Gengwen Zhao

Virginia Department of Transportation

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i-10 index

Research Trends

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Co-Authors

Chung C. Fu

University of Maryland, College Park

Timothy Saad

University of Maryland, College Park

Tim Saad

Yunchao Ye

Chaoran Xu

University of Maryland, College Park

Jian Li

Huazhong University of Science and Technology

Yi Zhou

University of Science and Technology Beijing

Lu Yang

Jilin Normal University

Yunlai Zhou

Anhui Medical University

Katsuhiro Dobashi

The University of Tokyo

Cooperative Institutions

Ghent University Hospital

National University of Singapore

Southeast University

University of Maryland, College Park

Central South University

The University of Tokyo

Public Works Research Institute

State Key Laboratory of Vehicle NVH and Safety Technology

Beijing University of Posts and Telecommunications

Anhui Medical University

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Research Field

Lack-of-fit Analysis and Locked-in Forces Calculation-A Case Study of a Curved Steel I-girder Bridge During Construction

Transportation Research Board 92nd Annual MeetingTransportation Research Board (2013)

Chung C. Fu Gengwen Zhao Changsheng Xiang Mohamed Salah Ahmed

Curved bridges generally exhibit critical attributes during construction, such as torsional deformations, diaphragm forces, and potential for uplift at bearings, which may induce fit-up difficulties. However, conventional analysis commonly employed in current practice only addresses the internal forces associated with no-load fit (NLF) detailing without considering lack-of-fit effects. In this article, a method of lack-of-fit analysis was adopted to solve this problem and applied to a real case study. In this case study, the supports of a steel-concrete composite curved bridge were uplifted in the course of construction. A 3D finite element model (FEA) was established by SAP2000 to simulate the erection procedures. Lack-of-fit analysis was conducted from total dead load fit (TDLF) detailing, in which locked-in forces in the structure were determined based on the diaphragm drops due to differential camber on and between girders. The results proved that the support uplift was temporary during erection and it was validated by bridge testing. It is concluded that this method of lack-of-fit analysis (3D-FEA method or even 2D-grid method) can simulate construction procedure, estimate lack-of-fit effects, and calculate locked-in forces from steel dead load fit (SDLF) detailing and total dead load fit (TDLF) detailing.

Internal forces

Structural load

Camber (aerodynamics)

Bridge (graph theory)

Diaphragm (acoustics)

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INVESTIGATION OF FATIGUE-INDUCED CRACK WITH K-TYPE BRACING SYSTEM

Chung C. Fu Gengwen Zhao Tim Saad Yunfeng Zhang Yi Zhou

Fatigue-induced cracking is a common failure mode in many steel bridges reaching their original design life. These aging bridge structures have experienced increasing traffic volume and weight, deteriorating components, as well as a large number of stress cycles. This paper presents a case study of fatigue assessment of an interstate highway steel bridge through real time monitoring under traffic. The bridge is a single-span, composite steel I-girder structure with K-type cross frame diaphragms. The study also included numerical analysis using 3D global finite element models. Based on the simulated traffic flow, statistical dynamic responses such as displacements and stress of bridge girders were studied for the cause of fatigue cracks that occurred in some cross frame connections. Meanwhile, long-term field monitoring has also been conducted. Furthermore, the influence of connection plate configuration and bracing system configuration was discussed using a series of controlled finite element tests. Based on the information from field tests, simulated numerical analytical results were verified. Thus, the performance of highway bridges under truck load can be predicted in a more realistic way to estimate the fatigue performance of highway bridges.

Bracing

Bridge (graph theory)

Fatigue cracking

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TMD wind-induced vibration control along wind direction for Beijing Olympic central broadcast tower based on its simplified model

Gengwen Zhao

Here,Beijing Olympic central broadcast tower was taken as a project case to investigate wind-induced vibration control with tuned mass damper(TMD)under fluctuating load along wind direction.First of all,based on the random vibration theory,fluctuating wind load along wind direction of this tower was simulated by means of M.Shinozuka method,and 6 correlated time history curves were obtained.Secondly,the 3D model of the tower was investigated by use of the 2D model,the accuracy and reliability of the 2D model was verified,and the calculation time was extremely saved taking advantage of the 2D model.Finally,the optimal TMD coefficients were obtained considering the wind-induced acceleration response of the upper story along wind direction as optimization objectives.The analysis results showed that the maximum peak acceleration response of the tower along wind direction under dynamic wind load is far beyond the allowable value of the code,the wind-induced responses are decreased greatly with TMD;and with the optimal parameters of TMD,the peak acceleration and displacement wind-responses of the upper story along wind direction are reduced respectively by 20.2% and 42.7%;TMD dissipates a large amount of input energy and plays an important pole in the wind-induced vibration control of the tower along wind direction.

