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Adobe masonry (AM) dwellings are a considerable portion of existing buildings stock worldwide, particularly in developing countries. Several earthquakes occurred during last decades dramatically showed a high seismic vulnerability of such constructions, which are not generally engineered. Therefore, several research groups have been involved in the investigation about effective and viable retrofitting solutions for AM buildings. Currently, most of studies available in literature addressed the issue by means of experimental programs consisting of dynamic or static tests on reduced- or full-scale specimens, representing partial or complete AM dwellings. Nevertheless, in those works, limited or no attention was generally paid to the crucial issue of the spatial variability of material properties within AM, which can produce critical forms of mechanical response and premature failure. In this study, three series of seven AM wallets were tested under monotonic diagonal compression load: one series consisted of unreinforced specimens (used as benchmark) and the remaining series were strengthened with two textile reinforced matrix (TRM) systems, made of either hemp or glass meshes. Masonry joints and matrix were produced using the same mud mortar, which is a typical mortar of existing Italian AM buildings. Experimental outcomes of tests in terms of observed damage and response curves are presented, along with a comprehensive characterization of mortar and bricks. Then, with the aim to draw out general and robust trends about TRM effectiveness as strengthening solution in the improvement of shear strength and ductility capacity, the response variability was quantitatively investigated via statistical analysis of recorded stress–strain samples.

Over the past decade, the fields of civil engineering, i.e., structural engineering, have increasingly used the building information modelling (BIM) approach in both professional practice and as the focus of research. However, the field of structural engineering, which can be seen as a sub-discipline of civil engineering, misses, as far as the authors are aware, a real state-of-the-art on the use of BIM in this regard. The aim of this paper, therefore, is to start bridging that gap. In particular, the authors have conducted a traditional literature review on the utilisation of BIM in structural engineering, enabling them to perform a detailed content analysis of publications. The qualitative investigation of the literature that the authors have conducted has highlighted six main BIM uses in structural engineering: (1) structural analyses; (2) production of shop drawings; (3) optimized structural design, early identification of constructability issues, and a comparison of different structural solutions; (4) seismic risk assessments; (5) existing-condition modelling and retrofitting of structures; and (6) structural health monitoring. Each of these is discussed in relation to their reference workflows; use of information models; information exchanges; and main limitations. In the conclusions, the authors identify current gaps in knowledge, as well as likely developments and improvements in the utilization of BIM in structural engineering. The authors also outline the possible significance of this work more broadly.

This research, which is based on the digital technologies building information modeling (BIM) and artificial intelligence, describes achievements in the field of detecting, assessing, and digitalising damage in existing buildings. The purpose of the study is to highlight the potential and current benefits of combining structural-assessment methods with the automatic digitisation of hazard-induced damage in affected buildings. To this end, the aforementioned technologies are employed in the form of an image-based recognition-BIM classification technique applied to on-site visual-damage data. By extending the methodology to existing masonry and concrete buildings, the results obtained open up new opportunities for speeding up the process of assessing, designing, and managing seismic repair/retrofit interventions using image data acquired in the manner described.

The advancements of additive manufacturing (AM) technologies are typically coupled with research addressing topology optimization, whose aim is to use optimization methods to achieve effective expressions of free-form design. While many studies emphasize the breakthroughs that topology optimization could bring into structural engineering, there are just a few scientific contributions that address design feasibility, accounting for the technological constraints that characterize the different AM techniques. By formulating a stress-constrained topology optimization problem with a more technologically oriented approach, this study aims to optimize concrete structures while enforcing the cross-section width and path-traceability restrictions that affect the feasibility and performance of geometries obtained through the layered extrusion technique. In particular, this paper proposes a curve-based Biased Random-Key Genetic Algorithm that optimizes stress-constrained structures and generates topologies that can be implemented without post-processing operations. The proposed algorithm, when tested on a diverse set of concrete beam configurations, effectively achieved optimized solutions that used between 81 % and 75 % less material than the full beam configuration. Additionally, each one of the designed topologies adequately met the stress requirements and process-specific constraints. Lastly, two experimental cases also highlighted the printability effectiveness of the proposed approach in conjunction with design of optimized solutions.

