Experimental Study on the Compressive Behavior of CFRP/ECCs

In this study, nine square concrete columns, including six CFRP/ECCs and three plain concrete control specimen columns, were prepared. The CFRP tubes with fibers oriented in the hoop direction were manufactured with 10, 20, or 40 mm rounded corner radii at vertical edges. A 100 mm overlap in the direction of fibers was provided to ensure a proper bond. Uniaxial compression tests were conducted to investigate the compressive behaviors including the axial strength, stress-strain response, and ductility. It is evident that the CFRP tube confinement can improve the compressive behavior of concrete core, in terms of axial compressive strength or axial deformability. Based on the experimental results and some existing test database attained by other researchers, a design-oriented model is developed. The predictions of the model for CFRP/ECCs show good agreement with test results.     

Mechanical Analysis of the Down-Hole String in a Deep Well

In a deep well, under high pressure and temperature, the force, deformation, and movement of the downhole string are very complicated. In this paper, based on the analysis of the working environment and load properties of the down-hole string in deep wells, the factors of high temperature, high pressure, and the complex structure of wells have been taken into consideration. The loads of the down-hole string, stability, back buckle configuration, dynamic characteristics, mechanical strength, and deformation have been systematically studied. On this basis, mechanical models of a down-hole string under different conditions have been established and software for aiding analysis has been developed. By using this software, deep well strings under different construction parameters can be simulated and analyzed, providing a theoretical basis and method for down-hole string assembly, as well as string down-hole construction and operation.     

翼缘削弱的型钢混凝土框架试验与有限元分析

通过对一榀两跨三层型钢混凝土框架模型的低周反复荷载试验,研究了翼缘狗骨式削弱的型钢混凝土框架的抗震性能。框架按＂强柱弱梁＂的原则设计,且对节点核心区附近梁端工字形型钢的上、下翼缘采取狗骨式削弱,并适当增加了梁端根部到型钢翼缘最大削弱部位纵向钢筋的配筋量。试验结果表明：框架的变形能力、承载能力、延性、耗能能力等受力性能均满足延性框架的抗震要求;这种构造措施能将塑性铰从梁端根部转移到翼缘削弱部位从而有利于型钢混凝土框架形成梁铰耗能机构,增强其耗能能力。采用ANSYS参数化程序设计语言（AP-DL）编制了命令流,对模型框架在低周反复荷载作用下的抗震性能进行了非线性有限元分析。计算结果与模型试验结果吻合较好,验证了基于分离模量理论计算的翼缘削弱的型钢混凝土框架结构全过程分析方法的可行性。     

荷载接触面形状对沥青路面力学响应的影响

沥青路面力学分析时,车辆荷载基本是被处理成通过轮胎与路面的接触面传递的,而且接触面假设为较为规则的几何形状以方便计算分析。通过对圆形、正方形、长方形、椭圆形及矩形+两半圆形接触面的荷载处理方式进行三维有限元计算,结果显示:矩形+两半圆形的接触面对竖向位移、面层剪应力及上面层层底拉应力响应是最敏感的;对下面层层底拉应力的响应最敏感的是长方形接触面;圆形接触面对路面的变形和应力力学响应是最不敏感的,其次是正方形接触面。     

6005A铝合金焊接接头的腐蚀行为

采用浸泡试验和电化学方法研究了6005A铝合金焊接接头在不同介质环境中的腐蚀行为,采用光学显微镜、扫描电子显微镜、电子能谱分析了焊缝微观组织和成分的变化．结果表明,由于ER5356焊丝Mg含量较高,致使焊缝中Mg含量高于母材,因此焊缝耐蚀性能低于母材;在浸泡试验中焊缝发生均匀腐蚀,表面呈多孔形貌,其对光线的反射明显弱于仅发生点蚀的母材,表现出焊缝发黑的现象;焊接接头在0．1MNaCl、0．1MNa2SO4和0．1MNaNO3溶液中的腐蚀速度为VNaCl〉VNa2SO4〉VNaNO3.     

