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An effective moment of inertia (y unified for reinforced concrete (RC) and reinforced steel fibrous concrete (RSFC) one-way slabs was presented. Two model parameters for the degree of tension stiffening and plasticization of concrete in compression (PZC), where the relationships of concrete stresses and strains deviate from its linear elastic stage, were calibrated using 26 test results of RC and RSFC slabs, including eight slabs tested in this study for three different reinforcement ratios (p) and fiber contents (Wf). Comparisons with test results revealed that underestimated deflections were predicted with the Ie currently adopted as basic formats in different codes, for RC slabs having relatively lower or higher p values and RSFC slabs with wide ranges of p typical to one-way slabs. However, regardless of the magnitudes of p and Wf, reasonable deflections were predicted with the unified Ie, which was constituted with linearized weightfunctions of the ratio of cracking moment to moment in service and modified to include the effects of p, PZC, and Wf. [ABSTRACT FROM AUTHOR]

The sustainable utility of industrial waste and by‐products is crucial to reduce environmental impact. Particularly relevant for the cement and concrete industry, where recycling and utilization of industrial waste can help to replace normal concrete and promote stable growth. One such waste material is aluminum computer numerical control waste (ALCNCW). This study investigated the performance of reinforced concrete beams incorporated with ALCNCW. It was decided to use the effects of the ALCNCW ratio and the proportion of longitudinal reinforcement as parameters. A total of 12 reinforced concrete beams were cast and tested with varying levels of lower reinforcement ratios (0.0125, 0.0074, and 0.0032) and ALCNCW ratios (1%, 2%, and 3% by weight), in addition to a control beam. The load‐carrying capacity, failure mode, crack patterns, ductility, and serviceability were analyzed. The findings of the experiments demonstrated that the cracking and bending effects of reinforced concrete beams were different depending on the quantity of tension reinforcement and ALCNCW that was used. The results indicate that adding 1% or 2% of ALCNCW to concrete beams has a negligible effect on the load capacity. However, the ductility of the beams was adversely affected. Nevertheless, adding ALCNCW to the concrete mix can still be implemented with a specific ratio. Finally, all 12 beams met the serviceability limit state requirements. [ABSTRACT FROM AUTHOR]

This manuscript proposes a probabilistic framework to quantitatively assess communities' resilience by simulating the state and serviceability of their infrastructure systems from the onset of a flood until the end of recovery. It comprises multiple interconnected models. Hazard model characterizes flood parameters (e.g., depth and velocity). Depth-damage curves estimate the damage to infrastructure systems' components. The HEC-FIA mortality model characterizes the flood-induced casualties. Serviceability models determine the ability of interdependent infrastructure systems to meet the demand during the recovery process. The recovery models estimate the recovery duration and cost of damaged components probabilistically. The Monte Carlo analysis is employed to consider multiple relevant uncertainties, generating distributions of the flood-induced losses under various scenarios. The ratio of total losses to the gross regional product characterizes the community's resilience. This framework facilitates the assessment of the impact of various resilience enhancement measures, guiding the selection of appropriate measures through a cost-benefit analysis. [ABSTRACT FROM AUTHOR]

The primary goal of in-situ load testing is to evaluate the safety and performance of a structural system under particular loading conditions. Advancements in building techniques, analytical tools, and monitoring instruments are prompting the evaluation of the appropriate loading value, loading process, and examination criteria. The procedure for testing reinforced concrete (RC) structures on-site, as outlined in the ACI Building Code, involves conducting a 24-h load test and applying specific evaluation criteria. This article detailed a retrofitting project for an RC slab-beams system by utilizing carbon fiber-reinforced polymer (CFRP) sheets to strengthen the structure following a fire incident. The RC structure showed indicators of deterioration, including deflections, concrete cracking, and concrete spalling in some zones. Whereas, a detailed presentation of the strengthening procedure as well as its evaluation, rationale for the loading procedure, instrumentation needs, assessment criteria, and outcomes of the field testing. The study concentrated on assessing the structure of the RC slab-beam system with widespread cracking in both the positive and negative moment areas. The finite element model was created and examined to help with the load test design, and it confirmed the field findings considerably. The proposed finite element (FE) model demonstrated a reduced estimation of net deflection value in comparison to the corresponding actual values. It maintained a highly acceptable mean value of 0.843 and a small deviation limit of 6.8%. [ABSTRACT FROM AUTHOR]

The Federal Aviation Administration (FAA) is developing new design procedures to extend airport pavement life beyond 20 years based on the concept of serviceability: the measure of how well a pavement fulfills user expectations. A key element is a new distress megaindex called serviceability level (SL) whose components represent independent aspects of airport pavement serviceability: low foreign object damage (FOD) potential, low skid potential, and smoothness. This research validates the assumption of independence previously used to develop a probability-based form for SL. Independence greatly simplifies the mathematics of the new form, in particular, the ability to decompose a pavement condition model into multiple relatively simple submodels. Friction is shown to not correlate to the other two components. FOD and roughness are conditionally independent with a latent variable of crack and spall density. Conditional independence means the proposed SL formulation is generally valid but requires that FOD and roughness measurements or predictions be made at the same time using the same assumptions. [ABSTRACT FROM AUTHOR]

The light weight and moderate stiffness of multistorey timber buildings make them susceptible to increased lateral displacements and accelerations under service-level wind loading. Therefore, the fulfilment of serviceability requirements is a major challenge. In this study, linear elastic finite element analysis was used to perform a parametric study of moment-resisting timber frames combined with cross laminated timber walls. In the parametric study, various mechanical and geometrical parameters were varied within practical ranges. The results of the parametric study were used to derive simplified analytical expressions and to train artificial neural networks which can be used to estimate fundamental frequency, mode shape, top floor displacement, maximum inter-storey drift, and wind-induced acceleration. The analytical expressions and the artificial neural networks can be used for the preliminary assessment of serviceability performance of moment-resisting timber frames with and without cross laminated timber walls, under service-level wind loading. [ABSTRACT FROM AUTHOR]

