Structural System Research Articles

Spectral incremental dynamic methodology for nonlinear structural systems endowed with fractional derivative elements subjected to fully non-stationary stochastic excitation

A novel spectral incremental dynamic analysis methodology for analysing structural response in nonlinear systems with fractional derivative elements is presented, aligning with modern seismic design codes, like Eurocode 8. Drawing inspiration from the concept of fully non-stationary stochastic processes, the vector of the imposed seismic excitations is characterised by time and frequency evolving power spectra stochastically compatible with elastic response spectra of specified damping ratio and ground acceleration. The proposed method efficiently determines the nonlinear system time-dependent probability density functions for the non-stationary system response amplitude by employing potent nonlinear stochastic dynamics concepts, such as stochastic averaging and statistical linearization. Unlike traditional incremental dynamic analysis curves found in the literature, the herein proposed method introduces a three-dimensional alternative counterpart, that of stochastic engineering demand parameter surfaces, providing with higher-order statistics of the system response. An additional noteworthy aspect involves the derivation of response evolutionary power spectra as function of spectral acceleration, offering a deeper insight into the underlying system dynamics. Besides its capabilities, the method maintains the coveted element of a particularly low associated computational cost, increasing its attractiveness and practicality among diverse applications of engineering interest. Numerical examples comprising the bilinear hysteretic model endowed with fractional derivative elements subject to an Eurocode 8 elastic design spectrum demonstrate the capabilities and reliability of the proposed methodology. Its accuracy is assessed by juxtaposing the derived results with germane Monte Carlo Simulation data.

Torsional effect analysis of high-rise reinforced concrete space grid cassette multi-tube structure system

The manuscript introduces a new structural system called the reinforced concrete (RC) space grid cassette multi-tube structure for high-rise buildings. A case study building is analyzed using this system and compared to a conventional RC frame-core tube structure. Through modal analysis in the software “Midas Gen”, the torsional effect and control indices like inter-story displacement ratio, maximum displacement, etc. are compared between the two structural systems. The results show that the space grid cassette system has smaller displacement ratios, displacements, inter-story torsion angles, and thus better torsional resistance compared to the conventional frame-core tube system. Based on these analyses, the manuscript concludes that the RC space grid cassette multi-tube structural system has superior seismic performance and is more suitable for irregularly shaped high-rise residential buildings.

Analysis of Tall Building by using Different Dimensions Under Wind Load Effects

Abstract: The expense of land is increasing day by day because of rapid increase in the population whereas vegetation is diminishing, due to diminished vegetation contamination is expanded. In this Research paper, we analyze the various types of the dimensions of the building considering them side ratios too and the effect of windward forces on the building in mainly X and Z direction. This paper is about the study of four-building models as Dimensions (30m*30m), (40m*25m), (55m*20m), (80m*15m) having their horizontal Aspect ratios viz. 1, 1.6, 2.75 & 5.33 at an angle of 0 degrees. The height of the building is 90m. Therefore, the research is proceeding to balance out the structure from an increasingly affordable perspective. To find out the best performance and economical for the lateral wind-force resisting system of different models of 25 storey buildings are modelled in STAAD-PRO, assuming the site location as AGRA (Uttar Pradesh), India. For the different structural systems that are compared for minimum and maximum storey displacement, storey drift. The structural system used is prototype. The axial force, shear force, moment, and reactions at various windward sides are used to compare the best performance of the structure. Above all, wind forces in x- direction shows the adequate displacement and drift values when compared to z- direction but from the economic point of view Model-2 gives the satisfactory result from all the above.

