完整版桥梁毕业设计外文翻译0.docx

1、完整版桥梁毕业设计外文翻译0Structural Rehabilitation of Concrete Bridges with CFRP Composites-Practical Details and ApplicationsRiyad S. ABOUTAHA1, and Nuttawat CHUTARAT2ABSTRACT: Many old existing bridges are still active in the various networks, carrying all kinds of environments. Water, salt, and wind ; and t

2、o extend the service life of concrete bridges is by the use of carbon fiber reinforced polymer (CFRP) composites. There appear to be very limited guides on repair of deteriorated concrete bridges with CFRP composites. In this paper, guidelines for nondestructive evaluation (NDE), nondestructive test

3、ing (NDT), and rehabilitation of deteriorated concrete bridges with CFRP composites are presented. The effect of detailing on ductility and behavior of CFRP strengthened concrete bridges are also discussed and presented.KEYWORDS: Concrete deterioration, corrosion of steel, bridge rehabilitation, CFR

4、P composites.1 IntroductionThere are several destructive external environmental factors that limit the service life of bridges. These factors include but not limited to chemical attacks, corrosion of reinforcing steel bars, carbonation of concrete, and chemical reaction of aggregate. If bridges were

5、 not well maintained, these factors may lead to a structural deficiency, which reduces the margin of safety, and may result in structural failure. In order to rehabilitate andor strengthen deteriorated existing bridges, thorough evaluation should be conducted. The purpose of the evaluation is to ass

6、ess the actual condition of any existing bridge, and generally to examine the remaining strength and load carry capacity of the bridge.1 Associate Professor, Syracuse University, U.S.A.2 Lecturer, Sripatum University, Thailand.One attempt to restore the original condition, and to extend the service

7、life of concrete bridges is by the use of carbon fiber reinforced polymer (CFRP) composites. In North America, Europe and Japan, CFRP extensively investigated and applied. Several design guides developed for strengthening of concrete bridges with CFRP composites. However, there appear to be very lim

8、ited guides on repair of deteriorated concrete bridges with CFRP composites. This paper presents guidelines for repair of deteriorated concrete bridges, along with proper detailing. Evaluation, nondestructive testing, and rehabilitation of deteriorated concrete bridges with CFRP composites are prese

9、nted. Successful application of CFRP composites requires good detailing as the forces developed in the CFRP sheets are transferred by bond at the concrete-CFRP interface. The effect of detailing on ductility and behavior of CFRP strengthened concrete bridges will also be discussed and presented.2 De

10、teriorated Concrete BridgesDurability of bridges is of major concern. Increasing number of bridges are experiencing significant amounts of deterioration prior to reaching their design service life. This premature deterioration considered a problem in terms of the structural integrity and safety of t

11、he bridge. In addition, deterioration of a bridge many cases, the root of a deterioration problem is caused by corrosion of steel reinforcement in concrete structures. Concrete normally acts to provide a against corrosion of the embedded reinforcement. However, corrosion will result in those cases t

12、hat typically experience poor concrete quality, inadequate design or construction, and , may turn into a strength problem leading to a structural deficiency, as shown in Figure1.Figure1 Corrosion of the steel bars is leading to a structural deficiency3 Non-destructive Testing of Deteriorated Concret

13、e Bridge PiersIn order to design a successful retrofit system, the condition of the existing bridge should be thoroughly evaluated. Evaluation of existing bridge elements or systems involves review of the asbuilt drawings, as well as accurate estimate of the condition of the existing bridge, as show

14、n in Figure2. Depending on the purpose of evaluation, non-destructive tests may involve estimation of strength, salt contents, corrosion rates, alkalinity in concrete, etc.Figure2 Visible concrete distress marked on an elevation of a concrete bridge pierAlthough most of the non-destructive tests do

15、not cause any damage to existing bridges, some NDT may cause minor local damage (e.g. drilled -destructive testing.In order to select the most appropriate non-destructive test for a particular case, the purpose of the test should be identified. In general, there are three types of NDT to investigate

16、: (1) strength, (2) other structural properties, and (3) quality and durability. The strength methods may include; compressive test (e.g. core testrebound test (e.g. Windsor probe), and pullout test (anchor test).Other structural test methods may include; concrete cover thickness (cover-meter), locating rebars (rebar locator), rebar size (some rebar locatorsrebar data scan), concrete moisture (acquametermoisture meter), cracking (visual testimpact echoul