我国桥梁用钢现状及耐候桥梁钢发展

我国桥梁用钢强度等级与韧性不断提高,焊接性能持续改善,钢板的适宜厚度逐步提高。铁路桥梁用钢、公路桥梁用钢、跨海大桥用钢成为我国桥梁用钢的主体。顺应时代发展要求的高性能耐候桥梁钢将是我国桥梁用钢发展的主要方向。耐候桥梁钢在我国已经有所应用,但需要系统建立或健全使用耐候桥梁钢的相关国家或行业标准。     

鞍钢集团

鞍钢集团核心钢铁产品包括汽车用钢、铁路用钢、石油石化用钢、家电板、船板、电工钢、集装箱板、机械用钢及精密钢管、核电管、模具钢和国防军工用钢等特殊用钢。建筑行业用钢鞍钢建筑行业用钢包括建筑结构用钢、桥梁用钢、高强镀锌板、高强镀铝锌板、高强彩涂板、高强预应力用钢、耐腐蚀钢等。鞍钢是国内首个生产桥梁用钢的企业.始终引领着国内桥梁用钢的     

浅述桥梁钢的发展现状和趋势

近几年,国内在建和待建大跨度、高钢度、高安全性的钢制桥梁数量越来越多,对桥梁用钢板提出的要求越来越高,进而促进桥梁用钢板生产技术的发展,钢板强度级别不断提升,高等级桥梁钢的工程应用也明显增加。基于近几年对桥梁钢市场需求和钢铁企业研发、生产情况的了解,通过国内与国外生产桥梁钢性能的对比分析,重点总结了国内桥梁用钢板的发展现状,同时从桥梁用钢板的研发及工程应用方面提出了个人见解。     

大跨度桥梁缆索用钢的发展及制造技术

总结了桥梁缆索用钢的典型成分体系与性能特点,阐述了国内外桥梁缆索用钢的发展以及国内外先进生产技术,特别分析了桥梁缆索用钢的生产技术新发展以及优缺点,从成分体系开发、制造技术等角度浅析了国内外桥梁缆索用钢的研发方向。     

日本的桥梁用钢

介绍了日本桥梁用钢的研发现状。其桥梁用钢的发展主要表现为高强度钢板、易焊性钢板及耐蚀性钢板等。高性能钢是日本桥梁用钢的发展方向。针对日本高性能钢的成分、力学性能及焊接性能进行了阐述。     

高性能耐候桥梁用钢HPS70W的生产实践

通过使用TMCP工艺生产高性能耐候桥梁用钢HPS70W的生产实践,主要讨论了两种不同厚度钢板的生产工艺和组织性能,该钢完全符合或超过美国标准《桥梁结构钢ASTM A709》的高性能桥梁用钢HPS70W的要求。     

TMCP桥梁钢焊接接头组织性能研究

采用CO_2气体保护焊对50 mm TMCP桥梁钢Q420q E进行焊接,用金相显微镜观察焊接接头微观组织,并检验接头拉伸、弯曲及冲击性能。结果表明,焊缝外观平整、组织均匀,焊缝和热影响区均具有良好的冲击韧性,焊接接头强度可以满足使用要求,TMCP桥梁钢焊接性能优良。     

15MnVNq钢的研制总结

15MnVNq 钢是在16Mnq 钢的基础上加入 V 和 N 而研制成的新钢种。通过试验研究和生产实践,证明该钢种综合性能良好,基本上能满足建造大跨度栓焊桥梁用钢的需要。15MnVNq 钢充分利用我国富有的合金资源,生产工艺较简单,与强度级别相同的钢相比较成本低,应进一步推广使用。     

高强度桥梁缆索用钢研究现状和发展趋势

概述了国内外桥梁缆索用钢的发展历史；介绍了桥梁缆索用钢丝强度、扭转性能、耐腐蚀性等重要性能的研究现状；并从成分设计、盘条控冷工艺等方面论述了桥梁缆索用钢不同生产工艺的特点及未来发展的方向，为新型桥梁缆索用钢的研发提供借鉴。     

高速及重载铁路桥梁用钢板的生产实践

结合我国高速及重载铁路桥梁建设用钢的要求,探讨了高强度、高韧性桥梁结构用钢的轧制、控冷及热处理工艺与组织和性能的关系,制定了高强度、高韧性桥梁用钢的生产工艺,满足了我国第一代高速及重载公铁两用大桥的建造需要。     

合金元素对桥梁结构钢HPS70W组织性能的影响

通过添加不同含量的Nb、Mo、V,研究了合金元素对桥梁结构钢板HPS70W力学性能、金相组织和第二相粒子析出的影响。试验结果表明:合金元素Mo、V对桥梁结构钢板HPS70W没有起到明显的析出强化作用,合金元素Nb对桥梁结构钢板HPS70W低温韧性、强度和塑性有显著的作用。     

铌对美标桥梁结构钢板性能的影响

通过向桥梁结构钢板HPS70W中添加不同含量的Nb元素,研究了合金元素Nb对桥梁结构钢板的力学性能、金相组织和第二相粒子析出的影响。试验结果表明,合金元素Nb对桥梁结构钢板HPS70W低温韧性、强度和塑性有显著影响。     

Optimization of HPS 70W Applications

In February 1996 the Tennessee Department of Transportation, in cooperation with the Federal Highway Administration, the American Iron and Steel Institute, the U.S. Navy, and various steel plate manufacturers, agreed to design the first bridge in the United States to use HPS 485W (70W) steel. Since that time the department has constructed a second bridge using HPS 485W (70W) and has let to contract a third bridge that uses HPS 485W (70W) in both quenched and tempered and thermomechanical controlled processing HPS 485W (70W) steel. This paper will discuss lessons learned in the process and present optimization techniques employed.     