大跨悬索桥桁架加劲梁的选型和设计

归纳国内外已建和在建的桁架加劲悬索桥的一般情况,论述了加劲梁的受力特点,分析了主桁、横联、水平联和桥面的各可选型式的特点,根据统计数据得到了若干设计参数的经验取用规则。分析研究表明,在大跨度悬索桥中,抗扭能力是桥面结构最主要的加劲要求;加劲桁梁的高跨比与桥面设计风速的平方存在线性回归关系,因此可以由跨径和风速参数来初步拟定桁高;桥面设置一定透空是桁式加劲梁增进气动稳定性的有效和简便手段;上下平联采用K形撑比X形撑获得的扭转刚度要小,但K形撑不参与主桁竖弯,受力状态相对简单。对比混凝土桥面、钢桥面和合成型钢桥面3种方案的技术经济特点,合成钢桥面有助于提高加劲梁扭转性能和结构轻型化。     

城市路口倒计时显示对驾驶行为的影响分析

倒计时显示可以提醒驾驶员在信号灯灯色发生改变的时间、在“停止”和“通过”两者间作出合适的选择。驾驶员和行人的问卷调查中超过85％的驾驶员和行人都愿意选择有倒计时显示的信号控制方式,并且认为有倒计时显示的路VI更安全。对北京市方庄某-4支交叉路口进行了倒计时显示安装前后各1周的驾驶行为录像观测。统计分析发现,安装了倒计时显示后,路口的交通量与没安装倒计时的交通量十分接近;相比于没安装倒计时装置驾驶员在黄灯通过行为和闯红灯行为都有显著降低。     

Evaluation of the effect of cooperative infrastructure-to-vehicle systems on driver behavior

In-vehicle technologies and co-operative services have potential to ease congestion problems and improve traffic safety. This paper investigates the impact of infrastructure-to-vehicle co-operative systems, case of CO-OPerative SystEms for Intelligent Road Safety (COOPERS), on driver behavior. Thirty-five test drivers drove an instrumented vehicle, twice, with and without the system. Data related to driving behavior, physiological measurements, and user acceptance was collected. A macro-level approach was used to evaluate the potential impact of such systems on driver behavior and traffic safety. The results in terms of speeds, following gaps, and physiological measurements indicate a positive impact. Furthermore, drivers’ opinions show that the system is in general acceptable and useful.     

自驾车旅游交通行为分析模型

随着我国私人小汽车保有量的迅速增加和旅游业的繁荣,自驾车旅游交通需求不断增加。由于旅游交通需求与传统通勤交通需求有很大的差异,在进行旅游交通规划时,必须对旅游交通需求进行分析。从行为分析的角度,在对旅游交通行为进行调查分析的基础上,利用Logit模型,分别建立了全国和北京市的周末自驾车旅游出行行为模型。分析结果表明：收入是影响个体自驾车旅游出行的主要因素。     

冲击碾压动荷载下水泥混凝土路面结构的力学行为

为了揭示冲击碾压动荷载下水泥混凝土路面结构的力学行为,基于动力三维有限元分析方法,考虑材料的弹塑性,拟定纵横板边、板中及板角4种典型荷载位置,在四楞冲击压路机冲击碾压水泥混凝土路面时,分析了路面各层结构的受力和变形特征。研究发现,各工况下混凝土板底部承受纵、横向弯拉应力是旧面板破裂的主要原因,基层与旧面板一起处于双向弯拉状态,土基三向受压,不同工况存在不同的有效影响深度。冲击碾压板角时,路面板竖向位移最大,影响深度最深;而冲击板中位置时,板竖向位移最小,分布最均匀,此时板体以纵向弯拉为主,易形成横向裂缝;当冲击纵向板边时,板体以横向弯拉为主,易形成纵向裂缝。可见,路面破碎效果是地基刚度、冲击能量与冲击位置的综合函数,建议基于具体路况选择相应的施工方案。