带防屈曲支撑的钢管混凝土框架抗震性能参数分析     

任凤鸣  ;张杰标 《地震学刊》2014,(4):422-428

设置防屈曲支撑的钢管混凝土框架是一种新型钢管混凝土减震结构。采用有限元软件Opensees对设置防屈曲支撑的单层单跨钢管混凝土减震框架进行数值模拟,研究了框架梁柱线刚度比、防屈曲支撑初始刚度以及钢管混凝土柱轴压比等设计参数对该减震结构抗震性能的影响。研究结果表明：1数值模拟和试验结果吻合较好,验证了有限元模型的正确性;2梁柱线刚度比在0.1~0.3之间变化时,钢管混凝土减震框架的抗震性能较好;3BRB耗能支撑的初始刚度K1在40~80kN/mm变化时,减震框架的耗能减震效应较明显;4在合理的钢管混凝土柱轴压比范围内,当轴压比较大时,在钢管混凝土框架中设置防屈曲支撑能明显地提高结构的耗能能力和改善结构的强度退化现象。  相似文献   

低速冲击下高强钢绞线网-高性能砂浆加固钢筋混凝土梁试验研究     

张伟  ;廖维张  ;田志敏 《地震学刊》2014,(3):359-364

研究了高强钢绞线网-高性能砂浆加固钢筋混凝土梁的抗低速冲击性能,利用落锤冲击试验法对4根简支钢筋混凝土梁进行对比试验研究,其中1根为普通梁,3根为加固梁,通过分析加固前后梁的破坏形态,结合挠度变化、钢筋的应变以及加速度的时程曲线,对比得到了钢筋混凝土梁加固后的抗冲击性能。研究结果表明：加固后钢筋混凝土梁的抗冲击能力显著提高,钢绞线和砂浆作为外加层,不仅增加了梁的抗弯剪能力和刚度,提高了结构的耗能能力,而且限制了裂缝的发展,使梁的整体性和延性更好;在相同冲击作用下,钢绞线直径的增加能适当提高结构的抗冲击性能。  相似文献   

Computational study of self‐centering buckling‐restrained braced frame seismic performance          下载免费PDF全文

Matthew R. Eatherton  Larry A. Fahnestock  David J. Miller 《地震工程与结构动力学》2014,43(13):1897-1914

Recent research developed and experimentally validated a self‐centering buckling‐restrained brace (SC‐BRB) that employs a restoring mechanism created using concentric tubes held flush with pretensioned shape memory alloy rods, in conjunction with a buckling‐restrained brace (BRB) that dissipates seismic energy. The present computational study investigated how the SC‐BRB can be implemented in real buildings to improve seismic performance. First, a computational brace model was developed and calibrated against experimental data, including the definition of a new cyclic material model for superelastic NiTi shape memory alloy. A parametric study were then conducted to explore the design space for SC‐BRBs. Finally, a set of prototype buildings was designed and computationally subjected to a suite of ground motions. The effect of the lateral resistance of gravity framing on self‐centering was also examined. From the component study, the SC‐BRB was found to dissipate sufficient energy even with large self‐centering ratios (as large as 4) based on criteria found in the literature for limiting peak drifts. From the prototype building study, a SC‐BRB self‐centering ratio of 0.5 was capable of reliably limiting residual drifts to negligible values, which is consistent with a dynamic form of self‐centering discussed in the literature. Because large self‐centering ratios can create significant overstrength, the most efficient SC‐BRB frame designs had a self‐centering ratio in the range of 0.5–1.5. Ambient building resistance (e.g., gravity framing) was found to reduce peak drifts, but had a negligible effect on residual drifts. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Seismic design and testing of the bottom vertical boundary elements in steel plate shear walls. Part 1: design methodology          下载免费PDF全文

