![]() A time-dependent reliability assessment method for simply supported T-beam bridges is proposed in this paper, which considers the influence of reinforcement corrosion on LLD. The traditional lateral load distribution (LLD) theory does not consider the influence of corrosion, which degrades the accuracy of bridge performance and reliability calculation. For use in Equations 1 and 2, the cracking moment can be taken as:Ībstract:The safety and reliability of bridges gradually decrease over time under the influence of disadvantageous environmental factors, primarily due to reinforcement corrosion caused by chloride ingress. 14), provides typical section properties for various uncracked wall sections. TEK 14-1B, Section Properties of Concrete Masonry Walls (ref. As such, any rational method of determining cracked section properties is permitted. The MSJC does not prescribe a method of determining the cracked moment of inertia, Icr. Second, forany other negative moment where a T-beam cantilever occurs (i.e., where moment redistributioncannot occur), the minimum steel should be increased as it is for determinate T-beams. First, for statically determinate T-beams (such as precast cantilevered tees) where redistributionof moments is not possible, the minimum negative steel is calculated based on the flangewidth or twice the web (stem) width, whichever is smaller (see Appendix Table A-5.9d). This logic does not apply in the following twosituations. The reason for this appears to havesomething to do with the redundancy of continuous (indeterminate) T-beam floor systems: redistributionof moments from supports to midspan is possible if failure at the negative-moment supportsrenders them incapable of sustaining bending stress, essentially turning the system into a series ofsimply-supported spans with positive moment only. It is permissible to design minimum steel areas for T-beams subjected to negative bending as ifthey were rectangular beams with b = bw in spite of the large area of concrete in the tension flange that could, in fact, sustain a much larger "uncracked" moment.
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