Reliability of Corroded Steel Bridge Girders PDF Download
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Author: Irene A. Cordahi Publisher: ISBN: Category : Languages : en Pages : 80
Book Description
Corrosion is one of the main causes of deterioration of bridges. Structures exposed to harsh environmental conditions are subjected to time-variant changes of their load-carrying capacity. Thus, there is a need for an evaluation to accurately assess the actual condition and predict the remaining life of a structure. System reliability can be used as an efficient tool in evaluation of existing structures. The traditional approach is based on the consideration of individual components rather than the system as a whole. However, it has been observed that the load-carrying capacity of the whole system often is much larger than what is determined by the design of components. Quantification of this difference is the scope of this study.
Author: Irene A. Cordahi Publisher: ISBN: Category : Languages : en Pages : 80
Book Description
Corrosion is one of the main causes of deterioration of bridges. Structures exposed to harsh environmental conditions are subjected to time-variant changes of their load-carrying capacity. Thus, there is a need for an evaluation to accurately assess the actual condition and predict the remaining life of a structure. System reliability can be used as an efficient tool in evaluation of existing structures. The traditional approach is based on the consideration of individual components rather than the system as a whole. However, it has been observed that the load-carrying capacity of the whole system often is much larger than what is determined by the design of components. Quantification of this difference is the scope of this study.
Author: Safaa Dardar Publisher: ISBN: Category : Civil engineering Languages : en Pages : 261
Book Description
Bridge - girder deterioration model is formed based on diffusivity process, corrosion development, and cracks propagation. The chloride diffusivity is studied based on previous researches0́9 experimental work while corrosion penetration is analyzed based on mathematical model. Corrosion products cause cracks then spalling. Therefore, in the few decades, the utilize of fiber-reinforced polymer (FRP) materials to strengthen highway bridges has obtained in popularity. sensible cost, speed and ease of installation, and limited disruption of the use of the structure have shared to the adoption of FRP systems over other strengthening options. In order to reduce the corrosion with the bridge deterioration. Fiber Reinforced Polymer (FRP) is one of the top solutions to reduce corrosion and strengthen bridge - girders, by placing FRP on the side(s) of the reinforced concrete beam and reduce the influence of chloride diffusivity through reinforced concrete. Thus, the deterioration with reinforced concrete based on corrosion with section warped with FRP is less than with the corrosion of reinforced concrete section unwrapped with FRP. The objective of this study is to develop a reliability - deterioration model based on corrosion in steel, concrete cover spalling, and FRP debonding. The reliability is reduced due to two independent deterioration factors that developed simultaneously with Life Cycle Time (LCT). The corrosion in steel rebar is the first deterioration factor that causes reduction in flexural moment capacity, and spalling. Moreover, the second deterioration factor is the surrounded environment that may causes FRP debonding. Monti Carlo Simulation (MCS) of reliability-based deterioration model is programmed and used in order to compute failure probability by using FORTRAN 90 to analyze the bridge 0́3 girder model including all design parameters.
Author: Hany Mohamed Seif Eldin Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Structural deficiencies in Railway steel bridges are usually the result of deterioration caused by ageing, corrosion, fatigue, and higher load demands. In this context, steel bridge girders are the structural members prone to corrosion which implies a substantially reduction of their flexural capacities. As a result, a large number of steel railway bridges are in need for strengthening or retrofit. In this thesis, experimental and analytical investigations are conducted to predict the reduction in the flexural capacity of existing deteriorated steel girders under static loading and several retrofitting schemes are developed in the light of strengthening the girder cross-section. The experimental study covers the use of two Carbon Fibre-Reinforced Polymer (CFRP) composite types, namely, normal modulus sheets (NM-CFRP) and high modulus strips (HM-CFRP). A total of thirteen medium-scale W-shape steel beams with a span of 1.6m were tested under four-point bending setup. The thirteen beams were divided in four groups such as: i) Group G1 consisted of four beams with different percentages of cross-sectional area reduction without any strengthening; ii) Group G2 consisted of four notched beams strengthened with bonded NM-CFRP sheets. Herein, two out of the four strengthened beams, were bonded using saturant epoxy, while the other two were strengthened using high performance adhesive; iii) Group G3 consisted of two notched beams strengthened with bonded HM-CFRP strip with and without a wrapping system; iv) Group G4 consisted of three notched beams strengthened with unbonding NM-CFRP sheets and a ductile anchoring system. The results of the experimental study underline the effectiveness of the proposed retrofitting schemes in terms of flexural capacity increase and deflection control of the existing corroded steel girders. In addition to the experimental program, an analytical model was developed to set up a numerical method that is capable of predicting the elastic and post-yield behaviour of the unstrengthened and strengthened deteriorated steel girders. This numerical method can be used by designers to calculate the losses in the moment capacity of the deteriorated steel girders to an acceptable level of accuracy. The analytical model was validated using the experimental results that were presented in the experimental program.
