Experimental analysis of bolts employed as shear connectors in circular concrete-filled tube columns

This paper presents experimental and theoretical analysis of bolts employed as shear connectors in circular concrete-filled steel tube columns (CFTs). The theoretical results, obtained from ABNT NBR 16239:2013 formulations, were compared with the experimental results. A series of push-out tests were carried out, where the diameter and length of the bolts, the number of connectors and the concrete strength were varied. From the experimental results, it was observed that the equations from ABNT NBR 16239:2013 are conservative. Therefore, it is proposed an adjustment to the formulations in order to consider the concrete confinement. It was also verified that increments in the diameter and the length of the bolt increase the load capacity of the connector. However, the variation of the quantity of bolts and the concrete strength did not interfere in the load capacity.

Keywords:
concrete-filled tube columns; circular tubular section; shear connector; bolt

Authorship

E. M. XAVIER

Universidade Federal de Ouro Preto, Programa de Pós Graduação em Engenharia Civil, Ouro Preto, MG, Brasil; ellen.mxavier@hotmail.com arlene.sarmanho@gmail.com leticiagualberto10@hotmail.comUniversidade Federal de Ouro PretoBrazilOuro Preto, MG, Brazil Universidade Federal de Ouro Preto, Programa de Pós Graduação em Engenharia Civil, Ouro Preto, MG, Brasil; ellen.mxavier@hotmail.com arlene.sarmanho@gmail.com leticiagualberto10@hotmail.com

https://orcid.org/0000-0001-8069-5866

J. G. R. NETO

Pontifícia Universidade Católica de Goiás, Goiânia, GO - Brasil; julianogeraldo.eng@gmail.comPontifícia Universidade Católica de GoiásBrazilGoiânia, GO, Brazil Pontifícia Universidade Católica de Goiás, Goiânia, GO - Brasil; julianogeraldo.eng@gmail.com

https://orcid.org/0000-0002-5448-7518

A. M. C. SARMANHO

https://orcid.org/0000-0001-6900-8551

L. ROQUETE

Universidade Federal de São João del Rei, Departamento de Tecnologia em Engenharia Civil, Computação e Humanidades, Ouro Branco, MG, Brasil. lucasroquete@gmail.comUniversidade Federal de São João del ReiBrazilOuro Branco, MG, Brazil Universidade Federal de São João del Rei, Departamento de Tecnologia em Engenharia Civil, Computação e Humanidades, Ouro Branco, MG, Brasil. lucasroquete@gmail.com

https://orcid.org/0000-0002-7937-822X

L. G. C. De PAULA

https://orcid.org/0000-0003-0437-9989

SCIMAGO INSTITUTIONS RANKINGS

Figures | Tables

Figures (19)
Tables (7)

Nomenclature P_i(j)_{- t -}n_-d_b-l_b-f_cm	D x t of the tube (mm)	Number of bolts n	Bolt diameter (inches) d_b	Bolt length (inches) l_b	f_cm (MPa)
P1(j)-8.2-4P-1/2”-2”-19.7	219x8.2	4	1/2”	2”	19.7
P2(j)-8.2-4P-1/2”-4”-19.7	219x8.2	4		4”	19.7
P3(j)-8.-4P-1/2”-2”-28.7	219x8.2	4		2”	28.7
P4(j)-9.5-4P-1/2”-4”-28,7	219x9.5	4		4”	28.7
P5(j)-9.5-8P-1/2”-2”-19.7	219x9.5	8		2”	19.7
P6(j)-9.5-8P-1/2”-4”-19.7	219x9.5	8		4”	19.7
P7(j)-8.-4P-5/8”-2”-19.7	219x8.2	4	5/8”	2”	19.7
P8(j)-8.-4P-5/8”-4”-19.7	219x8.2	4		4”	19.7
P9(j)-8.2-4P-5/8”-2”-28.7	219x8.2	4		2”	28.7
P10(j)-8.2-4P-5/8”-4”-28.7	219x8.2	4		4”	28.7
P11(j)-9,5-8P-5/8”-2”-19,7	219x9.5	8		2”	19.7
P12(j)-9.5-8P-5/8”-4”-19.7	219x9.5	8		4”	19.7
P13(j)-8.2-4P-3/4”-2”-19.7	219x8.2	4	3/4”	2”	19.7
P14(j)-9.5-4P-3/4”-4”-19.7	219x9.5	4		4”	19.7
P15(j)-9.5-4P-3/4”-2”-28.7	219x9.5	4		2”	28.7
P16(j)-9.5-4P-3/4”-4”-28.7	219x9.5	4		4”	28.7
P17(j)-9.5-8P-3/4”-2”-19.7	219x9.5	8		2”	19.7
P18(j)-9.5-8P-3/4”-4”-19.7	219x9.5	8		4”	19.7

