Title:
Cyclic Behavior of Steel-Jacket-Confined Ultra-High- Strength Concrete-Filled Steel Tubular Columns
Author(s):
Hong-Song Hu, Li Xu, Hai-Jin Qiu, and Konstantinos Skalomenos
Publication:
Structural Journal
Volume:
122
Issue:
1
Appears on pages(s):
129-142
Keywords:
cyclic behavior; jacket-confined concrete-filled steel tube (CFST) column; steel jacket; ultra-high-strength (UHS) concrete
DOI:
10.14359/51743295
Date:
1/1/2025
Abstract:
It has been experimentally proven that by using external confining
steel jackets at high-stress locations of columns, cyclic behavior of
steel or concrete columns can be improved. This study experimentally investigates the cyclic behavior of jacket-confined composite steel/concrete columns configured by square concrete-filled steel tubes (CFST) and ultra-high-strength (UHS) concrete (compressive strength nearly 125 MPa [18.1 ksi]). The CFST columns are locally confined by steel jackets at their base (that is, region of plastic hinge). Five novel steel-jacket-confined CFST (JC-CFST) columns are tested under combined constant axial and cyclic
lateral loading and their responses are compared with those of
three CFST counterparts. Test parameters include: (a) thickness
of steel jacket; (b) profile of jacket section (square or rounded
corners); (c) strength of steel tube (conventional and high-strength
steel); and (d) axial load ratio, n. Test results demonstrated that the
confining stresses provided by the steel jacket started increasing
after the concrete crashing. In JC-CFST specimens, the ultimate
drift ratio, θu, improved almost proportionately to the jacket
confinement index, λm, and significantly decreased as n increased.
The use of high-strength steel for the steel tubes was also effective
to increase θu by 20 to 25%. The cumulative energy dissipation of
the JC-CFST columns was found to be much greater than that of
the CFST counterparts due to the better deformation capacity of
the former. The lateral displacement of the column caused by the
base rotation was significant.