Experimental Study On The Behavior Of Partially Encased Composite Short Columns Made With Welded H-section Steel Under Eccentrically Load

A new composite column was researched in this paper, which was named partially encased concrete composite column (PEC). The new partially encased concrete compo- site column was consisting of a shop fabricated H type steel column with steel tie bars welded between the column flanges. The concrete was poured between the flanges. The column takes advantages of the formwork construction, pouring concrete expediently and the fire resistance property.The paper described the results of eight short column tests performed on partially encased concrete composite columns made with welded H-section steel to investigate the behavior of PEC columns. The main factors influencing ultimate load capacity of the PEC column were steel ratio, link spacing and eccentric ratio. The results indicated that steel and concrete could work together, the flange buckling did not occur before the peak load between the links. Failure of all columns was due to local buckling of the flanges along with concrete crushing.It could be concluded that the bearing capacity of partially encased concrete composite short column for eccentrically load improves with increasing of the steel ratio. Because of uniform restraint of concrete provided by transverse tie bar, flange and web, even if concrete cover exfoliated, partially encased concrete composite short columns still could bear a great load sequentially after reaching the ultimate bearing capacity. And which could provide with the better deformation capacity and stable later bearing capacity compared with reinforced concrete structure. The bearing capacity and ductility of partially encased concrete composite short column for eccentrically load enhanced along with increasing stirrup ratio. Eccentric ratio was the main factor for partially encased concrete composite short column. Finally, an equation was predicted the ultimate bearing capacity of the partially encased concrete composite column. Meanwhile, based on the test results, a numerical model for predicting the ultimate bearing capacity of the PEC column under eccentrically loads was developed. The calculated results were in good agreement with the test data.