高温下钢筋砼连续梁的破坏机构和内力重分布研究

通过对6根钢筋砼两跨连续梁进行高温试验,分析了连续梁的破坏特征、机构以及内力重分布情况.结果表明,在升温过程中,不但连续梁内力要发生剧烈的重分布,而且可能改变其破坏机构,与常温下具有显著的差异,塑性铰是一个可变铰.     

Further study on the flexural behaviour of concrete-filled steel tubes

This paper is a further study on the flexural behaviour of concrete-filled steel tubes based on the former work presented by Han [Han LH. Flexural behaviour of concrete-filled steel tubes. Journal of Constructional Steel Research 2004;60(2):313-37]. A total of 36 composite beam specimens filled with self-consolidating concrete (SCC) were tested. The main parameters varied in the tests are: (1) sectional types (circular and square); (2) steel yielding strength (from 235 to 282 MPa); (3) the ratio of tube diameter (or width) to wall thickness, D/t (from 47 to 105), and (4) the ratio of shear span to depth (from 1.25 to 6). Comparisons are made with predicted beam capacities using the existing methods, such as AIJ-1997 [Architectural Institute of Japan (AIJ). Recommendations for design and construction of concrete filled steel tubular structures. 1997], AISC-LRFD-1999 [AISC. Load and resistance factor design specification for structural steel buildings. Chicago: American Institute of Steel Construction, Inc.; 1999], BS5400-1979 [British Standard Institute: BS5400, Part 5, Concrete and composite bridges. 1979], EC4-1994 [Eurocode 4. Design of composite steel and concrete structures, Part 1.1: General rules and rules for buildings (together with United Kingdom National Application Document). DD ENV 1994-1-1:1994. London W1A2BS: British Standards Institution; 1994] and the method proposed by Han [Han LH. Flexural behaviour of concrete-filled steel tubes. Journal of Constructional Steel Research 2004;60(2):313-37].Applied calculation formulae of moment versus curvature curves and the flexural stiffness of concrete-filled steel tubular (CFST) beams are presented, based on the mechanics model of Han [Han LH. Flexural behaviour of concrete-filled steel tubes. Journal of Constructional Steel Research 2004;60(2):313-37]. Comparisons are made with predicted beam flexural stiffness using different methods, such as AIJ-1997, AISC-LRFD-1999, BS5400-1979, EC4-1994 and the method proposed in this paper. Comparisons are also made between the simplified model and the mechanics model, and generally good agreement is achieved.     

掺粉煤灰高强混凝土强度的试验研究

对以细度为600m^2／kg的粉煤灰为掺合料的高强混凝土的试验进行了研究，利用试验得出了水胶比为0．3，掺合量为20％的配比为最佳方案。同时亦表明了粉煤灰高强混凝土的强度受水胶比、掺合量、养护条件和温度等多方面因素综合影响。     

确保混凝土结构优质工程的相关措施

对原材料、钢筋工程、模板工程、混凝土工程的施工技术措施进行了介绍，并从人力资源管理、设备器具管理、过程管理、经济措施几个方面阐述了质量管理措施，以确保混凝土结构的工程质量。     

旋挖钻孔混凝土灌注桩常见质量问题防治措施

针对桩位偏移、桩孔倾斜、塌孔等旋挖钻孔混凝土灌注桩常见的质量问题，就其产生的原因进行了分析，并提出相应的预防措施和处理办法。     

高温条件下混凝土施工中的裂缝分析与控制

结合阿联酋混凝土工程施工状况，对影响混凝土裂缝问题的因素作了简要分析，总结了一些相关认识和观点，并提出了具体的预防措施，以使混凝土裂缝的发展降低到最小程度。     

少筋混凝土受弯构件设计方法综述

摘要介绍了国内、外主要规范关于少筋混凝土构件的设计方法,并作了比较和评述,归纳出一个适用于不同要求的少筋混凝土受弯构件脆性破坏的附加系数公式,作为结构重要性系数的一个组成部分,以便于设计.     

CFRP筋作体外预应力束的简支梁桥设计研究

本文介绍了c筋在预应力混凝土公路梁桥建设中的应用。该桥为整体现浇25m跨径简支梁,采用CFRP筋中的碳绞线(Carbon Fiber Composite Cable)作为体外预应力束。文中论述了设计中应关注的主要问题,运用理论方法和有限元方法对结构作了全面分析,并在造价上与普通预应力混凝土梁桥作了比较。     

沥青混凝土桥面铺装早期病害原因分析

对钢筋混凝土柔性桥面铺装的早期病害及其原因进行了分析与研究，在总结当前国内桥面铺装结构分析主要方法的基础上，通过理论分析，提出了用有限元进行结构分析时，需要重点研究的几个问题，指出了今后主要的研究方向。     

混合砂在C50清水混凝土中的应用研究

对比研究天然中砂和混合砂清水混凝土的工作性、物理力学性能、外观质量、收缩和抗渗性能.试验结果表明:机制砂和特细砂按适当比例混合.可以配制出性能高、外观质量好的C50清水混凝土.