Buildings, Volume 13, Issue 10 (October 2023) – 272 articles

Increasing women’s representation in male-dominated professions has become an unending debate due to different gender barriers across various sectors. This study examined the barriers to female construction graduates’ employment as construction faculty in Nigerian higher education institutions. This study developed a quantitative questionnaire to examine the barriers to female construction graduates entering academic careers using purposive sampling technique to identify Master of Science graduate students in higher education institutions in southwestern Nigeria. Three hundred copies of the questionnaire were administered to female construction graduate students, while two hundred and fifty-nine retrieved data were analysed. Firstly, data validity and reliability were determined using Cronbach’s alpha, the Kaiser–Meyer–Olkin (KMO) test, and Bartlett’s sphericity tests, followed by descriptive and exploratory factor analysis. The exploratory factor analysis clustered five factors of barriers to female graduate student recruitment as faculty in higher education institutions: gender profiling, academics competency requirements, non-prioritised support for female careers in academics, female enrolment, graduation, and job position difficulties and perceived difficulties in women’s recruitment, workload, and growth. The study recommends establishing grassroots female careers support, improving female enrolment and graduation rates, campaigning against gender profiling, and establishing career pathways in academics to improve gender inclusiveness in higher education institutions when recruiting female construction graduates as faculty. Full article

The double-skin roof has been applied in the design of modern granaries for energy saving. Compared with the ordinary parallel double plate, the double skin composed of an inclined upper plate can effectively improve the situation of a “hot roof” through an air exhaust, thus having better thermal performance. To study the advantages of a double-skin roof with an inclined upper plate and the effects of physical parameters on convective heat transfer, an experimental and numerical study was carried out in this work. According to the actual size of the grain depot in the application, an experimental setup was established based on the similarity theory with a scale of 1:28 to the real one. The double-skin roof consists of two plates: the lower one was used as the original surface of the depot, and the other was suspended above. For comparison, the two flat plates were arranged to be parallel or inclined. Changeable parameters included the flow rate through the air gap between the double plates, the thickness of the air gap, and the reducing ratio. Other parameters, such as the air temperature, were the same, and the influence of the above factors on the performance of the double-skin roof was studied. The results showed that both the flow rate and the air gap’s thickness can affect the roof’s thermal performance. Under the optimal working conditions in the parallel mode (with an air gap of 0.07 m and a flow rate of 60 m³/h), the temperature increment at the surface of the grain bulk was 1.88 °C, which was lower than the mode without a suspended upper plate. Moreover, the inclined design of the upper plate increased the air velocity along the flowing direction, which strengthened the convection at the outlet and, thus, improved the average thermal performance of the opened roof. The inclined mode controlled the temperature at the grain bulk surface within 24 °C, which dropped by 1 °C compared with the parallel mode under the same working conditions. In addition, a geometric model of the experimental setup was created, and the grid was divided through the software ANSYS ICEM 15.0 The convection term in the conservation equation was discretized with the QUICK scheme, and the solution for the flow field was obtained using the SIMPLE algorithm. The experimental data were used as the input profile for the model, and the numerical results were compared with the experimental results to verify the accuracy of the model. The average and the maximum errors were between 3% and 8.9%, respectively. The simulation results indicated the effects of the reducing ratio on the roof thermal performance with the analysis of the Rayleigh number and the Nusselt number. In the inclined mode, a smaller reducing ratio was beneficial to air convection. With a reducing ratio of about 0.5, the outlet velocity of the roof was higher by 30.6%, resulting in a larger local Nu number and better thermal performance. When the dimensionless length was in a range of 0.34~0.37, the Nu number was increasing. Near the inlet of the double-skin roof, the Nu number increased with the Ra number, given a dimensionless length of below 0.15. Therefore, the ventilated double-skin roof with an inclined upper plate is recommended for roof reconstruction design because of its advanced air convection. Full article

