Structural System Research Articles

Experimental investigation on retrofitting effects of circular steel rod damper systems on non-seismic detailed reinforced concrete frames

Existing non-seismically detailed low-rise reinforced concrete (RC) buildings are vulnerable to seismic attacks due to their insufficient seismic details including the spacing of transverse reinforcements and splice length at column critical regions. In order to mitigate those deficiencies, various retrofit strategies using externally-bonded reinforcing materials and adding external braced frames have been suggested, and adopted on the construction fields. Although various retrofit methods have been verified their retrofitting effects, there have been architectural concerns and difficulties in providing appropriate connections between supplemental structural systems and existing RC frames. One of the methods applying supplemental energy dissipating devices, this study introduces an externally retrofit method using circular steel rod dampers (CSRDs) which are installed between the existing RC frame and the external sub-frame. The existing RC frame have relatively long natural period and large displacement demand while the external sub-frame has short natural period and small displacement demand. Such relative displacement between two frames is a main mechanism acting the CSRDs. When the interaction of two frames occurs in the CSRD due to the seismic load, the load-transfer mechanism ensures stable hysteretic behaviors of the CSRD even during extreme earthquakes. To verify retrofitting effects of CSRD systems on non-seismically detailed RC frames, this study carried out component-level tests of CSRD systems and their hysteretic characteristics are investigated, especially in terms of their fatigue resistance. Then, full-scale cyclic tests are carried out with non-seismic detailed RC frames with and without CSRD systems in order to confirm the effectiveness of the introduced external retrofit method.

Stress in Chinese teachers who teach the mathematically gifted: a qualitative perspective.

Those who teach mathematically gifted high school students play a key role in both their identification and cultivation. Teachers who teach the Mathematical Olympiad in China work long hours and teach difficult content; they are under a significant amount of work-based pressure, and that is worthy of further study. This study analyzed the sources of stress for 33 Chinese teachers who teach the Mathematical Olympiad, collected data through semi-structured in-depth interviews, and adopted a subject analysis method based on Bronfenbrenner's ecological system that considers the influences that the complexity of socio-cultural and environment have on individual emotions. It is divided into five structural or environmental systems in which human beings develop, namely the macroscopic, external, meso, micro, and chrono systems. The research results show that the greatest influences on these teachers' stress come from the mesosystem and microsystem levels, and that the key players are students and school leaders. Educational policy and culture are found to be key factors from the macrosystem. Overall, long-term stress was seen to affect both teachers' moods and their physical health. Finally, the results offered implications for education policy and school management and suggestions for the cultivation and management of mathematics teachers who teach the gifted. Limitations of the study are discussed, and directions for future research are proposed.

Resilience of the governance systems of two MSC certified fisheries in northwestern Mexico

Incentive-based management is an encouraging option in the quest for sustainability, and the Marine Stewardship Council (MSC) is the most prestigious certification standard. It implies sustainability and resilience, but the latter has yet to be explored. Accordingly, we selected two MSC-certified fisheries, the small-scale red lobster fishery (RL) in Baja California (BC) and the small pelagic industrial fishery in Sonora (SP), to prove whether the certification success is reflected in a resilient governance network structure. To do so, we identify structural patterns that drive the resilience of the governance network in two MSC-certified fisheries. Data obtained through stakeholder interviews on different types of stakeholder relationships were used to construct weighted communication matrices to model governance networks. We assessed the individual role of each actor using centrality indices. We also analyzed how stakeholders are integrated into cohesive subgroups of the network. To evaluate resilience, we compared changes in the structure of governance networks by analyzing how network properties change each time the loss of an actor and/or its functionality is simulated. In both fisheries, most of the stakeholders belonged to the productive sector, actors involved in capture, processing, commercialization, and industrialization in the case of SP. For all centrality indices, the most relevant actors were similar or the same in both fisheries and belonged mainly to the regulatory and productive sectors. Cohesive subgroup analysis revealed that both networks are highly connected and collaborative systems. The simulations showed that in both fisheries, the decrease in the number of stakeholders did not cause abrupt changes in the structure of the governance systems. This approach reveals that, even in worst-case scenarios, the tolerance of governance systems to this severe loss of stakeholder diversity is high and suggests that following sustainable certification standards can lead to the promotion of effective and resilient governance networks.