Timber–concrete hybrid structures are commonly employed in multi-story timber buildings; however, further research is necessary to fully understand the seismic performance of these structures as well as the dynamic properties of the floor. The two dynamic concerns, seismic effects and the vibration of floors in hybrid structures, are key issues, in view of which this study aimed to investigate the small-seismic-response spectra and elastic time histories in a high-rise timber hybrid building, specifically the medical technology building of Jiangsu Provincial Rehabilitation Hospital in China. The dynamic characteristics of a localized cross-laminated timber (CLT) floor were tested in situ, and the impacts of human-induced vibration were quantified. Comprehensive theoretical analysis results reveal that the basic vibration pattern of the structure was mainly translational in nature and that the period ratio, inter-story displacement angle, and shear-to-weight ratio all met the demands of the Chinese timber building design code. The experimental test results show that the vertical natural frequency of the CLT floor was about 15.96 Hz and thus met appropriate requirements with respect to natural frequency. However, peak floor acceleration was found to be high under the conditions of a single person walking quickly, a single person trotting, and multiple persons walking randomly. In light of these findings, the floor should be paved with a fine-grained concrete building surface, according to design requirements, so that its serviceability might be improved. Overall, the relevant analytical methods presented in this paper provide guidance and practical reference for the seismic analysis of timber hybrid structures, as well as vibration serviceability analysis for CLT floors. [ABSTRACT FROM AUTHOR]

Based on the strain reduction coefficient methodology, which enables an analysis of a beam with external or internal unbonded tendons as a beam with bonded tendons, and using the age-adjusted effective modulus method for time analyses of prestressed concrete members under long-term loads, this paper proposes an equation for the calculation of prestress loss in simply supported beams with internal unbonded tendons. The proposed equation takes into account the effects of concrete creep, concrete shrinkage, relaxation of the prestressing steel, and the presence of a bonded, non-prestressed reinforcement. The main goal of this study is to reduce a relatively complex problem, in which it is necessary to analyse the member as a whole, to one of sectional analysis. As our main conclusion, we find that the loss of prestress obtained by applying the proposed equation has an accuracy that is comparable with the results of previous studies and with the application of existing formulations. [ABSTRACT FROM AUTHOR]

Using ultra‐high‐performance fiber‐reinforced concrete (UHPFRC) in profiled slabs, as opposed to normal strength concrete without fibers, has been shown experimentally to significantly increase both the bond between the profiled sheet and the concrete, and the tensile forces across cracked concrete. The consequence of these fiber benefits is to substantially increase the flexural rigidity leading to reduced deflections and also to substantially reduced crack widths leading to improved behavior under serviceability loads and to improved durability. To quantify these benefits so that they can be used in design, a rational partial‐interaction numerical model has been developed that can incorporate the material properties of any type of UHPFRC including time‐effects. This modeling should help in the development of simplified design rules for specific fiber types. [ABSTRACT FROM AUTHOR]

The accurate representation of real floor behavior is crucial for assessing human-induced vibration serviceability. Many researchers focus on developing computational models and field testing to reflect actual serviceability conditions. Although traditional boundary conditions are commonly used, limited attention has been given to optimizing these conditions. To begin with, this paper introduced semirigid boundary conditions into a finite-element model of the floor and optimized physical parameters and boundary constraint stiffness using the simulated annealing-particle swarm optimization (SA-PSO) method, resulting in a more realistic computational model. Subsequently, a random crowd load model was established by combining the social force model (SFM) and the pedestrian load model, and a random crowd-floor mutual coupling calculation model was established based on the improved pedestrian biomechanical model. In addition, the mode shape functions of the floor with semirigid boundary conditions were obtained by extracting the optimized mode shape vector of the floor and using cubic spline interpolation. The dynamic response of the floor was computed using the modal analysis method, and the accuracy of the suggested method and model was verified by experiment. Furthermore, the effect on the vibration serviceability of the floor was analyzed under crowd walks randomly on the floor with different boundary conditions both before and after optimization. This study revealed: (1) achieving a computational model consistent with real floors requires optimization of relevant parameters and boundary conditions, reducing the error in floor frequency from 39.48% to 5.44% compared to measured results. (2) The human-induced vibration serviceability for existing floors may be misjudged by using traditional boundary conditions. The mean value of peak acceleration of floor with semirigid boundary conditions increased by 35.92%, with a 42% increase in the probability of serviceability problems compared to the SSCC boundary. (3) High-frequency floors also experience human-induced vibration serviceability issues. For a floor with a fundamental frequency of 10.3540 Hz, simulation and experimental results during five-person random walks indicate that peak acceleration at the middle position of the floor exceeds serviceability limits. [ABSTRACT FROM AUTHOR]

Copyright of Public Administration & Civil Service / Memlekettìk Basķaru Ža̋ne Memlekettìk Ķyzmet is the property of Academy of Public Administration under the President of the Republic of Kazakhstan / Akademiya Gosun and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In light of growing environmental concerns, the reduction of CO2 emissions is increasingly vital. Particularly in the construction industry, a major contributor to global carbon emissions, addressing this issue is critical for environmental sustainability and mitigating the accelerating impacts of climate change. This study proposes the Optimal Green Design Model for Mega Structures (OGDMM) to optimise CO2 emissions, cost-effectiveness, and serviceability in highrise buildings with mega structures. The OGDMM examines the impact of each material and structural design of main members on these three critical aspects. Analytical results for high-rise buildings (120-200 m, slenderness ratio: 2.0-8.0) demonstrate that OGDMM can reduce CO2 emissions and costs by an average of 4.67% and 3.97%, respectively, without compromising serviceability. To ensure comprehensive evaluation, this study introduces five new evaluation indicators encompassing environmental, economic, and serviceability performances of high-rise buildings. Based on these criteria, optimised structural designs for high-rise buildings are classified into four categories according to slenderness ratio, leading to the formulation of corresponding design guidelines. The model's applicability is further validated through its application to a 270-m-tall high-rise building in Korea, showing reductions in CO2 emissions and costs by 8.99% and 18.50%, respectively, while maintaining structural serviceability. [ABSTRACT FROM AUTHOR]

