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32 m箱梁 1

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钢管复合桩;埋床法预制墩台;?75 mm预应力粗钢筋;正交异性钢桥面板;1 860 MPa斜拉索; 减隔震 1

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Experimental research on the mechanical property of prestressing steel wire during and after heating

ZHENG Wenzhong, HU Qiong, ZHANG Haoyu

《结构与土木工程前沿(英文)》 2007年 第1卷 第2期   页码 247-254 doi: 10.1007/s11709-007-0031-1

摘要: The mechanical property of prestressing steel wire during and after heating is the key factor in the design of fire resistance and after-fire damage evaluation of prestressed structures. Tensile experiment of 16 prestressing steel wires ( = 1770 N/mm, = 5 mm, low relaxation of stress) at high temperature and tensile experiment of 14 prestressed steel wires after heating are carried out. According to the experiment, the shapes of stress-strain curves of steel wire at high temperature go smooth and the mechanical property indexes of the steel wire such as strength, modulus of elasticity, etc., degenerate continuously as temperature increased. According to the experiment after heating, the mechanical property of steel wire varies little when the highest temperature that the steel wire has ever been heated to is lower than 300vH; while the stress-strain curves of steel wire become more ductile and the mechanical property indexes of the steel wire degenerate gradually when the highest temperature is higher than 300vH. By applying the theory of viscoelastic mechanics, stress-strain curves of steel wire at high temperatures without loading rate influence are obtained. The law of mechanical property indexes of the wire is presented. The mathematical models of the stress-strain relationship of the pre-stressed steel wire are established. All can serve as basic data for the analysis of fire resistance and after-fire damage evaluation of pre-stressed structures.

monitoring of the strengthening construction of a segmental box girder bridge and field testing of external prestressing

Ali Fadhil NASER, Zonglin WANG

《结构与土木工程前沿(英文)》 2012年 第6卷 第3期   页码 308-320 doi: 10.1007/s11709-012-0140-3

摘要: Prestressed concrete segmental box girder bridges are composed of short concrete segments that are either precast or cast in situ and then joined together by longitudinally post-tensioning internal, external, or mixed tendons. The objectives of this study are to monitor the construction process of the external prestressing tendons to strengthen the bridge structure and perform a field load test to measure the strain and the deflection of the anchorage devices of the external prestressing tendons to determine the state of these devices after tension forces are applied. The monitoring process of the external prestressing tendons construction includes inspecting the cracks in the diaphragm anchorage and the deviation block devices before the tension forces are applied to the external tendons; measuring the deformation of the steel deviation cross beam during the tension process; measuring the deformation of the box girder after different levels of tension forces are applied; measuring the elongation of the external tendons in each level of the tension; and measuring the natural frequency of the external tendons after the tension process is complete. The results of the monitoring process show that the measured values of the deformation, the elongation, and the natural frequency meet the requirements. Therefore, there is no damage during the construction and the tensioning of the external prestressing tendons. A field load test is performed to the anchorage beam, the steel deviation block devices, and the steel deviation cross beam. The field load test results of the anchorage devices show that the values of the strains, the stresses, and the deflection are less than the respective allowable limit values in the requirements. Therefore, the anchorage devices have sufficient strength, and the working state is good after the tension forces are applied to the external prestressing tendons.

关键词: prestressed concrete     box girder     monitoring     external tendons     strain     deflection    

武广客运专线32 m箱梁预应力效果监测及徐变上拱的控制措施

宋津喜

《中国工程科学》 2009年 第11卷 第1期   页码 60-66

摘要:

采用现场实测的方法对武广客运专线工程32 m预应力混凝土箱梁应力效果进行监测,并采用Midas/Civil结构分析程序进行了弹性上拱的理论分析,提出箱梁徐变上拱的控制措施,为同类工程提供借鉴及经验。

