The growing complexity and scale of modern bridges increasingly subject decks to combined axial forces and bending moments, creating critical design challenges. For steel-concrete composite cable-stayed bridges, achieving long spans requires careful consideration of these forces, particularly axial forces from cable inclination, alongside bending effects to ensure structural rigidity. Current design codes, such as Eurocode, inadequately address this interaction, omitting axial forces and associated shear lag effects while focusing exclusively on bending. This gap often forces designers to rely on computationally intensive finite element (FE) models (e.g., shell/brick elements) for accurate analysis. To address this limitation, this study proposes a novel methodology for the design and verification of twin-girder composite decks under combined axial and bending actions at both Ultimate (ULS) and Serviceability (SLS) Limit States. The paper incorporates the influence of steel-concrete connector deformability and introduces a novel non-dimensional Aspect Ratio parameter, enabling generalization across different cross-sectional geometries. The developed simplified approach is derived from a parametric FE study of generic twin-girder decks, enabling efficient stress distribution assessments by integrating results from universal beam models. The proposed procedure is more accurate than current regulations, as Eurocode provisions overestimate concrete stress under compression and combined loading compared to the reference shell model. Demonstrated through an application to an existing cable-stayed bridge, the methodology offers a practical alternative to complex linear and non-linear FE analyses and is readily adaptable to similar composite deck systems.

Contemporary design codes, including Eurocode 4, address the reduction of the effective width of the concrete slab primarily in relation to flexural behaviour, while the influence of axial forces is generally disregarded. This omission can lead to significant inaccuracies in the structural assessment of composite decks, particularly in cases where axial–bending interaction is non-negligible. Consequently, practitioners are often required to resort to advance linear or nonlinear Finite Element analyses employing computationally demanding shell or solid elements. To overcome these limitations, the present study proposes a novel, simplified design methodology for composite double-girder decks subjected to combined axial and bending actions. The proposed framework enables the direct verification of composite cross-sections at both the Ultimate and the Serviceability Limit State, in accordance with the provisions of Eurocode 4, while explicitly accounting for the deformability of shear connectors.

Timber–concrete composite floors are currently used as sustainable flooring solutions. To broaden their application, improvements in construction efficiency are required. The hybrid system herein proposed combining timber, steel, and concrete members eases on-site assembly and can be partially prefabricated in factory. Timber beams and steel members, connected with interposed wooden planks through mechanical fasteners, create an oak-beamed ceiling supported by timber–steel composite beams. The steel element, with height equal to the insulating layer already required for energy and comfort purposes, plays a key role during concrete casting, allowing timber-steel composite beams to support fresh concrete and workmen loads with limited deflection. This composite action reduces the timber beam depth, thus lowering material use, and eliminates temporary supports, simplifying construction and reducing costs. These advantages promote wider adoption of timber floors, valued for both sustainability and aesthetics. After concrete hardening, a three-member hybrid floor is obtained. Neither numerical evaluations nor specific experimental tests are required because, even disregarding the steel contribution, the system’s performance, simply evaluated with the rules of the Annex B of Eurocode 5, generally accepted also for timber–concrete composites, matches that of conventional solutions with deeper timber beams. The proposed hybrid floor thus combines sustainability, prefabrication, construction efficiency, and compatibility with existing design standards.

This paper presents an introduction to a tensegrity footbridge with a prestressed deck, focusing on its structural analysis and design. The inclusion of cable pretension leads to deck prestressing. Through finite element analysis, various aspects are investigated, including nonlinear geometric effects, key load cases, the influence of the main cable’s rise, and modal analysis of this unique structure. The study reveals that the tensegrity bridge exhibits favourable structural behaviour, making it a suitable choice for footbridges, although it differs from traditional bridge designs. The paper concludes by summarizing essential recommendations concerning structural design, material properties, and the overall behaviour of the tensegrity bridge.

This study investigates the optimization of gridshell dome shapes using seismic design demand parameters as the primary objective function. The innovative methodology integrates shape optimization with seismic analysis, deviating from traditional approaches that separate geometric design and seismic performance enhancement. By integrating computational methods, utilizing parametric modeling through Grasshopper, and structural analysis with OpenSees, the framework employs a genetic algorithm for optimization. Nonlinear time-history analysis, incorporating material and geometric nonlinearities, reveals that the optimal shape of the dome is significantly influenced by its seismic response. The results show that the optimal dome shape can vary substantially based on seismic performance criteria, indicating a dynamic interplay between structural form and seismic forces. Moreover, the optimal shape can be further influenced by implementing a supplementary damping system. In this case, both the gridshell shape and seismic dampers arrangement require adjustments to achieve optimal seismic performance. These findings highlight the critical role of integrated seismic analysis in shaping optimization, emphasizing that the ideal dome geometry is not static but evolves in response to seismic demands and damping configurations.