Author: Eulogio M. Javier III Publisher: ISBN: Category : Iron and steel bridges--Corrosion Languages : en Pages : 74
Book Description
Steel bridges commonly have corrosion at beam ends because of leaking joints, which provide a pathway for de-icing salts to fall onto the beams from the roadway above. Once beam ends have corrosion damage, it becomes more difficult to determine their remaining shear capacity to be used for load rating. This is because classical design equations are based on intact sections and do not account for corrosion damage. This study was conducted to understand better the structural behavior of unstiffened steel bridge beams that have section loss near the bearings and to determine a simple, effective method for determining the remaining shear capacity of corroded beams during load rating. Seventeen beams from four decommissioned structures throughout Virginia were experimentally tested in a laboratory to induce web shear failure near the bearing locations and were measured for load, vertical displacement, and web strain behavior. Strain was measured using a digital image correlation system to create a digital strain field at discrete load and beam displacement intervals during testing. The large-scale test results were compared to shear capacity calculations conducted in accordance with the AASHTO LRFD Bridge Design Specifications; AISC (American Institute of Steel Construction) 360-16; the Massachusetts Department of Transportation LRFD Bridge Manual; and other methods found in the literature for calculating the shear capacity of the damaged steel beam ends. The study found that using the shear capacity calculations presented by Tzortzinis et al. (2019a) in Development of Load Rating Procedures for Deteriorated Steel Beam Ends resulted in reliable shear capacity predictions. The study also concluded that AASHTOWare Bridge Rating (BrR) can be used for determining the capacity of steel beams with corrosion using the percent web thickness loss input in the program. When doing so for a corroded steel beam without holes, the accuracy of BrR can be improved by calculating the percent thickness loss input in the BrR deterioration profile using a portion of the web with a height equal to the bottom or top 3 in of the web, depending on the location of severe corrosion, and a length equal to the lesser of the bearing length plus the beam height or the extent of the corrosion damage near the bearing. When doing so for a corroded steel beam end with holes, the accuracy of BrR can be improved by using the same portion of the web and by modifying the remaining average web thickness using the guidelines provided in the Massachusetts Department of Transportation LRFD Bridge Manual before inputting the percent thickness loss into the BrR deterioration profile. Based on these conclusions, the study recommends that the Virginia Department of Transportation provide guidance (1) in a job aid to bridge inspectors for enhanced web thickness measurements and measurements of holes to be used when inspecting unstiffened corroded steel beam ends in Condition State 4 on bridges without diaphragms or a concrete deck, and (2) in its upcoming new load rating user manual to define the portion of the web and web thickness modification to account for holes when the same corroded steel beam ends are load rated.
Author: Irene A. Cordahi
Author: Irene A. Cordahi
Author: Artur A. Czarnecki
Author: Mohammed Shaalan Al Badran
Author: Chan-Hee Park
Author: Jack Raymond Kayser
Author: Safaa Dardar
Author: Michel Ghosn
Author: SHUENN-CHERN TING
Author: Hany Mohamed Seif Eldin
Author: Eulogio M. Javier III