Contents lists available at ScienceDirect Engineering Structures journal homepage: www.elsevier.com/locate/engstruct A non-destructive testing methodology for damage assessment of reinforced concrete buildings after seismic events Maria Rita Polimeno a , Ivan Roselli b, ⁎ , Vincenza A.M. Luprano a , Marialuisa Mongelli b , Angelo Tatì b , Gerardo De Canio b a ENEA, Brindisi Research Centre, SSTP-PROMAS-MATAS, SS Appia 7, km 706.00, 72100 Brindisi, Italy b ENEA, Casaccia Research Centre, SSPT-USER-SITEC, Via Anguillarese 301, 00123 Rome, Italy ARTICLE INFO Keywords: Non-destructive testing (NDT) Ultrasonic and sonic tests Tomography reinforced concrete (RC) building Seismic load Shaking table ABSTRACT In the present study non-destructive testing (NDT) methods involving ultrasonic and sonic wave propagation in the solid matter were applied in order to detect and investigate the modifications induced by the seismic load on reinforced concrete (RC) buildings. In particular, the aim of this experimental work was to delineate a metho- dology for quick and easy application on-the-field to provide information on the state of health of a RC structure subjected to a seismic event by investigating the columns in lower stories, which are generally more safely reachable for inspection. The methodology was experimented through shaking table tests reproducing several earthquakes. Shaking table tests were performed at ENEA Casaccia Research Centre on a full-scale 2-storey RC frame building designed under the current Italian code (NTC2008). Among the considered NDT techniques, direct and indirect sonic methods, as well as partial and complete approaches for ultrasonic tomography ap- plication were explored. The above NDTs were applied to the specimen before and after the shaking table testing. Numerical simulations by finite element methods (FEMs) were also adopted for a better comprehension of the dynamic behaviour of the specimen and interpretation of the experimental results. Through the com- parison with typical damage indicators formulated for RC buildings, derived from the modal parameters evo- lution and from the displacements of the structure during the seismic load, promising indications were obtained and the proposed NDT-based methodology was discussed. 1. Introduction In recent years, innovative non-destructive testing (NDT) techni- ques, applicable for the assessment of existing civil structures, have become available for in-situ analysis on reinforced concrete (RC) and masonry structures, but they are still not established for regular in- spections, especially after seismic events. The damage assessment of RC buildings after seismic events is a very relevant issue in Italy, where most of the constructions built in the last 50 years are RC structures [1]. A wide literature is available on the behaviour of RC buildings under dynamic loads, like seismic actions, and on techniques and methods focused on the localization of damage in the structure [2–7]. In general, both laboratory seismic tests and on-the-field observa- tions after earthquakes show that damages in regular RC frame build- ings often concentrate at lower stories and, in particular, at the columns and beam-column joints [8–11]. Large shaking tables capable of generating seismic loads to real- scale specimens are, by now, indispensable tools for laboratory ex- periments aimed at studying the dynamic behaviour and the evolution of structural damage caused by earthquakes. Thus, the experimental programme involved the reproduction of natural earthquakes by shaking table at ENEA Casaccia Research Centre. The tested specimen was designed under the recent Italian code NTC2008 [12], which was derived from the European EC8 code [13]. In order to detect and investigate the modifications induced by the seismic actions on the building, a NDT experimental campaign was conducted on the RC building before and after the shaking table tests. The applied NDTs were based on ultrasonic and sonic techniques, in- cluding tomography, which are methods exploiting the elastic waves propagation through the solid matter that constitutes the structural members. In recent years, NDT techniques and procedures for the as- sessment of concrete materials have become available and more at- tractive for on-site use on existing civil structures [14–22]. For ex- ample, Masi et al. [23] conducted in-situ NDTs on RC building https://doi.org/10.1016/j.engstruct.2018.02.053 Received 21 April 2017; Received in revised form 16 February 2018; Accepted 19 February 2018 ⁎ Corresponding author. E-mail addresses: femo1@libero.it (M.R. Polimeno), ivan.roselli@enea.it (I. Roselli), vincenza.luprano@enea.it (V.A.M. Luprano), marialuisa.mongelli@enea.it (M. Mongelli), angelo.tati@enea.it (A. Tatì), gerardo.decanio@enea.it (G. De Canio). Engineering Structures 163 (2018) 122–136 0141-0296/ © 2018 Elsevier Ltd. All rights reserved. T