Structural Typology Research Articles

The effect of the gravity column in the seismic design of steel CBFs

In this work, the effect of the gravity column in the seismic design of X-braced CBFs is analysed through a simplified design procedure. The analysis is performed by dividing the structural typology as a sum of two substructures: the Gravity Column (GC) substructure, with the primary aim of bearing vertical actions; and the Bracing substructure, mainly reacting to the horizontal actions. The analysis of the influence of the GC in the seismic design has been deepened by exploiting the Controlled Collapse Design Theory for CBFs. By imposing the collapse configuration, the storey displacement vector is obtained and, through the deformability matrix for the GC substructure, the horizontal actions acting on this substructure are defined. An analysis of the effects of seismic design is carried out considering the percentage of total shear force due to the GC substructure, for two case studies. In addition, a cost-(seismic) benefit analysis between the Controlled Collapse Design Theory and EC8 Design, is carried out.

Impact of the Structural Defects on Risk Assessment of Concrete Bridges According to the Italian Guidelines 2020

The Italian infrastructure network of roads and bridges is one of the most complex in the world due to the territory orography. Italy is strongly interested in seismic and hydrogeological hazards, and, in addition, degradation and obsolescence phenomena are common in infrastructures nowadays approaching the end of their nominal life. Furthermore, these infrastructures are subjected to continuous traffic load increase over time. In 2020, the Italian Ministry of Infrastructure and Transport (MIT) published the guidelines for risk classification and management, safety assessment, and monitoring of existing bridges (LG2020) as an attempt to unify the multiple procedures of inspection, monitoring, and maintenance of infrastructures. The multilevel approach proposed in the Italian guidelines for the management of the complex existing system of bridges is herein discussed and investigated, focusing on an operational methodology to evaluate the impact of structural defects on the risk assessment. This study aims to develop an operational methodology for the application of the procedure generically depicted in the LG2020 for the attribution of the level of defectiveness based on the outcomes of the periodical inspections. In particular, such a methodology is applied to two of the most widespread bridge structural typologies in the Mediterranean area: reinforced concrete (RC) and prestressed RC (PRC) bridges. The defects’ extent and level to structural members are associated with the proposed procedure for different bridge risk ratings. The work presents a useful tool to proceed from the outcomes of the inspections to the assignment of a level of defectiveness for the bridge, which enters into the risk assessment. This is to drive decision-makers in the definition of future actions and interventions, such as the detailed assessment of safety level and relevant strengthening interventions or installation of continuous monitoring systems.

Assessment of bridge Post‐Tensioning systems using non‐destructive (ND) inspection methods

AbstractReinforced concrete bridges with post‐tensioned cables are particularly critical structures, as the degradation of the tendons is not fully detectable through conventional investigation methods and/or through visual inspections, due to the intrinsic nature of the structural typology. After shortly reviewing the main applications of current non‐destructive (ND) methods available for investigating the deterioration of tendons and grout, the paper presents a simple procedure to rank these methods through a series of metrics formulated to evaluate the various technologies under four different aspects: accuracy of measurement, ease of use, cost, impact on the operation of the bridge. The procedure has the aim of providing bridge owners with a decision tool which can assist in the selection of the optimal ND technology available to detect a particular strand or grout defect.

Effect of uncertainties on seismic fragility for out-of-plane collapse of unreinforced masonry walls

A new approach for the evaluation of fragility curves of UnReinforced Masonry (URM) walls is proposed. Uncertainties on geometrical and mechanical properties, as well as on magnitude and position of the applied loads, are considered using fuzzy set theory. Fuzzy set theory has been broadly applied to civil engineering problems, particularly to reinforced concrete structures, though its application to masonry, to the authors’ knowledge, is investigated here for the first time to evaluate the seismic response of masonry walls in the presence on vague and imprecise information. The proposed procedure allows computing fragility curves based on available typological databases, integrated with experimental tests and survey data. One of the main advantages of this procedure is that it can account for the variability of structural typologies on a territorial scale. The effectiveness of the method is shown through numerical examples concerning walls made of fired clay bricks and lime mortar, which are typical construction materials in the Po River Plain, in Northern Italy. Linear kinematic and nonlinear time-history analyses are used to calculate the seismic response. The computed fuzzy-like fragility curves include both aleatory and epistemic uncertainties. An extensive sensitivity analysis based on suitable sets of representative input parameters is carried out to validate the proposed procedure.

