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Experimental research on the creep behavior and bearing capacity of repeatedly prestressed concrete beam

SHAO Xudong, LI Lifeng, YANG Jianjun

《结构与土木工程前沿(英文)》 2007年 第1卷 第3期   页码 305-311 doi: 10.1007/s11709-007-0040-0

摘要: In the prestress tensioning process of medium or short span prestressed concrete beam bridges, there are always many serious problems, such as the camber of straight beam being too large, curved beam going crosswise, and columns of rigid beam bridge cracking, that can be commonly seen because of its greater additional stress in prestressing. To solve the above problems, a new concept of repeatedly prestressed bridge structure was innovatively proposed in this work. It was proved, through theoretical and experimental comparison between this new structure and the traditional prestressed structure, that the application of repeated prestressing technology can greatly improve the mechanical and deformational performance of the low height beam during construction and long-term use. Furthermore, a kind of computational formula to calculate creep strain and deformation due to repeated prestressing in terms of time was derived in this paper and the bearing capacity of this new structure has been tested. Finally, the work concludes that there is a bright application prospect for this new structure for medium and short span prestressed beam bridges to control deformations.

关键词: computational     cracking     technology     prestressed concrete     application prospect    

Deflection behavior of a prestressed concrete beam reinforced with carbon fibers at elevated temperatures

Mohammed FARUQI, Mohammed Sheroz KHAN

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 81-91 doi: 10.1007/s11709-018-0468-4

摘要: Fiber reinforced polymer(FRP) have unique advantages like high strength to weight ratio, excellent corrosion resistance, improving deformability and cost effectiveness. These advantages have gained wide acceptance in civil engineering applications. FRP tendons for prestressing applications are emerging as one of the most promising technologies in the civil engineering industry. However, the behavior of such members under the influence of elevated temperatures is still unknown. The knowledge and application of this could lead to a cost effective and practical considerations in fire safety design. Therefore, this study examines the deflection behavior of the carbon fiber reinforced polymer(CFRP) prestressed concrete beam at elevated temperatures. In this article, an analytical model is developed which integrates the temperature dependent changes of effective modulus of FRP in predicting the deflection behavior of CFRP prestressed concrete beams within the range of practical temperatures. This model is compared with a finite element mode (FEM) of a simply supported concrete beam prestressed with CFRP subjected to practical elevated temperatures. In addition, comparison is also made with an indirect reference to the real behavior of the material. The results of the model correlated reasonably with the finite element model and the real behavior. Finally, a practical application is provided.

关键词: FRP     CFRP     concrete     elevated temperatures     deflections     prestress    

Experimental study on shear behavior of prestressed reactive powder concrete I-girders

Hui ZHENG, Zhi FANG, Bin CHEN

《结构与土木工程前沿(英文)》 2019年 第13卷 第3期   页码 618-627 doi: 10.1007/s11709-018-0500-8

摘要: As a new generation of concrete, RPC(Reactive Powder Concrete) has attracted great research attention for its ultra-high strength and high durability. In the present paper, experimental results from tests on eight prestressed RPC I-section girders failing in shear are reported herein. The beams with RPC of 120 MPa in compression were designed to assess the ability to carry shear stress in thin webbed prestressed beams with stirrups. The test variables were the level of prestressing, shear span-depth ratio ( / ) and stirrup ratio. Shear deformation, shear capacity and crack pattern were experimentally investigated in detail. With regard to the shear resistance of the test beams, the predictions from three standards (AFGC, JSCE and SIA) on the design of UHPC structures were compared with the experimental result suggesting that the experimental strength is almost always higher than predicted. RPC, as a new concrete, was different from normal concrete and fiber reinforced concrete. Further study should be needed to develop an analytical method and computation model for shear strength of RPC beams.