Understanding how pedestrians interact with the footbridge, in particular studying dynamic actions caused by pedestrian loads on footbridges, engineers can address any design deficiencies, such as excessive deflection, resonance, or discomfort experienced by pedestrians during bridge usage. For this, the paper consists in two main parts: In the first part, we extensively examine various factors essential for accurately modeling the dynamic actions induced by individual pedestrians or groups of pedestrians on footbridges. Our focus includes an analysis of relevant experimental studies conducted abroad, specifically regarding the closure of the Millennium Bridge. This section extensively discusses the identified issues and explores different mathematical models, particularly those capable of simulating dynamic forces resulting from walking, jogging, or jumping, whether by an individual or a group of walkers. The second part of the study centers around utilizing Finite Element Method (FEM) models to analyze a specific footbridge located in Carbonia. This footbridge was inaugurated in November 2001 but had to be closed within a year.

This paper introduces a design methodology to enhance the seismic response of gridshells by simultaneously optimizing their shapes and the configuration of viscoelastic dampers. While viscoelastic dampers effectively reduce seismic responses, their impact on gridshell geometry has received limited attention. The proposed framework integrates damper placement into the initial design stage to address this gap, unlike conventional approaches that treat geometry and damper design separately. Leveraging parametric geometric and structural modeling, combined with a genetic algorithm, the framework utilizes a multi-phase fitness function derived from static and dynamic analyses, accounting for damping effects and material and geometric nonlinearities. The findings reveal that, as the number of dampers increases, optimized gridshells tend to adopt more elliptical shapes while achieving substantial reductions in both maximum displacement (exceeding 50 % in some cases) and thrust forces (up to 40 %), with the effect being more pronounced in mid-rise domes. Notably, even configurations with as few as 32 dampers can yield satisfactory seismic performance. Overall, locally symmetric damper layouts are recommended. The proposed methodology underscores the benefit of integrating damper placement with shape optimization during the early design phase, enabling adaptable applications to other structural systems and supporting more informed performance-based design decisions.

Long and complex composite steel-concrete structures are becoming common, requiring a deep understanding of the effects induced by the simultaneous action of axial forces and bending. In fact, the axial force generated, for instance, by cable inclination in cable-supported structures can modify the stress distribution within the elements compared to bending scenarios, thereby necessitating a revision of the effective width to be utilized. Nonetheless, current design codes, including Eurocode specifications and others, lack provisions for addressing the combined effects of axial force and bending, as they are exclusively tailored for bending. This limitation can introduce design complexities, necessitating the implementation of intricate Finite Element (FE) models, which impose substantial computational loads and design efforts. The methodology proposed in this paper overcomes these challenges allowing to assess the stress distribution and resistance of composite deck at Serviceability Limit State (SLS) and Ultimate Limit States (ULS) by leveraging results obtained from standard beam models typically used by structural designers or practitioners. A comprehensive parametric analysis using nonlinear finite element models is performed to validate the developed methodology. A comparison with the Eurocode 4 formulations highlights that the proposed method provides superior accuracy in estimating peak stress in concrete slabs under combined compression and bending. Additionally, it facilitates straightforward verification at the ULS in compliance with Eurocode requirements.

Nonlinear analysis of the structural response of masonry buildings to horizontal actions, both using finite elements that takes into account cracks and yielding of piers and spandrels, and using discrete elements, often presents convergence problems and requires a considerable computational burden. In this respect, the approach with macroelements with the equivalent frame method is less problematic and allows the non-linear analysis of even very complex box-shaped buildings without significant computational problems. In this article the non-linear analysis by macroelements with the equivalent frame method is extended to buildings of cylindrical shape with a circular section of large dimensions, such as, for example, the important monumental building of neo-classical conception of the prison "La Rotunda" of Tempio Pausania in Sardinia, Italy. A non-linear static analysis (pushover) is performed in order to evaluate the response to the seismic action. The analysis shows how the response of the building to horizontal forces, up to the collapse of the structure, is strongly influenced by the interaction between the circular part of the building and the adjacent parallelepiped part located at the entrance to the "La Rotunda" prison.