Use of BIM with Modular Construction in Future Construction Techniques

Modular construction technology and applications are rapidly evolving. Modular construction is a process in which entire rooms or sections of rooms are built in a factory setting along with electrical, mechanical, and plumbing work and then transported to a final site for assembly. With modular construction, a building is built off-site, under controlled facility conditions, with the same materials and to the same codes and standards as conventionally built facilities, but in half the time. The modular construction method is used to build various types of buildings (whether they are apartment houses, office buildings, or hotels). This construction method is used for both permanent and relocatable projects. These projects can be built with two types of modules. These are 2D panels or 3D modules. These can be combined to form a third type, hybrid modular construction. Each has its advantages. 2D panels offer easy logistics and flexibility in building design and are mounted on site. Factory productivity is increased by using 3D volumetric solutions. They only need to be installed once they are delivered. The hybrid modular structure has the advantages of the previous two. With the recent development of Building Information Modeling (BIM), the use of modular construction methods in conjunction with BIM becomes more common. As with any method, this one has advantages as well as disadvantages. Disadvantages of this method, such as a higher number of complex decisions, front-loaded design, etc., can be solved with BIM. Furthermore, the BIM platform can resolve the disadvantages of traditional construction methods, such as the difficulty of pre-project planning and coordination among members of interdisciplinary professions. With BIM and the modular construction method, physical conflicts between the structural system and its mechanical, electrical, and plumbing systems can be easily identified early in the design process, and resolution can be expedited. This article includes general information about the modular construction method, future application scenarios, use, and advantages of BIM. The document analysis method, one of the qualitative methods, was used, and in the light of the data obtained, comments and scenarios were tried to be created about the future of BIM and modular construction techniques. What distinguishes this study is that the concept of quality is examined in detail by using these two methods together.

Predicting the compressive strength of advanced concrete structures by developed African vulture optimization algorithm-Elman neural networks

ABSTRACT: Concrete plate structures’ compressive strength and natural frequency are connected by the mechanical characteristics of the material and structural dynamics. Concrete’s elastic modulus rises along with its compressive strength, making the structure stiffer. Since the natural frequency is proportional to the square root of the stiffness over the mass, the increased stiffness raises the natural frequency. In this work, the relationship between natural frequency and compressive strength in advanced concrete constructions reinforced with graphene oxide particles is examined. Also, the structure is under applied pressure. By using a trigonometric shear deformation plate theory, we hope to improve compressive strength prediction accuracy. Navier’s technique is used as the analytical solution process in the analysis. This study contributes to the design and assessment of more durable and effective structural systems by offering a reliable framework for estimating the compressive strength of reinforced concrete structures. This paper presents a novel method by combining Elman Neural Networks (ENNs) with the developed African Vulture Optimization Algorithm (DAVOA) to estimate the frequency of the structure. With the help of this integration, researchers and engineers can now more precisely estimate the compressive strength of sophisticated concrete structures, leading to the creation of stronger and more robust structural solutions.

Matrix Approach for Modeling the Interrelationships of Business Processes and Organizational Structure of an Educational Institution

The complex model describing and taking into account the interrelationships between business processes, organizational structure and information systems of a secondary special education institution is considered. To represent the model the matrix approach with the use of matrix theory tools is used. Weight coefficients of interrelation of model elements are described using the method of expert evaluation and taking into account the zone of responsibility of employees in the performance of certain business processes. The model construction is based on the description of the operational business process “Training of specialists at the level of secondary specialized education”, including subprocesses of theoretical and practical training. The obtained model, consisting of three matrices, allows for accounting and analysis of organizational elements of the educational institution structure for errors, assessment of completeness and cohesion of interaction between structures in order to their further optimization and automation.

