Research On The Modal Parameter Identification Technology And Updating Of Finite Element Model For High-piled Wharf

High pile wharf is stakes into the soft soil foundation form pile foundation inorder to receive from the upper structure of the load. It is characteristic of simplestructure, can withstand the big load, material consumption, suitable for soft soil layerof silt coast. But the durability of the high pile wharf relative to other quay structureform poor and wharf component easy damage, repair hardly, the seismic performanceis poor. At present the detection method of wharf structure have artificial visit method,damaged method and nondestructive test. Visiting method hard to find hidden troubleand requires a lot of time, like water and the soil structure under part of structure.Based on the dynamic vibration test detection method is an effective nondestructivetesting method, it can achieve in the laboratory, also can be applied to practicalprojects, and no influence on the structure of normal use, can detect hidden parts ofstructure and damage diagnosis. How to identify the structure modal parameters ondynamic test condition is the foundation of the structure. This paper work has thefollowing two aspects:1、The theoretical basis of modal parameter is identified based on auto-crossspectrum density method by environment excitation.Large high-piled wharf physicalmodel is established with reinforced concrete as raw material and some port piledwharf as a prototype for modal test.Two order natural frequency of high-pile wharfstructure model are identified by auto-power spectrum cross-power spectrum crossspectrum phase and coherence function from time domain data of MATLABprogramming by using structure response only in different conditions.Finite elementmodel is established by analytical software ANSYS.Compared with the results ofexperiment,the ANSYS results near to them.The test results are reliable.The basis isprovided by research results of structure damage diagnosis and power calculation.2、Structure vibration of the finite element model is updated use of piled wharfphysical model test results in this paper. Finite element model is updated based on therestriction optimization theory upon the sensitivity analysis of the structurecharacteristics. The zero-order optimization algorithm and the first-order optimizationalgorithm are adopted in model modification.Comparing the two kinds ofoptimization algorithm,the results of first-order optimization algorithm is slightlyhigher accuracy, but the computational time need far more than zero-order algorithm. The reasonable initial finite element model is established of the key to modelmodification, so the soil-pile foundation-the upper structure interactionin isconsiderationed in the modal analysis.New finite element model of dynamic isapproached measured value on revised and provided standard for dynamic responseanalysis damage detecting and holistic approach for evaluation of high pile wharfstructure.