Patrício Rocha

EXPERIMENTAL AND NUMERICAL ANALYSIS ON THE CYCLIC BEHAVIOR OF BRIDGE PIERS WITH AND WITHOUT CFRP RETROFIT

The main objective of this paper is to evaluate the cyclic behavior of RC hollow piers, with and without with CFRP retrofit, by comparison of experimental tests results with structural numerical modeling. The retrofit techniques aim to increase the shear strength and the ductility capacity through the establishment of principles and strategies applied in an experimental cyclic campaign of RC hollow piers, carried out in the Laboratory for Earthquake and Structural Engineering (LESE) of the Faculty of Engineering of University of Porto (FEUP). The evaluation and calibration of the efficiency of several retrofit solutions is also performed. The numerical simulations are carried out using two different methodologies: (i) fiber model and (ii) damage model. The fiber models based in a finite element discretiztion with non-linear behavior distributed along the elements length and cross-sectional area, while the damage model is supported on refined finite element (FE) meshes, with high complexity and detail levels in the constitutive laws defined for both concrete and steel. The concrete is simulated with a continuum damage model where several applications for bridges with hollow section piers can be found at Faria et al. [1]. Results of the experimental campaign allow to discuss and conclude about the efficiency of each numerical method, namely regarding the shear strength and the ductility capacity assessment.

EXPERIMENTAL AND NUMERICAL STUDY OF RC COLUMNS UNDER BIAXIAL LOADING: AS BUILT

During last decades, have been made many studies about RC columns under uniaxial and biaxial horizontal cyclic loading , however, the knowledge about biaxial behavior is far of uniaxial behavior knowledge. Due to testing difficulties and because there are still open questions regarding the cyclic behavior both in 2D bending with constant axial force, very few experimental studies have, as yet, tackled the more general problem of 2D bending on repaired and retrofitted columns. In this work is presented the results of an experimental study about behavior under uniaxial and biaxial bending, with constant axial load of as built RC columns. Six columns were tested, three under monotonic loading and three under biaxial cyclic loading with diagonal loading path on as built specimens. After experimental work, was made a numerical nonlinear analysis to evaluate the accuracy of existent models in the representation of the RC columns behavior during a seismic event.

A Novel Approach to the in situ Compression Testing of Stone Masonry Walls

Masonry structures constitutes the urban core of several cities throughout the world, justifying the interest for the development of new testing techniques, capable of characterizing their main mechanical properties. The present paper approaches the in situ testing of stone masonry walls, describing the steps that led to the definition of a new compression test set-up. Said set-up was devised to be a modular and adaptable system, capable of being used in different types of walls, with different textures and unit types. Being self-balanced, the hereby-proposed scheme doesn´t introduce any new external loads into the whole building producing, at the same time, a uniform compression load. Throughout the paper, the peculiarities of masonry structures are mentioned, in order to justify some of the considerations taken into account in the development of the system. The results of an experimental campaign performed in an abandoned building in Oporto (Portugal) are presented, showing the outputs that can be extrapolated from the procedure, namely the characterization of the cyclic behavior of the walls and its deformability parameters.

Structural Repair and Strengthening of RC Elements with Concrete Jacketing

Extensive investigations on repair and retrofitting of reinforced concrete elements have been undertaken in recent years and many methods have been developed, tested and reported in the literature. The reinforced concrete jacketing has been considered as one of the important and used methods to correct design errors, deficient concrete production and execution processes, repair damage after earthquake, accidents or in the cases where it is needed to proceed with the change in the functionality of the structure etc. In this chapter is performed a brief review of the literature concerning the numerical and experimental research performed as well as the detailing recommendation and general criteria and procedures used in the concrete jacketing. In the end it is presented an example of an application of RC jacketing to correct a soft-storey mechanism in an existent RC building and it is presented the recent experience in the use of reinforced concrete jacketing in the Kathmandu University after the 2015 Gorkha Earthquake.

EFFICIENCY OF DIFFERENT RETROFITTING TECHNICHS FOR RC COLUMNS UNDER BIAXIAL LOADING: EXPERIMENTAL STUDY

Abstract. The main purposes of this work it to present an experimental campaign of different strengthening strategies of RC columns, and evaluating benefits concerning their structural behaviour cyclic loading. 9 RC columns were tested, two of them original and the rest composed by strengthened columns by CFRP and steel plates jacketing. The aim is, therefore, to contribute for developing and calibration a procedure that enables the evaluation of the efficiency of the strengthening strategies, their possibilities and application. It was also an objective of this work to explore the possibility of use this techniques on the improvement of existing buildings performance

EXPERIMENTAL CYCLIC TESTS OF HOLLOW PIERS WITH DIFFERENT RETROFIT STRATEGIES

Abstract. An experimental cyclic campaign of RC hollow piers has being carried out in the Laboratory for Earthquake and Structural Engineering (LESE) of the Faculty of Engineering of University of Porto (FEUP), aiming to establish, among other purposes, a strategy to retrofit RC hollow piers subjected to horizontal cyclic actions with axial load. The retrofit techniques intend to increase the shear strength and the ductility capacity through the application of CFRP sheets. The main objective of this paper is to evaluate and calibrate the efficiency of several retrofit solutions. The design criteria for the piers retrofit solutions and the different strategies for the practical application are presented, namely, the CFRP sheets for shear retrofit and CFRP base strip, with or without steel bars applied inside the hollow box, for ductility improvement, being the different types of retrofit grouped out in order to understand the main benefits of each one. Results of the experimental campaign allow to discuss and conclude about the efficiency of each retrofit solution, explicitly regarding the improvement of the shear strength and the ductility capacity.