Rapid Repair of Severely Damaged RC Columns with Different Damage Conditions: An Experimental Study

Abstract

Rapid and effective repair methods are desired to enable quick reopening of damaged bridges after an earthquake occurs, especially for those bridges that are critical for emergency response and other essential functions. This paper presents results of tests conducted as a proof-of-concept in the effectiveness of a proposed method using externally bonded carbon fiber reinforced polymer (CFRP) composites to rapidly repair severely damaged RC columns with different damage conditions. The experimental work included five large-scale severely damaged square RC columns with the same geometry and material properties but with different damage conditions due to different loading combinations of bending, shear, and torsion in the previous tests. Over a three-day period, each column was repaired and retested under the same loading combination as the corresponding original column. Quickset repair mortar was used to replace the removed loose concrete. Without any treatment to damaged reinforcing bars, longitudinal and transverse CFRP sheets were externally bonded to the prepared surface to restore the column strength. Measured data were analyzed to investigate the performance of the repaired columns compared to the corresponding original column responses. It was concluded that the technique can be successful for severely damaged columns with damage to the concrete and transverse reinforcement. For severely damaged columns with damaged longitudinal reinforcement, the technique was found to be successful if the damaged longitudinal reinforcement is able to provide tensile resistance, or if the damage is located at a section where longitudinal CFRP strength can be developed.

Collapse Vulnerability and Fragility Analysis of Substandard RC Bridges Rehabilitated with Different Repair Jackets Under Post-mainshock Cascading Events

“…4.1). The CFRP jacket was chosen as the first repair technique due to the excellent high strength-to-weight ratio which is becoming increasingly attractive for structural repair/retrofit projects (Priestley et al 1996;Buckle et al 2006;He et al 2013;Grelle and Sneed 2013). The steel jacket was the first and the most widely used retrofit technique (Priestley et al 1996;Buckle et al 2006;ElGawady 2009;Fakharifar et al 2013;), due to its availability, price, and ductile behavior when compared with FRP materials with brittle failure (Fakharifar et al 2015c).…”

“…The post-MS load carrying capacity of earthquake damaged structures depends on the extent of damage present (Aschheim and Black 1999;Terzic and Stojadinovic 2013;Priestley et al 1996;Buckle et al 2006;Vosooghi and Saiidi 2012;Fakharifar et al 2014a;He et al 2013;Grelle and Sneed 2013). While numerous studies have investigated the significance and efficacy of retrofit jackets application on RC bridge columns (Priestley et al 1996;Buckle et al 2006;Vosooghi and Saiidi 2012;Fakharifar et al 2014a;He et al 2013;ElGawady et al 2009;Saatcioglu and Yalcin 2003 amongst many others), this study is a preliminary attempt to investigate the efficacy of different repair jackets application on MS-damaged RC bridge piers subjected to AS attacks of multiple intensities.…”

“…While numerous studies have investigated the significance and efficacy of retrofit jackets application on RC bridge columns (Priestley et al 1996;Buckle et al 2006;Vosooghi and Saiidi 2012;Fakharifar et al 2014a;He et al 2013;ElGawady et al 2009;Saatcioglu and Yalcin 2003 amongst many others), this study is a preliminary attempt to investigate the efficacy of different repair jackets application on MS-damaged RC bridge piers subjected to AS attacks of multiple intensities. Study by Huang and Andrawes (2014) indicated very promising results that an improvement as high as 117 % in bridge overall performance subjected to real strong mainshock-aftershock sequences can be achieved through applying SMA confinement to piers.…”

“…Many studies have indicated the seismic vulnerability of MS-damaged bridge columns, if subjected to potential aftershocks, as substantial damage could accumulate during the MS event (Vosooghi and Saiidi 2012;Di Sarno 2013;He et al 2013;Li et al 2014). A MS-AS (or often termed FS-AS) sequence is illustrated in Fig.…”

Collision Capacity Evaluation of RC Columns by Impact Simulation and Probabilistic Evaluation

“…In particular, the multiple experiments required for parametric studies to obtain sufficient data for structural design purposes are too costly and difficult; therefore, the only feasible means to obtain a wide variety of data are precise impact simulation analyses. Precise simulations need to be performed using proven commercial explicit finite element programs such as LS-DYNA, which has been repeatedly validated by researchers and engineers (Nam et al 2009a(Nam et al , 2009bConsolazio and Cowan 2005;El-Tawil et al 2005;He et al 2013).…”