Load testing and health monitoring of monolithic bridges with innovative reinforcement

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kexin Zhang ◽  
Tianyu Qi ◽  
Dachao Li ◽  
Xingwei Xue ◽  
Zhimin Zhu

PurposeThe paper aims to investigate effectiveness of the strengthening method, the construction process monitoring, fielding-load tests before and after strengthening, and health monitoring after reinforcement were carried out. The results of concrete strain and deflection show that the flexural strength and stiffness of the strengthened beam are improved.Design/methodology/approachThis paper describes prestressed steel strand as a way to strengthen a 25-year-old continuous rigid frame bridge. High strength, low relaxation steel strand with high tensile strain and good corrosion resistance were used in this reinforcement. The construction process for strengthening with prestressed steel strand and steel plate was described. Ultimate bearing capacity of the bridge after strengthening was discussed based on finite element model.FindingsThe cumulative upward deflection of the second span the third span was 39.7 mm, which is basically consistent with the theoretical value, and the measured value is smaller than the theoretical value. The deflection value of the second span during data acquisition was −20 mm–10 mm, which does not exceed the maximum deflection value of live load, and the deflection of the bridge is in a safe state during normal use. Thus, this strengthened way with prestressed steel wire rope is feasible and effective.Originality/valueThis paper describes prestressed steel strand as a way to strengthen a 25-year-old continuous rigid frame bridge. To investigate effectiveness of the strengthening method, the construction process monitoring, fielding-load tests before and after strengthening and health monitoring after reinforcement were carried out.

2011 ◽  
Vol 71-78 ◽  
pp. 1392-1397 ◽  
Author(s):  
Wen Xiong Huang ◽  
Li Ying Tan ◽  
Kang Jing Zhou

Cracks on the Joint Part between Pier and Girder, namely Block NO.0 in the construction process, has become one of the major diseases of continuous rigid-frame bridges. Based on the real construction technology, process and environment of Yuquanxi Bridge, the uneven distribution of stress caused by various factors is precisely analyzed by ANSYS. The shrinkage difference of concrete, the excessive hydration heat, and the sunshine temperature difference is accurately simulated respectively. By comparing the numerical results with actual cracks condition, the results prove that the theoretical analyse is accord with the actual situation, and the real reason of cracks on Block No.0 of Yuquanxi Bridge is uncovered. This study is of great practical value in preventing cracks and improving bridge construction technology.


2014 ◽  
Vol 578-579 ◽  
pp. 1161-1169
Author(s):  
Li Wang ◽  
Wei Ming Yan ◽  
Hao Xiang He ◽  
Wei Wang

This paper is aiming to present the whole situation of a three spans prestressed continuous concrete rigid frame bridge’s SHM (structural health monitoring) system. Hardware structure and software exploitation of the system were respectively elaborated combining with the practical application situation, including details of sensors layout, data acquisition, storage and transform, the developing of monitoring and management system, etc. Emphasis is placed on data processing and analyzing which is collected from the bridge in the online continuously, such as modal identification of the measured acceleration responses, calculation of deflection curves in real time, observation of changing strains and stresses on the measuring points.


2014 ◽  
Vol 1030-1032 ◽  
pp. 750-753
Author(s):  
Hua Su

Accurate simulation of construction process of continuous rigid frame bridge is a foundation to make a bridge built accurately. Based on the suit iteration method, this paper used MIDAS to built a 3D finite elements model, the internal force and deformation results of each construction stage was obtained. This study provided a good theoretical reference for the control of long-span continuous rigid frame bridge construction..


2011 ◽  
Vol 255-260 ◽  
pp. 821-825 ◽  
Author(s):  
Yun Bo Zhang ◽  
Da Peng Liu

In the design of continuous rigid frame bridge setting reasonable pre-camber can eliminate the impact of various loads on the linear in construction process, reduce shrinkage and creep in the process of post-operation, the late loss of pre-stressed, deformation produced by live load and so on ,resulting in deflection phenomenon. Based on the current specifications of the continuous rigid frame bridge camber setting methods, this thesis proposes the reasonable setting suggestions of pre-camber and sets examples to illustrate this.