关键词: prestressed concrete     RPC(Reactive Powder Concrete)     concrete beams     shear strength     experimental study    

Seismic performance of prestressed concrete stand structure supporting retractable steel roof

Yiyi CHEN, Dazhao ZHANG, Weichen XUE, Wensheng LU

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 117-124 doi: 10.1007/s11709-009-0024-3

摘要: The seismic behavior of a structural system composed of pre-stressed concrete stand supporting a retractable steel roof was studied, which is typically based on the prototype of engineering project of Shanghai Qizhong Tennis Center. By elasto-plastic finite element analysis and shaking table test, the following were investigated: the effects of roof configurations in opening and closing, the effect of pre-stress on the structural seismic response, and the failure mechanism of the spatial stand frame systems featured with circularly arranged columns and inverse-cone type stands. It was found that the roof status has great effect on the natural period, vibration modes, and seismic response of the whole structure, the stand response to horizontal seismic excitation is stronger in roof opening configuration than in closing state, and the response mode is dominantly translational rather than rotational, though the stand is characterized by its fundamentally torsional vibration mode. The study indicated that the pre-stressed inverse-cone stands can keep the system from global side-sway collapse under gravity loads, even in the case that most columns loose moment capacity.

关键词: retractable steel roof     prestressed concrete     seismic performance     failure mode     inelastic response     shaking table test    

3D fracture modelling and limit state analysis of prestressed composite concrete pipes

Pengfei HE, Yang SHEN, Yun GU, Pangyong SHEN

《结构与土木工程前沿(英文)》 2019年 第13卷 第1期   页码 165-175 doi: 10.1007/s11709-018-0484-4

摘要: In this manuscript, we study fracture of prestressed cylindrical concrete pipes. Such concrete pipes play a major role in tunneling and underground engineering. The structure is modelled fully in 3D using three-dimensional continuum elements for the concrete structure which beam elements are employed to model the reinforcement. This allows the method to capture important phenomena compared to a pure shell model of concrete. A continuous approach to fracture is chosen when concrete is subjected to compressive loading while a combined continuous-discrete fracture method is employed in tension. The model is validated through comparisons with experimental data.

关键词: cylindrical concrete structures     limit state analysis     3D fracture modelling     prestressed composite pipes     reinforced concrete     three-point bending test    

Analysis on shear capacity of prestressed concrete spatial connections

XUE Weichen, LIU Zhenyong, JIANG Dongsheng

《结构与土木工程前沿(英文)》 2008年 第2卷 第4期   页码 309-317 doi: 10.1007/s11709-008-0052-4

摘要: Based on experimental results of prestressed concrete spatial connections, nonlinear finite element models were established to analyze the shear capacity of spatial connections and parametric studies were performed using ANSYS. It is found that the shear capacity of spatial connection is influenced by joint hoop, beam prestress, column compressive load, and direction of resultant shear force. The parametric studies also indicate that the shear capacity of spatial connection under biaxial cyclic loading is lower than that of corresponding connections under plane loading. A design formula for calculating the shear capacity of spatial connections is proposed based on the parametric studies and verified by the available test results.

关键词: available     direction     nonlinear     capacity     compressive    

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

《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    

Shear design of high strength concrete prestressed girders

Emad L. LABIB,Hemant B. DHONDE,Thomas T. C. HSU,Y. L. MO

《结构与土木工程前沿(英文)》 2014年 第8卷 第4期   页码 373-387 doi: 10.1007/s11709-014-0087-7

摘要: Normal strength prestressed concrete I-girders are commonly used as the primary superstructure components in highway bridges. However, shear design guidelines for high strength PC girders are not available in the current structural codes. Recently, ten 7.62 m (25 feet) long girders made with high strength concrete were designed, cast, and tested at the University of Houston (UH) to study the ultimate shear strength and the shear concrete contribution ( ) as a function of concrete strength ( ). A simple semi-empirical set of equations was developed based on the test results to predict the ultimate shear strength of prestressed concrete I-girders. The UH-developed set of equations is a function of concrete strength ( ), web area ( ), shear span to effective depth ratio ( / ), and percentage of transverse steel ( ). The proposed UH-Method was found to accurately predict the ultimate shear strength of PC girders with concrete strength up to 117 MPa (17000 psi) ensuring satisfactory ductility. The UH-Method was found to be not as overly conservative as the ACI-318 (2011) code provisions, and also not to overestimate the ultimate shear strength of high strength PC girders as the AASHTO LRFD (2010) code provisions. Moreover, the proposed UH-Method was found fairly accurate and not exceedingly conservative in predicting the concrete contribution to shear for concrete strength up to 117 MPa (17000 psi).