This study investigates the influence of laboratory facilities on maritime students' learning and extent of delivery of instruction at the Merchant Marine Academy of Caraga Inc. It emphasizes the need for improvements to align with industry requirements and prepare students for future challenges. The research examines the impact of specific facilities like the seamanship lab, bridge simulator, and chart room. The researchers used a quantitative approach to gather data from maritime students and instructors through surveys. The analysis focused on the serviceability of the labs in terms of equipment availability, maintenance, and safety standards. The justification for the research is further supported by the findings, which indicate that most facilities are in good working order, with serviceability ranging from 77% to 87%. Interestingly, the study highlights that instructor expertise is just as important as the facilities themselves. It emphasizes that instructor experience and teaching methods significantly impact student learning, suggesting a need for investment in instructor development alongside improvements to the laboratories. In conclusion, the abstract justifies the research by demonstrating that laboratory facilities are important for maritime student learning and that there is a need for improvement in order to prepare students for the challenges of the maritime industry. The abstract outlines a methodology to investigate this and presents preliminary findings that justify further research. [ABSTRACT FROM AUTHOR]

With continuous improvements in the social economy and living standards of individuals, the vibration comfort of building structures has gradually been emphasized by academic and engineering communities, such as vehicle-induced vibrations in buildings near traffic, human-induced vibrations in large-span structures, wind-induced vibrations in super-high-rise buildings, and machinery-induced structural vibrations. Comfort-based structural analysis is distinct from traditional safety-based structural analysis, and its theoretical systems and unified guidelines have not yet been established. This paper reviews recent research on structural vibration comfort, including major load categories and their impacts, comfort-based structural analysis, evaluation methods, and vibration-mitigation measures. By presenting the shortcomings of the existing research, potential topics for future study are suggested. [ABSTRACT FROM AUTHOR]

In northern regions, the long-term serviceability of infrastructure founded on frozen ground is adversely affected by climate warming. Rates of change in temperature, which are not identical spatially and temporally, can remarkably dictate the magnitude and evolution of permafrost degradation. Investigating such impacts requires a non-isothermal rate-dependent geomechanical constitutive model for ice-contained geomaterials. In this paper, a critical-state thermo-elasto-viscoplastic (TEVP) constitutive model is developed for modeling time- and temperature-dependent behavior of frozen soils using the concepts of thermo-elasticity and thermo-viscoplasticity. Solid phase stress (defined as the excess of total stress over fluid pressure), in addition to the cryogenic suction, are considered as the two independent stress state variables to establish the model. The proposed model is able to satisfactorily capture the rate-dependent behavior of frozen soils observed in the experimental tests reported in the literature. [ABSTRACT FROM AUTHOR]

Finding the minimum height of reinforced concrete (RC) slabs and beams at the early stages of design is critical for efficient material use. Hence, methods are needed for determining the maximum slenderness, L/h, that are both easy to use and able to consider as many influencing factors as possible, given that deflection typically controls the design of this kind of structure. One such method is the "long method of Rangan-Scanlon," with recent advances in new closed-form solutions enabling direct calculation. This study builds on those advances, presenting a parametric study for RC beams and one-way slabs to determine the effect of key factors (compressive strength of concrete, reinforcement cover, span, tributary width, load, and boundary conditions) on the effective moment of inertia factor α and slenderness L/h. The results provide practical design tools for determining the maximum slenderness of RC one-way slabs by previously finding the α factor and directly determining the maximum slenderness for RC beams. [ABSTRACT FROM AUTHOR]

This paper presents a rational approach for describing the cracking behavior of fully‐ and partially restrained fiber reinforced concrete members co‐reinforced with conventional reinforcement subjected to an axial force imparted by shrinkage. The proposed analytical model extends the approach developed by Gilbert for fully restrained reinforced concrete members to account for the post‐cracking strength offered by the fibers at each of the cracks as the concrete ages and dries. The effects of partial end‐restraint are also studied to gain a clearer understanding of the mechanism of direct tension cracking caused by restrained shrinkage and the factors affecting it. [ABSTRACT FROM AUTHOR]

The design of a floating wind turbine (FWT) should satisfy the serviceability limit state (SLS) requirement for an efficient and safe operation throughout the entire work life. The SLS requirements are introduced by the owner/developer of the wind turbine facility to achieve serviceability (production of power) or an efficient operation of the facility or a "first step" towards ensuring safety. Currently, there is limited information about SLS requirements in design standards. This study deals with an assessment of current methods, criteria, and procedure for the SLS design check with an emphasis on tilt/pitch and nacelle accelerations in view of power production and its fluctuations. Moreover, other criteria, on the borderline between serviceability and safety criteria, e.g., relating to clearance, are briefly discussed. The criteria relating to power production are illustrated in a case study with a 10-MW semi-submersible FWT considered for an offshore site in the Northern North Sea. Simplified static/dynamic analysis methods for use in the global design phase and high fidelity integrated, dynamic analysis methods for detailed design in terms of serviceability are presented, discussed, and applied in the case study. A good understanding of wind turbine dynamic performance associated with serviceability is essential to facilitate design decision-making. The relative contribution of wind and wave loads to the different SLS criteria is investigated. Finally, the main conclusions are summarized. In lieu of the current state of the art regarding SLS requirements for FWTs, we hope that this study provides a basis for improving design standards and guiding research and engineering practice for the semi-submersible floater design of FWTs. [ABSTRACT FROM AUTHOR]

