碳纤维加固板的应用研究

研究了碳纤维(CERP)加固在国内外的应用状况,阐述碳纤维加固板的技术研究、理论研究、工程应用和面临的问题,并展望其发展前景。     

钢筋混凝土柱钢筋套箍加固试验方法

钢筋套箍加固砼柱后，能对其所包围的核心起约束作用，使之处于三轴受压的后力状态，具有较高的抗压强度和极限压缩变形，此即砼的“套箍强化”。钢筋箍对约束砼抗压强度的增强作用因配箍数量、间距和构造而变化。影响的主要因素之一为约束指标λt。通过模拟工程结构投入使用前先进行加固和使用过程中出现裂缝后进行加固两种工程状况试验，可得到钢筋套箍加固柱的受力性能和承载力建议计算公式。     

钢管混凝土柱-环扁梁中节点静载试验研究

介绍了钢管混凝土柱-钢筋混凝土环扁梁中节点的构造和基本受力机理,以及环梁、环扁粱节点的静载试验结果.试验结果表明,通过合理设计,环梁、环扁梁节点能有效地传递框架梁、扁梁梁端的剪力和弯矩,具有良好的变形能力.     

混凝土二次振捣施工技术

如何在施工过程中提高混凝土的性能一直是工程领域的热点问题,其中混凝土二次振捣施工工艺便是一种简单高效的方法。本文介绍混凝土二次振捣的施工方法,并对二次振捣的机理进行了分析。     

水泥混凝土路面修复与加铺的质量控制

以厦门市仙岳路西段高架桥地面旧水泥混凝土路面改造工程为例,阐述了旧水泥混凝土路面的病害类型和处治方法、玻璃纤维格栅的应用、沥青混凝土加铺层类型的选用及SMA混合料配合比设计和施工.工程实践证明,上述各施工工艺和质量控制,能有效地减少反射裂缝产生,提高旧水泥混凝土路面沥青加铺层的路用性能.     

产生、发展、丧失和重建--浅谈油画语言的演变

文章阐述了油画语言的产生和发展，分析了在现当代艺术发展的剧烈波动期油画语言的变化以及油画新语言的发展。     

混凝土三轴等幅拉-压疲劳性能试验研究

Fatigue tests were conducted on tapered plain concrete prism specimens under triaxial constant-amplitude tension-compression cyclic loading. The low stress of the cyclic loading was taken as 0.2fc and the upper stress ranged from 0.20ft to 0.65ft. Three constant lateral pressures were 0.1fc, 0.2fc and 0.3fc respectively. Based on the results, the three-stage evolution nile of the fatigue stiffness, maximttm(minimum) longitudinal strain and damage were analyzed, and a unified S-N curve to calculate fatigue strength factors was worked out. The results show that the fatigue strength and fatigue life under triaxial constant-amplitude tension-compression cyclic loading are smaller than those under uniaxial fatigue condition. Moreover, the secondary strain creep rate is related to the fatigue life, a formula for describing their relation was derived. The investigation of this paper can provide information for the fatigue design of concrete structures.     

Natural Frequency of Full-Prestressed Concrete Beam

Dynamic tests of three bonded and two unbonded full-prestressed concrete beams were carried out.The purpose was to seek the relation between prestressing force and natural frequency.Test results indicate that the frequency of prestressed concrete(PSC)beam increases with the increase in prestressing force approximately.The results are different from the dynamic characteristics of isotropic material beam subjected to compressive axial force which were put forward by Clough et al.The reason is that the beams were considered as isotropic,homogeneous,linear elastic material in the traditional analysis method.However,more accurate results are required in the analysis of frequency of PSC beam.The constitutive mode of PSC member is analyzed based on microstructure of concrete in this paper.The orthotropic linear elastic mode is used to analyze the relation between dynamic frequency and prestressing force of concrete beam,at the same time the equivalent stiffness of prestressed tendon relating to the prestressing force is added to the bending deformation stiffness of the beam.The analytical value agrees well with the test result,indicating that the current analysis method in this paper is feasible to full-prestressed concrete beam.     

聚丙烯纤维砼的性能及其在水利工程中的应用

论述聚丙烯纤维砼的抗裂性、抗渗性、耐磨性等性能,为聚丙烯纤维砼在水利工程中的进一步应用提供一定的理论基础。     

择校教育与个体人力资本积累——北京市择校调查及实证归因

择校现象漫延和扩张的根源在其潜在的人力资本积累和发展价值,作为择校主体瞄准教育成本与个体人力资本增长的价值取向,在家庭经济收益的一定消费限度和学生个体能力发展潜质较大的情况下,择校成本作为学生个体人力资本的投入极易成为家长做出的最佳抉择路径。择校实质上是一种早期人力资本的投资现象,是择校主体为参与社会竞争而实施的个人战略性决策,因为选择优质学校教育无疑有利于全面提高学生的竞争实力,这就意味着个体未来发展机遇和经济价值的报偿及其回赠。