Demolition Analysis And Risk Control Of Pc Continuous Rigid Frame Bridges With Variable Cross-section

Bridge demolition is a complicated systematic process. Since the current theory and technology of bridge demolition is not fully mature, coupled with the changing environment of construction site, the risk of bridge demolition is relatively high. When accidents during bridge demolition occur, consequences are often very serious. Therefore, this paper focuses on demolition analysis and risk analysis of prestressed concrete (PC) continuous rigid frame bridges with variable cross-section.First, bridge demolition cases as well as the basic risk theory of bridge engineering are introduced in the paper. Reasons for frequent accidents during the demolition process are discussed, and the existing issues of bridge demolition and risk research are expounded.Secondly, based on current bridge demolition analysis, and according to the structural system, project scale and materials of bridges, demolition methods for PC continuous rigid frame bridge are proposed with the specific workflow. Additionally, in order to fully understand the working condition of the bridge, methods for performance assessment of existing bridges are introduced. To further reduce the risk of bridge demolition, construction monitoring as well as difficulties during the construction process are investigated.Then, a three-span (75+135+75) m PC continuous rigid frame bridge with variable cross-section is taken as a case study. After comparison of two construction schemes, the appropriate one is improved and adopted. The content and methods of demolition monitoring are determined. Finite element method is both used to assess the bridge capacity, and to carry out structural analysis for key demolition stages.Finally, combined with risk theories of bridge engineering, risk assessment framework for bridge demolition is established. Risk identification, risk analysis, significant risk estimation and risk control of the bridge demolition are carried out. And measures of risk management for the bridge demolition are recommended.Studies show that the proposed demolition scheme and risk analysis methods for bridge demolition are feasible.