The Peripheral Component Interconnect Express (PCI-Express or PCle) architecture has been the ubiquitous backbone interconnect in the evolving computing landscape for more than two decades. This paper delves into the multiple innovations driving the backward-compatible evolution of PCle for seven generations, doubling bandwidth every generation, while delivering power-efficient and cost-effective performance. Compute Express Link (CXL) overlays coherency and memory protocols on top of PCle for heterogeneous computing, addressing the memory wall, resource pooling and sharing across servers, and distributed computing using load-store based messaging. The die-todie industry-standard, Universal Chiplet Interconnect Express $^{TM}$ (UCle), offers orders of magnitude improvement in bandwidth density, power efficiency, and latency for PCle and CXL protocols on-package and pod-level connectivity with co-packaged optics. We foresee PCle will continue to evolve over the next few decades to serve future computing needs. It will do so by embracing alternate media while backward-compatible frequency scaling with copper will continue and protocol enhancements will enable non-tree fabric topologies. [ABSTRACT FROM AUTHOR]

This study investigates the gender equality barriers among maritime students in the Philippines, focusing on the influence of ethnicity and age on perceptions of these barriers. Utilizing a descriptive correlational method, the research involved 554 student respondents from the Merchant Marine Academy of Caraga, Inc. (MMACI). The study employed a questionnaire adapted from Fidan et al. (2020) to assess perceptions of structural and social barriers. The findings reveal significant gender disparities in the maritime education sector, with males dominating both BS Marine Engineering (BSMarE) and BS Marine Transportation (BSMT) programs. The study also highlights the interconnected nature of structural and social barriers, emphasizing the need for comprehensive interventions to promote inclusivity and equity. Additionally, the research identifies variations in perceptions of gender equality barriers based on ethnicity, particularly among BSMarE students. The study concludes by proposing an action plan to promote gender and development programs in the College of Maritime Education, emphasizing awareness, policy revisions, training, mentorship, and industry collaboration. [ABSTRACT FROM AUTHOR]

This study proposed a formwork-integrated hollow slab with an improved shape made of a hollow material. The performance of the proposed formwork-integrated hollow slab was evaluated through flexural and shear tests. The results of the VPS flexural performance test showed that, for both FPS-01-1 and FPS-01-2, the yield load value was approximately 94 to 101% compared to that of FPS-00, with an average value of 97.5%. FNS-01-1 and FNS-01-2 showed about 99.4% of the yield load of the FNS-00 specimen, while FNS-02-1 and FNS-02-2 showed approximately 95.2% of the flexural performance of the FNS-00 specimen. As a result of the shear performance test of the integrated formwork hollow slab, in the case of SPS-01, the yield load value was about 92.4% compared to that of SS-00, which was slightly less than that of SS-00. This is believed to be due to the fact that the concrete cross-section is missing when using the hollow material. Also, this study also evaluated the proposed slab’s safety against immediate deflection and long-term deflection. After measuring long-term deflection for three months, the deflection value presented in the ACI 318–19 standard was found to be satisfied. This is because the hydration of concrete was stabilizing to some extent, and the causes of deflection were changing from external load factors to deflection due to drying shrinkage and creep acting inside the concrete

The light weight and moderate stiffness of multistorey timber buildings make them susceptible to increased lateral displacements and accelerations under service-level wind loading. Therefore, the fulfilment of serviceability requirements is a major challenge. In this study, linear elastic finite element analysis was used to perform a parametric study of moment-resisting timber frames combined with cross laminated timber walls. In the parametric study, various mechanical and geometrical parameters were varied within practical ranges. The results of the parametric study were used to derive simplified analytical expressions and to train artificial neural networks which can be used to estimate fundamental frequency, mode shape, top floor displacement, maximum inter-storey drift, and wind-induced acceleration. The analytical expressions and the artificial neural networks can be used for the preliminary assessment of serviceability performance of moment-resisting timber frames with and without cross laminated timber walls, under service-level wind loading.

The study reported here aims to investigate the application of shape memory alloys (SMAs) in the form of strips for strengthening cracked reinforced concrete (RC) beams. The study proposes an innovative technique for prestressing RC beams by utilizing the shape recovery property of the alloy. Nine full-scale RC beams with a length of 3.75 m and a cross-section of 200 mm × 300 mm were categorized into three groups based on the steel reinforcement ratio, and tested under static loading. Three RC beams were used as control specimens and the other six were retrofitted with either one layer or two layers of SMA strips. The beams to be strengthened were exposed to an initial applied load before the installation of the SMA strip to simulate the deterioration scenario. SMA strips were retrofitted on the soffits of the deteriorated beams and activated by applying temperature from an external heat source while the temperature-deflection-strain measurements were monitored. Specimens were tested again up to failure to evaluate the strength improvement of the retrofitted specimens. Beams retrofitted with one layer of SMA experienced a deflection recovery up to 2.3 mm upon activation and an additional service load of up to 62%, whereas beams retrofitted with two layers experienced a deflection recovery up to 2.8 mm and an additional service load of up to 95%. In general, the deflection recovery was proportional to the ratio of the total reinforcement ratio after strengthening to the initial reinforcement ratio before strengthening. Therefore, tested specimens with two SMA layers experienced less improvement than specimens with one SMA layer. Finally, the experimental results were evaluated with two analytical methods: ACI method and the non-linear sectional analysis proposed by Oukaili. [ABSTRACT FROM AUTHOR]

The reliability and maintenance of machinery are essential aspects in modern industry, significantly impacting operational efficiency and production costs. This paper presents two practical case studies, addressing specific aspects of reliability and maintenance in an industrial context. The first part of the case study focuses on evaluating the reliability and maintenance of machinery in a production facility, using empirical data to calculate parameters such as mean time between failures (MTBF) and mean time to repair (MTR). The second part of the case study investigates the behavior of another set of machinery over ten operating cycles, analyzing the total cost of maintenance and the economic impact of production interruptions. By integrating empirical data with theoretical concepts in the field of reliability and maintenance, the paper provides a detailed perspective on the efficient management of machinery in the industrial environment. The findings contribute to the development of optimal strategies and practices in the field of reliability and maintenance, with significant implications for industry efficiency and competitiveness. [ABSTRACT FROM AUTHOR]

