南钢铁路专用线制梁场T梁施工方案

根据南钢铁路专用线的特点，结合T梁制造实践，从制梁场的组建、T梁制造工序流程布置、工艺要求，介绍T梁预制的施工方案。     

轨道车体端梁型材缺陷改进方案研究

在研究轨道车体典型端梁型材的挤压生产工艺及模具设计的基础上,通过对比试验分析了影响端梁性能及缺陷的工艺参数,阐述了端梁型材生产调控要点,并结合检测结果对模具进行了分析和优化。结果表明,通过扩大前室、降低阻料台,同时适当沉桥能够有效地避免壁厚差大、型腔复杂的端梁型材出现缩尾、焊合不良等低倍缺陷;合理设计模具同时优化棒温及速度是改善端梁型材低倍组织的有效途径。     

预应力叠合梁斜截面抗剪性能有限元分析

在国内外学者研究的基础上,从理论上分析了预应力叠合梁的受力性能,运用ANSYS有限元软件对预应力叠合梁和普通叠合梁分别进行了非线性有限元模拟分析,对比分析得出预应力对叠合梁斜截面抗剪性能的有利贡献是客观存在的,ANSYS能较好的模拟预应力叠合梁的受力特点,且模拟结果与理论分析能较好的吻合.     

基于COSMOSWorks的大盘卷步进梁有限元仿真

根据有限元理论,在大型非线性有限元软件COSMOSWorks建立了大盘卷步进梁有限元模型,并根据大盘卷步进梁的特点选择算例施加约束、载荷以及定义接触,进行了有限元模拟仿真,获取大盘卷步进梁在受到外载荷作用后的受力情况,得出其各个位置应力应变等情况,并对得到的结果进行对比分析,为步进梁结构的优化设计和可靠性设计提出了改进意见。     

铝合金枕梁厚板长直焊缝自动焊接研究

通过对地铁枕梁部件长直焊缝手工焊与自动焊的对比试验,研究了自动化焊接技术在枕梁焊接中的应用.从渗透检测、X射线及微观金相检测、力学性能测试等方面进行了分析,确定了枕梁自动化焊接工艺速度快,效果好,符合设计要求;所得焊缝外观好,金相组织细小、均匀.     

混凝土梁的钢筋配置与计算

建造各种类型的房屋,结构的设计很重要。它必须经过严密的设计计算才能保证其承载能力,而不是凭自已的感觉来设计。例如,混凝土梁的配筋,有人认为只要钢筋配置得越多,构件的承载能力就越大,事实上这种观点是片面的。如受弯的构件一梁来说,在混凝土强度和几何尺寸一定的情况下,提高钢     

偏心轮式升降步进梁升降运动分析

偏心轮式步进梁因为液压缸铰点随着动梁移动,而使得其运动过程和负载分析变得复杂,分析了偏心轮式步进梁升降过程,给出了计算模型,并分析了参数C对步进梁提升量、步进梁提升能力的影响。为步进梁设计提供了设计依据。     

钢吊车梁设计探讨

本文通过小方坯连铸工程钢吊车梁设计实例,简述了钢吊车梁的一般设计方法,就吊车梁的受扭设计作了更进一步的探讨,并指出在扭矩作用下产生的附加弯曲应力和剪力是形成吊车梁纵向疲劳裂缝的主要原因,要避免裂缝的形成与发展,设计过程中应考虑扭转,疲劳,焊接残余应力等的影响。     

步进梁液压系统常见故障分析

介绍了冷轧板厂步进梁液压系统工作原理,针对步进梁液压系统在运行过程中出现的常见故障进行了分析总结。     

钢吊车梁裂缝分析与处理

以实际工程为背景,对钢吊车梁裂缝产生的原因进行了分析,提出解决措施,以供类似工程处理参考。     

含铜核电结构用H型钢研究开发

针对核电结构用H型钢的特殊要求,采用Cu- Ni微合金化,合理设计化学成分,优化轧制工艺,避免了含铜钢“铜脆”现象的产生。核电结构用H型钢的屈服强度和冲击性能比S235J0都有提高,表明Cu、Ni的加入既提高了材料的强度,也提高了材料的冲击韧性。电化学试验表明,核电结构用H型钢的耐蚀性能有较大提高。开发钢种力学性能、表面质量及耐腐蚀性能完全满足核电结构用钢要求。     

Structural Behavior of Short Span Precast Channel Beam Bridges without Shear Reinforcement

This paper presents findings of a research study conducted by the writers for the Arkansas State Highway and Transportation Department. The study investigated precast nonprestressed concrete channel beam sections cast without shear reinforcement used in short, multispan bridges. The original objective of the study was to establish a correlation for inspection purposes between the beam’s visual deteriorated state and its corresponding approximate structural capacity. However, during four-point load testing of 33 beams, it was found that beam strength was more a function of a beam’s concrete compression strength rather than deterioration state. A national survey of state transportation departments within the contiguous states was conducted by the authors and found that 13 states currently use precast channel beam bridges. The particular section considered in this paper is a 5.79?m (19?ft) precast channel beam section used to cross small streams and depressions; however constructed without shear reinforcing steel. Bridges using these sections were constructed in the 1950s through to the early 1970s and were designed for H15 loading. Thirty-three formally in-service beams, in various states of deterioration, were load tested. The writers found that the majority of the beams exhibited load capacity greater than the initially required H15 design strength. Second, member strength was a function of concrete compressive strength. Of the 33 beams load tested, 28 beams showed ductile behavior; conversely, the other five beams failed without exhibiting a yield plateau.     

