Behavior of Full-Scale Porous GFRP Barrier under Blast Loads

This research paper is part of the SAS (Security of Airport Structures) Project funded by the European Programme for Critical Infrastructure Protection, whose objective was to develop and deploy a fiber reinforced polymer (FRP) fencing system intended to protect airport infrastructures against terrorist acts. In the paper, the efficacy of the proposed glass FRP discontinuous (porous) barrier under blast loads is presented by showing the results of the blast test campaign conducted on full-size specimens with a focus on the reduction of the blast shock wave induced by the barrier. A simplified model predicting the reduction of the shock wave beyond the barrier is proposed and validated via the experimental data obtained in the project

Experimental behavior of existing RC columns strengthened with HPFRC jacket under concentric and eccentric compressive load

Reinforced concrete (RC) structures built before the 1970 represent a large portion of the existing European buildings stock. Their obsolescence in terms of design criteria, materials, and functionality is becoming a critical issue for guaranteeing adequate compliance with current structural codes. Recently, a new jacketing system based on the use of high-performance fiber-reinforced concrete (HPFRC) has been introduced for strengthening existing RC building members. Despite the promising aspects of the HPFRC jacketing technique, currently, a comprehensive and systematic technical framework for its implementation is still missing. In this paper, the experimental performance of RC columns strengthened with the HPFRC jacket subjected to pure axial load and combined axial load-bending moment uncoupled from shear is investigated. The test outcomes confirmed a significant improvement of the structural performance for the strengthened columns, especially for higher values of eccentricity. Finally, a standard-based practice-oriented analytical tool for designing retrofit interventions using the HPFRC jacket is proposed. The comparison between the calculated and experimental results revealed a satisfactory prediction capability

Experimental study on the in-plane response of adobe masonry wallets strengthened with textile reinforced matrix systems

Seismic strengthening of existing adobe masonry (AM) buildings has been recognized as a critical issue due to the dramatic consequences of recent seismic events occurred especially in developing countries, where a great part of the population lives in those constructions. Previous studies investigated the effectiveness of different retrofitting techniques by means of experimental programs consisting of either dynamic or static tests on reduced- or full-scale specimens, representing partial or complete AM dwellings. In this study, the output of diagonal compression tests on adobe masonry panels before and after external strengthening are presented. Three series of specimens were tested, namely, unreinforced and strengthened wallets with textile reinforced matrix (TRM) systems made of either hemp or glass meshes. Those tests benefitted from the characterization of the mud mortar that was used for both masonry joints and matrix, representing typical characteristics of existing Italian AM buildings. Main testing outcomes obtained for the AM wallets, particularly in terms of observed damage and response curves, are presented and discussed. In the end, the effectiveness of the applied TRM systems in the improvement of shear strength and ductility capacity is assessed

H-BIM – Innovative and Digital Tools to Improve the Management of the Existing Buildings

With the introduction of the BIM methodology, the digitalization is consolidating mostly the process of new building design defining new standardized working procedures in order to optimize the data flow. On the contrary, pertaining to existing buildings, the rules are still dictated by the traditional methodology leading to fragmented and disaggregated information flow. However, some tools have been recently developed and are quickly upgrading to meet the specific aim to pursue progress, dynamism and experimentation in order to stay in tune with market demands. One common issue, is due to the fact that the documents are paper, hard to find and numerous so that the digitalization represents the best real solution to improve their management. In this regard, the heart of the informative flow is represented by the Common Data Environment (CDE), a cloud storage in which the documents are collected once uploaded and easily manageable with specific platforms. By way of example, a case study is developed in the paper in which the management process of the H-BIM of the XV century’s structure placed in the old town of Naples is carried out in a digital way, through the usBIM.platform (released by ACCA software company) using specific tools, like links, markers and tags. The goal of the paper is to define both a new organization for the data archive, in which the documents are structured and easily traceable, both a new way of conceiving the BIM model that it is thought as an informative vehicle and a key access to the information rather than a mere geometric representation

Experimental in-plane lateral response of a full-scale adobe masonry wall with opening

A large amount of world population lives nowadays in earthen buildings, often constructed only based on construction practice and within earthquake-prone regions. In the recent history, several strong earthquakes had dramatic consequences on these structures, highlighting their significant seismic vulnerability due to multiple reasons, such as poor mechanical properties, poor detailing, and large inertia mass. Several aspects of seismic performance of existing earthen constructions need to be investigated through full-scale experimental testing. In this regard, the present study aims at contributing to the investigation by testing a full-scale adobe masonry wall with a central door-type opening under in-plane lateral loading with cyclic fashion. The mechanical behaviour of materials, specimen's design, loading protocol and instrumentation setup are described. The experimental response curves, observed damage evolution and failure mode are discussed, especially focusing on dissipation capacity of the wall

Quality Assessment of Printable Strain Hardening Cementitious Composites Manufactured in Two Different Printing Facilities

Over the past few years, several studies have shown the potential of three-dimensional concrete printing (3DCP) for applications in building and civil engineering. However, only a few studies have compared the properties of the fresh printing material and the quality of the printed elements from different printing facilities. Variations in the manufacturing conditions caused by the mixing procedures, the pumping device and the nozzle shape and/or dimensions may influence the quality of the printed elements. This study investigates the differences in the fresh and hardened properties of a printing material tested in two different printing facilities. The pump pressure and temperature experienced by the printing material during the printing session are monitored real-time. Hardened properties are measured for the printed elements, such as the bending capacity, the apparent density, and the air void content. The research shows that two different printing facilities may result in printed elements with relative differences in flexural strength and volumetric density of 49% and 7%, respectively

Proposal of A Probabilistic Model for Multi-Hazard Risk Assessment of Structures in Seismic Zones Subjected To Blast for the Limit State of Collapse,” Structural Safety

a b s t r a c t It is desirable to verify the structural performance based on a multi-hazard approach, taking into account the critical actions the structure in question could be subjected to during its lifetime. This study presents a proposal for a probabilistic model for multi-hazard risk associated with the limit state of collapse for a reinforced concrete (RC) structure subjected to blast threats in the presence of seismic risk. The annual risk of structural collapse is calculated taking into account both the collapse caused by an earthquake event and the blast-induced progressive collapse. The blast fragility is calculated using a simulation procedure for generating possible blast configurations, and verifying the structural stability under gravity loading of the damaged structure, using a kinematic plastic limit analysis. As a case study, the blast and seismic fragilities of a generic four-storey RC building located in seismic zone are calculated and implemented in the framework of a multi-hazard procedure, leading to the evaluation of the annual risk of collapse