关键词: 武广客运专线     32 m箱梁     预应力效果监测     徐变上拱控制    

A numerical study of prestressed high strength steel tubular members

Michaela GKANTOU, Marios THEOFANOUS, Charalampos BANIOTOPOULOS

《结构与土木工程前沿(英文)》 2020年 第14卷 第1期   页码 10-22 doi: 10.1007/s11709-019-0547-1

摘要: The structural behavior of prestressed high strength steel (HSS) tubular members is investigated through the execution of advanced finite element modeling. Numerical models are developed and validated against published experimental data on HSS tubular members subjected to different levels of initial prestress and loaded either in tension or compression. The effect of the presence or absence of grouting on the strength and ductility of the members is also considered. To numerically replicate the structural response recorded in the tests, some key modeling features including the employed numerical solver, the adopted material models and the element types warrant careful consideration. Upon developing of the finite element models, the numerically generated ultimate loads, the corresponding failure modes and the full load-deformation curves are compared to the experimental ones, indicating a successful validation. As anticipated, prestressing enhances the load-bearing capacity for the tensile members, whereas it is detrimental for the compressive ones. A series of parametric studies is performed to assess the influence of key factors on the structural response of prestressed HSS members and the obtained results are discussed. Design guidance for tensile and compressive prestressed tubular members is also provided.

关键词: finite element     prestressing     tubular members     grout     high strength steel    

Investigation of mechanical performance of prestressed steel arch in tunnel

Yaqiong WANG, Yunxiao XIN, Yongli XIE, Jie LI, Zhifeng WANG

《结构与土木工程前沿(英文)》 2017年 第11卷 第3期   页码 360-367 doi: 10.1007/s11709-017-0429-3

摘要: In the traditional tunneling method, the steel arch are often adopted to support surrounding rock to ensure the structural stability. If the steel arch is prestressed in time, tunnel support can effectively prevent the development of rock crack, thereby increasing the overall strength of tunnel support and suppress the deformation of the surrounding rock. Based on the mechanical model of steel arch established in this paper, the stress distribution of steel arch is investigated via the numerical simulation method, and the impact on surrounding rock is also analyzed. Through a field test, the rules of the arch strain distribution are observed and discussed. The results show that the prestressed steel arch structure can provide effective support and the stress gradually decreases from stress point to another arch springing. Furthermore, the stress distribution applied by the prestressed steel arch on the surrounding rock is uniform in a certain extent, and it is suggested that this construction method utilizing the prestressed steel arch to squeeze surrounding rock is feasible from a theoretical view.

关键词: tunnel support     prestressing force     steel arch     numerical analysis    

概念加固思想及工程应用

段敬民,钱永久,张方,曾宪桃

《中国工程科学》 2005年 第7卷 第8期   页码 22-25

摘要:

提出了工程结构加固中新的思路——概念加固。概念加固是运用人的思维和判断,从宏观上决定工程加固中的基本问题、基本概念及基本原则,并阐述了基于“概念加固”思想指导下的整体预应力加固技术,介绍了在工程加固中的应用实例。

关键词: 工程结构     概念加固     整体预应力加固技术    

体外预应力凸块锚固区配筋设计研究

洪浩,童育强,贺志启,刘钊

《中国工程科学》 2013年 第15卷 第8期   页码 95-98

摘要:

混凝土凸块锚固区是体外预应力的一种常见锚固形式,目前尚没有成熟的设计方法。本文通过有限元数值分析,揭示了产生局部拉应力集中的3种作用效应;在此基础上,提出了这3种局部作用效应合拉力的解析计算公式,作为凸块锚固区定量化配筋设计的依据。通过南京长江第四大桥引桥凸块锚固区的设计实践,表明该方法具有良好的实用性。

关键词: 凸块锚固区     体外预应力     配筋设计     锚下劈裂     悬臂效应     锚后牵拉    

Shear behavior of ultra-high-performance concrete beams prestressed with external carbon fiber-reinforced polymer tendons