Irregular frame structures can exhibit an inefficient dynamic behavior, such as undesirable torsional effects and asymmetric displacements, that can severely affect structural performances in case of a seismic event. To mitigate the influence of geometric irregularities, the pre-dimensioning of structural elements is crucial to achieve the best possible seismic behavior. Identifying the optimal solutions in terms of elements’ cross-sections and orientations is a non-trivial problem that in general designers tackle following trial-and-error attempts which can become numerous in the most complicated cases. This paper formally describes the pre-dimensioning problem and presents a Learn-heuristic that hybridizes a Genetic Algorithm and a k-Means algorithm procedure for its solution. The algorithm is validated on a diverse set of 3D reinforced concrete structures and through a Structural Pre-dimensioning challenge, where the performances of the algorithm are compared against those accomplished by a group of Ph.D. candidates. The computational results evidenced that the proposed optimization framework achieves pre-dimensioning solutions that significantly improve the designs provided by the Ph.D. students, thus suggesting a favorable inclusion of the proposed solution method in classical pre-dimensioning processes.

Regulatory activity concerning the management of existing bridges has recently been affected by updates, for instance, in Italy, which calls for a speedy and pragmatic approach based on new technologies such as building information modeling (BIM), when dealing with the survey and risk classification as well as the evaluation and monitoring of structural safety. This paper focuses on the development and integration of a digital solution, based principally on the specific framework developed by the authors, which supports BIM modeling and information management activities, in the structural setting under investigation, through the use of several technologies and tools, namely BIM-authoring, CDE platform and visual programming, in addition to programming in Python. Starting from the organization of a specific BIM object library and the initial data, inserted by means of a custom-made input environment, it was possible to reproduce digital models of bridges in accordance with specific information requirements following the new Level of Information Need setting. The applicability of the proposal is tested on two judiciously chosen real-life cases with different characteristics. Through this implementation, a series of advantages emerge, including expediting traditional procedures for BIM modeling, accessibility and traceability of information—which are constantly updated to support the monitoring of structural safety over time—and the decision-making process related to the bridge management context.

In the field of infrastructure, the development and application of the openBIM (open Building Information Modeling) approach and related standards (principally Industry Foundation Classes) remain limited with regard to processes in O&M (Operation and Maintenance) phases, as well as the broader context of AM (Asset Management). This article deals with the activities carried out as part of a pilot project based on the need to manage the operation and assess the condition and value of existing infrastructure along the Cancello–Benevento railway line. The principal goal was to systematize information by digitalizing the infrastructure, in order to enable the assessment of possible performance gaps (compared to national railway standards) in the event of integration within the national infrastructure. In compliance with the project requirements, a digitalization strategy was designed for the definition of surveying activities and the implementation of openBIM systems for the development of an object library and a federated digital model, structured within the collaborative platform that was used, and allowing management, maintenance, and subsequent financial evaluation in the broader context of asset management. The project involved the collaboration of railway operators, a university, and a software company that implemented innovative concepts concerning IFC (specifically, IFC4x2 was used) through the development of dedicated software solutions. The digital solution we proposed enabled the use of digital models as access keys to survey and maintenance information (ERP platforms used by the railway operators) that was available in real time. This project was nominated at the buildingSMART awards 2021 and was one of three finalists in the “Asset Management Using openBIM” category.

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.

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.

The lateral seismic capacity and the in-plane failure pattern of adobe masonry may be understood by performing quasi-static experimental tests on full-scale adobe walls. Information regarding the maximum lateral capacity and the displacement ductility are normally obtained during these tests. Also, information about limit states could be obtained. Along the years, universities in Europe, Asia and Latin America have performed this type of tests and the results of some of these works are summarized in this chapter.

Due to the dynamic characteristics of natural events, innovative concepts and engineered systems for energy dissipation in buildings have recently been proposed. Several SMA-based original systems and devices have been designed to dissipate a part of the seismic energy and to reduce earthquake forces acting on the structure. SMAs have been integrated within these devices in many possible shapes and configurations, such as single and stranded wires, ribbons, strips, tubing, and bars, adding excellent key features to civil engineering applications. A collection of such SMA-based applications in buildings is presented, subdivided in sections based on the practical domain.