New Boca del Cerro Bridge at Section 1 of the “Tren Maya” railway

AbstractThe new Boca del Cerro Bridge is in southern Mexico at the exit of the Usumacinta River Canyon, in the city council of Tenosique in the state of Tabasco. A place of an extraordinary environmental value.This area is also a strategic crossing point, in which the actual Bridge over the Usumacinta River was built in 1950. It is a structure of extraordinary value, which is a milestone of the engineering of the time, with an upper arch of steel truss.The new Boca del Cerro Bridge has been designed, for the new Section 1 of the “Tren Maya” railway, parallel to the actual bridge. The solution adopted for the new bridge consists of a main span of double steel truss with double composite action (steel and concrete) and variable depth, that will be embedded in two lateral compensation spans of prestressed concrete.The new bridge has been designed in order to ensure a minimal “competition” and intrusion with the existing bridge and to enhance the beauty of the surrounding nature.The structural typology election has been conditioned by the advantages of its constructive process, that allows structure built‐up without riverbed support. To achieve this, the central span is planned to be erected by incremental cantilevers, carrying truss segments over the deck.

EVALUATION OF OVERTOPPING MODEL PERFORMANCE USING NOVEL EXPERIMENTAL DATA FROM INDUSTRIAL DESIGN PROJECTS

A critical requirement in successfully planning to mitigate wave overtopping is the ability to predict the frequency at which coastal defences will be overtopped. Many empirical formulae have been developed to predict wave overtopping rates for specific structural typologies and hydrodynamic conditions. More recently, Machine Learning methods have been deployed in an effort to make models that generalize across a wide range of structures and environments. A critical enabling factor has been the compilation of systematically parameterized physical model data, culminating in the EurOtop extended database. Practitioners now have the luxury of choosing between multiple, high-quality models. In addition, given the rapid advancement in usability of modern Machine Learning frameworks, training their own bespoke models is an increasingly realistic option. What is now needed is more information, showing how these models perform on unseen data, in a practical design context, in order to continue to refine guidance around their use.

Moment Resisting Frames under the light of Japanese and European Codes

AbstractThe aim of the work is to make a comparison between the European and Japanese approaches to design Seismic‐Resistant Steel Frames (MRFs) in high seismicity areas. Therefore, the design rules for both the seismic codes are analyzed and compared. These design rules are applied to design a benchmark structure in DC3 ductility class (according to the new prEN1998) and following the Route 3 procedure (according to the Building Standard Law in Japan, BSL). The examined structural typology is a Spatial Moment Resisting Frames with regularity in plan and elevation configuration. The Japanese approach is divided in two stages. The first one regards the Allowable Stress Design (Elastic analysis) in which all the parts of the structure must be kept elastic; service and damage limitation requirements are in demand. The second stage regards the Ultimate Strength Design (Plastic Analysis) in which no‐collapse requirement and the protection of the human life are in demand. The seismic performance of the designed structures is evaluated by means of pushover analyses.

Equivalent estimation method (EEM) for quasi-distributed bridge-deflection measurement using only strain data

Deflection is a crucial parameter for bridge health monitoring procedures. In this paper, an equivalent estimation method (EEM) is proposed for quasi-distributed deflection estimation using onboard strain data. Leveraging the installation of the self-designed sensing bar on the bridge girder, an equivalent analysis model is established. An innovative inverse finite element method (iFEM) is employed to discretize the model and to establish a strain-deflection transformation matrix. Then, quasi-distributed bridge deflections are estimated by reconstructing the deformed shape of the equivalent analysis model. The present model is simple and independent of the typology of bridge structures, making the EEM sufficiently general to analyse complex bridges. The EEM framework is computationally fast, powerful, and robust for real-time applications since iFEM enables deformation predictions by simple matrix–vector multiplication without a priori loading and material information. Experimental validation cases have been performed, and they demonstrate the excellent quasi-distributed sensing capability of the EEM.