SCOPE AND NATURE OF CHANGES IN THE CRISIS MANAGEMENT SYSTEM IN THE CIRCUMSTANCES OF CLIMATE CHANGE ON THE EXAMPLE OF THE POMERANIAN VOIVODESHIP

With the increasing impacts of climate change, especially in the context of rising temperatures,frequency and severity of extreme events, research into the preparedness of emergencymanagement systems is becoming a priority for governments and the international community.The purpose of the research was to identify the current state of the emergency managementsystem in the context of climate change and to assess its preparedness to operate under threatsgenerated by those changes, and to formulate proposals for improvement. The conducted researchwas based on an analysis of strategic documents, legal acts and an assessment of climate changeadaptation plans. An analysis of the preparedness of civil protection system structures for actionunder conditions of climate change at the local, regional and national levels was also carried out.The results of the research showed that the emergency management system of the PomeranianVoivodeship is insufficiently prepared for effective action under existing climate change risks.The discussion of the research results clearly indicates the need for systemic measures, coveringlegislative, organizational, educational and economic areas. Further research should focus ondeveloping tools for assessing the preparedness of civil protection system structures for actionunder conditions of climate change, and on developing more comprehensive adaptation plansat a local level. In addition, it is important to continue research on improving the warning andalert system, as well as increasing public awareness of climate risks. This research is a step towardeffectively preparing the emergency management system for operations under a changing climate,thus providing a more secure environment for local communities.

Localized structures in optical media and Bose-Einstein condensates: an overview of recent theoretical and experimental results

A survey of recent theoretical and experimental studies on localized structures that form and propagate in a broad class of optical and matter-wave media is presented. The article is structured as a resource paper that overviews a large series of theoretical and experimental results obtained in diverse research areas: linear and nonlinear optical waveforms, nonlinear surface waves, ultrashort few-cycle optical pulses, localized structures in fractional systems, rogue (freak) waves, and matter-wave localized states.

Probabilistic inference of material quantities and embodied carbon in building structures

In an effort to minimise the carbon footprint of building structures, a range of prediction tools and methods have been recently proposed, so to enable design practitioners evaluating how their design choices ultimately affect the carbon embodied in their designs. Such tools are most often targeted for use at the early stage of the design process, that is when exploration of alternative design options is usually undertaken, hence room for potential carbon reductions is greatest and at no extra cost of redesign. The overarching methodology behind existing tools predominantly relies on idealised models to characterise the structural system, usually employing closed-form design equations and/or numerical Finite Element to generate an inventory of material quantity data (that is ultimately required for embodied carbon estimates). Despite the very high level of complexity achieved by some models, the absence of any empirical reference with ‘as-built’ inventory data of material quantities leaves room for doubt on how accurate such models really are in capturing the complexities and inherent variability of the population of real building structures such models aim to represent. To bypass this limitation, a data-driven probabilistic graphical model is proposed here as alternative to existing approaches. A Bayesian Network was developed and tested as a proof of concept, trained on a dataset of 133 data-points of real building structures, leveraging on six design variables (at most) to fully characterise the entire design space of early design options. Despite the very small set of ‘explanatory’ design variables, the model exhibited a 73% accuracy (mean average absolute prediction error of 27%) when predicting the embodied carbon on a test sample of unseen real building structures. The study ultimately demonstrates the viability of adopting a probabilistic (data-driven) approach for such an inference task as an inherently robust alternative to data-blind models currently proposed in literature.