Keh‐Chyuan Tsai  Chao‐Hsien Li  Hung‐Chi Lee 《地震工程与结构动力学》2014,43(15):2237-2259

This research investigates the seismic design method and the cyclic inelastic behavior of the bottom column, also called the vertical boundary element (VBE), in steel plate shear walls (SPSWs). This study consists of two parts. This Part 1 paper discusses the anticipated pushover responses for properly designed SPSWs and the possible inelastic responses of the bottom VBE at various levels of inter‐story drift. Considering both the tension field action of the infill panel and the sway action of the boundary frame, this study develops a simplified method to compute the flexural and shear demands in the bottom VBE. Based on the superposition method, this approach considers various plastic hinge forming locations at different levels of inter‐story drift. One of the key performance‐based design objectives is to ensure that the top ends of the bottom VBEs remain elastic when the SPSWs are subjected to the maximum considered earthquake. This paper presents the comprehensive design procedures for the bottom VBE. Furthermore, this study conducted cyclic performance evaluation tests of three full‐scale two‐story SPSWs at the Taiwan National Center for Research on Earthquake Engineering in 2011 to validate the effectiveness of the proposed design methods. The experimental program, cyclic inelastic responses of the SPSWs and bottom VBEs, and numerical simulations are presented in Part 2. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

钢套管灌注群桩施工顺序对多隧道的影响     

宋福贵  王炳龙  黄大维  张超  李培妍 《岩土力学》2012,33(8):2330-2336

通过理论研究和数值分析方法,分析了钢套管桩不同的施工顺序对邻近既有隧道的影响,并结合现场实测数据对分析结果进行了验证。首先,采用理论方法分析钢套管旋转下压过程中土塞柱的受力情况,建立微分方程计算土塞柱底端的应力、土塞柱受到的剪切扭矩和自身抗剪扭矩,进而分析得到了土塞柱发生剪切破坏和土塞效应的临界深度。在此基础上按是否产生闭塞效应,分两种情况研究了钢套管旋压过程中产生的土体膨胀率。然后,利用既得的土体膨胀率,通过理论分析和数值模拟方法分析了群桩不同的施工顺序对既有多条盾构隧道的影响,得出了相对较优的群桩施工顺序方案。工程现场实测数据与数值模拟结果的对比分析表明,上述计算结果与实际情况能较好吻合。该研究对类似工程具有理论指导意义和实践参考价值。  相似文献   

超大型沉井首次接高受力及变形规律初探   总被引：1，自引：0，他引：1  

朱建民  龚维明  穆保岗  米长江 《岩土力学》2012,33(7):2055-2060

依托马鞍山长江大桥南锚碇沉井的首次接高,对其竖向沉降、隔墙墙底土压力和隔墙底板受力情况进行了监测。结果表明,超大型沉井兼有条形基础的特点和整体工作性能,能够承受较大的竖向变形,与单纯考虑地基承载力相比,更适合于按变形控制接高。沉井接高时普通隔墙下的土压力小于分区隔墙,并且普通隔墙下部土体会先达极限承载力,后续接高产生的荷载转而由分区隔墙（或井壁）来承担。沉井首节混凝土浇筑就已决定了隔墙底板的应力大小和分布情况,后续接高不会再引起大的改变;隔墙底板中间部分受力较小,外围拉应力较大,通过井壁外土体的密实回填可有效降低此部分拉应力。  相似文献   

浅埋大跨小间距黄土隧道支护技术研究     

何历超  王梦恕  李宇杰 《岩土力学》2013,34(Z2):306-310

以武-西高速公路桃花峪黄土隧道为研究对象,采用现场试验与数值模拟的方法,研究格栅和型钢支护结构对浅埋大跨小间距黄土隧道的影响规律。现场试验表明,施工引起的沉降比较均匀,格栅支护与型钢支护对控制整体沉降差别不明显。格栅钢架的受力比型钢钢架小且分布更为均匀,说明格栅钢架受力更为有利。格栅与型钢钢架受力状态相似且都合理。模拟计算表明,格栅支护与型钢支护相比,型钢支护的位移更小。较之格栅,型钢支护拱顶沉降减小16%~18%,边墙收敛减小23%,拱脚沉降减小18%。在V级黄土隧道中采用双侧壁法开挖大断面隧道,围岩将发生较大塑性变形。塑性区域发展范围较大,需及时支护,格栅支护与型钢支护对塑性发展范围基本一致。  相似文献   

Mechanical and low-cycle fatigue behavior of stainless reinforcing steel for earthquake engineering applications     

