现浇混凝土楼(屋)面板结构设计与经济分析

在现浇混凝土楼(屋)面板结构设计过程中,通过合理选用板厚、混凝土强度等级和钢筋强度等级,取得良好的经济效益。

Flexural fatigue strength of steel fibrous concrete containing mixed steel fibres

This paper reports investigation conducted to study the fatigue performance of steel fibre reinforced concrete (SFRC) containing fibres of mixed aspect ratio. An extensive experimental program was conducted in which 90 flexural fatigue tests were carried out at different stress levels on size 500 mm×100 mm×100 mm SFRC specimens respectively containing 1.0%, 1.5% and 2.0% volume fraction of fibres. About 36 static flexural tests were also conducted to determine the static flexural strength prior to fatigue testing. Each volume fraction of fibres incorporated corrugated mixed steel fibres of size 0.6 mm×2.0 mm×25 mm and 0.6 mm×2.0 mm×50 mm in ratio 50:50 by weight. The results are presented both as S-N relationships, with the maximum fatigue stress expressed as a percentage of the strength under static loading, and as relationships between actually applied fatigue stress and number of loading cycles to failure. Two-million-cycle fatigue strengths of SFRC containing different volume fractions of mixed fibres were obtained and compared with plain concrete.

结构规范修订对配筋的影响

结构规范的修订对结构配筋有着直接的影响,也直接对工程造价产生影响。结构规范的修订对结构配筋的影响体现在两个方面:一部分修订使配筋量减少,一部分修订使配筋量增大。做为设计人员,在学习和应用新版规范,关注规范安全度提高要求的同时,应注意规范修订所提出的细化和合理降低要求,提高材料的利用率。

某钢与混凝土混合结构超高层的抗震性能分析——弹塑性时程分析

某框架-核心筒超高层结构,采用钢管混凝土柱、型钢混凝土梁框架及钢筋混凝土核心筒的混合结构形式。弹塑性时程分析表明结构满足规范的"大震不倒"要求,并给出了结构薄弱部位。同时,以此工程为例,通过大量的计算,重点分析了地震波选取、阻尼比取值、钢筋强度等级等因素对计算结果的影响及大震弹性计算与大震弹塑性计算的区别。结果表明,对于超高层结构,地震波持时对结果影响很大,阻尼比改变对结果影响较小,采用HRB500钢筋后结构刚度有所增大,大震弹性和大震弹塑性的位移结果接近。