Experimental Study of Aged and Seriously Damaged RC Beams Strengthened Using CFRP Composites

Abstract

This paper presents results from experiments on aged and seriously damaged reinforced concrete (RC) beams strengthened with different arrangements of external carbon fiber-reinforced polymer (CFRP) laminates and end anchorages. Seven RC beams from an old bridge, measuring 250 × 200 × 2300 mm, were tested. All specimens were loaded to yield load to evaluate initial mechanical properties. Then, these seriously damaged specimens were repaired using different CFRP-reinforcing schemes and reloaded to failure. The yield load growth due to CFRP reinforcement ranged from 5% to 36%. Different parameters including CFRP dimension and position, bonding length, and end anchorage were investigated and facilitated conclusions on beam ductility, load-midspan deflection response, and failure mode. This research contributes to knowledge about the CFRP repair of aged and seriously damaged beams to ensure better performance in overloaded conditions.

Fundamental Investigation on Seismic Retrofitting Method of Aging Concrete Structural Wall Using Carbon Fiber Sheet‐Constitutive Law of Rectangular Section

“…But, it does not take into account the variation in confinement effect due to changes in chamfer radius of section corners (i.e., the impact of effective confinement area A e ) in rectangular sections. Moreover, it does First, authors set the cross-sectional shape factors C in equations (2), (4), (5), (7), (8), and (9) as functions of the effective confinement area ratio α e instead of fixed values. e previous Nakatsuka's work [13] used ϕ150 × 300 mm round specimens and 150 × 150 × 300 mm square specimens (with chamfer radius R equal to 30 mm for all).…”

“…Conversely, the ratio C exp /C est also becomes large as the longitudinal ratio d/b increases for ε T in Figure 10(b) and ε R in Figure 10(d). In this paper, authors modified the evaluation formulas for four components: E BT , ε T , E TR , and ε R from equations (5), (7), (8), and (9) to the following in order to take the longitudinal ratio d/b into account:…”

“…A construction method for strengthening aging-reinforced concrete buildings against earthquakes by wrapping structural members with carbon fiber sheets (CF sheets) has been proposed and implemented in recent years [1][2][3][4]. It was conventionally believed that seismic reinforcement using CF sheet jackets (CF reinforcement) is applicable to beam and column members with circular [5,6] or nearly square [7][8][9] cross sections and beam-column connections [10]. Lorenzis and Tepfers [5] proposed an evaluation formula for the axial strain at peak stress of FRP-confined concrete cylinders.…”

“…Carey and Harries [6] presented the recommendations for modeling and designing of axially loaded circular confined concrete. Zhuang et al [7] repaired the seriously damaged RC beam specimens with CFRP and was verified the seismic performance experimentally. Lee et al [8] presented the sectional renovation of RC beam members using CFRP composites.…”

Fatigue performance and life prediction of CFRP plate in the RC bridge roof reinforcement

“…As an effective alternative to traditional materials for strengthening and repairing damaged structures, CFRP-reinforced bridge structure has been extensively investigated (Lu et al, 2018;Peng et al, 2014;Hosseini et al, 2019;Shukri et al, 2018;Mashrei et al, 2019). Zhuang et al (2018) conducted an experimental study on the CFRP reinforced seriously damaged concrete beam. Different parameters were investigated and it demonstrated that CFRP plate can have good contributions to the performance of the damaged concrete beams.…”