ANALYSIS OF THE RELATIONSHIP BETWEEN BODY POSTURE AND TEMPOROMANDIBULAR DISORDERS

The temporomandibular joint (TMJ) is one of the most complex joints in the human body, being responsible for the movement of opening and closing the mouth. Dysfunctions that affect the temporomandibular joint have a multifactorial etiology that includes: the joint itself, the chewing muscles and other structures of the stomatognathic system. In this sense, postural movements can be associated as a predisposing factor for temporomandibular disorder (TMD), when analyzing the negative repercussions of body movements reflected in the TMJ. In this way, it is clear that a better understanding of such conditions would therefore contribute to more accurate diagnoses and more comprehensive, coherent and, consequently, more effective therapeutic approaches. A systematic review of the literature was carried out, with the aim of searching for works that support the impact between craniocervical posture and temporomandibular disorders, using references from scientific articles from the last five years in Portuguese and English. Therefore, it is clear that a better understanding of these conditions would therefore contribute to more accurate diagnoses and more comprehensive, coherent and, consequently, more effective therapeutic approaches.

Impact of ageing on structure of random sequential adsorption packings of discorectangles

The ageing processes in the systems of elongated particles (discorectangles) adsorbed on a plane was studied numerically. An off-lattice model with continuous positional and orientational degrees of freedom was tested. The initial jammed state was produced using the random sequential adsorption (RSA) model. The transition from the jammed to equilibrium states were performed via translational and rotational Brownian motions. An aspect ratio of the particles (length-to-width ratio) was varied within the range ε=1−12 . At ɛ < 10 the relaxation into the isotropic state was always observed. In the intermediate range, 10⩽ε⩽11 , the relaxation transition into the states with ordered domains was observed. Particularly, for ɛ = 10 this transition was related with significant finite size scaling effects. For particles with ɛ = 12 formation of the large scale quasi-nematic domains and unlimited domain growth was observed. The impact of the relaxation on the domain structure, porosity, percolation connectivity and tracer particle diffusion in such barrier systems was also discussed.

Sustainable and Collaborative Solutions for the Long-term Care of Heritage Earthen Sites in Seismic Areas in Peru

ABSTRACT The challenges posed by conserving historical earthen structures in seismic-prone regions prompted the initiation of the Seismic Retrofitting Project (SRP) by the Getty Conservation Institute (GCI) and the Ministry of Culture of Peru. Since 2009, the SRP has aimed to enhance the structural performance and safety of historic earthen buildings while preserving their historical fabric by combining traditional techniques, local materials, and technical expertise with advanced computational tools. The project has focused on four Peruvian earthen buildings as case studies, including the seventeenth-century adobe church of Kuñotambo. An intervention was carried out between 2016 and 2019 by the regional branch of the Ministry of Culture in Cusco based on techniques developed by the SRP. The GCI is now working on a monitoring and maintenance plan for the site, collaborating with local stakeholders, including the Ministry of Culture of Peru in Cusco, the Archdiocese of Cusco, and the community of Kuñotambo. This paper primarily discusses the practical aspects of on-site monitoring, including the tools and techniques used to track changes in the building and its decorated surfaces. It also outlines the implementation of a structural health monitoring system and the development of capacity-building activities for Latin American engineers. The overarching goal is to provide a sustainable framework for the long-term preservation of historic earthen structures in seismic-prone regions, highlighting the importance of community involvement and multidisciplinary collaboration.

Knowledge capital and innovation management: Impact of transboundary investment and assimilative capacity

Background: In today’s volatile and highly competitive business environment, the importance of knowledge capital and innovation management for multinational manufacturing firms has been widely recognised by both academia and industry.Aim: This article aims to explore the impact of transboundary investment and assimilative capacity on the association between knowledge capital and innovation management in this specific context.Setting: A total of 217 managers and employees were selected from 19 multinational manufacturing firms listed on the Ghana stock exchange to participate in the survey.Method: Using a theoretical-based association existing research model, data were collected through an online electronic questionnaire survey. The collected data were then analysed using path analysis, utilising SPSS 22.0 and AMOS 24.0 software to test the formulated hypotheses.Results: The study found that an organisation-wide unified system, technological, organisational resource and knowledge capital-enabling structures strongly influence multinational manufacturing firms. Besides, knowledge capital and innovation management have a positive mediating role and a significant impact on multinational manufacturing firms. However, there was no significant impact between knowledge of empirical capital and innovation management.Conclusion: The findings of this study highlight the importance of knowledge capital in enhancing innovation management and emphasise the role of transboundary investment and assimilative capacity in mediating this relationship.Contribution: This research contributes to the theoretical understanding of how knowledge capital and innovation management are interconnected, as well as the relationship between transboundary investment and assimilative capacity, and their respective roles in mediating this relationship.