Evaluating the Influence of Ecological Diversity on Glomalin Production and Its Implications for Multifunctionality in Ecosystem Services

This review examines the role of Glomalin, a glycoprotein produced by arbuscular mycorrhizal fungi, in soil ecosystems. It covers methods for extracting Glomalin, its molecular characterization, and its function in soil health, including nutrient cycling, heavy metal sequestration, and organic contaminant degradation. The review emphasizes the importance of ecological diversity, highlighting how plant diversity, mycorrhizal associations, and root exudates influence Glomalin production and microbial community structure. These factors contribute to Glomalin's key role in soil stability, carbon sequestration, and overall ecosystem health. The study also explores Glomalin's implications in various systems such as forestry, agroforestry, and agriculture. Glomalin contributes to soil structure, nutrient cycling, and carbon storage in forestry systems, with tree species diversity affecting its accumulation. Agroforestry practices enhance Glomalin levels, promoting soil health and carbon sequestration. In agricultural systems, farming practices like monoculture vs. polyculture and crop rotation strategies impact Glomalin production, influencing soil fertility and health. Despite the progress, the review identifies methodological challenges in Glomalin research and suggests future directions, including the need for standardized protocols, interdisciplinary collaboration, and integration of emerging technologies. Understanding Glomalin's role in ecosystem services and managing its production can lead to sustainable soil management and environmental conservation.

A general approach to assessing SHM reliability considering sensor failures based on information theory

Structural health monitoring systems (SHM) involve implementing damage identification strategies to determine the health state of structures. However, it is important to pay close attention to the system degradation, especially the effect of sensor degradation on the SHM system reliability. This paper aims to formulate a general framework for evaluating SHM reliability that takes sensor failures into account. The framework involves modelling sensor network degradation processes using Petri nets (PNs) and calculating the expected information gain of the sensor network. The PNs allow for identifying the location and number of sensor failures. Kullback–Leibler (KL) divergence with Bayesian inversion is used to calculate the expected information loss due to sensor failure. Two case studies are used to illustrate the methodology: (i) a damage localization scheme using an ellipse-based time-of-flight (ToF) model and (ii) a damage identification scheme using a guided waves damage interaction model. The proposed framework is demonstrated by both numerical and physical experimental case studies. Whereas the case studies are specific to an ultrasonic guided wave monitoring system, the proposed approach is generic. The proposed model is able to predict the health condition state and utility of SHM, which can potentially help in constructing asset management models in various industries.

Age-related differences in resting-state, task-related, and structural brain connectivity: graph theoretical analyses and visual search performance.

Previous magnetic resonance imaging (MRI) research suggests that aging is associated with a decrease in the functional interconnections within and between groups of locally organized brain regions (modules). Further, this age-related decrease in the segregation of modules appears to be more pronounced for a task, relative to a resting state, reflecting the integration of functional modules and attentional allocation necessary to support task performance. Here, using graph-theoretical analyses, we investigated age-related differences in a whole-brain measure of module connectivity, system segregation, for 68 healthy, community-dwelling individuals 18-78years of age. We obtained resting-state, task-related (visual search), and structural (diffusion-weighted) MRI data. Using a parcellation of modules derived from the participants' resting-state functional MRI data, we demonstrated that the decrease in system segregation from rest to task (i.e., reconfiguration) increased with age, suggesting an age-related increase in the integration of modules required by the attentional demands of visual search. Structural system segregation increased with age, reflecting weaker connectivity both within and between modules. Functional and structural system segregation had qualitatively different influences on age-related decline in visual search performance. Functional system segregation (and reconfiguration) influenced age-related decline in the rate of visual evidence accumulation (drift rate), whereas structural system segregation contributed to age-related slowing of encoding and response processes (nondecision time). The age-related differences in the functional system segregation measures, however, were relatively independent of those associated with structural connectivity.

Asymmetric Metal-Carboxylate Complexes for Synthesis of InGaP Alloyed Quantum Dots with Blue Emission.