This study explores parametric design and optimization to improve a reciprocal frame bridge’s structural efficiency while preserving its historical and architectural significance. The research aims to identify an optimal configuration that minimizes steel requirements for a self-supported bridge while satisfying structural requirements. This objective was achieved by modifying the bridge’s geometrical parameters using a genetic algorithm for mono-objective optimization. A finite element structural analysis was conducted to evaluate the maximum stress in the material, with a penalty function used to ensure structural safety. The parametric design software allowed for efficient and precise optimization of the bridge design. The results demonstrate that the proposed optimization method reduces material usage while maintaining the bridge’s original structural concept of traditional wooden Chinese bridge, validating the approach’s effectiveness for future design of reciprocal frame bridges.

The research focused on the design of a curved shell-supported footbridge using a form-finding algorithm and genetic optimization. The bridge was shaped through a parametric design code, which also allows optimization based on finite element structural analysis. The constrained optimization involved a mono-objective approach aided by penalty functions to control the maximum tension utilization of the concrete material. The objective was to find the optimal bridge shape in terms of minimizing displacement under vertical and horizontal loads, with both the topological optimization of the positions of the bridge supports and the optimization of the control points of the Bezier curve describing the form of the curved deck as key parameters. The results provide insights into effective techniques for optimizing the design of curved shell-supported footbridges subjected to earthquake loads.

BACKGROUND:Several studies have shown that in patients treated with vitamin K antagonists (VKAs) time spent in therapeutic range (TTR) is lower in females than in males. This retrospective study has evaluated a possible association among over-anticoagulation and gender, type and indications to VKAs, TTR and bleeding. Moreover, the decrease of the INR level, after VKAs withdrawal, was considered. METHODS:From December 2020 to January 2004, 1230 patients with venous thromboembolism or atrial fibrillation were enrolled. Age, gender, type of VKAs, clinical indications, INR values and bleeding events were recorded. TTR was calculated considering the entire period of treatment. RESULTS:A total of 1616 and 1759 over-anticoagulation episodes were found in males and females, respectively. The median INR value was 4.5 (4.0-19.04). Thirty-two percent of the patients did not have an overdose throughout the observation period. The median number of over-anticoagulation per year was significantly higher in females (0.39-year) than in males (0.28-year). After 24 h of VKAs withdrawal, INRs were similar in both genders. Logistic regression analysis showed that the episodes of over-anticoagulation per year were associated with females, atrial fibrillation, warfarin therapy, follow-up length longer than 4 years, and TTR <73%, but were not associated to bleeding episodes. CONCLUSION:The higher number of over-anticoagulation can explain the lower TTR in females. An excess of anticoagulation is not associated with bleeding events. The recovery of INR performs better when acenocoumarol is used, therefore, in patients who present several episodes of over-anticoagulation, acenocumarolo could replace warfarin.

Concrete Filled Steel Tubular (CFST) K-joints employed for truss structures gained high interest in the last years due to their widespread use in engineering practice. The overall performances of these joints can be efficiently improved by using steel studs welded in the inner surface of the steel chord filled with the concrete, avoiding punching shear failure, and improving the overall strength and ductility. However, a reliable prediction of the structural behavior of the joints is outmost of importance for the assessment of the capacity of new and existing structures, and there are no standardized design methods nowadays. In this paper, the structural performances of CFST K-joints with and without steel studs are investigated by Finite Element Modelling (FEM) approach with the aim to provide a predictive tool for the design. A comprehensive discussion of the key parameters that govern the FEM procedure as well as the calibration of the FE models was provided to give the basis for a reliable modelling of CFST K-joints with and without studs for the predictions of the load-displacement/strain response and the strength, considering the main failure mechanisms. In this context, in addition to the detailed FEM of CFST K-joints with steel studs, a simplified equivalent FEM approach is proposed to reduce computational effort keeping the same accuracy.

Earthen constructions are often built in seismic areas, notwithstanding their vulnerability to even low-intensity earthquakes. Numerical simulations and design methods to predict the seismic response of earthen constructions under future earthquakes and, if any, to design and implement retrofitting systems are hence required. This study aims at evaluating the applicability of the equivalent frame method (EFM) to assess the seismic performance of adobe masonry buildings through nonlinear static analysis, allowing a trade-off between computational efficiency and accuracy in the simulation of earthquake damage. Experimental results of shaking table tests performed on a half-scale adobe building specimen were compared to the output of numerical simulations performed on the prototype building through the EFM. A satisfactory numerical-experimental agreement was found both in terms of seismic capacity features and damage to load-bearing walls. Such results indicate that the EFM can be suitably used also in adobe buildings, hence confirming previous validations on other building typologies.