The analysis of modern researches in the field of composite materials on the basis of tungsten carbide used as surfacing materials is carried out. In particular, the influence of morphology of carbide phase on wear resistance of materials is analyzed. Particular attention is paid to the analysis of conducted studies of ultrafine and nanograined composite materials, their comparative analysis with conventional micrograin coatings. The expediency of research of application of tool high-speed steels as coatings, applied by vacuum electron-beam processing method, which allows to organize micro-metallurgical process with minimal impact on the base metal and possibility to form hardened layer, the thickness of which is adjustable within wide limits, is substantiated. [ABSTRACT FROM AUTHOR]

The durability of reinforced concrete (RC) structures and infrastructure has been the subject of significant attention from the engineering research community in recent years, mainly owing to the deterioration of RC elements due to corrosion of the embedded steel reinforcement. In this context, stainless steel reinforcement can provide an efficient solution to enhance the expected lifetime of concrete structures, reducing the damage due to corrosion of the reinforcement and carbonation and deterioration of the concrete. However, current international design standards for reinforced concrete structures do not include appropriate guidance for stainless steel reinforced concrete (SSRC). In order to investigate the behaviour of stainless steel RC beams, a series of six beam tests was conducted and is discussed herein. The key performance measures for RC beams such as load-deflection response, cracking behaviour and deflections at service load are assessed. The validity and applicability of existing design rules, which were developed for carbon steel RC, are also examined for stainless steel reinforced concrete members. Other recently developed design procedures, based on the Continuous Strength Method and including an accurate material model for the stainless steel bars, are also examined. [ABSTRACT FROM AUTHOR]

The two most common natural disasters in the Himalayas are earthquakes and landslides. Disaster-proof auditing is required for ongoing transportation infrastructure projects in this region. The Artificial Neural Networking (ANN) approach is used in the present study to train neural networks with input layers in terms of disaster parameters, structural configuration, and confining medium characteristics. This model will aid in predicting tunnel failure damage states during earthquake and landslide events. The proposed damage indices for various damage states of the portal and lining can be applied to define the co-seismic demand for individual structural elements. Co-seismic design recommendations will be useful in determining transportation infrastructure serviceability in post-disaster conditions. [ABSTRACT FROM AUTHOR]

In light of growing environmental concerns, the reduction of CO2 emissions is increasingly vital. Particularly in the construction industry, a major contributor to global carbon emissions, addressing this issue is critical for environmental sustainability and mitigating the accelerating impacts of climate change. This study proposes the Optimal Green Design Model for Mega Structures (OGDMM) to optimise CO2 emissions, cost-effectiveness, and serviceability in highrise buildings with mega structures. The OGDMM examines the impact of each material and structural design of main members on these three critical aspects. Analytical results for high-rise buildings (120–200 m, slenderness ratio: 2.0–8.0) demonstrate that OGDMM can reduce CO2 emissions and costs by an average of 4.67% and 3.97%, respectively, without compromising serviceability. To ensure comprehensive evaluation, this study introduces five new evaluation indicators encompassing environmental, economic, and serviceability performances of high-rise buildings. Based on these criteria, optimised structural designs for high-rise buildings are classified into four categories according to slenderness ratio, leading to the formulation of corresponding design guidelines. The model’s applicability is further validated through its application to a 270-m-tall high-rise building in Korea, showing reductions in CO2 emissions and costs by 8.99% and 18.50%, respectively, while maintaining structural serviceability.

The reliability and deterministic analyses of wood-cored stiffened deep cement mixing and deep cement mixing column-supported embankments (referred to as WSCSE and DCSE, respectively) considering serviceability limit state requirements are presented in this paper. Random field theory was used to simulate the spatial variability of soil−cement mixing (SCM) material in which the adaptive Kriging Monte Carlo simulation was adopted to estimate the failure probability of a column−supported embankment (CSE) system. A new method for stochastically generating random values of unconfined compressive strength (qu) and the ratio (Ru) between the undrained elastic modulus and qu of SCM material based on statistical correlation data is proposed. Reliability performance of CSEs concerning changes in the mean (μ), coefficient of variation (CoV), and vertical spatial correlation length (θv) of qu and Ru are presented and discussed. The obtained results indicate that WSCSE can provide a significantly higher reliability level and can tolerate more SCM material spatial variability than DCSE. Some performance of DCSE and WSCSE, which can be considered satisfactory in a deterministic framework, cannot guarantee an acceptable reliability level from a probabilistic viewpoint. This highlights the importance and necessity of employing reliability analyses for the design of CSEs. Moreover, consideration of only μ and CoV of qu seems to be sufficient for reliability analysis of WSCSE while for DCSE, uncertainties regarding the Ru (i.e. both μ and CoV) and θv of qu cannot be ignored.

Timber–concrete hybrid structures are commonly employed in multi-story timber buildings; however, further research is necessary to fully understand the seismic performance of these structures as well as the dynamic properties of the floor. The two dynamic concerns, seismic effects and the vibration of floors in hybrid structures, are key issues, in view of which this study aimed to investigate the small-seismic-response spectra and elastic time histories in a high-rise timber hybrid building, specifically the medical technology building of Jiangsu Provincial Rehabilitation Hospital in China. The dynamic characteristics of a localized cross-laminated timber (CLT) floor were tested in situ, and the impacts of human-induced vibration were quantified. Comprehensive theoretical analysis results reveal that the basic vibration pattern of the structure was mainly translational in nature and that the period ratio, inter-story displacement angle, and shear-to-weight ratio all met the demands of the Chinese timber building design code. The experimental test results show that the vertical natural frequency of the CLT floor was about 15.96 Hz and thus met appropriate requirements with respect to natural frequency. However, peak floor acceleration was found to be high under the conditions of a single person walking quickly, a single person trotting, and multiple persons walking randomly. In light of these findings, the floor should be paved with a fine-grained concrete building surface, according to design requirements, so that its serviceability might be improved. Overall, the relevant analytical methods presented in this paper provide guidance and practical reference for the seismic analysis of timber hybrid structures, as well as vibration serviceability analysis for CLT floors.