Drift‐based risk‐oriented method for the explicit consideration of ground motion duration in seismic design

AbstractThis study proposes a method to explicitly account for ground motion duration in seismic design by modifying structural deformation capacity. An equation is presented to adjust the design drift limit prescribed in the New Zealand standard NZS 1170.5, based on the anticipated reduction in structural deformation capacity for ground motion durations longer than a critical value. The proposed relationship is used to derive designs corresponding to three duration targets each for two case‐study steel moment frame buildings ‐ a 4‐storey and a 12‐storey, located on a site in Nelson, New Zealand. Hazard‐consistent collapse risk assessment of the design versions is conducted using a structural reliability framework employing incremental dynamic analysis. Results indicate that buildings designed for lower drift limits have a lower mean annual frequency of collapse. The application of the proposed method is found to reduce the variation in the collapse risk of steel frame buildings designed for different duration targets, compared to the existing approach. The method proposed in this study is simple and easy for practical applications and can be modified for other design codes and a range of structural typologies.

Seismic performance of Chilean concentrically braced frame industrial structures: effects of recent code modifications

Few seismic design codes for industrial structures exist worldwide. Among them, the Chilean design code was put to the test by the Maule earthquake of 2010, one of the largest seismic events in recent years. Although the seismic performance of industrial steel structures designed under these provisions was satisfactory, the standard was revised based on the accumulated evidence on the performance after the event and the advances in seismic design since the code was released in 2003. The revision process led to a number of modifications to the provisions, including those for structures based on concentrically braced frames (CBFs), a structural typology widely used in the industry. The modifications, mainly aimed at improving seismic performance in severe events, ranged from the seismic demand to the provisions for sizing structural elements and connections. This work evaluates the effect of these modifications on the design and seismic performance of CBFs. For this purpose, six industrial steel structures were designed using the current standard and the proposed version. The performance was evaluated through static non-linear analyses in 3D models according to the methodology prescribed by the FEMA P695 standard. The models included the non-linearity of braces, columns, beams or struts, and anchor bolts. The results showed similar performance between the structures designed using the proposed and the current version of the standard, in terms of overstrength and response modification factors. However, the performance improved when comparing the maximum drift that the structures can reach and the energy levels they are able to accumulate at these drifts. In terms of the cost–performance ratio, the improvement in performance is associated with moderate increases in cost.

Accounting for hysteretic characteristics in P‐delta analysis of structures

AbstractStudies in the literature have shown that P‐delta () effects are highly influenced by the hysteretic characteristics of a structural system. However, international buildings and bridge codes prescribe ‐induced amplification factors, limits for negligible effects and limits for dynamic instability that neglect this influence. As a result, different margins of safety against actions are currently specified for different structural systems, with steel structures, for example, presenting reduced margins of safety with respect to concrete structures. Adopting a sub‐set of the PEER earthquake record database composed of 1964 earthquake records, this paper presents a statistical analysis of displacement amplification ratios for systems with different hysteretic models, fundamental periods and ductility levels. In terms of both elastic and inelastic stability coefficients, limit values of the stability coefficient for negligible effects and dynamic instability are proposed for the most common structural typologies, such as steel, well and poorly detailed reinforced concrete, and self‐centering structures. Analytical estimates of the median, 84th and 98th percentile values of the displacement amplification that take into account the combined effect of stability coefficient, ductility level and hysteretic properties are proposed.