D x t of the tube (mm)	f_y (MPa)	f_u (MPa)	Elongation (ΔL ) (%)
219 x 8.2	385	582	33
219 x 9.5	398	570	40

d_b of the bolt (inches)	f_ub (MPa)
1/2”	660
5/8”	650
3/4”	665

Bolt length (l_b) of 2"			Bolt length (l_b) of 4"			Comparison average of V_R,exp (%)
Prototype	V_R,exp (kN)	Average V_R,exp (kN)	Prototype	V_R,exp (kN)	Average V_R,exp (kN)
P1(1)-8.2-4P-1/2”-2”-19.7	102	102	P2(1)-8.2-4P-1/2”-4”-19.7	113	109	7.4
P1(2)-8.2-4P-1/2”-2”-19.7	101	102	P2(2)-8.2-4P-1/2”-4”-19.7	105	109	7.4
P3(1)-8.2-4P-1/2”-2”-28.7	122	109	P4(1)-9.5-4P-1/2”-4”-28.7	107	105	-3.7
P3(2)-8.2-4P-1/2”-2”-28.7	95	109	P4(2)-8.2-4P-1/2”-4”-28.7	102	105	-3.7
P5(1)-9.5-8P-1/2”-2”-19.7	98	98	P6(1)-9.5-8P-1/2”-4”-19.7	94	94	-4.6
P5(2)-9.5-8P-1/2”-2”-19.7	-	98	P6(2)-9.5-8P-1/2”-4”-19.7	93	94	-4.6
P7(1)-8.2-4P-5/8”-2”-19.7	126	124	P8(1)-8.2-4P-5/8"-4”-19.7	149	133	7.3
P7(2)-8.2-4P-5/8"-2”-19.7	122	124	P8(2)-8.2-4P-5/8"-4”-19.7	117	133	7.3
P9(1)-8.2-4P-5/8"-2”-28.7	122	117	P10(1)-8.2-4P-5/8”-4”-28.7	119	119	1.3
P9(2)-8.2-4P-5/8"-2”-28.7	112	117	P10(2)-8.2-4P-5/8”-4”-28.7	118	119	1.3
P11(1)-9.5-8P-5/8”-2”-19.7	129	127	P12(1)-9.5-8P-5/8”-4”-19.7	138	137	7.9
P11(2)-9.5-8P-5/8”-2”-19.7	125	127	P12(2)-9.5-8P-5/8”-4”-19.7	136	137	7.9
P13(1)-8.2-4P-3/4”-2”-19.7	121	119	P14(1)-9.5-4P-3/4”-4”-19.7	147	146	23.2
P13(2)-8.2-4P-3/4”-2”-19.7	116	119	P14(2)-9.5-4P-3/4”-4”-19.7	145	146	23.2
P15(1)-9.5-4P-3/4”-2”-28.7	154	147	P16(1)-9.5-4P-3/4”-4”-28.7	154	153	3.7
P15(2)-9.5-4P-3/4”-2”-28.7	140	147	P16(2)-9.5-4P-3/4”-4”-28.7	151	153	3.7
P17(1)-9.5-8P-3/4”-2”-19.7	121	129	P18(1)-9.5-8P-3/4”-4”-19.7	136	139	7.8
P17(2)-9.5-8P-3/4”-2”-19.7	136	129	P18(2)-9.5-8P-3/4”-4”-19.,7	141	139	7.8

