Analysis On Time-dependent Load Effects And Reliability Design Of Wharf Components

Structure safety, duration and reliability are controlled by ultimate limit state andserviceability limit state in design reference period, respectively. Research onreliability of serviceability limit state, targeting at duration, is still at the beginningstate. Research on reliability of serviceability limit state of container high-piledterminal in design reference period can be conducted, which will provide theoreticalbasis for real-time prediction for time-varying reliability of wharf structure, lifeevaluation, safe application and maintenance scheme.Terminal load mainly depends on the stochastic process of time. Structuralresistance gradually reduces with time. And the current reliability analysis isconducted without consideration of time varied factors. The paper has summarizedanalysis method of reliability, suitable for terminal structure in normal servicecondition, on the basis of which, time-dependent analysis of load effects and timevarying mechanics of reliability in normal service condition were done. The paperfirst built time-varying models of load effects of ship impact load by using calculationexamples, applying a Monte Carlo method of random sampling and considering therandomness of temporal variation, types of berthing ship, strike frequency and loadvalues; then, built time-varying models of duration and load effects of container craneby considering different states of container crane and single duration model of eachstate; finally, simulated time-dependent reliability of computing architecture in thecontrol of crack in normal service condition.The following conclusions can be drawn from the study:（1）The key of establishing more comprehensive analysis methods, suitable forport engineering in serviceability limit state is to build reasonable time-varyingmodels of load and resistance;（2）The random fitting problems of load effects of ship impact load, types ofberthing ships and strike frequency can be better solved on the basis of randomprocess theory by combining Monte Carlo and structural finite element analysisstating with berth occupancy factor, the difference value for the results of which andstandard value of load effects without consideration of random factors is15%; （3）The control load case of container crane is working state, and momentdesign value of working state doesn’t differ much from design values calculated ascode. However, the difference value of equal permanent value is around50%, and thevalue of equal permanent coefficient requires further investigation;（4）According to the index of time-varying reliability and computing results offailure probability: the reliability index gradually reduced with the growth of serviceduration of terminal structure, which coincided with facts, and confirmed feasibility ofthe time-varying analysis methods. Some constructive suggestions about undecidedreliability index of port engineering in normal service condition are put forward.