Experimental Study On The Behavior Of Partially Encased Composite Stub-columns Made With Welded H-section Steel

The composite structure of steel and concrete has developed fast in our country in the last several decades. A new composite column is described in this paper, which is named partially encased composite (PEC) column. The new partially encased composite column consists of a shop fabricated H type steel column with steel tie bars welded between the column flange tips. The concrete is in two blocks separated by the web. The column takes advantages of the in-plant prefabrication of steel, the speed of erection of steel structure and the fire resistance property.The paper describes and presents the results of nine stub-column tests performed on partially encased composite columns made with welded H-section steel. The H-section steel is stiffened with transverse link and concrete is poured between the flanges of the steel section. A comprehensive study under axially load has been conducted on all specimens to investigate the behavior of PEC columns. The results indicate that failure of all columns was due to local buckling of the flanges along with concrete crushing. The main factors influencing ultimate load capacity of the PEC column are steel ratio and link spacing. Smaller link spacing improves the ductility of the columns; however, the measurements show that in general yielding did not occur before the peak load in the links. Finally, an equation was proposed to predict the ultimate axial capacity of the partially encased composite column. Meanwhile, based on the test results, a numerical model for predicting the ultimate load capacity of the PEC column under axial load is developed. The calculated results are in good agreement with the test data.