Reliability And Environmental Impact Assessment Of RC Beams By Considering The CFRP Flexural Strengthening Mode

With the rapid development of china economy, the construction of our country’s infrastructure has also experienced rapid development. The amount of highway bridges is on increase. By the end of 2014, the amount of highway bridges in our country reached 757.1 thousand. By the end of 2020, the amount of highway bridges will reach 800 thousand. During the service life, the highway bridges suffer vehicle load and external environmental, resulting in decline in performance of bridge. We need assess the existing bridges from the viewpoint of reliability and strengthen the existing bridges. Confirm the number of reinforcement on account of reliability degradation model. At the same time, construction and reinforcement of highway bridges will consume plenty of natural resources and energy resources, and it is required to assess the environmental implication by construction and reinforcement. Since there are different environment conditions including alternation of wetting and drying, alternation of freezing and thawing, wet region along the coast and so on, it is necessary to study the effect of different environment conditions on strengthening times and environmental impact. Strengthening method with carbon fiber reinforced polymer has many advantages than traditional strengthening methods and get wide application, but there are very few researchs on highway bridge reliability and environment impact after strengthening with carbon fiber reinforced polymer. In this paper, in the following aspects of study was conducted:(1) Propose performance functions of RC bridge flexural member before and after reinforcement with CFRP. Present a reliability calculation method by combining with Monte-Carlo sampling method and second order moment method.(2) Under four different environment conditions, introduce checking coefficient according to Specification for Inspection and Evaluation of Load-bearing Capacity of Highway Bridges, and strengthen flexural bridge members with carbon fiber sheet and carbon fiber plate, and compare the flexural reliability index after strengthening with the two carbon fiber reinforced materials.(3) Calculate environmental impact potential by single strengthening with carbon fiber sheet and carbon fiber plate. Introduce reliability index degradation model, and obtain the number of strengthening and environmental impact potential during the whole strengthening phase, as well as get life cycle environmental impact potential of the RC beam, and introduce the concept of annual mean of environmental impact potential and calculate environmental impact potential of every year.(4) Taking different environment conditions, as well as degradation and overloading 10%,20%,30%,40% and 50% into consideration. Consider twenty different conditions. Under each condition, bridge flexural members are strengthened with carbon fiber sheet and carbon fiber plate, and reliability index and environmental impact potential of the bridges strengthening with the two different CFRP materials are compared. Finally, calculate life cycle environmental impact potential of the bridges.