Research And Application Of Ribbed Steel Formwork For Annular Wal

As the number of unique architectural structures in China continues to increase,building designs are becoming increasingly diverse,and the number of unique-shaped buildings is increasing year by year.Circular concrete walls are a common form of unique-shaped buildings.Due to their distinctive shape,template design is the key focus and difficulty in construction.At present,customized steel templates with vertical and horizontal ribs or on-site assembled wooden templates are often used for template construction of circular concrete walls.For circular structures,using wooden templates is time-consuming and labor-intensive and cannot guarantee the quality of the formed structure.Factory-customized steel templates are suitable for circular concrete structures that can be used multiple times,but for small-volume circular structures with few turnovers,using customized steel templates is expensive and takes longer.This article presents a circular ribbed steel template suitable for on-site production and processing.Numerical analysis of different parameter variables of the template was carried out using finite element software and was applied in practical engineering.The research content and results are as follows:(1)Using BIM technology,a ribbed steel template for circular walls that only has radial ribs without longitudinal ribs was designed.No pull bolts need to be connected between the inner and outer circular wall steel templates.Combining the characteristics of circular structures,the calculation method of the ribbed steel template for circular walls was analyzed,and the installation process of the template system was explained.(2)Using ANSYS finite element software,theoretical analysis was performed on the ribbed steel template of the circular wall,with variables including the rib spacing,concrete pouring height,panel thickness,and diameter of the circular wall.38 template models were designed to study the effect of each design parameter on the mechanical performance of the ribbed steel template.The results show that changes in rib spacing and panel thickness will affect the load-carrying capacity of the ribbed steel template,with a non-linear relationship.Decreasing rib spacing and increasing panel thickness gradually diminishes the improvement of the template’s mechanical performance,and the degree of decline continues to increase.Increasing the pouring height results in a linear increase in stress on the ribbed steel template of the circular wall,but displacement increases significantly with height.After the template diameter exceeds 10 m,the increase in displacement and stress is 2-3 times the increase in diameter.(3)The numerical simulation results were further analyzed and summarized.Combined with the requirements of GB/T50214-2013 "Technical Code for Steel Formwork for Concrete," the design parameters of ribbed steel templates with different panel thicknesses,rib spacing,and pouring heights for circular walls with diameters of 10 m and below were obtained.The results show that: 1)When the pouring height of the inner and outer templates is 1m,3mm,4mm,and5 mm thickness panels can be selected.For the 3mm thickness panel,the rib spacing should not exceed 330 mm.For the 4mm or 5mm thickness panel,the rib spacing should not exceed 500 mm.2)When the pouring height of the inner and outer templates is 2m,4mm and 5mm thickness panels can be selected.For the 4mm thickness panel,the rib spacing of the inner template should not exceed 250 mm,and that of the outer template should not exceed 200 mm.For the 5mm thickness panel,the rib spacing of the inner template should not exceed 500 mm,and that of the outer template should not exceed 400 mm.3)When the pouring height of the inner and outer templates is 3m,a 5mm thickness panel should be selected,and the rib spacing of the inner template should not exceed 300 mm,and that of the outer template should not exceed 250 mm.(4)Combined with the actual engineering of the circular wall in the new building of the Qingzhou Museum,a ribbed steel template with a diameter of 7.8m was designed and numerically analyzed using finite element software.The eight-point steel wire positioning method and short steel bar positioning method were used to achieve precise positioning of the circular template.Eight strain measurement points and four displacement measurement points were set up on the circular steel template,and the strain and displacement of the ribbed steel template of the circular wall were monitored during the pouring process.The measured data and theoretical data had a high degree of agreement,which verified the rationality and feasibility of the design.