Epicentre News Publication

Seced talk on 27 April 2016

13 April 2016

EPICentre is pleased to announce that Jose Melo and Daniel Pohoryles will give a SECED talk on the development of Realistic CFRP Retrofit Schemes for Existing Reinforced Concrete Structures. The talk will take place on 27/04/2016 at 6:00 pm at the Institution of Civil Engineers in London.

Synopsis

The brittle collapse of reinforced concrete (RC) structures built before the introduction of detailed seismic design codes (pre-1970’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, shear or bond failures have potentially catastrophic impacts that could be addressed by repair and retrofit solutions.

In recent years, retrofits with fibre reinforced polymers (FRP) have become increasingly popular due to the benefits of extended durability, corrosion resistance, high strength-to-weight ratio and reduced labour time. Experimental evidence for the efficiency of such schemes for joint strengthening can be found in the literature. A previous study has shown that the reduced scale of most tested specimens, as well as the omission of slabs and transverse beams in many studies may lead to an unrealistic assessment of FRP retrofit schemes. In this study, realistic pre-1970’s full-scale interior beam-column joints with slab and transverse beams were tested under realistic conditions and cyclic lateral loading in order to propose and assess new, realistic FRP retrofit solutions for seismic actions.

Three carbon FRP (CFRP) retrofit schemes with selective retrofit objectives were devised aiming at improving the performance of inadequately reinforced RC beam-column joints. The retrofit schemes are composed of a combination of selective FRP strengthening and selective weakening components to ensure failure of the specimen according to capacity design principles. The objectives of the schemes were enhancement in lateral capacity, ductility enhancements, improved performance under repeated cyclic loading, as well as changing the failure mechanism.

Results from the full-scale cyclic tests on the CFRP retrofitted specimen are compared to the behaviour of a deficient specimen and a specimen designed to modern guidelines (EC 8). To evaluate the effect of the realistic set-up, the results are also compared to specimens without slab and transverse beams, highlighting their importance.

About the speakers

Daniel Pohoryles is a PhD student at the UCL EPICentre, since 2013. He joined to EPICentre as a PhD student in 2012. Before joining EPICentre, he was working as a structural engineer at the London office of Peter Brett Associates LLP. Daniel has a background in Chemistry, with a BSc from Imperial College, and has completed a Graduate Diploma and MSc in Civil Engineering at UCL. His research interest focusses on the retrofit of pre-1970’s reinforced concrete structures that were found to perform poorly under recent seismic events and are deemed particularly vulnerable. The aim of his PhD project is to evaluate different FRP (fibre-reinforced polymers) retrofit schemes by means of full-scale testing.

José Melo is a Research Associate at EPICentre, Department of Civil, Environmental & Geomatic Engineering of University College London, UK since 2014 and a post-doc researcher at Civil Engineering Department, Faculty of Engineering, University of Porto, Portugal since 2015. He joined to EPICentre as a PhD student in 2012. He received his civil engineering degree, master's degree in civil engineering and PhD in civil engineering from the University of Aveiro, in 2008, 2009 and 2014, respectively. His research interests include assessment and strengthening of existing building structures, structural testing and modelling, structural analysis methods and seismic engineering.

The work presented is supervised by Professor Tiziana Rossetto (UCL EPICentre), Professor Humberto Varum (Porto University) and Professor Dina D’Ayala (UCL EPICentre).

Further information

This evening meeting is organised by SECED and chaired by Tiziana Rossetto (UCL EPICentre). Non-members of the society are welcome to attend. Attendance at this meeting is free. Seats are allocated on a first come, first served basis. Tea and biscuits will be served from 5.30pm - 6pm. The presentation is scheduled to finish before 7.30 pm. For further information, please contact Greg James (tel. 020 7665 2229). This meeting will be preceded by the SECED AGM at 5.00pm and the EEFIT AGM at 5.15pm.

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