Melo, Jose

A Realistic Full Cfrp Retrofit of RC Beam-Column Joints Compared To Seismically Designed Specimens

Abstract eng:
The brittle collapse of reinforced concrete (RC) structures built before the introduction of detailed seismic design codes (pre1970’s) in recent earthquakes, has underlined the need for significant upgrades to the existing RC building stock. In particular, the observation of weak-column/strong-beam mechanisms has potentially catastrophic impacts that could be addressed by retrofit solutions. Retrofits with fibre reinforced polymers (FRP) have become increasingly popular and experimental evidence for their effectiveness can be found in the literature. The lack of tests on full-scale specimens with slabs and transverse beams in many studies may however lead to an unrealistic assessment of FRP retrofit schemes. In this study, three realistic full-scale interior beam-column joints with slab and transverse beams are tested under cyclic loading in order to propose and assess practical FRP retrofit solutions. A complete Carbon FRP (CFRP) retrofit strategy aiming to obtain a similar performance to a specimen designed to modern European design guidelines (Eurocode 8) is presented. The retrofit scheme is composed of selective strengthening and weakening components to ensure ductile failure of the specimen according to capacity design principles. Results from full-scale cyclic tests on the CFRP retrofitted specimen are compared to the behaviour of a deficient, pre-1970’s design specimen and a specimen designed to modern guidelines. The observed failure mechanisms and global lateral capacities for the Eurocode 8 and retrofitted specimen show that the CFRP retrofit is effective in improving seismic behaviour. By means of a combined selective weakening and strengthening scheme, a change in hierarchy of strengths can be achieved, which leads to an improved ductile behaviour with significant strength enhancement. The results suggest that a CFRP retrofit scheme can be devised for realistic, significantly under-designed structures in order to achieve a similar performance to modern RC structures designed to sophisticated seismic guidelines.

Contributors:

Pohoryles, Daniel

Conference Title:

Proceedings of the 16th World Conference on Earthquake Engineering

Conference Title:

16th World Conference on Earthquake Engineering

Conference Venue:

Santiago (CL)

Conference Dates:

2017-01-09 / 2017-01-13

Rights:

Text je chráněný podle autorského zákona č. 121/2000 Sb.