Indium phosphide (InP) quantum dots (QDs) have attracted significant interest as next-generation light-emitting materials. However, the synthesis of blue-emitting InP-based QDs has lagged behind that of established green- and red-emitting InP QDs. Herein, we present a strategy to synthesize blue-emitting QDs by forming an InGaP alloy composition. The introduction of asymmetric In-carboxylate and Ga-carboxylate complexes resulted in a balanced synthetic reactivity between In-P and Ga-P, leading to the formation of InGaP alloyed QDs. The resultant In1-xGaxP alloyed QDs exhibited a broad range of photoluminescence (PL) tunability, spanning from 535 nm (InP) to 465 nm (In0.62Ga0.38P), depending on the In/Ga ratio used in the synthesis. In contrast, synthesis with symmetric In-carboxylate and Ga-carboxylate complexes produced a core/shell structure of InP/GaP QDs, which did not exhibit a blue shift of the PL peak with Ga addition. By employing a core/shell structure of In0.62Ga0.38P/ZnS QDs, we achieved a PL quantum yield of 42% at 475 nm. This work highlights the material-processing strategy essential for forming alloyed structures in III-V ternary systems.

Diagnostics of premature damage to surface-hardened industrial concrete floors

The article presents the diagnostic results on surface-hardened industrial concrete floors. Selected examples of floors showcased premature damage to surface layers, characterized by intense dusting, delamination, and local spalling, while the structural system remained unaffected. Quantitative petrographic analysis of concrete was applied to core specimens from the floors, involving the examination of digital images from a polarizing optical microscope and a scanning electron microscope. The hardening compound and powdered specimens of the cement matrix were characterized using differential thermal analysis and X-ray diffraction. A multiple microindentation method was employed to assess local variations in mechanical properties. Concrete cross-section analysis revealed areas with a non-uniform distribution of air voids, identified regions exhibiting increased porosity, highlighted areas of cracking in the concrete, indicated local variability in the phase composition of cement hydration products, and pointed out the presence of carbonated areas. The causes of the damage were discussed based on these findings,. The crucial role of quantitative petrographic analysis in diagnosing premature surface damage to industrial floors was demonstrated.

Architectural techniques for protecting industrial buildings

The article will discuss the architectural features of industrial buildings that are resistant to potential terrorist and other attacks. The most typical threats will be considered (external attacks, threat of explosion from outside and inside) and the corresponding protection goals (protection of the site perimeter, control of entry points, use of sustainable structural systems, safe finishing elements, use of protective structures at the landscape level). A brief historical excursion will show what fortification techniques may be relevant in our time. Modern analogues of industrial buildings are studied, new innovative protection measures are analyzed. As conclusions, architectural means that must be taken into account in the layout of industrial buildings and the master plan of industrial zones in general will be described to create a safe environment that is protected from possible attacks.

State Control Design of Ostensible Metzler Linear Systems with Unsigned Input Parameters

This paper deals with the design of a complete state control for input unsigned, rank deficient matrix parameters of a linear system with system dynamics defined by ostensible structures of Metzler matrices. The proposed solution is based on the principle of diagonal stabilization of positive systems and uses a stabilizing additional component over the decomposition of the Metzler matrix in solving the incomplete internal positivity of such linear system structures. The novelty of the proposed approach is the unified representation of the parametric constraints of the Metzler matrix and the structurally constrained system inputs using linear matrix inequalities, which guarantees that the closed-loop system will be asymptotically stable. Despite the complexity of the constraint conditions on this class of linear continuous systems, the design conditions are formulated using sharp linear matrix inequalities only. A detailed design process is presented using a system-linearized mathematical model to verify the superiority and practicality of the proposed method.

An investigation on the craft of Tianche: traditional timber salt well structures of the Sichuan Basin, China

