混合门式刚架合理构成

阐述了混合门式刚架和带拉杆混合门式刚架的杆件组成,分别给出了在荷载作用下,两种门式刚架各杆件的内力图,并比较两种门式刚架的技术经济指标,说明了带拉杆混合门式刚架的优越性及合理性,可供设计人员参考。     

用扒杆浮吊进行水中墩钢管桩施工设计及验算

扒杆浮吊是水中钢管桩施工中常用的一种施工方法,文中结合六潜高速公路淠河总干渠大桥水中墩所采用的钢管桩平台施工,探讨了用扒杆浮吊进行钢管桩施工设计及验算,以供大家参考。     

一种新方法模拟空间预应力

依据曲线论和预应力损失计算相关理论,推导出适合任意曲线函数的预应力摩擦损失计算公式和沿程荷载分布力计算公式,通过实例计算表明所推公式是简便且可靠的,可为空间有限元程序的编写及预应力结构理论分析和设计提供理论依据。     

带约束拉杆矩形钢管混凝土短柱抗震性能试验研究

为研究带拉杆约束矩形截面钢管混凝土短柱的抗震性能,以轴压比、约束拉杆间距和截面长宽比为主要参数,进行了4个无拉杆约束和11个带拉杆约束矩形钢管混凝土短柱试件的低周往复加载试验。研究了其破坏过程、滞回性能、承载能力、变形能力、刚度退化及耗能能力等,并基于数值分析给出了带约束拉杆矩形截面钢管混凝土短柱压弯承载力计算式。结果表明：钢管板件宽厚比为50和67、剪跨比为3的矩形截面钢管混凝土短柱的滞回曲线饱满,没有明显的捏缩;设置约束拉杆提高了试件的承载能力、变形能力及耗能能力;带约束拉杆试件的极限位移角在1/19~1/50之间,位移延性系数在3.28~6.25之间;破坏时的等效黏滞阻尼系数在0.3以上;增加轴压比降低了试件的延性;减小约束拉杆间距可明显改善柱的抗震性能;保持截面宽度不变,增加截面长宽比,可提高试件承载力,但延性降低。提出的带约束拉杆矩形截面钢管混凝土短柱的压弯承载简化计算式的计算结果与试验结果吻合较好。     

我国钢筋混凝土材料抗火性能研究回顾与分析

在对大量文献进行研究与对比分析的基础上，回顾了近40年来中国在混凝土与钢筋材料抗火性能方面的研究成果，包括混凝土的高温热工性能及力学性能、钢筋的高温力学性能及高温中(后)混凝土与钢筋之间的粘结性能等。结果显示：高温会使混凝土和钢筋的力学性能衰减，使钢筋与混凝土之间的粘结性能大幅下降，但由于试验对象、方法和设备上的差异，试验结果呈一定离散性。     

地震区建筑用钢的韧性对建筑物抗震性能的影响

根据地震区建筑用钢在交变地震载荷下的服役条件及其失效模式的特点 ,分析了钢的韧性对建筑物抗震性能的影响。介绍了国外有关动态及国内现状 ,提出了地震区建筑用钢避免低温低应力脆断的建议     

通过附加节点斜筋转移梁上塑性铰的试验研究

对 6个不同构造方式的 1∶2的梁柱节点试件进行反复循环荷载下试验研究。结果表明 ,与传统的箍筋相比 ,附加节点斜筋能和梁筋有限度地共同工作 ,从而将塑性铰从柱面转移。这样改善了钢筋的粘结状况 ,避免中等延性范围内纵筋的屈服向节点核心区扩展 ,地震能量被更有利的耗散机制吸收。同时 ,斜筋使节点本身的强度和刚度也得到进一步加强。结果可供中等烈度区抗震设计时参考     

Flexural strengthening of reinforced lightweight polystyrene aggregate concrete beams with near-surface mounted GFRP bars

Application of near-surface mounted (NSM) fibre reinforced polymer (FRP) bars is emerging as a promising technology for increasing flexural and shear strength of deficient reinforced concrete (RC) members. In order for this technique to perform effectively, the structural behaviour of RC elements strengthened with NSM FRP bars needs to be fully characterized. This paper focuses on the characterization of flexural behaviour of RC members strengthened with NSM glass-FRP bars. Totally, 10 beams were tested using symmetrical two-point loads test. The parameters examined under the beam tests were type of concretes (lightweight polystyrene aggregate concrete and normal concrete), type of reinforcing bars (GFRP and steel), and type of adhesives. Flexural performance of the tested beams including modes of failure, moment–deflection response and ultimate moment capacity are presented and discussed in this paper. Results of this investigation showed that beams with NSM GFRP bars showed a reduction in ultimate deflection and an improvement in flexural stiffness and bending capacity, depending on the PA content of the beams. In general, beams strengthened with NSM GFRP bars overall showed a significant increase in ultimate moment ranging from 23% to 53% over the corresponding beams without NSM GFRP bars. The influence of epoxy type was found conspicuously dominated the moment–deflection response up to the peak moment. Besides, the ultimate moment of concrete beams reinforced with GFRP bars could be predicted satisfactorily using the equation provided in ACI 318-95 Building Code.     

An inferential confidence interval method of establishing statistical equivalence that corrects Tryon's (2001) reduction factor.

Evidence of group matching frequently takes the form of a nonsignificant test of statistical difference. Theoretical hypotheses of no difference are also tested in this way. These practices are flawed in that null hypothesis statistical testing provides evidence against the null hypothesis and failing to reject H? is not evidence supportive of it. Tests of statistical equivalence are needed. This article corrects the inferential confidence interval (ICI) reduction factor introduced by W. W. Tryon (2001) and uses it to extend his discussion of statistical equivalence. This method is shown to be algebraically equivalent with D. J. Schuirmann's (1987) use of 2 one-sided t tests, a highly regarded and accepted method of testing for statistical equivalence. The ICI method provides an intuitive graphic method for inferring statistical difference as well as equivalence. Trivial difference occurs when a test of difference and a test of equivalence are both passed. Statistical indeterminacy results when both tests are failed. Hybrid confidence intervals are introduced that impose ICI limits on standard confidence intervals. These intervals are recommended as replacements for error bars because they facilitate inferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

带肋钢筋孔型设计实践

通过多次技术改造,发现了生产热轧带肋钢筋套用传统的孔型设计参数存在的问题,因而对连铸方坯在箱形孔型、方轧件在平椭圆孔型中宽展系数的选取进行了研究,并介绍了在连铸坯一火成材改造中,通过改进孔型系统改善了咬入状态,使轧制更加稳定。