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171.
H. Ghaffarzadeh M.R. Maheri 《地震工程与工程振动(英文版)》2006,5(1):151-158
1 Introduction Braced steel frames are commonly used to resist seismic loads. Their seismic behavior was extensively studied during the past decades (Bertero et al.., 1989; Roeder, 1989; Jain, 1978). Their design is governed by the buckling behavior of the bracing members (ASCE, 1994,2002; CSA, 1994). To prevent or delay the seismic buckling of compressive members in concentrically braced frames in steel structures, a great number of methods have been proposed. These include the use of sp… 相似文献
172.
优质膨润土泥浆在大直径深桩基工程中的应用 总被引:1,自引:0,他引:1
为解决在澳门美高梅金殿超濠博彩场及酒店项目桩基工程中大直径深护筒无法回收的难题,笔者在分析港澳地区灌注桩传统工艺缺陷的基础上,采用具有预处理能力的优质膨润土泥浆.施工实践表明,2#配方泥浆能有效的保持桩孔稳定性,桩孔的平均充盈系数为1.0794;改善了钻进泥浆的性能,使泥浆的重复利用率提高到45.33%,泥浆废弃率仅为2.38%;降低了工程成本,减小了对环境的影响.同时,为钻孔灌注桩施工总结了各个阶段泥浆性能标准. 相似文献
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钻孔灌注桩常见问题分析与探讨 总被引:3,自引:0,他引:3
从对常见灌注桩的缺陷入手,找出造成缺陷的原因.在此基础上分别对影响成孔及灌注质量的有关因素进行了分析,并提出提高钻孔灌注桩质量的对策. 相似文献
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Ping Wu Yang Guo Dayong Zhu Weiliang Jin Zhenhua Zhang Rongzhu Liang 《Marine Georesources & Geotechnology》2020,38(5):518-526
AbstractThis study developed prestressed high-strength concrete (PHC) piles reinforced with high-strength materials (glass fiber-reinforced polymer (GFRP) bars) for flexural performance enhancement. Flexural strengths and behaviors of PHC piles reinforced with hybrid GFRP and steel bars were experimentally investigated, respectively. Large-scale specimens with total lengths of 12,000?mm and diameters of 600?mm were constructed and tested under bending, accompanied by evaluation of effects of non-prestressed reinforcement type and longitudinal reinforcement ratio. J-factors were calculated to evaluate deformability of all the specimens. PHC piles reinforced with GFRP bars were demonstrated to have much higher flexural capacity than those reinforced with steel bars. Moreover, strains at the midspans of cross sections of all the specimens basically conformed to the assumption of plane section. Failure of PHC piles reinforced with GFRP bars was attributable to gradual concrete crushing, while that of PHC piles reinforced with steel bars resulted from steel yielding. Results of this study were expected to provide theoretical basis for wide engineering applications of PHC piles reinforced with hybrid GFRP bars and steel bars in marine structures. 相似文献
176.
触地段(Touchdown zone, TDZ)是在役钢悬链线立管(Steel catenary riser, SCR)的关键部位,在复杂载荷作用下,极易形成损伤缺陷,其载荷寿命的评估是深海结构工程中的一个关键问题。本文以大型有限元软件ABAQUS为平台,运用损伤管道实体单元与土弹簧阻尼单元相互作用的模型模拟触地段损伤海底管道在复杂载荷作用下的动力响应,数值计算考虑了管-土相互作用过程中的材料非线性、几何非线性以及接触非线性。讨论了单一环向体积损伤位于触地段管道的不同位置时,触地段损伤管道在不同载荷作用下的动力特性及特征点的动力响应。结果表明,管道所受内外压力以及管道提升端的竖向位移载荷会影响结构的自振频率;体积损伤部位的动力响应较完好部位更剧烈;体积损伤的位置和动力载荷频率对管道动力放大系数的影响很大;当动力载荷的激励频率越接近结构基频时,损伤管道的动力响应及动力放大系数越大。 相似文献
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Conductor casing jetting technique has been increasingly applied in deepwater drilling. The insight into the jetting excavation mechanisms is critical in guiding a successful conductor casing jetting operation. The real- time continuous jet excavation process is simulated with the volume of fluid (VOF) multiphase method of CFD (Computational Fluid Dynamics) ANSYS Fluent calculation software in the current study. The cohesive soil is modelled by using a kind of viscous fluid with Herschel-Bulkley model. In addition, a laboratory half round nozzle jet excavation test is designed for verification by comparison of the observed jet excavation profile with the numerical results. The sensitivity parameters affecting the conductor jetting excavation mechanism in cohesive soil are thus investigated. It is found that the application of Herschel-Bulkley (HB) model for cohesive soil and the VOF method of Fluent can provide a good simulation of jet excavation process. The maximum excavation depth can be determined by the undrained ultimate bearing capacity of the circular foundation with a bearing capacity factor of 6.7. The nozzle position, jet velocity and soil strength have significantly influence on the depth and width of the jet excavation profile in conductor oblique jet. 相似文献