Ultrasonic machining, as an effective method to regulate the input external energy, is widely used in surface generation and modification. It can fabricate the microstructure through the precise regulation of interface energy. In order to promote the application of ultrasonic machining for fabricating surface micro-texture and enhancing the part's serviceability, firstly, the current processing methods for surface micro-texture are compared, and the focus is on the comprehensive review of ultrasonic vibration-assisted machining. The characteristics of ultrasonic vibration-assisted turning, milling, grinding, and ultrasonic reinforcement surface micro-texture are analyzed in terms of different vibration forms and ultrasonic dimensions, and the limitations of each process application and the key problems that need to be solved are summarized. Secondly, based on the surface micro-texture fabricated by each process, the serviceability such as friction, wetting, and structural color regulation is analyzed. The analysis mainly elaborates on the friction and wear, friction coefficient, bearing capacity, contact performance, and optical property regulation of surface micro-texture. The results show that surface micro-texture can improve the part’s wear resistance, hydrophobic characteristics, and optical functional characteristics to a certain extent. Finally, considering the issues to be further investigated, the surface micro-texture and serviceability in ultrasonic vibration-assisted machining are discussed for future prospects.

Timber, a lightweight and environmentally friendly material, has gained popularity in construction due to its positive impact on sustainability. However, concerns regarding occupant comfort arise from the lightweight of timber, leading to various vibration issues of tall buildings. This study compares the performance of three structural systems: frames, shear walls, and diagrid systems, under wind loads. This research aims to identify the most efficient structural solutions by analyzing deflection, inter-story drift, and peak acceleration under design wind loads. The performance of these structural systems was evaluated based on ISO 10137 comfort level. The results demonstrate that the diagrid system outperforms the frame and shear wall systems regarding withstanding lateral forces, exhibiting higher natural frequencies and lower peak acceleration. Furthermore, considering the deflection of each system, which is influenced by structural stiffness, the diagrid system demonstrates a deflection of only 13.24 mm under design loads, which is lower than that of the frame and shear wall system.

This article examines experimentally and numerically the flexural performance of low-strength reinforced concrete (RC) beams strengthened using near-surface mounted (NSM) carbon fibre reinforced polymer (CFRP) rods. Five RC rectangular beams were tested in four-point bending until failure. Four of these beams were strengthened using Bottom NSM (BNSM) or Side NSM (SNSM) rods. The results are discussed in terms of observed damage, load capacity, and midspan deflection. It is shown that the SNSM strengthening solution enhanced the cracking load of the beams by up to 19%. Similarly, the yield and ultimate load-carrying capacities of the strengthened beams increased by up to 31% and 64%, respectively. It is also shown that moment-curvature and FE approaches predict well the deflections of the strengthened RC beams within 20% and 10% of accuracy at failure. The results from nonlinear Finite Element (FE) analyses showed a better agreement with the experimental results up to failure (within a 10% of accuracy). For the beams presented in this study, the crack widths calculated by Eurocode 2 match reasonably well the measured values. [ABSTRACT FROM AUTHOR]

With continuous improvements in the social economy and living standards of individuals, the vibration comfort of building structures has gradually been emphasized by academic and engineering communities, such as vehicle-induced vibrations in buildings near traffic, human-induced vibrations in large-span structures, wind-induced vibrations in super-high-rise buildings, and machinery-induced structural vibrations. Comfort-based structural analysis is distinct from traditional safety-based structural analysis, and its theoretical systems and unified guidelines have not yet been established. This paper reviews recent research on structural vibration comfort, including major load categories and their impacts, comfort-based structural analysis, evaluation methods, and vibration-mitigation measures. By presenting the shortcomings of the existing research, potential topics for future study are suggested.

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This paper aims to analyze practical considerations in the design of glass fiber-reinforced polymer-reinforced concrete (GFRP-RC) beams based on the newly adopted ACI CODE-440.11-22, addressing strength, serviceability, and detailing criteria. A beam example was taken from the ACI Reinforced Concrete Design Handbook and redesigned using GFRP bars and stirrups to analyze the effect of changing the reinforcement type. In the first phase, the beam was designed as an over-reinforced member with high-modulus (Ef = 60,000 MPa) and low-modulus (Ef = 44,815 MPa) GFRP bars. In the second phase, a parametric study was carried out to analyze the impact of changing key design parameters--namely, bond factor kb, concrete compressive strength fc', and the maximum deflection limit. GFRP-RC beams require more reinforcement area compared to conventional steel-RC, which may result in bar congestion. Current Code provisions related to detailing in particular are based on conservative assumptions due to a lack of experimentation and greatly penalize the design of GFRP-RC beams. The current Code provisions for development length, bar spacing, skin reinforcement, and stress at service make GFRP-RC design challenging. [ABSTRACT FROM AUTHOR]

Cross-laminated timber (CLT) is an innovative engineering wood product made by gluing layers of solid timber boards placed in an orthogonally alternating orientation to the neighbouring layers. CLT panels provide an efficient solution for floors in single and multi-storey buildings. Due to their light weight and often long-span, the design of these floors is generally governed by serviceability limit state criteria, that is, deflection or vibration limits. Vibrations induced by dynamic actions, such as people walking and their everyday activities, cannot result in structural failure but may cause discomfort to occupants if vibrations are not properly controlled. This paper gives an overview of some available methods for the vibration serviceability design of residential CLT floors. Differences between these methods are discussed through the consideration of criteria and their limit values. Although some criteria are common to certain methods, it may happen that the same criteria take into account different factors. In order to get a better description of the actual behaviour of floor structure, certain classifications of floors based on vibration serviceability performance were introduced in design methods.