Prototype	Crushing of the concrete (kN)		Shear of bolt (kN)	Crushing of the tube wall (kN)	V_R,teo (kN)	V_R,exp (kN)	V_R,exp / V_R,teo
Prototype	l_b d_b f_cm	5d_b ² f_cm	$0.4 π \frac{d_{b}^{2} f_{u b}}{4}$	2.4d_b tf_u	V_R,teo (kN)	V_R,exp (kN)	V_R,exp / V_R,teo
P1(1)-8.2-4P-1/2”-2”-19.7	11	16	33	145	11	102	9.57
P1(2)-8.2-4P-1/2”-2”-19.7	11	16	33	145	11	101	9.48
P2(1)-8.2-4P-1/2”-4”-19.7	23	16	33	145	16	113	7.11
P2(2)-8.2-4P-1/2”-4”-19.7	23	16	33	145	16	105	6.61
P3(1)-8.2-4P-1/2”-2”-28.7	16	23	33	145	16	122	7.86
P3(2)-8.2-4P-1/2”-2”-28.7	16	23	33	145	16	95	6.12
P4(1)-9.5-4P-1/2”-4”-28.7	34	23	33	165	23	107	4.62
P4(2)-8.2-4P-1/2”-4”-28.7	34	23	33	145	23	102	4.41
P5(1)-9.5-8P-1/2”-2”-19.7	10	16	33	165	10	98	9.48
P5(2)-9.5-8P-1/2”-2”-.9.7	10	16	33	165	10	-	-
P6(1)-9.5-8P-1/2”-4”-19.7	23	16	33	165	16	94	5.92
P6(2)-9.5-8P-1/2”-4”-19.7	23	16	33	165	16	93	5.85
P7(1)-8.2-4P-5/8”-2”-19.7	13	25	51	182	13	126	9.46
P7(2)-8.2-4P-5/8”-2”-19.7	13	25	51	182	13	122	9.16
P8(1)-8.2-4P-5/8”-4”-19.7	29	25	51	182	25	149	6.00
P8(2)-8.2-4P-5/8”-4”-19.7	29	25	51	182	25	117	4.71
P9(1)-8.2-4P-5/8”-2”-28.7	19	36	51	182	19	122	6.29
P9(2)-8.2-4P-5/8”-2”-28.7	19	36	51	182	19	112	5.77
P10(1)-8.2-4P-5/8”-4”-28.7	43	36	51	182	36	119	3.29
P10(2)-8.2-4P-5/8”-4”-28.7	43	36	51	182	36	118	3.26
P11(1)-9.5-8P-5/8”-2”-19.7	13	25	51	206	13	129	9.99
P11(2)-9.5-8P-5/8”-2”-19.7	13	25	51	206	13	125	9.68
P12(1)-9.5-8P-5/8”-4”-19.7	29	25	51	206	25	138	5.56
P12(2)-9.5-8P-5/8”-4”-19.7	29	25	51	206	25	136	5.48
P13(1)-8.2-4P-3/4”-2”-19.7	16	36	76	218	16	121	7.57
P13(2)-8.2-4P-3/4”-2”-19.7	16	36	76	218	16	116	7.26
P14(1)-9.5-4P-3/4”-4”-19.7	35	36	76	248	35	147	4.25
P14(2)-9.5-4P-3/4”-4”-19.7	35	36	76	248	35	145	4.20
P15(1)-9.5-4P-3/4”-2”-28.7	23	52	76	248	23	154	6.82
P15(2)-9.5-4P-3/4”-2”-28.7	23	52	76	248	23	140	6.20
P16(1)-9.5-4P-3/4”-4”-28.7	50	52	76	248	50	154	3.06
P16(2)-9.5-4P-3/4”-4”-28.7	50	52	76	248	50	151	3.00
P17(1)-9.5-8P-3/4”-2”-19.7	15	36	76	248	15	121	7.81
P17(2)-9.5-8P-3/4”-2”-19.7	15	36	76	248	15	136	8.77
P18(1)-9.5-8P-3/4”-4”-19.7	35	36	76	248	35	136	3.93
P18(2)-9.5-8P-3/4”-4”-19.7	35	36	76	248	35	141	4.08