An archetype-based automated procedure to derive global-local seismic fragility of masonry building aggregates: META-FORMA-XL

The paper presents an automated procedure for deriving fragility curves for typological masonry aggregates, named META-FORMA-XL (MEchanical-Typological Approach FOR Masonry Aggregates – X Local). The topic deals with the urban-scale seismic vulnerability analysis, which can provide powerful information for developing risk mitigation plans and implementing strategies for reducing expected losses. However, when masonry buildings in aggregate are analysed, many issues arise, related to the lack of data, the complexity of the structural configurations and the presence of uncertainties. To this scope, the proposed procedure aims to investigate the seismic behaviour of masonry aggregates, based on numerical analyses carried out on ideal representations of the existing building stock, indicated as archetypes, by modelling geometrical and mechanical uncertainties characterizing buildings in the studied area. The archetype buildings are made according to exposure analyses by combining typical inventory collection forms and information derived from freely available databases. By investigating the seismic response of numerical models for a high number of archetype buildings, fragility curves are derived for all limit-states and two main directions, accounting for global and local damage mechanisms. The procedure is tested on low-rise row masonry aggregates in Southern Italy. The output of the procedure is validated on a real case study, for which a near-full information on the geometrical and mechanical features is available, providing a critical comparison in terms of fragility curves. Results highlight several advantages of the proposed approach, such as the possibility of identifying the most likely collapse mechanism for a specific masonry aggregation, the simplicity and the celerity of the analyses despite the large number of archetype models, and the exhaustive consideration of the uncertainties. Finally, the proposed concept can be readily extended to other aggregation forms and structural typologies.

USABILITY AS A PROBLEM OF EXPRESSIVE WEB DESIGN TOOLS: FROM THE PRACTICE OF WEB USABILITY TO THE CONTEXT OF WEB ACCESSIBILITY

The article is devoted to the problem of analyzing the issue of web usability and web accessibility of using educational web resources in the context of the problems of expressive web design tools. The author considers web usability and web accessibility systems as components of a universal design problem that goes beyond narrow technical issues of website content consumption. An important component of the research discourse of the publication is the study and interpretation of the experience of using educational Internet resources from the point of view of the system of expressive means, aesthetic solutions and artistic and project properties of web design. It is concluded that the artistic nature of an educational website has the capacity for representation within the user experience. It is proved that the parameter of external consistency of expressive means is extremely important for the problem of web accessibility. If a website's learning model uses more than one visual system, this requires coordination of visual solutions at all levels of interface design. The author emphasizes that the practice of gaining experience using an educational web resource is based on functional criteria. At the same time, the usability characteristics are not enough to identifythe typological structure of a certain site and to determine, on this basis, a universal approach to the construction of visual solutions. Practically in all the considered cases there are artistic-figurative or aesthetic-stylistic features, which are either part of the functioning system, or are considered as independent aesthetic components. The inevitability in the functioning of websites requires designers to come up with such solutions that would determine not only the functional properties of the website, but also its artistic direction. The conducted analysis shows that the aesthetics of network Internet resources is formed based on the principles of usability and is a utilitarian system that has its own functionality and a wide range of usage norms. Based on this, educational websites have significant differences compared to representative web resources that form visual messages within a different artistic and figurative system.

THE ARCHITECTURAL GEOMETRY OF THE CHURCH OF CRISTO OBRERO Y NUESTRA SEÑORA DE LOURDES

Abstract. The object of study of this paper is the Church of Cristo Obrero y Nuestra Señora de Lourdes, in the city of Atlántida, Uruguay, designed and built by Uruguayan engineer Eladio Dieste between 1956 and 1960, and proclaimed as a UNESCO World Heritage Site in 2021. Furthermore, the object of study is the outset of Eladio Dieste’s experimentations with reinforced brickwork, which resulted in innovative thin-shell structural typologies. Hence, the objective of this article is to verify the geometrical relationships within the continuous gaussian vaults of the Cristo Obrero’ roof and the ruled surfaces of its lateral walls. The proposed methodological procedures for this research were the in situ visitation of the object of study, followed by the consultation of original construction drawings, as well as the exploratory parametric modeling and polynomial regression of the architectural geometry of the Church of Cristo Obrero. Amongst the expected contributions for this research reside the dissemination of Latin-American modern architectural heritage sites within European academic journals, digital design technologies within Latin-American research centres, as well as the fostering of the comprehension of the design and construction process of the Uruguayan engineer Eladio Dieste.