美国高性能桥梁用钢研发现状

介绍了美国高性能桥梁用钢研发现状,包括其组织机构、研发历程、用钢特点以及生产和应用现状,并对其开发的HPS 50W、HPS 70W和HPS 100W系列钢种的化学成分和力学性能进行了对比、分析.     

Assessment of AASHTO LRFD Specifications for Hybrid HPS 690W Steel I-Girders

This paper details research conducted to determine the applicability of the 2nd and 3rd editions of the AASHTO LRFD Specifications to hybrid I-girders fabricated from high-performance steel (HPS) 690W (100?ksi) flanges and HPS 480W (70?ksi) webs. Specifically, the scope of this paper is to evaluate the applicability of the negative moment capacity prediction equations for noncomposite I-girders subjected to moment gradient. This evaluation is carried out using three-dimensional nonlinear finite-element analysis to determine the ultimate bending capacity of a comprehensive suite of representative hybrid girders. In addition, a design study was conducted to assess the economical feasibility of incorporating HPS 690W (100?ksi) in traditional bridge applications. This was accomplished by designing a series of I-girders with varying ratios of span length to girder depth (L/D ratios) for a representative three-span continuous bridge. Results of this study indicate that both the 2nd and 3rd editions of the specifications may be used to conservatively predict the negative bending capacity of hybrid HPS 690W (100?ksi) girders, however increased accuracy results from use of the 3rd edition of the AASHTO LRFD Specifications. Thus, it is concluded that the restriction placed on girders fabricated from steel with a nominal yield strength greater than 480?MPa (70?ksi) can be safely removed. Additionally, results of the design study demonstrate that significant weight saving can result from the use of hybrid HPS 100W girders in negative bending regions, and that hybrid HPS 690W/HPS 480W girders may be ideally suited to sites with superstructure depth restrictions.     

High Performance Steel: Research Front—Historical Account of Research Activities

This paper provides a summary of the major research studies conducted or being conducted in the U.S., to address design issues related to use of high performance steel (HPS) in bridge construction. Emphasis of the paper is on the work related to HPS-485W steel, which has specified minimum yield strength of 485 MPa (70 ksi). Design issues that are addressed in this paper include (1) flexural capacity of compact and noncompact HPS sections in negative bending; (2) issues related to ductility of HPS composite girders in the positive sections (this section presents a simplified ductility check for composite plate girders); (3) tensile ductility of HPS plates; (4) shear capacity of the hybrid steel plate girders; (5) live load deflections; and (6) brief overview of the work that is underway to develop innovative bridge configurations capable of incorporating the advantages of HPS.     

Finite-Element Modeling of Heat-Curved I-Girders

Heat curving is extensively used for fabricating structural steel girders for bridges. Current American Association of State Highway and Transportation Officials (AASHTO) specifications limit usage to Grade 345 steel (Fy = 50?ksi), ruling out Grade 485 (Fy = 70?ksi) high performance steel (HPS). This paper presents results of a three-dimensional finite-element analysis to assess the applicability of existing AASHTO provisions for HPS 485W sections. The finite-element package NASTRAN was used to conduct the analysis and the model calibrated against experimental data obtained from full-scale tests conducted previously by U.S. Steel Corporation. Comparisons include curvatures, lateral deformations, and residual stresses. The calibrated model was used to predict the performance of an identical HPS girder subjected to the same heat/cool cycles. The three-dimensional analysis predicted smaller curvatures as compared with Grade 250 (Fy = 36?ksi) or Grade 345 (Fy = 50?ksi) steel. Comparable curvatures could be obtained by using higher temperatures.     

Fatigue and Fracture of Steel Girders

This paper presents an overview of materials selection, design, and detailing of steel girders for fatigue and fracture limit states. The historical context of the fracture control plan for bridges is presented. A discussion of fracture toughness of structural steel and weld metal is presented along with typical Charpy and fracture-toughness test data, including the new high-performance steel A709 HPS 485W. Fatigue of cover plate details and distortion-induced cracking are discussed. Methods of dealing with variable-amplitude loading are then compared to test data.     

Strength and Ductility of HPS-100W I-Girders in Negative Flexure

In current AASHTO LRFD bridge design specifications, the nominal flexural strength of I-girders made from steel with a yield stress >345 MPa (>50 ksi) is limited to the yield moment rather than the plastic moment and inelastic design procedures are not permitted. With the recent development of high performance steel (HPS) for highway bridges, the need for these restrictions should be revisited. This paper focuses on I-girders made from HPS-100W steel. Two I-girders were designed with HPS-100W steel according to the AASHTO LRFD specifications, neglecting current restrictions related to the use of high strength steels. The I-girders were tested to failure under three-point loading, which simulated the condition of negative flexure at the pier of a continuous-span bridge. The flexural strength and ductility of the HPS-100W I-girders are compared with the strength and ductility anticipated by the AASHTO LRFD specifications for conventional steel I-girders. In addition, the results of relevant previous tests of conventional steel I-girders are summarized and compared with the HPS-100W I-girder test results.