is large, and the strain at the middle and tip is relatively small. Whereas the contact pressure is small at the top of pile and large at the middle and tip. From the dynamic responses of the superstructure, it is found that the PSSI amplifies the peak displacements and interstory drifts of the structures supported by pile group foundations by comparing with the fixed‐base structure. Whereas the peak acceleration and interstory shear force of the structure are reduced considering seismic PSSI. The results show that the seismic SSI is not always favorable, however, it may increase certain dynamic responses of the structure. Consequently, the seismic SSI should be considered reasonably, providing insight towards the rational seismic design of buildings rested on soft soils. 相似文献
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利用ABAQUS有限元软件建立了不同框架结构地震反应的计算模型,对框架结构地震下的反应进行了数值模拟研究,得出了不考虑土结动力相互作用以及考虑土结动力相互作用两种情况下框架结构地震反应的差异,为设计人员进行更精准的结构设计提供了指导。 相似文献
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根据上海某高层建筑地基基础结构数据建立软土地基上桩基础高层建筑平面动力有限元计算模型,以横观各向同性材料模拟软土地基,弹性阻尼人工边界模拟地基半无限体,薄膜单元模拟桩-土间接触滑移性能,并考虑桩-土-结构相互作用,采用上海地铁某车站地震监测数据作为地震波输入进行动力有限元计算。基于此计算模型,在其他条件不变的情况下选择各种桩基直径进行计算,根据计算结果分析讨论了在该模型条件下桩径选择对上部结构以及桩基础整体抗震性能的影响,提出了优化方案,进行总结并得出结论。 相似文献
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Takashi Hara Shinichiro Tsuji Atsushi Yashima Kazuhide Sawada Naoki Tatta Y.U. Otake 《Soils and Foundations》2010,50(5):565-571
Our aim in this study was to achieve an independent reinforced soil structure with pile foundation that can be applied to such structures as earth retaining walls and countermeasures against the collapse of embankments or rockfall impact built on narrow construction sites, such as on slopes. In order to confirm the effectiveness of the application of pile foundation to reinforced soil structures by geogrid for improvement of the lateral resistance of the structure and to investigate the interaction between pile and reinforced soil structure, a dynamic centrifuge model test (25 G) was carried out. Two geogrid reinforced soil, one with piles and one without, were used in a countermeasure to reduce the deformation of a road embankment built on a slope in the event of an earthquake, and the effectiveness of the pile foundation to the reinforced soil structure was considered with regard to it affected the road surface. The details and the results of the dynamic centrifuge model test, as well as the interaction between pile and reinforced soil structure are described, and the effectiveness of the application of pile foundation to reinforced soil structure is discussed in this paper. 相似文献
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支盘桩–土–高层建筑结构振动台试验的研究 总被引:4,自引:2,他引:2
设计和实施支盘桩–土–高层建筑结构动力相互作用体系的振动台试验,再现框架结构和桩基的震害现象。通过振动台试验,研究相互作用体系的地震响应、支盘桩对结构体系的阻抗作用和单、双跨框架结构抗震性能的差异,对该体系的试验现象、基频、阻尼比、振型、位移反应和上部结构顶层加速度反应进行了计算和分析。结果表明:相互作用对结构的动力特性和地震反应均有较大的影响,支盘桩具有较好的抗压、抗拔和抗扭曲作用;相同工况时上海人工波激励下的结构最大位移反应比El Centro波大,说明结构的破坏除与震级有关外,还与地震波的波形有关;双跨框架结构的抗震性能明显好于单跨,并与汶川地震中很多单跨教学楼倒塌的现象一致。研究结果对抗震设计和防灾减灾具有重要的研究意义。 相似文献
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由于弹性地基梁法能够反映支挡结构与土的相互作用,并可有效考虑基坑开挖、回填过程中各种基本因素和复杂情况对支护结构内力和变形的影响,本文根据Winkler弹性地基梁的计算原理和方法,编制了弹性杆系有限元计算程序,对深圳市民广场深大基坑桩锚支护结构进行了设计计算,获得了支护桩桩身位移和弯矩随开挖过程的分布变化规律,计算结果有效指导和优化了基坑支护设计,保证了基坑和邻近基坑的地铁区间隧道结构的安全,支护设计取得了显著的经济效益。 相似文献
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Kamyar Kildashti Kiarash M. Dolatshahi Rasoul Mirghaderi 《Structure and Infrastructure Engineering》2016,12(12):1614-1633
Different concepts for modelling of soil-foundation in complete dynamic interaction analysis for a 110-m height 70-m span arched structure on 180 piles were investigated in this paper. The modelling approaches consisted of a sophisticated procedure to account for soil compliance and foundation flexibility by defining frequency-dependent springs and dashpots; namely, flexible-impedance base model. The results of this model were compared with those of the conventional modelling procedures; namely, fixed base model and flexible base model by defining frequency-independent springs. In the flexible-impedance base model, the substructure approach was employed through finite element modelling. To account for the kinematic interaction, the numerical model of the soil, foundation and piles were developed using a verified finite element model in ABAQUS. The free field time history and design spectrum were modified to obtain the foundation input motion. The impedance of pile groups with different length was obtained by the finite element model to assess the inertial interaction. The comparison of the results of the employed models showed that rocking and torsional responses were greatly affected by soil–structure interaction, indicating redistribution of seismic demands. It was also proven that the internal demands of the conventional model considering frequency-independent Winkler springs might be higher than those of the model including pile–soil–structure interaction effects. 相似文献
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