Experimental and numerical investigations of the compressive behavior of carbon fiber-reinforced polymer-strengthened tubular steel T-joints

Abstract

A method for strengthening damaged tubular steel T-joints under axial compression by wrapping them with carbon fiber-reinforced polymer (CFRP) sheets was proposed and evaluated. The influence of the CFRP strengthening on the failure mode and load capacity of T-joints with different degrees of damage was investigated using experiments and finite element analyses. Five T-joints were physically tested: one bare joint to obtain the peak load and corresponding displacement (D_1m), two reinforced joints to provide a reference, and two pre-damaged then retrofitted joints to serve as the primary research objects. The ratio of the pre-loaded specimen chord displacement to the value of D_1m was considered to be the degree of damage of the two retrofitted joints, and was set to 0.80 and 1.20. The results demonstrate that the maximum capacity of the retrofitted specimen was increased by 0.83%–15.06% over the corresponding unreinforced specimens. However, the capacity of the retrofitted specimen was 2.51%–22.77% lesser compared with that of the directly reinforced specimens. Next, 111 numerical analysis models (0.63≤b≤0.76, 9.70≤g≤16.92) were established to parametrically evaluate the effects of different geometric and strengthening parameters on the load capacity of strengthened tubular T-joints under different degrees of damage. The numerical analysis results revealed that the development of equivalent plastic strain at the selected measuring points was moderated by strengthening with CFRP wrapping, and indicated the optimal CFRP strengthening thickness and wrapping orientation according to tubular T-joint parameters. Finally, reasonable equations for calculating the load capacity of CFRP-strengthened joints were proposed and demonstrated to provide accurate results. The findings of this study can be used to inform improved CFRP strengthening of damaged tubular steel structures.

Keywords

tubular T-joint / carbon fiber-reinforced polymer / degree of damage / numerical analysis / equivalent plastic strain

References

[1] Shi G, Zhou W J, Bai Y, Lin C C. Local buckling of 460 MPa high strength steel welded section stub columns under axial compression. Journal of Constructional Steel Research, 2014, 100(Sep): 60–70

[2] Shi G, Wang J J, Bai Y, Shi Y J. Experimental study on seismic behavior of 460 MPa high strength steel box-section columns. Advances in Structural Engineering, 2014, 17(7): 1045–1059

[3] Qu H, Huo J S, Xu C, Fu F. Numerical studies on dynamic behavior of tubular T-joint subjected to impact loading. International Journal of Impact Engineering, 2014, 67(May): 12–26

[4] Zhu L, Song Q M, Bai Y, Wei Y, Ma L M. Capacity of steel CHS T-joints strengthened with external stiffeners under axial compression. Thin-walled Structures, 2017, 113(Apr): 39–46

[5] Li W P, Zhang S G, Huo W Y, Bai Y, Zhu L. Axial compression capacity of steel CHS X-joints strengthened with external stiffeners. International Journal of Impact Engineering, 2014, 67(May): 12–26

[6] Lee M M K, Llewelyn-Parry A. Offshore tubular T-joints reinforced with internal plain annular ring stiffeners. Journal of Structural Engineering, 2004, 130(6): 942–951

[7] Yang J, Shao Y B, Chen C. Static strength of chord reinforced tubular Y-joints under axial loading. Marine Structures, 2012, 29(1): 226–245

[8] Hossein N, Mohammad Ali L Y, Hamid A. Static performance of doubler plate reinforced tubular T/Y-joints subjected to brace tension. Thin-walled Structures, 2016, 108(Nov): 138–152

[9] Choo Y S, Liang J X, van der Vegte G J, Liew J Y R. Static strength of doubler plate reinforced CHS X-joints loaded by in-plane bending. Journal of Constructional Steel Research, 2004, 60(12): 1725–1744

[10] Fung T C, Chan T K, Soh C K. Ultimate capacity of doubler plate-reinforced tubular joints. Journal of Structural Engineering, 1999, 125(8): 891–899

[11] Qu H, Li A L, Huo J S, Liu Y Z. Dynamic performance of collar plate reinforced tubular T-joint with precompression chord. Engineering Structures, 2017, 141: 555–570