George C.Lee  Jerome S.O''Connor 《地震工程与工程振动(英文版)》2010,9(3):449-457

Use of stainless reinforcing steel (SRS) in reinforced concrete (RC) structures is a promising solution to corrosion issues. However, for SRS to be used in seismic applications, several mechanical properties need to be investigated. These include specified and actual yield strengths, tensile strengths, uniform elongations and low-cycle fatigue behavior. Three types of SRSs (Talley S24100, Talley 316LN and Talley 2205) were tested and the results are reported in this paper. They were compared with the properties of A706 carbon reinforcing steel (RS), which is typical for seismic applications, and MMFX II, which is a high strength, corrosion resistant RS. Low-cycle fatigue tests of the RS coupons were conducted under strain control with constant amplitude to obtain strain life models of the steels. Test results show that the SRSs have slightly lower moduli of elasticity, higher uniform elongations before necking, and better low-cycle fatigue performance than A706 and MMFX II. All five types of RSs tested satisfy the requirements of the ACI 318 code on the lower limit of the tensile to yield strength ratio. Except Talley 2205, the other four types of RSs investigated meet the ACI 318 requirement that the actual yield strength does not exceed the specified yield strength by more than 18 ksi (124 MPa). Among the three types of SRSs tested, Talley S24100 possesses the highest uniform elongation before necking, and the best low-cycle fatigue performance.  相似文献   

Relationship between magnetic parameters and heavy element contents of arable soil around a steel company, Nanjing   总被引：2，自引：0，他引：2  

BLAHA U  ROESLER W  APPEL E 《中国科学:地球科学(英文版)》2010,(3)

Magnetic parameters and element contents were determined in core NJ008 collected from the uppermost ca. 40 cm in a steel company in southwest Nanjing. The results showed that magnetic susceptibility (χ), saturation isothermal remanent magnetization (SIRM) and anhysteretic remanent magnetization (ARM) were enhanced in the uppermost 20 cm, with a mean magnetic susceptibility value of 112.5×10-8 m3 kg-1. Below 20 cm, χ decreased sharply with a mean value of 27.8×10-8m3 kg-1. Low-coercivity minerals such as magnetite dominate in arable soils, while the relative content of antiferromagnetic minerals increases below 20 cm. Heavy metals (Ni, Cu, Fe, Pb, V, and Zn) have similar vertical trends as χ. Principal component analysis reveals common high loadings of the same factor for magnetic concentration parameters (χ, ARM, and SIRM) and elements (Ni, Cu, Fe, Pb, V, and Zn) with an excellent linear correlation (0.69≤R≤0.98) between them. Magnetic susceptibility of paddy soil core NJ013, which had the same parent material as NJ008 but was far from pollution sources, showed stable values of magnetic concentration parameters along the whole core. Absolute values correspond to the so-called magnetic background value (below 20 cm) of NJ008. This indicates that pesticide and fertilizer had little effect on magnetic signals of the upper part of core NJ008 and the extremely enhanced magnetic concentration parameters originate from the steel company emission. Although, the arable soil does not reveal the pollution history and transportation due to annual ploughing, the significant linear relationship between magnetic concentration parameters and heavy metal contents suggests that magnetic parameters can serve as a proxy for quickly detecting soil metallic pollution and estimating the extent of contamination.  相似文献   

高层钢结构地震失效模式控制的失效路径修正法   总被引：1，自引：0，他引：1  

孙爱伏  欧进萍 《地震工程与工程振动》2010,30(1)

本文主要研究高层钢框架结构的地震失效模式及其控制方法。首先,给出了高层钢结构的地震失效模式的分析方法;其次,提出了根据结构的失效路径来加强构件对高层钢结构的地震失效模式进行控制的方法;然后,提出了结构整体抗震能力的分析方法以及分别相应于设计能力和屈服能力的能力储备分析方法;最后,通过对一座15层的钢框架结构进行典型地震动下的极限时程分析和极限pushover分析,得到高层钢框架结构的失效模式和整体抗震能力以及相应于最弱失效模式的能力储备,并验证了本文中地震失效模式控制方法的有效性。本文的研究表明,高层钢结构的地震失效模式控制可以采用结构失效路径修正(薄弱构件加强)来实现。  相似文献