Breach diameter prediction of reinforced concrete wall under contact/near-contact explosives using deep neural network

In recent years, the use of Machine Learning (ML) has been expanded to several engineering fields with applications in structural engineering. Deep Neural Network (DNN) models have been widely implemented to predict the response of structural systems under conventional loading. The accuracy of these DNN models relies on the size of the dataset used, which can vary from hundreds to thousands of data points, typically formed by images, test data, and/or finite element models built for a specific environment. Such dependency becomes a limitation when DNN models are intended to be used in blast analysis and/or design, as data are typically scarce or restricted. This paper introduces the implementation of an ML/DNN model for the prediction of breach diameter of a reinforced concrete target subjected to contact and near-contact explosions. The DNN model predicts the breach diameter using experimentally collected concrete breach data. The DNN model considers several parameters related to the charge (e.g., type, geometry, orientation, casement properties) and wall target (e.g., material properties, geometry, reinforcement, fiber content), as well as proximity between the target and explosive. It was found that charge geometry, charge placement type, target thickness, scaled distance, and fiber content in the mix were important features affecting the breach diameter prediction.

Experimental investigation of the effective parameters on the lead extrusion damper performance

Lead extrusion dampers (LED) are employed for seismic response control of various structures due to their advantages over other energy-dissipative devices. However, a reliable design algorithm and an optimization process are essential to ensure optimal performance within the host structural system. Thus, the influence of device parameters on the damper behavior must be clearly understood. In the first part of this comprehensive study, the effect of different parameters on the LED performance was experimentally investigated. To this end, 23 specimens with different prestressing levels, bulge-to-shaft diameter ratios, shaft-to-bulge transition zone geometries, and device length ratios were cyclically tested under varying displacement amplitudes, i.e., 5 mm, 10 mm, and 20 mm, and loading rates, 0.5 mm/s, 1.0 mm/s, and 2.0 mm/s. Subsequently, they were exposed to a ramp-type loading up to the amplified design displacement. After satisfactorily completing the experimental tests, the behavior of the LEDs was compared in terms of their hysteretic behavior, energy dissipation capacities, temperature change, and stable behavior. It was concluded that the most influential parameters on the LED behavior were the bulge-to-shaft diameter ratio and the prestressing level on the lead. In addition to its effects on improving the hysteretic behavior, having a smooth shaft-to-bulge transition zone geometry was essential to guarantee a stable damper behavior.

Reliability evaluation of reinforced concrete arch bridges during construction based on LGSSA‐SVR hybrid algorithm

AbstractDuring the cantilever casting process of reinforced concrete arch bridges with cantilever cast‐in‐situ method, it is difficult to select representative training samples for reliability analysis due to its complex structural system. Many random variables and large computational sample size, this paper proposes to solve the reliability indexes based on the combination of the improved sparrow search algorithm (LGSSA) and the support vector regression (SVR) method. Firstly, random variables are selected according to the actual situation of the bridge structure. Then representative training samples are designed to be substituted into the finite element model through the homogeneous method. The resultant data samples are used to fit the functional function by the support vector regression. Then combined with the penalized function method to transform the nonlinear optimization into the problem of solving the extreme value of the function. Based on the improved SSA to solve the extreme value of the final function. Finally the reliability index of the structure is obtained. With the background of reinforced concrete arch bridge of 200 m, the method is used to analyze the reliability of its buckling cable stress, arch stress, buckling tower deviation and structural system reliability during the cantilever casting process. The results show that the overall structural reliability of the arch ring during cantilever casting is 3.502–3.608. The indexes of buckling cable stress reliability are 3.806–6.784. The indexes of arch ring stress reliability are 4.379–7.562, and the indexes of buckling tower deflection reliability are 3.608–8.123.

