Axial Compressive Performance Of Cold-formed Steel Stud Walls Considered Ice And Snow Loads

In recent years,the cold-formed steel stud walls as the main vertical bearing units of the cold-formed steel residence has been more and more concerned.However,the sheathing makes support and constraint to cold-formed steel studs and affects buckling characteristic and load capacity of stud walls,the different parameters have greatly influence on the axial bearing capacity.Nowadays,the axial bearing capacity calculation method of cold-formed steel stud wall system on specifications at home and abroad is based on effective width method,and the calculate process of effective width method is cumbersome and complex,but the calculate process of direct strength method is more simpler.At present,the direct strength method of members has been adopted into the revised draft of "cold-formed steel structure technical specification".But,it becomes a problem to be solved that how to make direct strength method applied to the cold-formed steel stud walls.By the way,ice and snow disasters occurred frequently in recent years,it has a huge destructive power on housing.The axial compressive properties of cold-formed steel stud walls considered ice and snow loads is should be further studied.It has proved the validity of the finite element simulation method by comparing the test results of bearing capacity of the wall with the results of ANSYS.It also made the finite element analysis on the axial bearing capacity of cold-formed steel wall stud system by changing the parameters,such as wall height,sheathing material,stud spacing and self-tapping screw spacing.It showed that the wall height,stud spacing,and the self-tapping screw spacing have little impact on the buckling mode of wall stud,but sheathing materials may change the buckling mode;The changing of wall height has little influence to the wall sheathed on the both sides of stud,but the axial bearing capacity of the cold-formed steel skeleton and the wall sheathed on one side of stud will obviously decreased with the increase of wall height;The changing of sheathing material may influence the axial bearing capacity;The changing of stud spacing and self-tapping screw spacing has little influence on the axial bearing capacity.Based on existing calculation formula,the spring stiffness of 36 groups has been calculated,and the influence of spring stiffness to elastic buckling stress has been analyzed by CUFSM.Compared the calculate results and the results of finite strip,it has been proved that the applicability of the existing calculation formula of elastic distortional buckling stress is validated.At the same time,according to the revised draft of the technical specification for cold-formed steel structure,practical calculating method of cold-formed steel stud wall system at home was put forward in this paper,which suits material mechanical properties in our country better.And applicability of the formula was verified well and it can be used as a reference for related design and research.In this paper,it takes two layers of cold-formed steel house as example and the wall sheathed on the both sides of stud as the research object to calculate vertical loads with different roof under snow and ice loads.The vertical load is compared by the results of direct strength method in this paper and proposed by Schafer.It shows that for the wall that under the slope of 35 degrees of single span shed roof and double slope roof with a skylight considering the snow and ice load,the interior wall exceeded the bearing capacity only.So that the roof slope should be greater than 35 degrees in the form of cold-formed steel residence with the two kinds of roof above.