高强度H型钢的研究与开发

研究了控制轧制中各相关因素和铌、钒等微合金元素在钢中的作用机制;阐述了微合金化和控制轧制技术在高强度H型钢开发过程中的应用效果;开发出了400 MPa以上级别的高强度H型钢。     

关于大规格H型钢生产难点的探讨

从变形机理上对大规格H型钢生产存在难点进行了分析,并对国内为生产大规格高强度H型钢的几种可行技术进行了探讨。     

Behavior of FRP-Retrofitted Joints Built with Plain Bars and Low-Strength Concrete

Two series of tests on eight full-scale exterior beam-column joint subassemblages built with plain bars and low-strength concrete were conducted. No transverse reinforcement was present in the joint cores. In the first series of tests, which included three specimens, the behavior of joints before fiber-reinforced polymer (FRP) retrofitting was investigated. In the second series, which included five specimens, the behavior of the FRP-retrofitted joints was investigated. The six specimens consisted of a column, an in-plane beam, a transverse beam, and a slab part, and two specimens were plane members without transverse beams and slabs. The utilized retrofitting scheme is easily applicable for actual exterior beam-column joints, even in the presence of a transverse beam and a slab. Two types of strength limitation were observed for specimens in the first series. The strength of the specimen with beam longitudinal bars sufficiently anchored to the joint core was limited by the shear strength of the joint. The strengths of the other two specimens were limited by the slip of the beams’ longitudinal bars at their anchorages. In the second series of tests, significantly better performance was obtained both in terms of shear strength and ductility, provided that the slip of the beam bars was prevented. Furthermore, by using a simple theoretical algorithm based on truss analogy, the strength and deformability characteristics of the tested reference and FRP-retrofitted joints are predicted with reasonable accuracy. The same algorithm is used for predicting the joint shear strength of specimens tested by other researchers, and satisfactory agreement is obtained between the predictions and test results.     

空间预应力砼梁预应力分布的数值模拟与计算

文章结合预应力钢筋混凝土梁的非线性特性,以工字形混凝土简支梁为例,分析和计算了梁中预应力的分布情况,并将计算结果与工程实践进行比较,证明该数值方法可有效地模拟钢筋混凝土梁的受力性能,为梁的强度计算和合理设计莫定理论基础.     

Nb微合金化H型钢控制轧制技术研究

用热模拟试验方法确定了Nb微合金化H型钢生产工艺参数，介绍了马钢Nb微合金化H型钢生产工艺和Nb微合金化H型钢达到的实物质量水平，同时对马钢生产的H型钢和国外同类产品的性能做了对比，马钢Nb微合金化H型钢具有良好的强韧性。     

高强度汽车大梁用钢W610L的研制

采取在碳锰钢中添加适量的铌和钛,通过细晶强化和沉淀强化成功开发出高强度汽车大梁用钢W610L。该钢钢质纯净、晶粒细小、强度高、韧性好,成功应用于国内多家知名汽车制造厂的汽车纵梁、横梁、支撑结构件等构件的制作。     

Effect of Contamination on Reinforcing Bar-Concrete Bond

Current specifications require the removal of reinforcing bar contaminants that reduce bond prior to placing concrete. This study focused on the interactions of contaminant type, bar size, epoxy coating, concrete strength, and test method (beam and direct pullout). The majority of the beam tests showed the bond strength was not significantly affected, with certain exceptions. However, the direct pullout tests revealed a significant reduction of bond strength in most situations. Although the bond strength was still greater than that required by code, it is recommended that specifications for removal of contaminants should not be relaxed until further study is performed.     

Effect of FRP Confinement on Bond Strength of Hooked Bars: Normal-Strength Concrete Structures

To assess the viability of the external confinement of normal-strength concrete beam–column joints with carbon fiber-reinforced polymer (CFRP) sheets in increasing the bond strength of hooked bars anchored in the joints, 12 hooked bar specimens were tested. The variables were beam tensile bar size, anchorage length, mode of confinement of the beam hooked bars in the beam–column joint (whether the hooked bars were anchored within or outside the column reinforcement cage, denoted as “confined specimens” or “unconfined specimens”), and presence or absence of FRP wraps. The specimen simulated the rigid connection of a cantilever beam to a column. The tensile beam reinforcement consisted of two bars anchored in the base column using hooked-bar anchorages. Test results indicated that FRP sheets were effective in increasing the anchorage capacity and the ductility of the load–deflection history for both unconfined and confined specimens. However, FRP sheets had a more significant influence on unconfined specimens than companion confined specimens. As compared with unconfined specimens without FRP wrapping, unconfined FRP specimens had an average of a 23% increase in bond strength, confined non-FRP specimens had an average 30% increase in bond strength, and confined FRP specimens had an increase of 54%.