This study investigates the craft of Tianche, an ancient towering timber structure used in well salt production in Sichuan Province, China. Originating in the Han Dynasty and maturing in the late Qing Dynasty, Tianches can reach heights of up to 110 m and represent a unique craft and structural system that is rare worldwide, yet remains largely unexplored in scholarly research. The Tianches are under threat due to a lack of maintenance and extinction of the craft. This study aims to document and elucidate the procedure and principles of the Tianche craft to help conserve this heritage. The key question is how to employ traditional craft to assemble over 100-m-tall structures from small-sized logs using pre-industrial technology. The study combines anthropological fieldwork and principles of mechanics to analyze the scientific validity and rationality of traditional crafts. The study reveals the principles of the Tianche craft, including mature craft procedure and reliable binding joints. Its advantages, namely self-locking structure, frictional force transmission, and hollow cylindrical columns, enhance the structure’s strength and stability and are fundamental for constructing 100-m-tall timber structures. Additionally, the study identifies two limitations of the craft: restricted column diameters and the tendency of the inverted dragon member’s tenon to break. This study investigated Tianche timber structures featuring hollow, bundle-like columns with frictional force transmission mechanism, presenting new possibilities beyond mainstream timber structural systems. The findings may contribute to enhancing research on the Tianche craft and could lay the foundation for future conservation practices related to Tianche heritage.

Implementation of an Automated Code Checking Algorithm Based on Site Analysis

To date, BIM has been primarily utilized in cost and schedule management, an interference check between architectural and structural models and systems based on geometric data in the process of the construction life cycle. However, there is a lack of research that utilizes the information contained in the BIM model to review whether the proposed architectural model is appropriately designed in accordance with each country’s building regulations or building codes or that proposes a model optimized for laws and standards. ‘Building code checking’ is the step of reviewing whether a building designed based on the building codes is suitable for being constructed as a building. However, this process consumes significant time and money and leads to human errors due to the manual review process. This study included implementation of an algorithm based on the Korean building code. In this study, there was the process of selection of codes when architects interpret building codes in common and implementation based on the codes selected. Next, modeling based on DXF files from NGII (National Geographic Information Institute) was applied to the algorithm developed in this study. Last, it includes case studies that compare the outputs of the algorithm with the real buildings, which had received real code checking, to make sure the algorithm in this paper is working properly. The implementation of such an automated system has the potential to significantly improve the efficiency and effectiveness of the building design and construction process. It can help architects to quickly and accurately identify potential legal issues and provide alternative solutions that meet regulatory requirements. This, in turn, can lead to reduced project costs, improved quality of designs, and faster project delivery times.

SELECTION OF OPTIMAL PARAMETERS OF A LIGHTWEIGHT FLAT FLOOR WITH VOIDS MADE OF PLASTIC BALLS

Formulation of the problem. Architectural and construction design of buildings using reinforced concrete has led to an increase in the number of objects with an individual space-planning structure, a rich variety of facade and volumetric solutions. Today the question of the effectiveness of using flat prefabricated monolithic lightweight floors in the construction of multi-storey buildings with individual space-planning and architectural solutions is relevant. In a market economy interest in the issue of rational use of resources, namely the cost of concrete and reinforcement in construction, has sharply increased, which is directly related to attracting investment. As it is known, when designing buildings from prefabricated monolithic reinforced concrete, in contrast to prefabricated concrete, there is greater freedom in adopting the space-planning parameters of the building, and there may also be simpler design solutions, in particular for floors. The constructive solution of floors depends on numerous requirements for the building as a whole and directly for the floor. One of the requirements that influences the attraction of investments is a small material-intensive floor covering with significant spans of buildings of various structural systems. The effective use of lightweight precast monolithic reinforced concrete floors with voids made of plastic balls in construction requires a comprehensive technical and economic analysis of this innovative solution for the precast monolithic reinforced concrete floor structure. The purpose of the article is to perform a technical and economic comparison of various design options for a flat lightweight prefabricated monolithic floor. The influence of floor parameters on the consumption of concrete and reinforcement is considered. Conclusion. As a result of the research, it was established that it is rational to use hollow balls made from recycled materials as a material for making voids from balls in flat floors. Moreover, all studied floor options with spans of 6 m, 7 m, 8 m and void sizes made of balls with diameters of 180 mm, 315 mm and 50 0mm meet the requirements of the first and second groups of limit states.

Superior Performance of Hollow Plasmonic Cubic Structures for Solar Energy Harvesting, Conversion, and Storage Systems

Superior Performance of Hollow Plasmonic Cubic Structures for Solar Energy Harvesting, Conversion, and Storage Systems