Flexural performance of corroded continuous RC beams rehabilitated by ICCP-SS

Abstract

Continuous beams have the capability to redistribute internal forces due to their indeterminate structural features, leading to enhanced beam deformability, reduced reinforcement congestion and more effective cross-section capacity usage. Thus, continuous reinforced concrete (RC) beams are popular members in most structures. However, RC structures located in corrosive environments might be degraded due to steel reinforcement corrosion. In this study, a recently proposed dual-functional intervention method, impressed current cathodic protection and structural strengthening (ICCP-SS), is adopted to repair degraded beams. The carbon fabric-reinforced cementitious matrix (C-FRCM) composite serves dual functions in the intervention method. The effects of reinforcement corrosion, cathodic protection and the C-FRCM strengthening system on the behaviors of continuous beams should be investigated. The aims of this study are to provide experimental data of continuous RC beams rehabilitated by ICCP-SS technology in corrosive environments and to investigate the structural responses, moment redistributions and design rules of these beams. This paper includes an experimental program, a discussion of the results and a design proposal. The results of electrochemical monitoring showed that the steel reinforcements in continuous beams under corrosive environments are successfully

Fatigue behaviour and design of corroded reinforced concrete beams intervened by ICCP-SS

“…For the bonding material, Lambert et al [7] proposed electrically conductive epoxy, which is conductive pigments in epoxy adhesive, while Su et al [5,8] developed a high-performance cementitious matrix. Several experimental programmes have been conducted to prove the effectiveness of the ICCP-SS system on degraded structural members subjected to static loads, including RC short columns [4], simply supported beams [5,7] and continuous beams [9]. Experimental results show that the ICCP-SS intervention can not only effectively prevent the corrosion of steel re-bar in concrete but also significantly improve the static structural performance of the degraded structures when the structures are subjected to corrosion.…”

Continuous Reinforced Concrete Beams Strengthened with Fabric-Reinforced Cementitious Matrix: Experimental Investigation and Numerical Simulation

“…Simply supported beams fail once the midspan section reaches its moment capacity. Conversely, the load capacity of continuous RC beams is governed by the rotational and moment capacities of critical sections at both sagging and hogging regions [21][22][23][24][25][26]. When one of the critical sections reaches its moment capacity in two-span RC beams, the beam can still carry additional loads and sustain further deformations prior to complete failure.…”

“…To the best knowledge of the authors, only two studies published recently examined the behavior of continuous RC beams strengthened with FRCM composites [25,26]. The beams tested in these two studies had two spans reinforced with the same amount of steel on both tension and compression sides and strengthened with the same type of FRCM (C-FRCM).…”

“…Findings of these two studies indicated that strengthening of continuous RC beams with FRCM resulted in a negligible improvement in the load capacity and a severe ductility reduction. The poor performance of the FRCM strengthening was attributed in one of the studies to the poor surface preparation and insufficient impregnation of the carbon fibers into the matrix [25]. It was reported also that FRCM weakened the moment redistribution capacity between the sagging and hogging regions [25,26]; therefore, it resulted in a significant ductility reduction and an insignificant gain in the load capacity.…”

“…The poor performance of the FRCM strengthening was attributed in one of the studies to the poor surface preparation and insufficient impregnation of the carbon fibers into the matrix [25]. It was reported also that FRCM weakened the moment redistribution capacity between the sagging and hogging regions [25,26]; therefore, it resulted in a significant ductility reduction and an insignificant gain in the load capacity. It is believed that the small value of a/d adopted in these two studies did not allow for a meaningful assessment of the flexural behavior of continuous RC beams because of the possible development of an arch action effect.…”