In the past few years, several works focused on the integration of methodologies within the field of Structural Health Monitoring to build reliable automatic damage-assessment procedures. Within this context, only a few papers specifically refer to the automatic assessment of tendon malfunctions in prestressed concrete (PSC) structures, despite the key role that this construction paradigm plays in modern infrastructure networks. This paper describes a novel Extreme Learning Machine (ELM) framework characterized by a layout-aware weight generating procedure (LA-ELM), that analyzes stress data to accurately detect and localize damages affecting the prestressing system of a target PSC bridge. A comprehensive computational study is conducted, testing the proposed methodology of three structural specimens, and comparing the proposed LA-ELM with classical Machine Learning algorithms. The numerical results evidence that the proposed methodology achieves remarkable accuracies in short computational times, and the LA-ELM obtains statistically significant improvements compared to the classical ELM implementation.

Although the enormous potential, to date, only few effective real-scale retrofits of existing heritage structures have been realized through the implementation of SMA-based systems, mainly to repair and strengthen historical structures after the seismic damage. Compared with traditional steel systems, SMAbased retrofits are able to reduce acceleration and forces, increasing the seismic efficiency of the 20 structure and reducing its vulnerability. A review of SMA-based retrofitting techniques is presented, including the exemplary case study of the bell tower of the S. Giorgio (Trignano) church: the retrofitted monumental building has not suffered from significant damages after subsequent earthquakes.

The development of sustainable methods is a demanding challenge posed by Global civilizations for improving the life quality in many ways. A key role in achieving sustainability goals could be the implementation of the new building materials models for the future environmental requirements. The presented process deals with the recycling of carbon fibers wastes deriving from automotive industry and the reusing within a building system, increasing in value the approach of circular economy and providing a solution to many negative economic and environmental impacts. To quantify potential benefits, in this work the behavior of cement-matrix composites containing short carbon fibers is described. An experimental campaign, starting from a specific surface treatment of the “pre peg” composite material sheets and an accurate study of the dimensional distribution of the carbon fibers, is presented. The aim is the evaluation of the influence of the percentage and length of fibers usage on the mechanical performance of cement based carbon fibers-reinforced mortars, following different approaches of mixture. The results show a good increase in stiffness and in flexural strength up to 11% and 20% respectively, for the samples characterized by fibers in percentage of 6.4% by volume of mixture and of 2–5 mm length and by a reduced amount of cement. A strong connection between the mixture workability and fibers size is observed. Finally, the assessment of the entire life cycle of the product is discussed for quantifying effective environmental impacts.

In concrete structures realized by digital fabrication techniques, such as 3D concrete printing, under severe dynamic loadings (e.g. earthquakes and impact loads), the strength at the bond interfaces between layers is weak. Since these contact zones, also referred as cold joint, could potentially compromise the structural stability and also the durability of printed elements, their behaviour under high dynamic loads is fundamental to investigate. An experimental program on 3D printed concrete elements varying the waiting time, through medium and high strain-rate tensile tests is running, with a Hydro-Pneumatic Machine and a modified Hopkinson tensile bar respectively. The results of dynamic tensile tests at three different strain rates (10-5, 50 and 200 s-1) on 3D printed cementitious elements for waiting times of 0min, 10min and 30 min have been presented, in terms of Dynamic increase factors DIF versus strain rate, showing a behaviour highly strain-rate sensitive, recording an increase in tensile strength DIF up to 7.6 in the case of high strain-rate and waiting time of 30 min. The results exhibited a decrease in the dynamic interface tensile strength with the waiting time up to over 90% for a medium strain-rate and over 20% for a high strain-rate.