Distributed observer for fault estimation in Load-Frequency Control of multi-area power systems with communication delays

This paper proposes an innovative approach to designing a distributed observer for fault and state estimations in Load Frequency Control (LFC) of time-delayed multi-area interconnected power systems. To reach this goal, the paper first provides exhaustive information and analysis on the structure, disturbances, and faults in multi-area power systems. Then, an L1 observer with the capability to simultaneously estimate the system’s states, process/actuator faults, and sensor faults is proposed. This observer exhibits robustness against various types of disturbances as well as time delays present within both the system and the communication network. The sufficient conditions for designing the proposed observer, guaranteeing the system stability, and minimizing the L1 performance index, are expressed as optimization problems employing Linear Matrix Inequality (LMI) techniques. Additionally, the effectiveness and credibility of the proposed distributed observer in estimating all states and faults in all areas are validated through simulation results.

Data-driven prediction of strain fields in auxetic structures and non-contact validation with mechanoluminescence for structural health monitoring

Recent advancements in 3D printing technology have significantly enhanced the potential of auxetic structures, which are notable for their negative Poisson&amp;rsquo;s ratio, particularly in applications such as sensor technology and structural health monitoring. Central to the performance of these structures is the accurate estimation of the effective strain parameter, a critical metric for assessing structural integrity. However, as structural complexity increases, estimating this parameter becomes increasingly challenging. The fabrication and real-world validation of these structures are equally important challenges. This paper introduces two key innovations for the practical application of auxetic structures. First, we present a multi-kernel hierarchical deep neural network that leverages finite element simulation data to accurately predict effective strain fields in complex auxetic configurations. This model architecture not only reduces the number of parameters requiring training but also enhances feature learning and generalization capabilities, achieving over 90% accuracy in predicting strain fields. Second, we validate these predictions using a 3D-printed specimen embedded with mechanoluminescent (ML) particles. This approach enables direct, non-contact visualization of strain in real-time, offering high spatial and temporal resolution. The alignment observed between predicted and observed strain concentration areas demonstrates the efficacy of integrating ML technology into auxetic designs. This integration significantly improves the reliability and diagnostic capabilities of advanced structural systems.

Frame buildings are not an answer for earthquakes: The case of the February 2023 earthquakes in Türkiye

The February 2023 earthquakes in Türkiye caused widespread devastation and fatalities, highlighting the critical contrast in the seismic performance of reinforced concrete (RC) buildings with moment-resistant frames and those with structural walls. This study employs analyses of nonlinear single-degree-of-freedom (SDOF) systems using selected accelerograms from the earthquakes to evaluate the behavior of these structural systems. Three SDOF systems representing flexible and stiffer frame buildings, alongside RC wall buildings, were examined. The results highlighted the susceptibility of frame buildings to severe damage and collapse compared with the excellent performance of RC wall buildings. Moreover, the study emphasizes a shift of design focus from life safety to functional recovery. It also identifies potential scenarios regarding consecutive earthquake effects. Overall, the findings advocate adequately designed RC wall buildings for enhanced seismic performance and immediate occupation following major earthquakes.

Evaluation and optimization of urban hydrological connectivity based on graph theory: A case study in Chengdu, China

