Jerome F. Hajjar - Department of Civil and Environmental Engineering - Northeastern University

Table of Experimental Studies on Load Transfer in CFT Systems

General Information

Reference	Experiment Synopsis	Number of Tests	Loading Method	Results Reported	Main Parameters	Comments
Kilpatrick and Rangan 1999	Bond tests of circular CFT columns and beams having various interface conditions including maximum bond, partial bond and minimum bond. HT tubes were also tested under axial load	3 CFTs, 1 HTs (stub cols.) 6 CFTs, 2 HTs (short and slender cols) 4 CFTs, 1 HT (beam)	Axial load applied to the steel and concrete simultaneously Column supported on the steel and concrete simultaneously at the bottom	P vs. ε_s P vs. δ	nterface condition L/D
Morishita and Tomii 1982	Cyclic push-out tests of square CFTs	24	Constant axial load applied with cyclic shear force at the top Axial load applied either to the conc. and steel tube simult. or or only to the steel tube Cols. supported on the steel tube and concrete simul	H vs. R L vs. ε_s P -f_bs vs. d_s	P f'_c method of applying axial load at the top of the column (steel tube alone or steel tube and concrete simult.)
Mouli and Khelafi 2007	Push-out test of rectangular CFTs with normal weight and light weight concrete	4 Rectangular Hollow Section CFTs	Tested in Standard Compression machine	P vs. slip	Normal Weight concrete vs. Lightweight concrete L	Bond strength and squash load tested
Parsley, Yura, and Jirsa 2000	Push-out test of rectangular CFTs with and without shear tab connections supporting the steel tube	8	Load applied through spherical crosshead at the top on the concrete alone Steel tube was supported at the bottom either by bearing or a shear tab connection	P vs. slip P_steel vs. L f_b vs. t/b²	D support of steel section
Roeder, Cameron, and Brown 1999	Push-out tests of circular CFTs filled with concrete having moderate or little shrinkage potential	20	Concentric, eccentric and cyclic concentric load applied on the concrete alone Columns supported on the steel tube at the bottom	f_b vs. L f_b vs. D f_b vs. D/t P vs. d_s P_u,f_b	D t shrinkage strain of concrete
Shakir-Khalil 1993	Push-out tests of square and circular CFTs with shear connectors Push-out tests of rectangular, square and, circular CFTs with dry or oiled interface	56 (30 square, 26 circular) 40 (16 rectangular, 12 square, 12 circular)	Axial loading on to the concrete at the top Axial loading through steel brackets or plates attached to the steel tube Columns supported on the steel tube alone at the bottom Monotonic or repeated axial load applied on the concrete concentrically Columns supported on the steel tube alone at the bottom	P vs. d_s P vs. ε_s P_u, f_b d_s P vs. d_s P vs. ε_s P_u f_b d_s	Tube shape type and number of shear connectors type of loading Tube shape interface condition interface length loading type number and location of shear connectors
Shakir-Khalil and Hassan 1994	Push-out test of rectangular CFTs	52	Monotonic axial loading of the concrete alone at the top while the column supported on the steel tube at the bottom	P vs d_s P_u f_b d_s	Shear connector type Number and location of shear connectors Concrete Strength (f'_c)
Tomii, Yoshimura, and Morishita 1980	Push-out tests of circular CFTs	91	Axial load applied at the top on the concrete alone and the column supported on the steel tube at the bottom	f_b f_bs vs. d_s	Age of concrete f'_c L D compaction of concrete surface treatment
Virdi and Dowling 1980	Push-out tests of circular CFTs	91	Axial load applied at the top on the concrete alone and the column supported on the steel tube at the bottom	f_b f_bs vs. d_s	Age of concrete f'_c L D compaction of concrete surface treatment

