Experimental study on effectiveness of retrofitting via normal strength concrete filling on damaged circular steel tubes subjected to axial and horizontal loads

Abstract Following an idea derived from the concrete-filled steel tube (CFT), this research aims to enhance the structural responses of a damaged hollow steel tube by filling it with concrete. A series of experiments are conducted to investigate the effectiveness of this technique, simulating repair but more importantly retrofitting after the tube is damaged by accidental loads such as earthquakes. To this end, loading tests are performed on the modeled specimens. The level of damage induced on the steel tube by loading is one of the parameters investigated. Concrete filling is found to improve the load-carrying capacity as well as the stiffness and ductility of a damaged hollow steel tube even with severe local buckling. The load-carrying capacity of the retrofitted steel tube is more than 1.5 times that of a hollow steel tube and was 72–89% of that of a traditional concrete-filled steel tube calculated using the design codes presented by Japan Society of Civil Engineers. From these experimental results, concrete filling promises to be an effective means of enhancing the structural response of a damaged hollow steel tube.

[1]  Hanbin Ge,et al.  Uniaxial stress–strain relationship of concrete confined by various shaped steel tubes , 2001 .

[2]  John B. Mander,et al.  Observed Stress‐Strain Behavior of Confined Concrete , 1988 .

[3]  Yoshiaki Goto,et al.  Nonlinear Finite-Element Analysis for Hysteretic Behavior of Thin-Walled Circular Steel Columns with In-Filled Concrete , 2010 .

[4]  K. Maekawa,et al.  Nonlinear mechanics of reinforced concrete , 2003 .

[5]  Cj Burgoyne,et al.  Uniaxial stress-strain relationship of spirally confined concrete , 2005 .

[6]  Tetsuhiko Aoki,et al.  Behavior of partially concrete-filled steel tube bridge piers under bi-directional seismic excitations , 2014 .

[7]  J. Mander,et al.  Theoretical stress strain model for confined concrete , 1988 .

[8]  Fariborz Nateghi-A.  Retrofitting of earthquake-damaged steel buildings , 1995 .

[9]  Toshiyuki Kitada,et al.  Ultimate strength and ductility of state-of-the-art concrete-filled steel bridge piers in Japan , 1998 .

[10]  Hanbin Ge,et al.  Strength of Concrete‐Filled Thin‐Walled Steel Box Columns: Experiment , 1992 .

[11]  Lin-Hai Han,et al.  Concrete-filled Tubular Members and Connections , 2010 .

[12]  Akh Kwan,et al.  A constitutive model for predicting the lateral strain of confined concrete , 2015 .

[13]  Baris Binici,et al.  An analytical model for stress–strain behavior of confined concrete , 2005 .

[14]  Mervyn J. Kowalsky,et al.  Impact of D/t on seismic behavior of reinforced concrete filled steel tubes , 2015 .

[15]  Kimiro Meguro,et al.  SEISMIC RETROFITTING OF EARTHQUAKE-DAMAGED CONCRETE COLUMNS BY LATERAL PRE-TENSIONING OF FRP BELTS , 2006 .

[16]  Tamer El-Maaddawy,et al.  Retrofitting of Severely Shear-Damaged Concrete T-Beams Using Externally Bonded Composites and Mechanical End Anchorage , 2012 .

[17]  Hanbin Ge,et al.  Behaviour of partially concrete-filled steel bridge piers under cyclic and dynamic loading , 1997 .

[18]  Jerome F. Hajjar,et al.  Concrete‐filled steel tube columns under earthquake loads , 2000 .

[19]  Moriaki Suzuki,et al.  Seismic performance evaluation of circular steel bridge piers which have damage and concrete filled repair , 2015 .

[20]  Tetsuhiko Aoki,et al.  Residual strength of damaged steel bridge pier with circular cross section and its repair method , 2009 .

[21]  Dennis Lam,et al.  Behaviour of normal and high strength concrete-filled compact steel tube circular stub columns , 2006 .