关键词: shear design     high strength concrete     prestressed girders     full-scale tests    

Flexural behavior of high-strength, steel-reinforced, and prestressed concrete beams

Qing JIANG, Hanqin WANG, Xun CHONG, Yulong FENG, Xianguo YE

《结构与土木工程前沿(英文)》 2021年 第15卷 第1期   页码 227-243 doi: 10.1007/s11709-020-0687-3

摘要: To study the flexural behavior of prestressed concrete beams with high-strength steel reinforcement and high-strength concrete and improve the crack width calculation method for flexural components with such reinforcement and concrete, 12 specimens were tested under static loading. The failure modes, flexural strength, ductility, and crack width of the specimens were analyzed. The results show that the failure mode of the test beams was similar to that of the beams with normal reinforced concrete. A brittle failure did not occur in the specimens. To further understand the working mechanism, the results of other experimental studies were collected and discussed. The results show that the normalized reinforcement ratio has a greater effect on the ductility than the concrete strength. The cracking- and peak-moment formulas in the code for the design of concrete (GB 50010-2010) applied to the beams were both found to be acceptable. However, the calculation results of the maximum crack width following GB 50010-2010 and EN 1992-1-1:2004 were considerably conservative. In the context of GB 50010-2010, a revised formula for the crack width is proposed with modifications to two major factors: the average crack spacing and an amplification coefficient of the maximum crack width to the average spacing. The mean value of the ratio of the maximum crack width among the 12 test results and the relative calculation results from the revised formula is 1.017, which is better than the calculation result from GB 50010-2010. Therefore, the new formula calculates the crack width more accurately in high-strength concrete and high-strength steel reinforcement members. Finally, finite element models were established using ADINA software and validated based on the test results. This study provides an important reference for the development of high-strength concrete and high-strength steel reinforcement structures.

关键词: high-strength steel reinforcement     high-strength concrete     flexural behavior     crack width    

FRP筋预应力混凝土梁抗弯性能研究进展

邓宗才,王作虎,杜修力,刘景园

《中国工程科学》 2006年 第8卷 第8期   页码 86-91

摘要:

FRP筋预应力混凝土结构已成为国内外工程领域研究的重点,文章分别介绍了国内外体内有粘结、体内无粘结和体外无粘结FRP筋预应力混凝土梁抗弯性能研究的主要成果,并对今后拟开展的研究工作提出了建议。

关键词: FRP筋     预应力混凝土梁     抗弯性能    

Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

《结构与土木工程前沿(英文)》 2009年 第3卷 第2期   页码 158-164 doi: 10.1007/s11709-009-0002-9

摘要: A field test was conducted to investigate the distribution of temperature field and the variation of thermal stress for a prestressed concrete (PC) box-girder bridge. The change of hydration heat temperature consists of four periods: temperature rising period, constant temperature period, rapid temperature fall period and slow temperature fall period. The peak value of hydration heat temperature increases with the increasing casting temperature of concrete; the relation between them is approximately linear. According to field tests, the thermal stress incurred by hydration heat may induce temperature cracks on the PC box-girder. Furthermore, the nonlinear distribution of temperature gradient and the fluctuation of thermal stress induced by exposure to sunlight were also obtained based on continuous in-situ monitoring. Such results show that the prevailing Chinese Code (2004) is insufficient since it does not take into account the temperature gradient of the bottom slab. Finally, some preventive measures against temperature cracks were proposed based on related studies. The conclusions can provide valuable reference for the design and construction of PC box-girder bridges.

关键词: box-girder bridge     field test     hydration heat     temperature field     temperature gradient     thermal stress    

大跨度混凝土连续梁桥的病害成因分析

林帆,王萍,肖开军,李伟

《中国工程科学》 2010年 第12卷 第4期   页码 78-81

摘要:

自20世纪80年代以来,我国建成了大量大跨度预应力混凝土连续体系桥梁,取得了辉煌成就,但随着桥梁建设数量与使用年限的增加,该类桥梁在施工与运营期陆续出现一些具有共性的病害:跨中挠度过大、箱梁开裂与跨中合龙段底板剥离等,而且有些病害已经导致桥梁重大的安全事故与经济损失。文章对国内数十座桥梁出现的病害随时间变化发展的趋势、在空间上分布的形态等进行了分析。根据现有的理论研究成果,分析了腹板斜裂缝、底板纵向裂缝、合龙段底板分层等病害的形成机理,提出了控制裂缝等病害发生的措施,并说明了这些控制措施在泰州大桥预应力桥