[12] Su Y, Li W Y, Wang X Y, Ma T J, Ma L, Dou X M. The sensitivity analysis of microstructure and mechanical properties to welding parameters for linear friction welded rail steel joints. Materials Science and Engineering A, 2019, 764: 138251

[13] CECS (China Association for Engineering Construction Standardization). Technical Specification for Strengthening Concrete Structures with Carbon Fiber Reinforced Polymer Laminate CECS146: 2003(2007). Beijing: China Planning Press, 2007 (in Chinese)

[14] ACI 440R07. Report on Fiber-reinforced Polymer (FRP) Reinforcement for Concrete Structures. ACI, 2007

[15] Lesani M, Bahaari M R, Shokrieh M M. Experimental investigation of FRP-strengthened tubular T-joints under axial compressive loads. Construction & Building Materials, 2014, 53: 243–252

[16] Peng H, Zhang J R, Shang S P, Liu Y, Cai C S. Experimental study of flexural fatigue performance of reinforced concrete beams strengthened with prestressed CFRP plates. Engineering structures, 2016, 127(Nov.15): 62–72

[17] Teng J G, Zhang J W, Smith S T. Interfacial stresses in reinforced concrete beams bonded with a soffit plate: A finite element study. Construction & Building Materials, 2002, 16(1): 1–14

[18] Zaki M A, Rasheed H A, Alkhrdaji T. Performance of CFRP-strengthened concrete beams fastened with distributed CFRP dowel and fiber anchors. Composites. Part B, Engineering, 2019, 176: 107117

[19] Kadhim M M A, Wu Z J, Cunningham L S. Experimental and numerical investigation of CFRP-strengthened steel beams under impact load. Journal of Structural Engineering, 2019, 145(4): 04019004

[20] Benachour A, Benyoucef S, Tounsi A, Adda bedia E A. Interfacial stress analysis of steel beams reinforced with bonded prestressed FRP plate. Engineering Structures, 2008, 30(11): 3305–3315

[21] Shaat A, Fam A. Axial loading tests on short and long hollow structural steel columns retrofitted using carbon fibre reinforced polymers. Canadian Journal of Civil Engineering, 2006, 33(4): 458–470

[22] Harries K A, Peck A J, Abraham E J. Enhancing stability of structural steel sections using FRP. Thin-walled Structures, 2009, 47(10): 1092–1101

[23] Lesani M, Bahaari M R, Shokrieh M M. Numerical investigation of FRP-strengthened tubular T-joints under axial compressive loads. Composite Structures, 2013, 100: 71–78

[24] Lesani M, Bahaari M R, Shokrieh M M. FRP wrapping for the rehabilitation of Circular Hollow Section (CHS) tubular steel connections. Thin-walled Structures, 2015, 90: 216–234

[25] Fu Y G, Tong L W, He L, Zhao X L. Experimental and numerical investigation on behavior of CFRP-strengthened circular hollow section gap K-joints. Thin-walled Structures, 2016, 102: 80–97

[26] Aguilera J, Fam A. Retrofitting tubular steel T-joints subjected to axial compression in chord and brace members using bonded FRP plates or through-wall steel bolts. Engineering Structures, 2013, 48: 602–610

[27] Zahedi L, Vatani Oskouei A. A numerical study on steel tubes wrapped with CFRP Laminates: Carbon Fibre Reinforced Polymers applications on offshore marine structures. International Journal of the Constructed Environment, 2013, 3(3): 75–86

[28] Haddad R H. Hybrid repair configurations with CFRP composites for recovering structural performance of steel-corroded beams. Construction & Building Materials, 2016, 124: 508–518

[29] Wu Y F, Yun C, Wei Y Y, Zhou Y W. Effect of predamage on the stress-strain relationship of confined concrete under monotonic loading. Journal of Structural Engineering, 2014, 140(12): 04014093

[30] Dalgic K D, Ispir M, Ilki A. Cyclic and monotonic compression behavior of CFRP-jacketed damaged non-circular concrete prisms. Journal of Composites for Construction, 2016, 20(1): 04015040