The standardization of river system structures has reduced hydrological connectivity, exerting significant pressure on both river ecology and urban development. The precise diagnosis and proposal of optimization strategies remain key challenges. This study utilizes graph theory to delineate the river network topology in Chengdu city and establishes an evaluation index system (α, β, and γ) for hydrological connectivity. Spatiotemporal changes in Chengdu's hydrological connectivity from 2000 to 2020 are analyzed, alongside a validated optimization scheme focusing on “pressure dispersion” among river network nodes. The findings reveal a simplification of Chengdu's river network structure over the past two decades, marked by a reduction of 72 nodes and 81 river segments. Particularly in the city center (region II), these changes have significantly diminished overall connectivity. Following the implementation of the “pressure dispersion” optimization method, the distribution of critical nodes in Region II has been more equitably, enhancing resilience against disasters like floods by diversifying the burden on key nodes. Furthermore, the hydrological connectivity indices in Region II showed improvements post-optimization, with the α, β, and γ indices rising by 75%, 7.26%, and 7.26%, respectively, thereby validating the efficacy of the approach. Analyzing variations in hydrological connectivity parameters across river systems identifies vulnerable links and fundamental issues, laying groundwork for future improvements. The proposed optimization methodology offers insights applicable to cities worldwide grappling with similar connectivity challenges.

Enhancement of mechanical characteristics and novel damage assessment for timber post and beam structures with K-braces

Glued-laminated Timber Post and Beam Structural System (GTPBSS) gains widely application in timber engineering because of direct force transmission and simple construction. The present work investigates the influence of introducing K-bracing on the lateral performance of the GTPBSS. To this end, four full-scale GTPBSS specimens with and without braces under horizontal loading conditions were carried out. The obtained test results highlight that the GTPBSS without braces exhibited large deformation. The failure modes predominantly centered on the occurrence of wood cracking at both the column-base joint and beam-column joint. In contrast, the GTPBSS specimens equipped with K-bracing elements exhibited failure modes marked by the instability of the brace components. The inclusion of brace system within the GTPBSS structures yielded positive results, effectively reducing lateral deformations while concurrently augmenting both the elastic stiffness and the later maximum load-carrying capacity. However, it is essential to exercise caution with regard to potential out-of-plane instability. A dual-parameter damage assessment model was developed to evaluate structural damage, incorporating factors related to energy dissipation and deformation. The evaluation results derived from this model were consistent with the test results, affirming the rationality and validity of the proposed approach. This model is expected to provide a scientific foundation for formulating strategies for repair and maintenance.

System Design of Ocean Temperature Measurement System Using Brillouin Lidar Based on Dual Iodine Cells

Ocean temperature profile information plays a key role in understanding the marine environment. The passive remote-sensing technique can provide sea surface temperature measurements over large areas. However, it is sensitive to the atmospheric environment and cannot provide seawater temperature profile information. The lidar technique is the only way to carry out seawater temperature profile measurements over large areas. However, it is insufficient for measuring speed, the receiving field, stability, spectral integrity, simple system structures, and so on. Therefore, we propose a Brillouin lidar method combining two iodine cells at different temperatures to realize temperature measurements, where one iodine cell is used as a filter to absorb the elastic scattering and the other as an edge detection discriminator to obtain the seawater temperature measurement. The system has a fast measurement speed, a large receiving field, a simple system structure, and high stability. The system feasibility was verified via principle simulation and real iodine absorption curve measurements. For an ocean temperature of [5 °C, 15 °C], a laser wavelength of 532.10495 nm was more appropriate, corresponding to the iodine pool temperature combinations of 50 °C and 78 °C. For an ocean temperature of [15 °C, 32 °C], a laser wavelength of 532.10518 nm was more appropriate, corresponding to the iodine cell temperature combinations of 60 °C and 78 °C. When the laser intensity reached a measurement precision of 1‰, the temperature could be predicted with an accuracy of up to 0.2 K. This work shows promise as a potential solution for seawater temperature profile measurement.

Functional ventilation building envelope integrated photovoltaic modules and phrase change material in subtropical climate: An in-depth numerical investigation