Insights on the role of local site effects on damage distribution in the Izmir metropolitan area induced by the October 30, 2020 Samos earthquake

On the 30th of October 2020, a 6.6 magnitude earthquake occurred 14 km north of Samos Island, causing 119 casualties (117 in Izmir, Türkiye, and 2 in Samos, Greece) and significant damage in the 3rd biggest city of Türkiye, Izmir. Although the city is roughly 70 km far away from the epicenter, the damage was significant and concentrated in the city center settled on alluviums. This paper aims to analyze the distribution of damage in Izmir province, by crosschecking the recorded motions, the subsoil conditions and the evidence of damage as collected by an ad-hoc on-site reconnaissance. The intrinsic behavior of the Samos earthquake was investigated by employing three different ground-motion prediction equations. The results of the analyses revealed that site effects play a significant role in the amplification of ground motions, and valley effects are responsible for the concentration of damage. The damage in buildings was classified in terms of the intensity and structural typologies for the 30 districts of Izmir metropolitan area. In-depth analysis of the distribution of damages revealed that the earthquake caused damage all over the boundaries of Izmir province, and the concentration of damage in Bornova and Karşıyaka districts has a clear correlation with double resonance effects.

Computational methods applied to earthen historical structures

Earthen structures have an important representation among the UNESCO World Heritage List sites as well as among the built environment in general. Unfortunately, earthen heritage structures are also numerous within the UNESCO List of World Heritage in Danger whereas other existing common earthen structures are extremely vulnerable to seismic and climate change events. Within the field of heritage conservation, structural analysis contributes to the safety evaluation of the structure, the diagnosis of the causes of damage and decay, and to the validation of interventions. Thus, the need to develop effective and accurate computational methods suitable for the study of both monumental and vernacular earthen structures becomes evident. This paper compiles, summarizes, and highlights the latest developments and implementations of computational methods for the study of such structure typologies. The literature has been explored following the PRISMA-S checklist methodology and a narrative synthesis was used for the presentation of results. Finally, future trends, opportunities, and challenges are discussed.

EXPANSION AND NATURALIZATION OF ADVENTIVE BUTTERFLY SPECIES (LEPIDOPTERA: PAPILIONOIDEA) ON THE NORTHEASTERN PART OF THE RUSSIAN PLAIN

Data on composition and naturalization patterns of more than twenty adventive butterfly species expanded to the northeastern part of the Russian Plain during the period of 1990-2021 are compiled. It is shown that lines of transport communications such as highways, railways, power lines, gas and oil pipelines serve as main immigration corridors for butterfly species from southern regions. Anthropogenic transformation of indigenous taiga forests through industrial logging operations, largely expanding areas of open habitats, which are more suitable for butterflies, promotes successful naturalization of adventive species. Linear systems of technical and industrial constructions together with river valleys play a role of semi-natural corridors for the expansion of adventive species. Furthermore, secondary small-leaved and mixed forests surrounded by a network of forest edges and meadows represent a kind of staging areas for the establishment of adventive species’ populations. Groups of adventive species are delineated based on their naturalization status that was estimated on the basis of an integral assessment of their biocenotic stability and landscape activity. It is drawn a conclusion that ongoing expansion and naturalization of adventive butterfly species on the northeastern part of the Russian Plain will increase changes in the composition of local and zonal faunas and the spatial and typological structure of their populations.