Tuned mass damper

Wind engineering

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Dynamic Response Simulation of Steel Bridges under Truck Loading

Structural Materials Technology (2014)

Gengwen Zhao Chung C. Fu Yunchao Ye

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Wind characteristics of Sutong bridge based on long-term monitored data

Zhendong yu chongji (2010)

Gengwen Zhao

Located in the coastal area of eastern China,the structural health monitoring system of Sutong Bridge has collected more than one year's wind data since the opening of the bridge in May 2008.In order to build the wind characteristic database of the bridge spot,the measured data were analyzed to obtain the wind rose plots of the annual maximum 10-min mean wind velocity,the turbulence intensity,the turbulence integral length and its power spectrum,etc.Comparing with the suggested values of the bridge wind-resistance codes,the wind characteristics and rules of the bridge spot were summarized.The results could provide the measured basis for the wind-resistance evaluation of Sutong Bridge,and provide a reference for the wind-resistance study on other engineering structures in the region.

Bridge (graph theory)

Structural Health Monitoring

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Truck Loading Simulation for the Fatigue Assessment of Steel Highway Bridges

Gengwen Zhao

10.13016/m2wd17

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Citations (1)

Non-linear buffeting response analysis of long-span suspension bridges with central buckle

Earthquake Engineering and Engineering Vibration (2010)

Hao Wang Aiqun Li Gengwen Zhao Jian Li

Buckle

Aeroelasticity

Suspension

Bridge (graph theory)

10.1007/s11803-010-0011-7

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Citations (17)

Serviceability-related Issues for Bridge Live Load Deflection and Construction Closure Pours

Chung C. Fu Gengwen Zhao Yunchao Ye Fan Zhang

This study investigated the design criteria and practices in an effort to improve the quality of bridge designs in the State of Maryland and beyond. This first criterion investigated was the live load deflection for steel bridges. The second design/construction criterion investigated was designing and detailing bridge deck closure pours. Previous and current practices and future planning on the serviceability of bridges have been documented. State-of-the-practice methods from federal and other state agencies were collected. Three bridges were chosen for refined analyses to investigate the live load deflections. Field measurements for these three bridges were collected from the research team to facilitate this study. Thirty steel girder bridges from the Maryland State Highway Administration’s (SHA) inventory were selected for statistical analyses. Steel bridges designed with the live load deflection limit have been evaluated. Closure-pour analyses were conducted by line-girder models, two-dimensional grid models or three-dimensional finite element models. All three methods generate accurate enough camber diagrams to predict differential deflections between stages for straight girder systems, if creep is not considered. Creep effect could be alleviated by proper camber and scheduling on pouring.

Serviceability (structure)

Limit state design

Structural load

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Bridge Optimization - Inspection and Condition Monitoring

IntechOpen eBooks (2019)

Yunlai Zhou Magd Abdel Wahab Linya Liu Mitsuru Uesaka Yuki Mitsuya

This is a collection of several applications for condition monitoring and damage identification in bridge structures. Bridge structural condition monitoring is essential since it can provide early warning of potential defects in bridges, which may induce catastrophic accidents and result in huge economic loss. Such bridge condition monitoring relies on sensing techniques, especially advanced sensing techniques that can provide detailed information on bridge structures. Additionally, postprocessing systems can interpret the captured data and warn of any potential faults. This book will give students a thorough understanding of bridge condition monitoring.

Bridge (graph theory)

Identification

Condition Monitoring

Structural Health Monitoring

10.5772/intechopen.79062

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Citations (2)

Fatigue Assessment of Highway Bridges under Traffic Loading Using Microscopic Traffic Simulation

IntechOpen eBooks (2019)

Gengwen Zhao Chung C. Fu Lu Yang Timothy Saad

Fatigue is a common failure mode of steel bridges induced by truck traffic. Despite the deterioration caused by environmental factors, the increasing truck traffic volume and weight pose a premier threat to steel highway bridges. Given the uncertainties of the complicated traffic loading and the complexity of the bridge structure, fatigue evaluation based on field measurements under actual traffic flow is recommended. As the quality and the quantity of the available long-term traffic monitoring data and information have been improved, methodologies have been developed to obtain more realistic vehicular live load traffic. A case study of a steel interstate highway bridge using microscopic traffic simulation is presented herein. The knowledge of actual traffic loading may reduce the uncertainty involved in the evaluation of the load-carrying capacity, estimation of the rate of deterioration, and prediction of remaining fatigue life. This chapter demonstrates a systematic approach using traffic simulation and bridge health monitoring-based fatigue assessment.

Bridge (graph theory)

10.5772/intechopen.81520

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Citations (1)