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首先介绍了钢筋混凝土渡槽结构在地震荷载作用下的分析理论,根据这些理论建立了渡槽结构的动力有限元分析模型,分别采用干模态法、附加质量法和ALE法考虑渡槽结构液固耦合作用,通过具体的工程算例,对钢筋混凝土渡槽结构进行了不同工况下的数值模拟研究,包括混凝土非线性材料分析、渡槽结构静水与动水响应分析、渡槽结构自振特性分析和槽墩的能力曲线分析。研究表明,考虑固液耦合作用的渡槽实体有限元模型能较好地模拟渡槽结构地震反应,并得到相应的渡槽结构地震反应规律。 相似文献
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By the theories of potential flow and structural vibration, the formulae for evaluating the ‘wet’ (with water) frequencies and mode shapes of the beam‐supported aqueduct are derived through a simplified fluid‐structure interaction analysis. The time‐history formulae of structural responses to the vertical seismic excitation are obtained. Applying the response‐spectrum principle, the equivalent vertical earthquake load exerted on the beam and the corresponding effects are also derived. Several illustrative examples are conducted. The analytical results show that: (i) The ‘wet’ frequencies of the structure are lower than the corresponding ‘dry’ (without water) frequencies due to the participating water mass, but the ‘wet’ mode shapes are identical to the corresponding ‘dry’ ones. (ii) The water mass plays an important role in the vertical seismic response, which varies with the different geological sites. For the different seismic inputs, the deeper the water is, the greater are the structural responses. (iii) The vertical seismic effects on the beam are generally not too small to be neglected and should be considered in the structural designs of a beam‐supported aqueduct. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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渡槽中流体非线性晃动的边界元模拟 总被引:20,自引:0,他引:20
应用边界元法分析了流体非线性晃动及其对渡槽的作用效应,将所得结果与线性解析结果作了比较.数值计算表明:流体以较大幅度晃动时,线性模型结果与非线性边界元结果有较大偏差,计算有限幅流体晃动反应宜采用非线性模型. 相似文献
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This paper reports on a semi‐analytical/numerical method to model sloshing water in an arbitrarily shaped aqueduct. The water motion is assumed to be inviscid, compressible, and linear (small displacement). The transverse sloshing fluid in an aqueduct is equivalently simplified as a fixed rigid mass M0 and a mass–spring system (M1, K1). According to a rule that the actual fluid (computed with finite element model) and its equivalent mechanical model have the same first sloshing frequency and acting effects on the aqueduct, the analytical solutions of the fixed (impulsive) mass M0, sloshing (convective) massM1, spring stiffness K1, and their locations in the aqueduct body are acquired by the least squares (curve fitting) algorithm. Applying this equivalent principle, the equivalent mechanical models are respectively obtained for the sloshing water in rectangular, semicircular, U‐shaped, and trapezoid aqueducts. The equivalent principle and fluid models are validated through comparison investigations involving rectangular and U‐shaped aqueducts. The dynamic properties and seismic responses of the original and equivalent systems are simulated, compared, and discussed for a U‐shaped aqueduct bridge. The main purpose of this paper is to provide a simplified model of sloshing fluid for the seismic/wind‐resistant computation of the support structures of the aqueduct bridge. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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本文对于排架支承式渡槽结构的风致反应进行了动力有限元计算分析和研究,得出了排架支承式渡槽结构风致反应的一些规律,为渡槽结构的抗风设计提供了参考依据。 相似文献
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阐述了南水北调中大型渡槽的抗震问题,分别介绍了基于常微分方程求解器(ODE)和有限元方法的大型渡槽动力计算模型、动力特性分析和设置铅芯橡胶支座(LRB)的隔震分析。研究表明,基于ODE求解器的解析和半解析方法有很好的精度和可靠性,可用于大型渡槽的初步设计。结合所得的研究成果,对南水北调的渡槽抗震提出了合理化建议。 相似文献
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In the present work, the relationship between intrinsic factors, mechanical properties and durability of Miocene sandstones used in the architectural heritage of Tunisia, specifically in the Roman aqueduct of Oued Miliane and Uthina site, are studied. The petrographic study and the characterisation of porous network have been carried out using optical microscopy, mercury intrusion porosimetry and laser scanner confocal microscopy (LSCM). The hygric behaviour has also been determined from water absorption under vacuum, drying, capillary water absorption and water vapour permeability. The mechanical properties have been assessed from compressive strength and abrasion tests. Rock durability has been evaluated from salt crystallization (sodium sulphate) accelerated aging tests. The results show good hygric behaviour characterised by a high evaporation rate and almost no retention of water; due to the macroporous character of the rock and the good connectivity of the pore network. Because of the poor lithification, the stone has a very low mechanical strength which makes it very vulnerable to the salt crystallization effects. The absence of chemically unstable minerals preserves the rock from chemical alteration. The durability of the building stone is mainly conditioned by salt loading of the monument. 相似文献