Identification and Trend Analysis of Multistorey Timber Buildings in the SUDOE Region

The construction sector has one of the most polluting economic activities. In this context, several policies are being launched by the European Union to promote the transition to a sustainable economy, and timber construction is a safe way to contribute to it. Due to the recent development of multistorey timber buildings, the architectural and structural typologies have not been widely studied yet and with not many studies from Southern Europe. In this context, the main objective of this research is to identify and analyse the trends in the use of wood as a structural material in multistorey timber buildings (≥4 floors) in the SUDOE region, i.e., Spain, Portugal, and Southwest France. The methodology involved identifying 28 timber buildings in the SUDOE region and 101 worldwide, most of them in Europe, and sending online information request forms to different actors involved in their design and construction, collecting plans and BIM models, and performing technical study visits to the identified reference buildings. The collected information was included in open-access technical datasheets, and different indicators in terms of building uses, structural system, wood species, and wood volume, among others, were defined. The results showed that there is a tendency to construct taller timber buildings in the SUDOE region with a predominant use of local softwood species, with ratios of wood volume per built area varying between 0.3 and 0.4 m3/m2. The mass timber typology using cross-laminated timber (CLT) is mainly used for residential buildings, while post and beam are used for educational and offices buildings. In addition, a potential embodied CO2 equivalent depending on the building typology and use was also analysed.

CARTIS: a method for the typological-structural characterization of Italian ordinary buildings in urban areas

Large-scale risk assessments relevant to natural hazards are commonly based on very poor exposure and vulnerability data, often drawn from census data. In fact, obtaining a detailed knowledge of the built heritage is a very hard task especially for those countries, like Italy, characterized by very high urban density and large variety of building typologies, where a building-by-building knowledge can sound as a utopian ambition. Nevertheless, exposure and vulnerability are two of the four factors governing, along with hazard and capacity, risk convolution, and hence their uncertainties yield to corresponding uncertainties in the resulting expected losses. The lack of suitable information on building typologies is responsible of very strong simplifications in risk analyses, like the assumption of the same building typologies, indistinctly scattered all over the Country territory, without distinctions at a local or at a regional level. With the goal of improving exposure description and reducing such uncertainties, since 2014 the Italian Civil Protection Department (ICPD) has undertaken a new research branch in the framework of ReLUIS (Network of University Laboratories in Earthquake Engineering) projects, dedicated to territorial analyses, by funding also the CARTIS project. The project has the goal to characterize the building structural typologies trough a data collection at a local and an extensive scale in Italy, with the final aim to improve the reliability of seismic risk analyses. The paper describes the method and some first statistics so far elaborated.

An energy-based methodology to estimate the ultimate condition of complex continuous masonry structures

Performance-based assessment procedures for existing structures based on pushover-like nonlinear static analyses require the definition of progressive damage states on the pushover curve, which may be associated with proper limit states for safety verification purposes. In Codes, the “ultimate condition” of the structure, i.e. a damaged state in which the structure is conventionally supposed to be no longer able to carry vertical and horizontal loads, is typically identified when the base shear shows a decay higher than a given threshold (usually 15–20%). In the case of masonry structures, this issue is not always straightforward depending on the complexity of the structure and the failure mode activated. The challenge especially arises in case of monumental buildings, such as complex continuous structures (e.g. towers) and buildings composed of many macro-elements (e.g. churches), dominated by flexural failure modes (e.g. overturning mechanisms). Indeed, in these cases, pushover curves may not show a significant softening for large horizontal displacements (e.g. masonry crushing is not activated). Accordingly, the application of the aforementioned approach results impossible. In this paper, an energy-based methodology to estimate the ultimate condition of masonry structures is introduced. Although the procedure is potentially applicable to any typology of masonry structure, it is tentatively applied here to continuous tower-like structures. A preliminary calibration phase to set the energy ratio thresholds is addressed by considering various simplified benchmarks subjected to several load scenarios. To this aim, the model is subdivided into several portions, and the ratio between the dissipated energy and the total energy is tracked in each portion of the structure along with the pushover analysis. The ultimate condition of the structure is then found as soon as such ratio reaches a pre-defined threshold in a portion, calibrated in such a way to highlight where in the structure the damage is mainly localized. The methodology is then tested on a real case study application, i.e., the bell tower of the San Francesco da Paola church in Rome, modelled through a suitable nonlinear continuum modelling approach. Results prove that the methodology is general, effective, and easy to use.