[31] Gong Y Z, Liu M T, Li H, Tan T. Flexural behavior of existing damaged RC plate girders strengthened with CFRP sheets. Journal of Tianjin University (Science and Technology), 2018, 51(12): 1246–1252 (in Chinese)

[32] Kenta N, Chikako F, Tsutomu N. Damage mechanism of existing RC slabs with reinforcing steel plate. MATEC Web of Conferences, 2019, 258: 05011

[33] Gao P, Wang J, Li Z Y, Hong L, Wang Z L. Effects of predamage on the compression performance of CFRP-confined rectangular steel reinforced concrete columns. Engineering Structures, 2018, 162: 109–120

[34] Vanlanduit S, Vanherzeele J, Longo R, Guillaume R. A digital image correlation method for fatigue test experiments. Optics and Lasers in Engineering, 2009, 47(3–4): 371–378

[35] Rabczuk T, Belytschko T. Cracking particles: A simplified meshfree method for arbitrary evolving cracks. International Journal for Numerical Methods in Engineering, 2004, 61(13): 2316–2343

[36] Rabczuk T, Belytschko T. A three-dimensional large deformation meshfree method for arbitrary evolving cracks. Computer Methods in Applied Mechanics and Engineering, 2007, 196(29–30): 2777–2799

[37] Rabczuk T, Zi G, Bordas S, Nguyen-Xuan H. A simple and robust three-dimensional cracking-particle method without enrichment. Computer Methods in Applied Mechanics and Engineering, 2010, 199(37–40): 2437–2455

[38] Nguyen-Xuan H, Rabczuk T. Adaptive selective ES-FEM limit analysis of cracked plane-strain structures. Frontiers of Structural and Civil Engineering, 2015, 9(4): 478–490

[39] Pantelides C P, Nadauld J, Cercone L. Repair of cracked aluminum overhead sign structures with glass fiber reinforced polymer composites. Journal of Composites for Construction, 2003, 7(2): 118–126

[40] Nadauld J D, Pantelides C P. Rehabilitation of cracked aluminum connections with GFRP composites for fatigue stresses. Journal of Composites for Construction, 2007, 11(3): 328–335

[41] Fam A, Witt S, Rizkalla S. Repair of damaged aluminum truss joints of highway overhead sign structures using FRP. Construction & Building Materials, 2006, 20(10): 948–956

[42] CMC (China Ministry of Construction). Technical specification for welding of steel structure of building JGJ81-2002. Beijing: China Architecture and Buildings Press, 2002 (in Chinese)

[43] SAC (Standardization Administration of China). Metallic Materials-Tensile testing-Part 1: Method of Test at Room Temperature GB/T 228.1-2010. Beijing: China Standards Press, 2010 (in Chinese)

[44] Msekh M A, Cuong N H, Zi G, Areias P, Zhuang X, Rabczuk T. Fracture properties prediction of clay/epoxy nanocomposites with interphase zones using a phase field model. Engineering Fracture Mechanics, 2018, 188: 287–299

[45] Hamdia K M, Msekh M A, Silani M, Thai T Q, Budarapu P R, Rabczuk T. Assessment of computational fracture models using Bayesian method. Engineering Fracture Mechanics, 2019, 205: 387–398

[46] Bao Y, Wierzbicki T. On fracture locus in the equivalent strain and stress triaxiality space. International Journal of Mechanical Sciences, 2004, 46(1): 81–98

[47] Zhou T H, Li W C, Guan Y, Bai L. Damage analysis of steel frames under cyclic load based on stress triaxiality. Engineering mechanics, 2014, 31(7): 146–155 (in Chinese)

[48] Liao F F. Study on micro fracture criterion of steel and its prediction for connections ductile fracture. Dissertation for the Doctoral Degree. Shanghai: Tongji University, 2012 (in Chinese)

[49] Wang W, Liao F F, Chen Y Y. Ductile fracture prediction and post-fracture path tracing of steel connections based on micromechanics-based fracture criteria. Engineering mechanics, 2014, 31(3):101–108, 115 (in Chinese)

[50] Shen Z Y. Calculation of the ultimate load bearing capacity of the junction of straight welded pipe. Steel structure, 1991, 14(4): 34–38 (in Chinese)

RIGHTS & PERMISSIONS

Higher Education Press