《结构与土木工程前沿(英文)》 2021年 第15卷 第6期   页码 1426-1440 doi: 10.1007/s11709-021-0783-z

摘要: The ultra-high-performance concrete (UHPC) and fiber-reinforced polymer (FRP) are well-accepted high-performance materials in the field of civil engineering. The combination of these advanced materials could contribute to improvement of structural performance and corrosion resistance. Unfortunately, only limited studies are available for shear behavior of UHPC beams reinforced with FRP bars, and few suggestions exist for prediction methods for shear capacity. This paper presents an experimental investigation on the shear behavior of UHPC beams reinforced with glass FRP (GFRP) and prestressed with external carbon FRP (CFRP) tendons. The failure mode of all specimens with various shear span to depth ratios from 1.7 to 4.5 was diagonal tension failure. The shear span to depth ratio had a significant influence on the shear capacity, and the effective prestressing stress affected the crack propagation. The experimental results were then applied to evaluate the equations given in different codes/recommendations for FRP-reinforced concrete structures or UHPC structures. The comparison results indicate that NF P 18-710 and JSCE CES82 could appropriately estimate shear capacity of the slender specimens with a shear span to depth ratio of 4.5. Further, a new shear design equation was proposed to take into account the effect of the shear span to depth ratio and the steel fiber content on shear capacity.

关键词: beam     external prestressing     ultra-high-performance concrete     fiber-reinforced polymers     shear behavior     design equation    

PBO纤维片材预应力外粘结加固集成新技术

吴智深,岩下健太郎,牛赫东

《中国工程科学》 2005年 第7卷 第9期   页码 18-24

摘要:

近年采用外部粘结纤维增强复合材料(FRP)来加固结构越来越受到许多研究开发机构和生产单位的重视。结合作者在FRP方面的研究成果和最新开发出的高强高性能的PBO纤维材料,系统地提出了一种更为有效的预应力外粘结加固方法;通过与玻璃纤维、炭素纤维和芳纶纤维等的比较,认清了新型PBO纤维材料的特性;根据既有的试验和研究成果提出了一套完整的预应力加固方法的流程,包括概念、原理和几种降低端部界面应力和新型锚固的措施;室内小型试验和室外大型试验的结果表明,PBO片材预应力技术能够提供令人满意的加固性能。

关键词: 纤维增强聚合物(FRP)     PBO纤维片材     增强加固     外粘结     锚固措施    

港珠澳大桥设计理念及桥梁创新技术

孟凡超,刘明虎,吴伟胜,张革军,张 梁

《中国工程科学》 2015年 第17卷 第1期   页码 27-35

摘要:

介绍了港珠澳大桥的工程概况、建设目标和总体设计方案,重点阐述了以“大型化、工厂化、标准化、装配化”的设计理念和总体原则指导下,设计采用的新材料、新技术、新工艺、新设备。创新技术的应用,为提高工程品质、确保设计使用寿命提供了坚实基础和有利保障。

关键词: 钢管复合桩;埋床法预制墩台;?75 mm预应力粗钢筋;正交异性钢桥面板;1 860 MPa斜拉索; 减隔震    

标题 作者 时间 类型 操作

Experimental research on the mechanical property of prestressing steel wire during and after heating

ZHENG Wenzhong, HU Qiong, ZHANG Haoyu

期刊论文

monitoring of the strengthening construction of a segmental box girder bridge and field testing of external prestressing

Ali Fadhil NASER, Zonglin WANG

期刊论文

武广客运专线32 m箱梁预应力效果监测及徐变上拱的控制措施

宋津喜

期刊论文

A numerical study of prestressed high strength steel tubular members

Michaela GKANTOU, Marios THEOFANOUS, Charalampos BANIOTOPOULOS

期刊论文

Investigation of mechanical performance of prestressed steel arch in tunnel

Yaqiong WANG, Yunxiao XIN, Yongli XIE, Jie LI, Zhifeng WANG

期刊论文

概念加固思想及工程应用

段敬民,钱永久,张方,曾宪桃

期刊论文

体外预应力凸块锚固区配筋设计研究

洪浩,童育强,贺志启,刘钊

期刊论文

Shear behavior of ultra-high-performance concrete beams prestressed with external carbon fiber-reinforced polymer tendons

期刊论文

PBO纤维片材预应力外粘结加固集成新技术

吴智深,岩下健太郎,牛赫东

期刊论文

港珠澳大桥设计理念及桥梁创新技术

孟凡超,刘明虎,吴伟胜,张革军,张 梁

期刊论文