Specimen Information

Reference	Length (L) (in)	Interface Length (in)	Bond Strength (f_b) (psi)	Shear Connectors
Kilpatrick and Rangan 1999	13.78 (stub) 40.83 (short) 76.85 (slender) 82.68 (beam)	13.78 (stub) 40.83 (short) 76.85 (slender) 82.68 (beam)	1.5-114.0	Self-tapping screws (Double helix pattern with a pitch length of 3.15 in) (length = 1.18 in., diameter = 0.193 in.)
Morishita and Tomii 1982	35	29	21.3-49.8	none
Mouli and Khelafi 2007	21.65	Fy = 49.3-52.65 ksi	117.48-121.83 (NWC), 60.92-62.37 (LWC)	none
Parsley, Yura, and Jirsa 2000	48-60	47-59	27.0-71.0	none
Roeder, Cameron, and Brown 1999	46	41.5	N.A.	none
Shakir-Khalil 1993	17.7 9.8, 17.7, 25.6	15.8 7.9, 15.7, 23.6	63.8, 120.4 29.0-580.2	Hilti nails (2.44 in long, 0.146 in. diameter) Grade 4.6 M12 Black Bolts (1.97 in long) Grade 4.6 M12 Black Bolts (1.97 in long)
Shakir-Khalil and Hassan 1994	17.72	15.74	28.4-77.3	Grade 4.6 Black bolts Grade 8.8 Black bolts threaded bars
Tomii, Yoshimura, and Morishita 1980	28.94	29.53	28.5-56.9 (circular) 21.3-42.7 (square and octagonal)	none
Virdi and Dowling 1980	5.88-18.25	4.38-16.75	48.1-433.8 (avg. values)	none

Cross Section Information

Reference	Tube Dimensions	Steel Properties	Concrete Properties
Kilpatrick and Rangan 1999	◌: diam. (D) □: depth (D) x width: 4 Wall Thickness (t) (in): 0.094 Diameter/thickness (D/t): 42.3	Cold-formed F_y = 50.8 ksi	f'_c = 15.30 ksi
Morishita and Tomii 1982	◌: diam. (D) □: depth (D) x width: 5.88 x 5.88 Wall Thickness (t) (in): 0.166-0.170 Diameter/thickness (D/t): 35	Cold-formed mild steel F_y = 49.2-50.9 ksi	f'_c = 3.32, 3.86, 5.08 ksi
Mouli and Khelafi 2007	◌: diam. (D) □: depth (D) x width: 4.72 x 3.15, 3.94 x 5.91 Wall Thickness (t) (in): 0.2 Diameter/thickness (D/t): 15.75, 29.55	F_y = 49.3-52.65 ksi	f'_c = 6.5 (NWC) , 5.32 (LWC) ksi
Parsley, Yura, and Jirsa 2000	◌: diam. (D) □: depth (D) x width: 8 x 8, 10 x 10 Wall Thickness (t) (in): 0.25 Diameter/thickness (D/t): 32.0-40.0	F_y = 48.0 ksi	f'_c = 5.86-6.55 ksi
Roeder, Cameron, and Brown 1999	◌: diam. (D) □: depth (D) x width: 10.3-23.8 (circular) Wall Thickness (t) (in): 0.28-0.53 Diameter/thickness (D/t): 19.4-108.0	N.A.	f'_c = 4.05-6.86 ksi
Shakir-Khalil 1993	◌: diam. (D) □: depth (D) x width: 5.91 x 5.91, 7.87 x 7.87 (square) 6.63, 8.63 (circular) Wall Thickness (t) (in): 0.19, 0.0248 Diameter/thickness (D/t): 30.0, 31.7 (square) 33.6, 34.8 (circular) ◌: diam. (D) □: depth (D) x width: 4.72 x 3.15 (rectangular) 5.91 (square) 6.63 (circular) Wall Thickness (t) (in): 0.197 Diameter/thickness (D/t): 24 (rectangular) 30 (square) 33.7 (circular)	Mild steel Grade 43	f'_c = 5.22-6.16 ksi f'_c = 5.50-6.43 ksi
Shakir-Khalil and Hassan 1994	◌: diam. (D) □: depth (D) x width: 5.91 x 3.94 Wall Thickness (t) (in): 0.197 Diameter/thickness (D/t): 30	N.A.	f'_c = 3.19-12.18 ksi
Tomii, Yoshimura, and Morishita 1980	◌: diam. (D) □: depth (D) x width: 5.91 (circular) 5.91 x 5.91 (square and octagonal) Wall Thickness (t) (in): 0.126 Diameter/thickness (D/t): 46.9	Cold-formed mild steel F_y = 36.6 ksi (smooth) 36.3 ksi (checkered)	f'_c = 2.42-6.69 ksi (expansive) 2.89-4.92 ksi (ordinary)
Virdi and Dowling 1980	◌: diam. (D) □: depth (D) x width: 5.84-12.05 Wall Thickness (t) (in): 0.22-0.40 Diameter/thickness (D/t): 14.8-32.3	Mild steel	f'_c = 3.19-6.72