Research On Extreme Wind Loads Of Small And Medium-sized Railway Stations As Well As Wind-induced Elastoplastic Behaviors Of The Single Span Canopy Rigid Frame

Railway platforms belong to open buildings,are sensitive to wind loads,and a large number of stations are being built.Modern station canopies are mostly constructed with light high-strength steel structure and thin-wall metal envelop enclosure.Wind load is the controlling load in the design,since the envelop enclosure and main steel structure of canopies are easily destroyed by strong wind.Currently,there are relatively few researches and regulations about the extreme wind load of envelop enclosure of railway stations.The wind load is determined mainly based on experience,resulting in great safety risks in structure.For main steel structure,since current load design specification is also based on the wind pressure that my occur once-in-a-half-century,it lacks assessment of the performance of steel structure in case of a rare strong wind.In this theme,based on wind tunnel test and finite element simulation,the extreme wind load of canopies and station building roofs and wind resistance of main elastoplasticity-based steel structure are researched respectively.The main research content and conclusions are as follows:(1)Through a survey of a series parameters at small and medium-size high-speed railway stations,the parameters of experimental model were determined;the wind tunnel test was carried out in the simulated type B wind field,so as to analyze the law of distribution of mean value,root-mean-square value and extreme value of wind pressure with typical wind direction and the law of influence of minimum wind pressure coefficient at center section of canopies under different parameters.(2)Based on the law of distribution of minimum wind pressure with full wind direction obtained from the experiment and by reference to the partition scheme of minimum wind pressure with full wind direction for single slope roofs and flat roofs of open buildings in U.S.ASCE 7-16 and AIJ-2004,a partition scheme of minimum wind pressure with full wind direction for canopies and station building roofs at small and medium stations was summarized.Furthermore,the maximum mean value in the partition of the most unfavorable wind pressure coefficient with full wind direction at the partition of canopies and station building roofs was given under changing parameters,thus providing reference for designing envelop enclosure.(3)As to the representative wind direction of steel structure of single-span canopies,incremental dynamic time-history analysis was adopted to calculate non-linear wind-induced response time-history of canopy’s steel structure.Then,displacement response characteristics,plasticity development law and destruction of structure under different basic wind pressure were researched.Based on the wind load spectrum obtained from wind tunnel test,a multiple sets of wind load samples were generated for analyzing dynamic plasticity of canopies to obtain statistics of development of wind-induced plasticity.