A new jacketing technique consisting in a thin layer of Fibre Reinforced Cementitious Composites (light FRCC jacketing) in replacement of the original cover has been recently proposed for increasing durability and load bearing capacity of existing reinforced concrete (RC) structures. Although the advantages in terms of durability have been widely investigated, the behaviour of retrofitted columns under cyclic loading still deserves attention. This paper deals with the seismic response of RC columns retrofitted with a light FRCC jacketing. To this scope, flexural and shear critical RC columns were retrofitted and tested under load reversal. The resulting damage pattern was analysed by means of the Digital Image Correlation (DIC) technique. The cyclic response of the FRCC jacketed columns was compared with that of bare columns, to assess the suitability and effectiveness of the FRCC jacketing as a seismic retrofit technique. The experimental results demonstrated that the FRCC jacketing can represent a valid strengthening solution for shear critical members. In the case of flexural columns, the FRCC jacketing was able to provide an increase in ductility but induced a rocking behaviour. Preliminary modelling considerations for assessing the seismic response of FRCC jacketed columns have been finally provided, based on experimental evidences.

This paper investigates the creation and use of integrated IFC models to modernise traditional processes for applications to building authorities for structural engineering approvals and permits. First, we provide a brief overview of e-permit systems in the AEC sector, with the focus on solutions that implement openBIM standards like IFC, MVD, and IDM. Second, we conduct a study on the information requirements of Italy’s seismic-authorisation processes relating specifically to the field of structural engineering. Third, we describe preliminary research on defining the structural engineering information that needs to be incorporated in the IFC format for e-permitting scopes. Fourth, we present our early work on the development of an MVD that would enable the automatic extraction of integrated IFC models. Fifth, we illustrate the reference workflow of the Str.E.Pe. project and propose a preliminary proof-of-concept that makes use of an IFC model, which has been integrated with structural information to support the activities of the building authority in Avellino. The officers there have developed a SWOT analysis using IFC models to assist them in assessing the compliance of structural projects with seismic requirements. Finally, the paper sets out additional research we intend to undertake and our conclusions.

The problem of managing existing structures before and after seismic events has led to the development of many different strategies across the globe. These aim to mitigate the catastrophic effects of earthquakes on the occupants of a building, as well as improve the management of the emergency that inevitably ensues. This paper explores the use of an openBIM approach to resolve the issues referred to above, which is possible because of two new standards: Industry Foundation Classes and Information Delivery Manuals. A review of the most popular strategies adopted in both the pre- and post-earthquake phases is conducted using a process map. This organizes the relevant steps and processes into tasks, and additionally identifies the points at which information is produced and exchanged and the party responsible for doing so. Also described is how BIM models can be utilized in essential pre- and post-earthquake activities, as well as current benefits and ongoing developments intended to improve the processes themselves.

Non-prismatic beams are widely employed in strategic structures like bridges and sport arenas, requiring accurate analyses for a reliable and effective design. Unfortunately, features of non-prismatic beams lead their modeling to be a non-trivial task: (i) variations of both cross-section area and second moment of area impede an easy computation of analytical solutions compelling to use approximated methods; (ii) stress distributions in prismatic and non-prismatic beams are substantially different, as proved by analytical results available since the beginning of the past century; and (iii) the peculiar stress distribution in non-prismatic beams entails complicated constitutive relations, as highlighted in recent publications. Usually, commercial software does not properly account for all the features of non-prismatic beams, leading to inconsistent structural analyses, erroneous estimations of the stress distribution, and -consequently- coarse predictions of the structural element strength. The present paper proposes a strategy to effectively overcome the above-mentioned problems. We derive an accurate analytical model for 2D non-prismatic beams, able to handle the non-trivial stress distribution and the complicated constitutive relations. Thereafter, we compute both homogeneous and particular solutions using the symbolic calculus software MAPLE and we analytically define the Finite Element (FE) stiffness matrix for a planar, symmetric, linearly-tapered beam. Finally, we compare the proposed FE and SAP2000 solutions, considering several beams with different geometries, loads, and constraints. Numerical results highlight the reliability of the proposed modeling strategy, since the resulting FE consistently handles all the critical issues of non-prismatic beams with an extremely low computational cost. Conversely, SAP2000 solution remarks the need of ad hoc analysis tools and modeling strategies to be used for the design of non-prismatic structural elements.

