岩体结构面抗剪强度估算方法研究进展

结构面抗剪强度是工程岩体稳定性评价的重要参数，经验估算方法是获得结构面抗剪强度参数的有效途径之一。随着研究的不断深入，估算方法有可能替代直剪试验直接提供岩体结构面抗剪强度。本文介绍了岩体结构面抗剪强度经验估算方法的研究现状，评述了经验估算方法不同公式的特点，并指出经验估算方法的发展趋势。     

Evaluation of in-plane shear test methods for composite material laminates

In-plane shear properties of composite material laminates are very important in structural design of composite material. Four commonly used in-plane shear test methods were introduced in this paper. In order to study the differences of various shear test methods, two ASTM standard in-plane shear test methods for composite material laminates were experimentally investigated. They are ±45° tensile shear test (ASTM D3518) and V-notched rail shear test (ASTM D7078). Five types of composite material laminates composed of E-glass fiber fabric and vinyl ester resin were utilized, whose stacking sequences are 03s, 0/903s, CSM/0/902s, ±453s and (0/90)2/(±45)2/(0/90)2s, respectively. The test results indicate that the ±45° tensile shear test can predict shear moduli of composite material laminates accurately. However, the predictions of shear strength using ±45° tensile shear test are significantly lower than those of V-notched rail shear test.     

冠心病与血清脂质和血液流变学的关系探讨

本文对55例冠心病患者和5O例正常人作了甘油三酯、胆固醇、载脂蛋白AI,载脂蛋白B、高密度脂蛋白和高密度脂蛋白亚组分含量的测定,同时还作了全血比粘度、聚集指数、血浆比粘度、红细胞压积等血液流变学指标的测定。冠心病组和正常对照组比较,经统计学处理有显著性差异(P<0.01)。并用灵敏性和特异性两个指数将血清脂质血流变学进行比较。在血清脂质中HDL_2—Ch在病人组改变最为明显,其灵敏性为71％,特异性为92％在血液粘度中以低切粘度改变最为明显,其灵敏性为67％,特异性为88％。HDL_2—Ch可作为冠心病发病首选危险因子。血液粘度对冠心病的辅助诊断有一定参考价值,并可作为冠心病的治疗和预后判断指标,HDL_2—Ch和血液低切粘度结合起来应用,对冠心病的诊断、治疗和预后具有重要指导意义。     

光电光杠杆在杨氏模量智能测量中的应用

严格推导了待测金属丝纵向振动频率与其杨氏模量的关系,并根据此测量原理，将光电光杠杆应用于拉伸法杨氏模量测量仪中，设计了一种高精度杨氏模量智能测量系统。     

Shear strengthening of pre-damaged reinforced concrete beams with carbon fiber reinforced polymer sheet strips

This paper presents the results of an experimental investigation on the response of pre-damaged reinforced concrete (RC) beam strengthened in shear using applied-epoxy unidirectional carbon fiber reinforced polymer (CFRP) sheet. The reasearch included four test rectangular simply supported RC beams in shear capacity. One is the control beam, two RC beams are damaged to a predetermined degree from ultimate shear capacity of the control beam, and the last beam is left without pre-damaged and then strengthened with using externally bonded carbon fiber reinforced polymer to upgrade their shear capacity. We focused on the damage degree to beams during strengthening, therefore, only the beams with side- bonded CFRPs strips and horizontal anchored strips were used. The results show the feasibility of using CFRPs to restore or increase the load-carrying capacity in the shear of damaged RC beams. The failure mode of all the CFRP-strengthened beams is debonding of CFRP vertical strips. Two prediction available models in ACI-440 and fib European code were compared with the experimental results.     

DYNAMIC RESPONSE AND ENERGY DISSIPATION ANALYSIS OF THE WALL WITH HORIZONTAL SHORT KEYWAYS AND LOWRISE SHEARWALL

A new type of ductile lowrise shearwall with many short horizontalkeyways is proposed in this paper in order to improve the earthquake resistant behav-ior of ordinary lowrise shearwall.The behavior of this wall is studied through low-frequency cyclic loading test.Based on the test results,the paper puts forward thedifferent restoring force models for different lowrise shearwalls,and a program fortheir nonlinear dynamic analysis is worked out.Thr(?)h directly inputting earth-quake waves,the paper analyses the dynamic response and energy dissipation of 3types of lowrise shearwalls.The calculation results dem(?)strate that the newly de-vised ductile shearwall has good earthquake resistant behavior.     

Distinct Element Modelling of Unreinforced Masonry Wall Under Seismic Loads with and without Cable Retrofitting

To retrofit and strengthen existing unreinforced masonry (URM) structures to resist the potential earthquake damages has become an important issue in Australia. In order to secure the performance of URM under seismic loading in the future, a research project was carried out aimed at developing a simple and high strength seismic retrofitting technique for masonry structures. A series of experimental testing on URM walls retrofitted with an innovative technique by cable system have been conducted. The results indicated that both the strength and ductility of the tested speci-mens were significantly enhanced with the technique. An analytical model which is based on Dis-tinct Element Method (DEM) has also been developed to simulate the behaviour of URM walls be-fore and after retrofitting. The model is then further developed by applying a seismic wave to the wall to simulate the wall behavior under earthquake loads before and after retrofitting.     

高层住宅中短肢剪力墙结构的设计探讨

本文对短肢剪力墙结构体系在高层住宅中的应用作了一些探讨,并对设计中要注意的问题进行了分析论述,可供在设计时参考。     

坝基岩体的抗滑稳定分析

重点讨论了坝基抗滑稳定验算中加塞处理情况下的计算、第三原则的运用，详细讨论了现行“规范”对抗滑稳定系数K值要求的合理性，提出了相应建议。     

大跨混凝土箱梁桥温度荷载作用下剪力滞效应分析

混凝土箱梁以其良好的结构整体受力性能在现代大跨桥梁结构中得到广泛的应用, 但迄今所修建的混凝土箱梁桥中, 在施工阶段或在运营阶段, 箱梁上均存在较多的由温度引起的开裂现象, 造成这一现象的主要原因是现有计算方法的不完善, 其中之一就是未考虑箱梁在温度荷载作用下的剪力滞效应。本文采用有限元法对大跨混凝土箱梁桥在温度荷载作用及自重作用下的剪力滞效应进行了详细的分析, 其结果表明在温度作用下, 箱梁翼板底面存在着较为严重的剪力滞现象, 并获得了箱梁在温度荷载作用下剪力滞效应的一般规律和初步结论,为箱梁的温度应力计算提供了参考。