A great number of reinforced concrete structures are approaching the end of their service life and they are strongly affected by progressive deterioration processes due to insufficient maintenance. A fundamental understanding of all damage phenomena acting together on reinforced concrete, RC, structures under service loads is a crucial step toward more sustainable structures. The present work aims to study the creep of RC beams in the cracked state. To achieve this objective, an analytical model was developed based on Bernoulli’s theory and the global equilibrium of the RC beam. A Newton–Raphson algorithm was also proposed to solve the non-linear equilibrium equations related to the non-linearity in the adopted materials models. The proposed model allows predicting the instantaneous and long-term behavior under any loading level up to the steel yielding, and it takes into consideration the effect of creep on the behavior of concrete both in tension and compression. In addition to the evolution of the deflection with time, the model is also able to follow the height of the compression zone as well as the evolution of crack’s height and width under any sustained service load. The comparison between analytical and experimental results found in the literature for long-term loaded beams showed a good agreement.

Biodegradable jute geotextiles (JGTs) are an effective reinforcing material for unpaved roads, but its serviceability is limited because of faster microbial degradation. Different methods are in use to improve the serviceability of jute geotextiles. In this paper, the influence of CA-chitosan treatment, road design, and rainfall intensity on the time-dependent serviceability of JGTs has been studied. Chemically treated jute geotextiles are laid in unpaved road designs with and without sand layer, for 30, 60, and 90 days’ duration, and are exposed to simulated rainfall intensities of 50 and 100 mm/hr. With an increase in time of usage, breaking load and puncture resistance decrease due to microbial attack, and pore size decreases due to clogging of soil in JGTs. Chemical treatment is observed to have a greater influence on the serviceability, followed by the presence of a sand layer in road design and the rainfall intensity and shows retention % in tensile strength of 87.42% and 91.21% after 30 days duration. Further, the overall performance of CA-chitosan treated JGTs is observed to be better than untreated JGTs.

Fiber-reinforced polymer (FRP) composites have gained increasing recognition and application in the field of civil engineering in recent decades due to their notable mechanical properties and chemical resistance. However, FRP composites may also be affected by harsh environmental conditions (e.g., water, alkaline solutions, saline solutions, elevated temperature) and exhibit mechanical phenomena (e.g., creep rupture, fatigue, shrinkage) that could affect the performance of the FRP reinforced/strengthened concrete (FRP-RSC) elements. This paper presents the current state-of-the-art on the key environmental and mechanical conditions affecting the durability and mechanical properties of the main FRP composites used in reinforced concrete (RC) structures (i.e., Glass/vinyl-ester FRP bars and Carbon/epoxy FRP fabrics for internal and external application, respectively). The most likely sources and their effects on the physical/mechanical properties of FRP composites are highlighted herein. In general, no more than 20% tensile strength was reported in the literature for the different exposures without combined effects. Additionally, some provisions for the serviceability design of FRP-RSC elements (e.g., environmental factors, creep reduction factor) are examined and commented upon to understand the implications of the durability and mechanical properties. Furthermore, the differences in serviceability criteria for FRP and steel RC elements are highlighted. Through familiarity with their behavior and effects on enhancing the long-term performance of RSC elements, it is expected that the results of this study will help in the proper use of FRP materials for concrete structures. [ABSTRACT FROM AUTHOR]

A great number of reinforced concrete structures are approaching the end of their service life and they are strongly affected by progressive deterioration processes due to insufficient maintenance. A fundamental understanding of all damage phenomena acting together on reinforced concrete, RC, structures under service loads is a crucial step toward more sustainable structures. The present work aims to study the creep of RC beams in the cracked state. To achieve this objective, an analytical model was developed based on Bernoulli's theory and the global equilibrium of the RC beam. A Newton–Raphson algorithm was also proposed to solve the non-linear equilibrium equations related to the non-linearity in the adopted materials models. The proposed model allows predicting the instantaneous and long-term behavior under any loading level up to the steel yielding, and it takes into consideration the effect of creep on the behavior of concrete both in tension and compression. In addition to the evolution of the deflection with time, the model is also able to follow the height of the compression zone as well as the evolution of crack's height and width under any sustained service load. The comparison between analytical and experimental results found in the literature for long-term loaded beams showed a good agreement. [ABSTRACT FROM AUTHOR]

The new computing paradigm, fog computing, enables advanced services, such as navigation, self-driving cars, and augmented reality, by integrating with vehicular networks to provide smart transportation solutions. This emerges fog-empowered vehicular ad-hoc networks (FEVANETs), which enable smart vehicles to communicate with fog nodes (FNs) using association policy, such as signal strength and/or favorite contents. However, a deluge arrival of vehicles to the network can cause a load imbalance among FNs. This impacts the severe reduction in the network service capability and resource utilization efficiency. To address this problem, we propose an algorithm, dynamic resource management (DRM), for assigning the resources of FNs to smart vehicles by migrating services among FNs. The problem is formulated as integer linear programming (ILP) and determines its NP-hardness by reducing it from Seminar Assignment Problem. A polynomial-time algorithm is presented by formulating the problem as a graph in which vertices represent the FNs and edges represent the vehicles present in the overlapped region of the pairs of FNs. The proposed algorithm considers the set of vehicles that are in overlapped coverage regions of FNs and communicates with those corresponding FNs. Then it migrates the resource blocks (RBs) of the set of vehicles between pairs of FNs to minimize the allocated RBs. The DRM is simulated extensively, and the simulation outcomes show that the DRM enhances service capability, serviceability, availability, throughput, and resource utilization efficiency compared to the four existing algorithms. [ABSTRACT FROM AUTHOR]

