Capacity Assessment of RC Subassemblages Upgraded with CFRP

Abstract

Many gravity load designed (GLD) reinforced concrete (RC) structures located in seismic areas are in need of upgrade. As an alternative to traditional upgrade solutions, an innovative technique based on the use of Fiber Reinforced Polymer (FRP) composites was proposed and experimentally validated. The technique consists of strengthening reinforced concrete connections by means of the combined use of FRP laminates and FRP near surface mounted (NSM) bars. In parallel, a theoretical approach for the assessment of the connection capacity was developed based on the analysis of each component (i.e., column, beam and joint), in order to determine which component controls failure. The outcomes of the analysis were compared to the experimental results with considerations on the reliability of the approach and aspects slated for future investigations. The behavior of the FRP-confined column cross section was also analyzed and it is herein discussed based on recorded strains in internal steel bars and FRP jacket.

Seismic behavior of a full-scale RC frame repaired using CFRP laminates

“…Fiber texture was differentiated for the two columns with the objective of comparing the performance of the two solutions. Tests conducted by Antonopulos and Triantafillou [4] and Prota et al [9] showed the effectiveness of such a solution in order to increase both strength and ductility of exterior and interior joints, respectively.…”

Performance-Based Seismic Retrofit Strategy for Existing Reinforced Concrete Frame Systems Using Fiber-Reinforced Polymer Composites

“…Due to the scope of that investigation ͑evaluation of the FRP contribution to the joint shear strength͒, the design of the retrofit strategy aimed at guaranteeing that the damage occurred in the joint region. A selective seismic strengthening technique for gravity-load-designed frames, relying on both FRP laminates and near mounted surface, has been recently proposed by Prota et al ͑2002͒. In this contribution, unidirectional carbon fiber laminates ͑high-modulus CFRP, Table 3͒ were adopted for both exterior and interior joints in the configurations illustrated in Figs. 13 and 14.…”

Analysis Research Progress on the FRP Reinforced RC Beam-Column Joints in Civil Engineering

“…Porta etc. [7] proposed a method using FRP sheets to reinforce design safety factor insufficient RC beam-column joints. The calculating formulas of shear strength of beam-column joints reinforced with FRP were presented and the suggesting values of calculating parameters for engineering designing were introduced [8].…”

“…Porta etc. [15][16][17] tested RC beam-column joints reinforced by NSM CFRP and EBR CFRP and the results showed that NSM CFRP can improve the flexural bearing capacity of column and EBR CFRP can improve the ductility of column as well as the property of compressive concrete.…”