Behavior Of Bridge Cutoff Light-Gauge Steel Enclosing Walls Experimental Study

In this paper,the thermal insulation performance of light steel cladding panel in cold area is studied,and a new structural form of keel is proposed:PVC plate and thin-walled steel are combined to form a Cutoff bridge light steel keel.In addition,the performance test of this new type of light steel keel with Cutoff bridge is carried out.The main contents and conclusions of this paper are as follows:1.The experimental research on the flexural performance of the light steel keel with broken bridge is carried out.The strain values of the cross section of the keel at each position of each stress stage are measured under the simple support state of the keel,which verifies that the stress state of the cross section of the light steel keel with broken bridge satisfies the calculation assumption of the plane section.The influence of the PVC height,thickness,material and other parameters at the web on the flexural performance of the light steel keel with broken bridge is analyzed The results show that compared with the traditional C-type light steel keel,the bending rigidity of the broken bridge type light steel keel is reduced by 32%,and the ultimate bending capacity is reduced by 21.3%.During the bending test,there was no shear failure and slippage at the bonding position of PVC and galvanized steel plate,which indicated that PVC and galvanized steel plate could work together in the light steel keel of the bridge,and the connection mode of PVC and galvanized steel plate was reasonable and feasible.2.The comparative experimental study on the flexural performance of the light steel keel wall panel with broken bridge and the light steel keel wall panel with C-type was carried out.Compared with the C-type light steel keel wall,the overall flexural rigidity and ultimate flexural capacity of the broken bridge light steel keel wall are reduced by 28.4%and 30%respectively.When the light steel keel wall of bridge cutoff type reaches the deflection deformation standard value,the bending bearing capacity is7.5kN/m~2,which meets the requirements of building curtain wall(GB/T21086-2007)that the bending bearing capacity of exterior wall is greater than 5kN/m~2.3.The steady-state heat transfer performance of the light steel keel wall with Cutoff bridge is studied,and the heat transfer performance of the C-type light steel keel wall is compared.In the steady-state environment,compared with the C-type light steel keel wall,the minimum surface temperature of the hot side wall increases by 4℃,which indicates that the design of the keel structure as the Cutoff bridge light steel keel can reduce the"hot bridge effect"of the wall;the temperature difference of the keel flange on the hot and cold side increases by 6.3℃,which indicates that the PVC partition board can greatly block the heat transfer at the keel web;the heat transfer coefficient of the wall 34.5%reduction shows that the thermal insulation performance of the wall can be significantly improved by the Cutoff bridge type light steel keel.The measured heat transfer coefficient of the light steel keel wall with Cutoff bridge is0.269W/(m~2·K),which is in line with the provisions of JGJ26-2010 standard for energy conservation design of residential buildings in severe cold and cold areas,and all requirements of DB22/T1887-2013 standard for energy conservation design of residential buildings(75%energy conservation)of Jilin Province.