Elena Ciampa

Strengthening systems for existing reinforced concrete (RC) structures are increasingly needed due to several problems such as degradation of materials over the time, underdesign, serviceability or seismic upgrading, or new code requirements. In the last decades, strengthening by fibers composite materials applied with various techniques (FRP, FRCM, NSM) were largely investigated and theoretical formulations have been introduced in national and international design guidelines. Although they are an excellent strengthening solution, steel plates may represent still a valid traditional alternative, due to low costs, ductile stress-strain behavior, simple and fast mounting with possibility of reusing the material. Guidelines for a correct design are still lack and, therefore, detailed models and design formulas are needed. In this paper, the bond behavior at the plate-concrete interface, which plays a key role for the effectiveness of the strengthening system, is analyzed by means of 3D finite element models calibrated on experimental results available in literature. Parametric analyses were carried out by changing some meaningful parameters.

In years 1950 the first bridges realized with the emerging technique of Prestressed Concrete (PC) were designed and constructed in Italy. In this paper the design of San Nicola bridge erected in Benevento (Italy) and designed by Riccardo Morandi in 1952-1955 is presented in order to analyse its conceptual design. The original design has been examined evidencing a careful process of optimization by adopting an innovative method of construction with precasted segments. The influence of some choices in geometry, static scheme, prestressing procedure on the structural response of the structure are discussed also by simple examples. (C) 2021 Asociacion Espanola de Ingenieria Estructural (ACHE). Published by Cinter Divulgacion Tecnica S.L. All rights reserved.

In this paper the authors present and validate a procedure, which intends to combine the latest state of the art models in bridge monitoring with freely available satellite data. Through the Differential SAR interferometry (DinSAR) technique, a dataset of displacements for the Morandi bridge in Genoa (Italy), before its collapse, has been created, by using images downloaded by the Copernicus Open-Access Hub and the ASFVertex Hub. The data have been processed through the ESA SNAP software to identify the rate of displacements in the parts of the bridge where collapse occurred. Results demonstrate that the adopted procedure has great potentiality in the application field, as it represents a simple and inexpensive method to monitor large structures in a continuous way, by helping to better quantify risks and guide effective mitigation countermeasures. Moreover, the same procedure, once properly validated, could be effectively extended to the current and future performance estimation of civil infrastructures.

The aging and deterioration of structures such as bridges or buildings is becoming an urgent social issue; regular inspections for the preservation of the structures are needed, but it means high cost especially in terms of safety for workers due to the difficulty to access. Visual inspection of workers can be replaced by using basic drones, which share many advantages such as speed, safety for the workers, cost-effectiveness, share-ability with more stakeholders instantly and manoeuvrability by making use of automated flights. A visual inspection made by drone is the first part of a complex survey campaign, and its use allows planning experimental investigation for diagnostic. This study analyses both the positive and negative aspects of the use of drones for structural inspection, underlying the low cost, immediacy, instant measurement and the possibility of developing a 3D model, with an acceptable level of definition and reliable for a diagnostic process. Two application examples are proposed.