This research investigates the preparation and characterization of new organic&ndash, inorganic geopolymeric foams obtained by simultaneously reacting coal fly ash and an alkali silicate solution with polysiloxane oligomers. Foaming was realized in situ using Si0 as a blowing agent. Samples with density ranging from 0.3 to 0.7 g/cm3 that show good mechanical properties (with compressive strength up to &asymp, 5 MPa for a density of 0.7 g/cm3) along with thermal performances (&lambda, = 0.145 &plusmn, 0.001 W/m&middot, K for the foamed sample with density 0.330 g/cm3) comparable to commercial lightweight materials used in the field of thermal insulation were prepared. Since these foams were obtained by valorizing waste byproducts, they could be considered as low environmental impact materials and, hence, with promising perspectives towards the circular economy.

The anisotropic behavior of the 3D concrete printing elements represents a crucial key feature to be closely investigated. It is mainly due to the layered extrusion process, the most widespread digital concrete technology, which creates weak planes at the interface, known as “Cold Joints”, by placing material layer upon layer. To investigate the interface bond failure mechanism, the bond strength at the interface between layers was measured in this study, especially with respect to printing time gap between layers. In particular, this work provides a characterization of the mechanical properties of 3D printed concrete elements’ interfaces through the design and the implementation of an experimental setup supported by DIC technique, in order to study the shear behavior of layer interfaces. The study investigates different 3d concrete elements produced with 100 s, 200 s, 1800 s as time gap between layer deposition, showing a significant decrease in terms of maximum load up to about 50% for the elements realized with the higher value of resting time compared to bulk elements.

Digital fabrication with cement-based materials requires specific attention to be paid to the rheological and mechanical material properties both in the fresh and hardened state. For the layered extrusion process, the cement-based material needs to satisfy the “printability” requirement. Generally, printable mortars exhibit brittle mechanical behaviour due to the absence of reinforcement. In order to overcome this issue, many different strategies can be implemented. Among them, the addition of short fibers in the mortar represents a first step towards the development of robust materials for 3D printing in construction. In this context, the paper focuses on the early stage tensile properties of fiber-reinforced cement-based material to be used in the layered extrusion process. The embedment of discrete fibers in a printable mix is expected to improve the mechanical behaviour but, at the same time, it implicates a loss of workability in the mix, which could lead to problems during the printing process (in terms of extrudability and pumpability of the mix). In this paper, the mechanical response under direct tensile is investigated as a function of the type/concentration of fibers as well as the mortar resting time. Furthermore, the effect of varying the amount of the superplasticizer to guarantee the printability requirement of the printable mortar is also investigated. In a quality control framework, the development of tensile fracture properties, in the considered production time frame, is fundamental to determine the printability of the mix, with reference not only to the quality of the finishing but also to the speed of the printing process.

Digital fabrication techniques combined with suitable cementitious materials have successfully led to the implementation of innovative manufacturing processes for concrete-like products. However, although significant advantages are expected in layered extrusion (LE) concrete technology, manifold engineering challenges arise from the process itself, such as the full control of the mechanical properties evolution during printing. Primarily, printed materials should satisfy specific early-age mechanical and rheological requirements, whose definition remains unstandardized. Additionally, scarce literature on testing procedures for early-age printable mortars is currently available. In this paper, uniaxial compressive tests are performed on cylindrical samples to determine the time-dependent compressive behavior and the early-age creep effects on fresh concrete. The load application conditions are varied in the experimental campaign in order to propose a proper mechanical characterization procedure for 3D printable cementitious mortars. Finally, results are implemented in an analytical model to predict the accumulated creep strain during the printing process. The outcomes highlight the role of the early-age creep in the development of global deformations.

Digital fabrication with concrete enables the efficient and quick creation of architectural/structural elements without formworks. This technology does, however, introduce new challenges, especially concerning the mechanical requirements of printable materials. Consequently, the mechanical characterisation of early-age printable mortar is essential for designing, controlling and modelling the printing process, but no standardised testing procedures are currently available. In this paper, the results of uniaxial compressive tests performed on cylindrical samples are compared by varying the testing procedures, with the ultimate goal being to investigate their effect on the time-dependent mechanical properties of printable mortar. Finally, the results are used to predict failure during the printing process due to self-buckling or excessive compression on the first mortar layer. The outcomes highlight the role of specimen preparation, as well as the displacement rate on the predicted critical number of layers.