关键词: 预应力     混凝土     连续体系桥梁     病害     控制    

预应力混凝土简支箱梁足尺模型试验及非线性全过程分析

方志,唐盛华,何鑫

《中国工程科学》 2012年 第14卷 第10期   页码 73-81

摘要:

对一片30 m跨的预应力混凝土小箱梁和一片20 m跨的预应力混凝土空心板进行了足尺模型试验,破坏模式分别为预应力筋拉断和顶板混凝土压碎,按能量的观点计算的延性指标小箱梁和空心板分别为1.99和1.23。基于平截面假定,采用有限条带法编制了非线性计算程序,可对包括卸载过程在内的全过程受力性能进行分析。重点介绍了卸载曲线如何在应力-应变、弯矩-曲率及荷载-位移3个层面进行计算。通过程序,对预应力筋配筋量、预应力筋张拉系数对结构的承载力、变形性能及延性的影响进行了分析。

关键词: 预应力混凝土     箱梁     足尺模型试验     非线性分析     承载力     延性    

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

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    

On the seismic stability analysis of reinforced rock slope and optimization of prestressed cables

Wenbo ZHENG, Xiaoying ZHUANG, Yongchang CAI

《结构与土木工程前沿(英文)》 2012年 第6卷 第2期   页码 132-146 doi: 10.1007/s11709-012-0152-z

摘要: The evaluation of the seismic stability of high rock slopes is of vital importance to ensure the safe operation of the hydropower stations. In this paper, an equivalent pseudo-static force analysis based on the finite element method is developed to evaluate the seismic stability of reinforced rock slopes where the prestressed cables are modeled by the bar elements applied with nodal forces and bounded only at the anchored parts. The method is applied to analyze a high rock slope in south-west China and the optimization of cables. The stabilization effects of prestressed cables on the seismic stability of the slope are studied, the simulations of the concrete heading are discussed and the potential failure modes of the shear concrete plug are compared. Based on this, the optimization of cables is studied including the anchor spacing and inclined angles.

关键词: high rock slope     reinforced system     optimization     prestressed cable     seismicity    

标题 作者 时间 类型 操作

Experimental research on the creep behavior and bearing capacity of repeatedly prestressed concrete beam

SHAO Xudong, LI Lifeng, YANG Jianjun

期刊论文

Deflection behavior of a prestressed concrete beam reinforced with carbon fibers at elevated temperatures

Mohammed FARUQI, Mohammed Sheroz KHAN

期刊论文

Experimental study on shear behavior of prestressed reactive powder concrete I-girders

Hui ZHENG, Zhi FANG, Bin CHEN

期刊论文

Seismic performance of prestressed concrete stand structure supporting retractable steel roof

Yiyi CHEN, Dazhao ZHANG, Weichen XUE, Wensheng LU

期刊论文

3D fracture modelling and limit state analysis of prestressed composite concrete pipes

Pengfei HE, Yang SHEN, Yun GU, Pangyong SHEN

期刊论文

Analysis on shear capacity of prestressed concrete spatial connections

XUE Weichen, LIU Zhenyong, JIANG Dongsheng

期刊论文

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

期刊论文

Shear design of high strength concrete prestressed girders

Emad L. LABIB,Hemant B. DHONDE,Thomas T. C. HSU,Y. L. MO

期刊论文

Flexural behavior of high-strength, steel-reinforced, and prestressed concrete beams

Qing JIANG, Hanqin WANG, Xun CHONG, Yulong FENG, Xianguo YE

期刊论文

FRP筋预应力混凝土梁抗弯性能研究进展

邓宗才,王作虎,杜修力,刘景园

期刊论文

Field test on temperature field and thermal stress for prestressed concrete box-girder bridge

Baoguo CHEN, Rui DING, Junjie ZHENG, Shibiao ZHANG

期刊论文

大跨度混凝土连续梁桥的病害成因分析

林帆,王萍,肖开军,李伟

期刊论文

预应力混凝土简支箱梁足尺模型试验及非线性全过程分析

方志,唐盛华,何鑫

期刊论文

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

Ali Fadhil NASER, Zonglin WANG

期刊论文

On the seismic stability analysis of reinforced rock slope and optimization of prestressed cables

Wenbo ZHENG, Xiaoying ZHUANG, Yongchang CAI

期刊论文