Analysis On Lightweight Design And Mechanical Behavior Of A New-type Prefabricated Ribbed Beam Stairs

Prefabricated buildings are gradually becoming an inevitable trend of the construction industry because of their high degree of mechanization,short construction period,and small environmental impact.However,prefabricated reinforced concrete stairs used in the current market are of major importance,poor mold versatility,difficult to install,and high cost of shortcomings.According to this situation,this paper proposed a new type of prefabricated ribbed beam combination stairs,which divided the original prefabricated section into two “T-shaped” components in the longitudinal direction,aimed to reduce the weight of the prefabricated stairs,improve the efficiency of the staircase construction,reduce the cost of production and hoisting.According to the data of the stairs in the Prefabricated Reinforced Concrete Slab Stairs of the National Building Standard Design Atlas(15G367-1),the scissors stairs and the double-run ribbed beam combination stairs were optimized.Finite element software was used to analyze the static performance of a new type of prefabricated ribbed beam combination stairs components.The seismic performance of the frame structure with a new type of prefabricated ribbed beam combined stairs was analyzed.The main work and conclusions were as follows:(1)According to the prefabricated reinforced concrete slab stairs with different story heights and stairwell widths in the National Building Standard Design Atlas(15G367-1),the scissors stairs and double-run ribbed beam combination stairs were optimized respectively.According to the limit state of the carrying capacity and the limit state of normal use,the optimal section size of the new type of prefabricated ribbed beam combination stairs were determined,and the hoisting checking calculations were carried out.(2)Comparing the floor weight,the amount of concrete by selecting the optimal ribbed beam combination of the stairs components with different kinds and the corresponding sections of the National Building Standard Design Atlas(15G367-1),theresults showed that the optimized floor weights of the scissors and ribbed beam combination stairs are reduced by 14.85%~30% compared with the standard atlas,and the double-run ribbed beam combination stairs are reduced by 11.5%~15.5% compared with the standard atlas.(3)ANSYS software was used to analyze the static performance of the scissors stairs and the double-run ribbed beam combination stairs.The results showed that the scissors stairs and the double-run ribbed beam combination stairs can meet the requirements of the bearing capacity and have good deformation ability.(4)Using PKPM software to analyze the seismic performance of the frame structure with scissors and double running ribs combined stairs,the results showed that the scissors stairs and the double-run ribbed beam combination stairs reduce the lateral stiffness and the base shear resistance of the frame structure compared to the existing slab stairs.It was indicated that the ribbed beam combination stairs can reduce the bracing effect of the frame structure under the action of the horizontal earthquake,and can improve the seismic performance of the frame structure.