Bearings are widely used in the industry due to their ability to support the movement of rotating bodies. The spacer rings are a key component of double-row roller bearings; therefore, the characteristics and properties of the spacer rings have a significant impact on the bearing functions. However, the lack of the characteristics and performance analysis of the spacer ring limits the improvement of bearing performance. To analyze the characteristics of spacer rings and establish a basis for improving their performance, a new testing method for the characteristics and performance of the spacer ring was presented and corresponding experiments were developed. The test procedure entails the evaluation of basic characteristics, surface properties, and serviceability. Basic characteristics were determined through element testing and cross-section morphological observation; surface properties were assessed through surface morphology and surface roughness detection; and serviceability was identified by cross-section hardness and frictional wear tests. The results show that the proposed test method can comprehensively characterize the performance of the spacer rings. The spacer ring composition mainly contains Fe, Al, P, Si, Ca, and S, which contribute to excellent wear resistance, hardness, strength, and corrosion resistance. The cross-sectional morphology exhibits porous characteristics, which enhance lubricity. In terms of surface property, the surface of the spacer ring is relatively flat, and the surface roughness is generally less than 0.6 μm Sa. The average friction coefficient is 0.85, and the friction and wear properties of the spacer ring are good. This study contributes to establishing the testing and evaluation criteria for the performance of spacer rings in engineering, which helps to improve the performance of bearings.

Among the most valuable types of renewable energy available today is wind energy. The reliability of WF systems must be regularly evaluated at every stage of their "life," from design to operation, if a wind farm energy system is to be effective and function damage-free. Three key goals are presented in the article. The theory of fundamental quantities in reliability and maintenance analysis should be derived and explained first. Second, as a consequence of maintainability, theoretical correlations between reliability and mean time between failures (MTBF) are provided. The three-state theory of the WF procedure for operation presented in the research serves as the foundation for the analytical analysis of WF reliability. The time between failures is investigated as a function of maintainability, and the dependability of the WF under examination is assessed as a function of service life. The WF owner can make the best decisions to renew the WF and increase its reliability, energy, financial efficiency, etc. by being aware of the existing reliability of the WF system in use. [ABSTRACT FROM AUTHOR]

Basalt fiber-reinforced polymer (BFRP) composite is one of the promising structural materials recently introduced to the construction industry as internal reinforcement for the purpose of prestressing concrete. In this study, experimental and analytical investigations have been carried out to assess the flexural performance of BFRP-prestressed concrete (PSC) beams designed as over-reinforced, under-reinforced, and significantly under reinforced, as well as non-prestressed concrete beams. The assessment has been made based on the flexural strength, serviceability, and deformability/ductility. The current findings have revealed that even though the non-prestressed beams have exhibited a comparable flexural strength and good deformability, they did not satisfy the serviceability requirements of deflection and crack width. On the other hand, the significantly under-reinforced PSC beams have satisfied the serviceability and strength requirements, however, exhibited reduced cracking and poor deformability. The over- and under-reinforced PSC beams have performed reasonably well in strength and serviceability performances. The partial prestressing of the beams with multiple layers of tendons has been found effective in improving the ductility by introducing a kind of progressive failure based on sequential rupturing of the BFRP tendons. Thus, it is concluded that the proposed under-reinforced design may offer the potential to avoid the sudden or catastrophic failure typically experienced by the single-layered fully prestressed concrete beams, and may hence be considered besides the over-reinforced design recommended in most of the international codes/standards. [ABSTRACT FROM AUTHOR]

This paper presents a new bridge deck reinforcement alternative using hybrid reinforced concrete (Hybrid) consisting of Glass Fiber Reinforced Polymer (GFRP) rebar and alkali-resistant fiberglass composite macrofibers added to the concrete mixture. Fiberglass composite macrofibers are a miniaturized GFRP reinforcing bar that is a composite of resin and glass fibers. An experimental testing program and analytical modeling were conducted to evaluate the structural performance at the service and ultimate limit states. Thirteen full-scale bridge deck specimens were constructed and tested under static and fatigue loading. The fatigue loading was applied up to two million cycles at a frequency of 4 Hz. Post-fatigue, the specimens were tested to failure to compare pre-and post-fatigue behavior. Simplified and moment-curvature analytical models were used to predict the specimens' flexural strength at the ultimate level, and both were found to be accurate for predicting pre- and post-fatigue strength. Deflection and crack width were monitored throughout the fatigue loading, and these values were compared to the recommended AASHTO LRFD serviceability limits. Testing and analytical results showed that the Hybrid deck is a viable alternative to steel-reinforced and GFRP-reinforced bridge decks for flexural behavior. The service and ultimate level behavior of each bridge deck type was adequate as compared to the AASHTO LRFD service limits. The exceptional post-peak energy absorption demonstrated by the Hybrid adds ductility to previously elastic GFRP reinforced sections. [ABSTRACT FROM AUTHOR]

Steel cable bridges are relatively light and known to be prone to large deformation and vibration. However, excessive vibration may cause serviceability problems such as discomfort or motion sickness to pedestrians and passengers. Recently, several excessive or abnormal vibration events on cable bridges have been reported from various places around the world. In this study, vibration serviceability is evaluated and compared for several steel cable bridges during the recent typhoons passing the Korean peninsula and abnormal vibration cases. Assessment criteria used in this study are Reiher-Meister curve using displacement amplitude and ISO 2631–1 using weighted RMS (root-mean-square) acceleration. Most cable bridges are equipped with a monitoring system that measures displacement, acceleration, wind speed, temperature, and etc. Displacement amplitudes were calculated using displacement data at mid-point of the main span using the GNSS system. RMS acceleration were also calculated from acceleration data at mid-point of the main span and weighting factors described in ISO 2631–1. Evaluation of vibration serviceability was performed on four cable bridges during nine typhoons passing in 2019 and 2020. Evaluations were also done in two cases of abnormal vibrations on two cable bridges in 2014 and 2019. Based on these results, equations for limit and warning values for displacement amplitude and RMS acceleration, are proposed respectively. Results of this study may be the basis for evaluation criteria for vibration serviceability in steel cable bridges. [ABSTRACT FROM AUTHOR]