2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Dansheng Wang ◽  
Junbing Zhang ◽  
Hongping Zhu

Piezoelectric lead zirconate titanate (PZT) is one of the piezoelectric smart materials, which has direct and converse piezoelectric effects and can serve as an active electromechanical impedance (EMI) sensor. The design and fabrication processes of EMI sensors embedded into concrete structures are presented briefly. Subsequently, finite element modeling and modal analysis of a continuous rigid frame bridge are implemented by using ANSYS and MIDAS and validated by the field test results. Uppermost, a health monitoring technique by employing the embedded EMI and strain sensors is proposed in this paper. The technique is not based on any physical model and is sensitive to incipient structural changes for its high frequency characteristics. A practical study on health monitoring of the continuous rigid frame bridge is implemented based on the EMI and strain signatures. In this study, some EMI and strain sensors are embedded into the box-sectional girders. The electrical admittances of distributed EMI active sensors and the strains of concrete are measured when the bridge is under construction or in operation. Based on the electrical admittance and strain measurements, the health statuses of the continuous rigid frame bridge are monitored and evaluated successfully in the construction and operation stages using a root-mean-square deviation (RMSD) index.


2011 ◽  
Vol 71-78 ◽  
pp. 1511-1515
Author(s):  
Can Bin Yin ◽  
Fang Yu

Take Longtan river super large bridge as example,establishing finite element model with Bridge Doctor to analysis the influence shrinkage and creep.The deformation prediction of the bridge in the construction process and after completion was made based onseveral.Each prediction results were analyzed and compared.


2013 ◽  
Vol 361-363 ◽  
pp. 1380-1383
Author(s):  
Ning Zhao ◽  
Bing Zhu ◽  
Wen Jia Suo ◽  
Liang Du ◽  
Fan Wang

Combining with specific engineering example, we used the finite element calculation software and analyzed the lateral deformation and stress of variable cross-section curved continuous rigid frame bridge during cantilever construction. Their some change rules are obtained. They accumulate during cantilever construction, and system transformation influences them greatly. We also put forward some understanding and advice about design and construction.


Author(s):  
Ying hua Li ◽  
Kesheng Peng ◽  
Junyong He ◽  
Qiangjun Shuai ◽  
Gang Zou

When the bridge components needing maintenance are the world problem at present, and the health monitoring system is considered to be a very helpful tool for solving this problem. In this paper, a large number of strain data acquired from the structural health monitoring system (SHMS) installed on a continuous rigid frame bridge are adopted to do reliability assessment. Firstly, a calculation method of punctiform time-dependent reliability is proposed based on the basic reliability theory, and introduced how to calculate reliability of the bridge by using the stress data transformed from the strain data. Secondly, combined with “Three Sigma” principle and the basic pressure safety reserve requirement, the critical load effects distribution function of the bridge is defined, and then the maintenance reliability threshold for controlling the unfavorable load state which appears in the early operation stage of this type bridge is suggested, and then the combination of bridge maintenance management and health monitoring system is realized. Finally, the transformed stress distribution certifies that the load effects of concrete bridges practically have a normal distribution; as for the concrete continuous rigid frame bridge with C50 strength grade concrete, the retrofit reliability threshold should be valued at 6.13. The methodology suggested in this article can help bridge engineers do effective maintenance of bridges, which can effectively extend the service life of the bridge and bring better economic and social benefits.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Kexin Zhang ◽  
Dachao Li ◽  
Xinyuan Shen ◽  
Wenyu Hou ◽  
Yanfeng Li ◽  
...  

PurposeThis paper aims to describe carbon fiber reinforced plastics (CFRP) bars as a way to strengthen a 40-year-old stone arch bridge. To investigate effectiveness of the strengthening method, fielding-load tests were carried out before and after strengthening.Design/methodology/approachHigh-strength CFRP bars with minor radius, high tensile strain and good corrosion resistance were used in this reinforcement. The construction process for strengthening with CFRP bars – including CFRP bars cutting, crack grouting, original structural surface treatment, implant drilling, CFRP bars installation and pouring mortar – was described. Ultimate bearing capacity of the bridge after strengthening was discussed.FindingsThe results of concrete stress and deflection show that the strength and stiffness of the strengthened bridge are improved. The strengthened way with CFRP bars is feasible and effective.Originality/valueThis paper describes CFRP bars as a way to strengthen a 40-year-old stone arch bridge.


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