| Based on theoretical analysis, experimental studies and nonlinear stochastic finiteelement simulation, the stochastic characteristics of surface topography，the stochasticfield of corrosion depth on surface, the load-capacity，the stochastic model of resistanceand reliability of corroded H-shape steel members are studied in this paper.The main aspects of this study are as follows:(1)Measuring and interpreting corrosion depth on the surface of corroded H-shapesteel specimens at neutral salt fog environmentIn this part of this study, the corrosion depth on corroded Q235H-shape steelspecimens, which is corroded with the accelerated method of neutral salt spraytest(NSS), were tested with PS503D profiling that is an automated non-contact surfacescanning device, the corroded surface profiles and the datum of corrosion depth on thesurface of corroded specimens can be obtained, and the distribution characteristics ofcorrosion depth on the surface of corroded steel members was analyzed, the resultssuggested that it obeys normal distribution for corrosion depth on the surface ofcorroded H-steel members, significantly.(2)The study on stochastic field mold for corroded H-shape steel members atneutral salt fog environmentIn the part of this paper, Ergodic characteristics and stationary of the datum ofcorrosion depth obtained from PS503D profiling are tested, the results indicated thatthe ergodic and stationary is a characteristic of stochastic field of corrosion depth. Established the stochastic field of corrosion depth at neutral salt fog environment atdifferent corrosion ratio, with all the2D profiles of corroded steel specimens obtainedfrom PS503D profiling, and expressed the2D profiles which used as the samplefunction of stochastic field of corrosion depth with trigonometric functions.(3) Experimental studies on the eccentric compressive load-capacity of corrodedH-shape steel membersIn this part of the paper,10H shape members were corroded with an acceleratedprocedure tested in eccentric compression, and2un-corroded members were also testedas a control. Then, established the formulas for load-capacity and deflection in themiddle of the column for corroded H shape steel members under eccentric compression.This paper also made a detailed analysis of the effect of corrosion on eccentriccompression strength of corroded steel H-shape members, the corrosion of compressionflange, tension flange and web was analyzed respectively. Then, we came to theconclusions that the effects of corrosion on flange on eccentric compression strength ofcorroded steel H-shape members is more obviously than on web, and corrosion ofcompression flange is much more obviously than tension flange.The effect of corrosion on material performance of corroded steel was alsoanalyzed.(4)The studies on nonlinear stochastic finite element method for the load-capacitypredicting of corroded H-shape steel membersIn this part of this paper, based on the characteristics of the random thickness ofcorroded H-steel members and the stochastic stiffness of plane stress element and platebending element, established the in plane, out plane and nonlinear stochastic stiffnessfor the plane shell element and plane shell structureIn the end of this part, a program with C++language for the load-capacitypredicting of corroded steel structure is written. The program can be used for planeproblem, rectangular thin-plate bending and rectangular shell element, compared theresults obtained from the model and the results obtained from experiment, we can getthe conclusions that the load-capacity obtained from the model are complied with theexperimental values well, we can also get the conclusions that the nonlinear stochasticfinite element method is an effective method for the load-capacity predicting of corroded steel structure, which can simulate the stochastic characteristics of thethickness of corroded steel members.(5)The stochastic model of residual load-capacity and the reliability analyzing forcorroded H-shape steel membersIn this part, a stochastic model for residual resistance of corroded H-steel memberswas established, and analyzed its eccentric resistance with this model, The resultsshowed that the results obtained from the method are complied with the results obtainedfrom experiment well, the mean values of resistance of corroded H-shape steel structurewere decreased and the coefficient of variation of eccentric resistance increasedobviously with the corrosion ratio increased.Based on the reliability analyzing of corroded H-shape steel eccentric compressionmembers, the effects of corrosion on the steel structures and the members of steelstructures were analyzed, the results indicated that the reliability and the reliabilityindex of corroded steel structure was worsen then the un-corroded with the corrosionratio increased. |
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