Study On Wind-induced Effects Of Large-scale Gas Holder

With the rapid development of metallurgical industry and chemical industry,the large-scale gas holder began to be built substantially in our country.This type of gas holder is generally towering thin-walled spatial structure with high softness and low damping characteristics,and easy to deform under wind load.The main control load of the gas holder is the wind loads.In order to guarantee the security of gas holder,it is necessary for it to carry on wind resistant design.Taking the large-scale gas holder as the research object in this paper,Some parameters,which are the mode,surface wind pressure and wind-induced base shear,have been discussed through field measurement,wind tunnel test and finite element calculation.The conclusions can act as a reference for other wind resistant design.First of all,two finite element models-with and without cover,were utilized to calculate and analyze the modal parameters of the gas holder respectively.Modal parameters of both models are compared with those received from field measurement.Moreover,the model without cover which is similar with actual structure can be picked and improved when the finite element calculation is proved.Secondly,the wind pressure characteristics of the gas holder what are studied through the wind tunnel pressure test are compared with those obtained from field measurement.The results show that the average wind pressure coefficients obtained from the wind tunnel test basically agree with those obtained from the field measurement.They are basically equal on the windward and the right wind surface,but the value of the wind test results on the leeward and the left wind surface is significantly larger than that of the field measurement.The trend of the root-mean-square wind pressure coefficient obtained from the wind tunnel test basically agrees well with that obtained from field measurement,but the specific data is very different.The coherences of the measuring points obtained from the wind tunnel test are fundamentally the same as those of field measurement on the windward surface,but they are larger than those on the leeward side and the left wind surface and less than those on the right wind surface.Finally,the effects of adjacent gas holder interference on wind-induced base shear of gas holder is studied in different wind directions and net distances through wind tunnel force measurement.The results show that along-wind mean base shear interference effect can be divided into three types(i.e.shielding effect,channeling effect and wake effect)according to wind direction.The shielding effect and channeling effect gradually become remarkable with the decrease of the net distance,while the wake effect is not obvious in the small net distance.The root mean square interference effect of along-wind fluctuating base shear becomes observable when the wind direction belongs to the condition that the channeling effect owns and the net distance is small.The root mean square interference effect of across-wind fluctuating base shear is concerned with the location of adjacent gas holder.The interference effect of the adjacent holder located upstream is larger than the adjacent holder located downstream,and the interference effect of the adjacent holder located downstream becomes remarkable only in small net distance.At the same time,the global shape coefficient of gad holder without and with interference calculated in this paper is compared with the one in load code for the design of building structures in china.