Structural optimization is an important tool for structural designers that helps them to find innovative design solutions and structural forms with a better exploitation of materials as well as decreased self-weight and minimum material costs. In this article, a design procedure coupling the influence matrix method and genetic algorithms to optimize stay cables in cable-stayed bridges is presented. Following that, the design procedure is utilized in the preliminary design of a twin towers double-cable planes cable-stayed bridge to be located in Ferrara, Italy. The cable cross-sectional areas and corresponding pre-tension forces are optimized simultaneously. The results demonstrate that the proposed procedure is a powerful tool for designing stay cables and predicting the optimum cross-sectional areas of stay cables under certain stress and displacement constraints.

Curved cable-stayed bridges have been regularly accepted due to their ability to cross long spans, and a number of studies have been conducted to investigate the mechanical or dynamic performance of them. Meanwhile, currently just a few studies focus on the curved composite cable-stayed bridges. In this study, an operational modal testing and finite element model updating of a conventional straight bridge with the steel-concrete composite girder were conducted to investigate the performance of the potential methods for the model updating, which included the direct method and the sensitivity-based iterative method. Then, dynamic tests were performed for one typical curved steel-concrete composite cable-stayed bridge as the key case study. A highly refined finite element model of the bridge was developed and then calibrated based on the aforementioned methods in reference to the experimental results. Finally, the dynamic behavior of the curved steel-concrete composite cable-stayed bridge was studied based on the model. It is found that the solution accuracy of the finite element model can be improved significantly by employing the structural health monitoring technique. Moreover, by using the iterative method, the solutions of the updating parameters are generally more accurate compared with the solutions of the direct method. Nevertheless, when the appropriate choices are made for the algorithmic parameters, both methods can lead to the updated models with satisfactory numerical analysis results as compared to the experimental data.

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.

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.

BACKGROUND:Common risk factors for gastrointestinal bleeding (GIB) are advanced age and the use of antiplatelet or anticoagulants drugs for the prevention of cardiovascular diseases.METHODS:In this prospective real-world observational study, oral anticoagulated patients were recruited and followed between June 2013 and December 2019. The primary end-point was to evaluate a possible relationship between bleeding events and patients' clinical history of gastrointestinal disease prior to the start of the therapy. The secondary end-points were time of GIB appearance and the percentage of idiopathic or provoked events, i.e., bleeding due to a gastrointestinal disease. In case of GIB event all the patients were studied by means of endoscopic procedures. Cox regression was used to calculate the relative hazard ratios (HRs) of GIB for each considered clinical variable.RESULTS:734 patients on both VKAs or DOACs were studied. Overall, 46 hemorrhagic events were recorded: 6 were major bleeding (0.42/100 patient-years) while 43 were clinically relevant non major bleeding (2.8/100 patient-years). The Cox regression analysis did not show any relationships among GIB and the variables considered.CONCLUSION:The patients' clinical history is neither a predictor for GIB bleeding nor a guide to the choice of the oral anticoagulant to be administered. Routinely applying bleeding risk screening, such as occult blood in the stool, should be added to the periodic laboratory checks for early recognition of patients at higher risk of GIB.

Pile buckling is infrequent, but sometimes it can occur in slender piles (i.e., micropiles) driven into soils with soft layers and/or voids. Buckling analysis of piles becomes more complex if the pile is surrounded by multi-layered soil. In this case, the well-known Timoshenko’s solution for pile buckling is of no use because it refers to single-layered soils. A variational approach for buckling analysis of piles in multi-layered soils is herein proposed. The proposed method allows for the estimation of the critical buckling load of piles in any multi-layered soil and for any boundary condition, provided that the distribution of the soil coefficient of the subgrade reaction is available. An eigenvalue-eigenvector problem is defined, where each eigenvector is the set of coefficients of a Fourier series describing the second-order displaced shape of the pile, and the related buckling load is the eigenvalue, thus obtaining the effective buckling load as the minimum eigenvalue. Besides the pile deformed shape, the stiffness distribution in the multi-layered soil is also described through a Fourier series. The Rayleigh–Ritz direct method is used to identify the Fourier development coefficients describing the pile deformation. For validation, buckling analysis results were compared with those obtained from an experimental test and a finite element analysis available in the literature, which confirmed this method’s reliability.