Most of existing solar ventilation envelope systems adopt a single structure including a glass cover a massive wall, which possesses the drawbacks of low thermal efficiency and poor stability. In recent decades, auxiliary power generation devices, led by photovoltaic (PV), have made epochal achievements in integrated building applications, while the superior thermal regulation capability of thermal storage materials, represented by phrase change materials (PCM), has further helped to improve the thermal environment of buildings, and the above two technologies have demonstrated great energy conservation potential. In order to explore the application and synergistic effect of the above two energy-conservation technologies in passive ventilation envelopes, a novel functional ventilation building envelope (FVBE) integrated with PV panel and PCM is proposed in this paper. A comprehensive exploration of the influence of various key parameters on the thermal performance of the FVBE-PV/PCM system. The electrical and thermal performance of the system is explored based on different seasonal climates. Specifically, effects of thickness as well as the melting temperature of PCM and the air channel width has been provided in this study. Taking the inner wall surface temperature (Tinner_wall), equivalent indoor load (Qload) and electrical efficiency (ηe) as evaluation indexes, the thermal efficiency, electrical performance and the coupling mechanism was assessed. Specifically, the coupling mechanism between the thermal performance and electrical performance of the FVBE-PV/PCM system was analyzed from the perspective of combined heat and power, revealing the functional characteristics of the system. Meanwhile, the article conducted a comparative study on the thermal and electrical performance of a typical building integrated PV (BIPV), FVBE-PV system FVBE-PV/PCM system. In particular, energy and exergy analysis is carried out to characterize the energy utilization of the FVBE-PV/PCM system in different structural systems. The research found that increasing the thickness of both the PCM and air channel leads to lower indoor temperature and heat flux, with different optimal phase transition temperatures for summer and winter. Although the FVBE-PV system exhibited a maximum 3.12 % reduction in power generation efficiency compared to the BIPV system due to increased PV temperature caused by air layer insulation, incorporating PCM can reduce exergy losses by an average of 31.731 % to mitigate this drawback and improve energy efficiency. Additionally, the analysis revealed varying coupling correlations between thermal performance and power generation based on two key parameters. This study could contribute to the functional improvement of the building envelope and simultaneous indoor thermal regulation.

Vegetation structure and bird diversity in silvopastoral systems of the Amazonian piedmont of Colombia

Vegetation structure and bird diversity in silvopastoral systems of the Amazonian piedmont of Colombia

Introducing a comprehensive methodology for optimizing the mass of realistic roofing structural systems using cold-formed steel profiles

This study aims to introduce a comprehensive methodology for optimizing complete real structural systems for roofs involving trusses, purlins, and bracing systems jointly, taking into account realistic loads and constraints dictated by technical codes, thereby offering a more accurate representation of practical scenarios. The objective is to achieve the minimum mass through size, shape, and topology optimization of both the main truss and purlin structural subsystems. To achieve this goal, the Enhanced Particle Swarm Optimization (EPSO) algorithm is implemented. An example of a realistic case, which takes into account multiple actual constraints such as stress, displacement, buckling, and natural frequency limits, is thoroughly evaluated. After that, 144 other interactions among dimensions of the building and loads applied are simulated, and the mass of the system is obtained for each one of them. The results indicated that the graphs generated from the various simulations allow for the determination of the optimized mass for different building dimensions. Consequently, the cost and raw material consumption can be estimated for common applications. Therefore, it is concluded that this work presents a significant contribution to structural designers, as the proposed methodology enables structural optimization quickly and easily for practical engineers.

Innovative hierarchical fatigue analysis of critical riveted railway bridges: A case study

Existing railway bridges are fundamental assets to expand the capacity of the railway network towards an eco-friendly transport for people and goods. As one of the main sources of structural degradation, fatigue represents a major concern for infrastructure managers, requiring the development of assessment methods that allow for reduced conservatism and increased reliability. Despite the multiscale problem, the implementation of local fatigue methods to large structures can be achieved efficiently when framed within a multiphase global-local assessment. This paper presents an innovative approach for hierarchical modelling based on a three-scale concept applied to riveted connections, which are significant in aging bridges. A structural system that presented failure during operation is investigated, allowing to confront the numerical results against observable damage, which provides a rare opportunity to parametrically understand the roots of fatigue. Numerical models properly validated by experimental results allowed computing fatigue lives that align with real damage, demonstrating the accuracy of the assessment process. Multiscale modelling tools are provided in an engineering framework to extend the fatigue life of existing riveted railway bridges.