Prototype	Crushing of the confined concrete (kN) [¹¹[11] ARAÚJO, A. H. M.; SARMANHO, A. M.; BATISTA, E. M.; REQUENA, J. A. V.; FAKURY, R. H.; PIMENTA, R. J. Projeto de Estruturas de Edificações com Perfis Tubulares de Aço, Belo Horizonte: Ed. do Autor, 1ed, 2016, 598 p.]		Shear of bolt (kN)	Crushing of the tube wall (kN)	V_R,teo (kN)	V_R,exp (kN)	V_R,exp / V_R,teo
Prototype	l_b d_b σ_c,Rn	5d_b ² σ_c,Rn	$0.4 π \frac{d_{b}^{2} f_{u b}}{4}$	2.4d_b tf_u	V_R,teo (kN)	V_R,exp (kN)	V_R,exp / V_R,teo
P1(1)-8.2-4P-1/2”-2”-19.7	238	355	33	145	33	102	3.05
P1(2)-8.2-4P-1/2”-2”-19.7	238	355	33	145	33	101	3.02
P2(1)-8.2-4P-1/2”-4”-19.7	192	286	33	145	33	113	3.38
P2(2)-8.2-4P-1/2”-4”-19.7	192	286	33	145	33	105	3.14
P3(1)-8.2-4P-1/2”-2”-28.7	262	391	33	145	33	122	3.65
P3(2)-8.2-4P-1/2”-2”-28.7	262	391	33	145	33	95	2.84
P4(1)-9.5-4P-1/2”-4”-28.7	239	357	33	165	33	107	3.20
P4(2)-8.2-4P-1/2”-4”-28.7	211	315	33	145	33	102	3.05
P5(1)-9.5-8P-1/2”-2”-19.7	193	288	33	165	33	98	2.93
P5(2)-9.5-8P-1/2”-2”-19.7	193	288	33	165	33	-	-
P6(1)-9.5-8P-1/2”-4”-19.7	156	232	33	165	33	94	2.81
P6(2)-9.5-8P-1/2”-4”-19.7	156	232	33	165	33	93	2.78
P7(1)-8.2-4P-5/8”-2”-19.7	213	318	51	182	51	126	2.45
P7(2)-8.2-4P-5/8”-2”-19.7	213	318	51	182	51	122	2.37
P8(1)-8.2-4P-5/8”-4”-19.7	154	229	51	182	51	149	2.90
P8(2)-8.2-4P-5/8”-4”-19.7	154	229	51	182	51	117	2.27
P9(1)-8.2-4P-5/8”-2”-28.7	234	349	51	182	51	122	2.37
P9(2)-8.2-4P-5/8”-2”-28.7	234	349	51	182	51	112	2.18
P10(1)-8.2-4P-5/8”-4”-28.7	169	252	51	182	51	119	2.31
P10(2)-8.2-4P-5/8”-4”-28.7	169	252	51	182	51	118	2.29
P11(1)-9.5-8P-5/8”-2”-19.7	173	258	51	206	51	129	2.51
P11(2)-9.5-8P-5/8”-2”-19.7	173	258	51	206	51	125	2.43
P12(1)-9.5-8P-5/8”-4”-19.7	125	186	51	206	51	138	2.68
P12(2)-9.-8P-5/8”-4”-19.7	125	186	51	206	51	136	2.64
P13(1)-8.2-4P-3/4”-2”-19.7	195	290	76	218	76	121	1.60
P13(2)-8.2-4P-3/4”-2”-19.7	195	290	76	218	76	116	1.53
P14(1)-9.5-4P-3/4”-4”-19.7	147	219	76	248	76	147	1.94
P14(2)-9.5-4P-3/4”-4”-19.7	147	219	76	248	76	145	1.91
P15(1)-9.5-4P-3/4”-2”-28.7	242	361	76	248	76	154	2.03
P15(2)-9.5-4P-3/4”-2”-28.7	242	361	76	248	76	140	1.85
P16(1)-9.5-4P-3/4”-4”-28.7	160	238	76	248	76	154	2.03
P16(2)-9.5-4P-3/4”-4”-28.7	160	238	76	248	76	151	1.99
P17(1)-9.5-8P-3/4”-2”-19.7	158	235	76	248	76	121	1.60
P17(2)-9.5-8P-3/4”-2”-19.7	158	235	76	248	76	136	1.79
P18(1)-9.5-8P-3/4”-4”-19.7	104	155	76	248	76	136	1.79
P18(2)-9.5-8P-3/4”-4”-19.7	104	155	76	248	76	141	1.86