1. |
- Xiang, Yiqiang, et al.
(författare)
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Cracking Mechanism and Simplified Design Method for Bottom Flange in Prestressed Concrete Box Girder Bridge
- 2011
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Ingår i: Journal of Bridge Engineering. - 1084-0702 .- 1943-5592. ; 16:2, s. 267-274
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Tidskriftsartikel (refereegranskat)abstract
- Serious cracking has occurred frequently in the bottom flange of box girders during construction in recent years. This paper aims at studying the cracking mechanism and countermeasures. The stress field in the bottom flange associated with the bottom continuity tendon is presented, and the propagation of cracks during tensioning is simulated by nonlinear analysis according to the actual construction sequence. A cracking mode, which is not easy to detect in field investigation, is illustrated through numerical and theoretical study. It is caused by the deficient shear strength of the bottom flange attributed to the void in tendon ducts. Based on numerical results and field investigation, four types of cracking in the bottom flange are proposed and discussed, and a simplified design method is recommended for control of cracking.
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2. |
- Xiang, Yiqiang, et al.
(författare)
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Risk Analysis and Assessment of Public Safety of Submerged Floating Tunnel
- 2010
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Ingår i: ISAB-2010 - FIRST INTERNATIONAL SYMPOSIUM ON ARCHIMEDES BRIDGE. - : Elsevier BV. ; , s. 117-125
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Konferensbidrag (refereegranskat)abstract
- Based on the structural characteristics and preliminary design of submerged floating tunnel (SFT) prototype in Qiandao Lake, this paper gives the risk index system of public safety of SFT and risk assessment methods by analyzing different impact factors of SFT public safety. Moreover, the public safety risk is evaluated during construction and operation of SFT prototype in Qiandao Lake by the presented analytic hierarchy process method. The results show that in spite of facing many technical problems and potential risks, these potential risks of SFT can be controlled or reduced to a minimum level with the help of reasonable design and certain measures
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3. |
- Xiang, Yiqiang, et al.
(författare)
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Risk analysis and management of submerged floating tunnel and its application
- 2010
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Ingår i: ISAB-2010 - FIRST INTERNATIONAL SYMPOSIUM ON ARCHIMEDES BRIDGE. - : Elsevier BV. ; , s. 107-116
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Konferensbidrag (refereegranskat)abstract
- Combining with the characteristics of submerged floating tunnel (SFT) and surrounding environment, it is of great theoretical and practical significance to develop research in the areas of potential risk and impact factors, risk index system, risk level of SFT. This paper summarized the main content of risk analysis of SFT, and classified the risk management into six stages: planning, feasibility study, design, tendering, construction and operation. Risk management workflow of SFT was given. Then, we focused on discussing the potential risks of SFT in investment, design, and environmental condition during planning and feasibility study stage. After identifying the risk factors of SFT, the risk assessment method of SFT was described by the presented fuzzy AHP method (FAHP). Finally, taking environment risks assessment of SFT prototype in Qiandao Lake as an example, environment risk assessment of SFT was completed by the programmed integration evaluation system of SFT based on Matlab7.5. Some measures and suggestions in risk control strategy were given.
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