In the absence of industry data, organisms, and researchers leverage free and available data, specifically building and demolition permits. Geospatial processing is essential to integrate information from various files into a single GIS layer containing all relevant attributes for analysis. This article proposes a Geographic Information System (GIS) processing model aimed at monitoring construction and demolition dynamics in the European metropolis of Lille to quantify the urban production of mineral waste from buildings. Author methodology is based on that that the deposit potential can be analyzed using the observation of the spatiotemporal dynamics of building and demolition permits. The results demonstrate that combining construction and demolition (C&D) permits with other GIS layers allows us to produce data to quantify demolition surfaces per year in a given French area. The applicability of this methodology extends to all French regions, providing insights into the impact of crises on deconstruction activities and C&D waste generation. The study focuses on C&D French public data bases (French government and European Metropolis of Lille) attributed to the region (area) of the European Metropolis of Lille (MEL) between 2013 and 2022. Some data for 2022 were incomplete due to ongoing treatment, emphasizing the importance of understanding the dynamics of demolition rates or surfaces to identify data gaps or errors. Historical trajectories of C&D permits were quantified and analyzed, revealing over 21,000 permits granted from 2013 to 2022, categorized by site type (new construction, rehabilitations, prior declarations, and demolitions). Construction sites during this period covered approximately 3,345,948 m², constituting 20% of the MEL’s building stock, while demolition sites amounted to 1,977,911 m², equivalent to 5% of the total area of buildings in the metropolis. Employing GIS allowed for a spatial analysis, visualizing data by municipality, urban fabric, and year. The analysis highlighted territories with high and low potential for demolition and construction, as well as the most impacted urban fabrics and dynamic periods. The article discusses potential crisis impacts (e.g., COVID-19 or economic downturns) and the implications of incomplete data. Finally, the study demonstrates how these findings can be utilized to quantify C&D waste, leveraging GIS and the production rate calculation method (GRC). Full article

Demand response techniques can be effective at reducing heating costs for building owners. However, few studies have considered the dynamic marginal costs for district heating production and taken advantage of them for building-level demand response. In this study, a district heating network in the Finnish city of Espoo was modeled to define dynamic district heat prices. The benefits of two demand response control approaches for a Finnish office building, the demand response control of space heating and a thermal energy storage tank, were evaluated by comparing them to each other and utilizing them together. A 5 m³ storage tank was installed in a substation of a conventional high-temperature district heating network. A new demand response control strategy was designed to make the most of the storage tank capacity, considering dynamic district heat prices and the maximum allowed return water temperature. The results indicate that the demand response control of space heating and the storage tank cut district heat energy costs by 9.6% and 3.4%, respectively. When employing the two approaches simultaneously, 12.8% savings of district heat energy costs were attained. Additionally, thermal energy storage provides more potential for peak power limiting. The maximum heating power decreases by 43% and the power fee reduces by 41.2%. Therefore, the total cost, including the district heat energy cost and the power fee, can be cut up to 22.4% without compromising thermal comfort and heat supply temperatures to ventilation systems. Full article

Carbon-reinforced concrete (CRC) is increasingly utilized in construction, due to its unique properties, such as corrosion resistance, high-tensile strength, and durability. Understanding its behavior under different loads is crucial to ensuring its safe and effective use in various construction applications. In this study, three-point bending tests were performed in combination with large-scale in situ computed tomography (CT). This paper presents the related three- and four-dimensional evaluation methods, with emphasis on crack width and quality control. The focus was on large CRC beams, with cross-sectional sizes of up to 80 mm by 160 mm. Such dimensions require extremely high energy during a CT scan. Therefore, a new experimental setup with energies of up to 8 MeV was used in this study. However, such high energies posed new challenges to the analysis methods. Therefore, two methods (digital volume correlation and grayscale profile analysis) for accurate crack width estimation were adapted and applied to the 3D reconstructions. In addition, a photogrammetric stereo image sequence was acquired and analyzed, using digital image correlation to cross-validate the results derived from the 3D crack width estimates. The 3D CT images also played a key role in the quality control measures, including the localization of the carbon-reinforcement and the assessment of porosity within the concrete structure. Full article

This study explored self-healing in geopolymer mortar cured at ambient temperature using polypropylene fibers and bacterial co-cultures of Bacillus subtilis and Bacillus megaterium. Damage degree, compressive strength, ultrasonic pulse velocity (UPV), strength-regain percentage, and self-healing percentage were evaluated. A full factorial design was used, which resulted in an eight-run complete factorial design with four levels in the first factor (polypropylene content: 0%, 0.25%, 0.5%, and 0.75%) and two levels in the second factor (bacteria concentration: 0 (without) and 1 (with)). The results indicate that increasing the polypropylene fiber content enhanced strength regains up to 199.97% with 0.75% fibers and bacteria. The bacteria alone improved strength-regain percentages by 11.22% through mineral precipitation. The analysis of variance (ANOVA) showed no interaction between fibers and bacteria, but both independently improved the compressive strength. Only bacterial samples exhibited positive self-healing, ranging from 16.77 to 147.18%. The analysis using a scanning electron microscope with energy dispersive X-ray (SEM-EDX) and X-ray fluorescence (XRF) also revealed greater calcite crystal formation in bacterial samples, increasing the strength-regain and self-healing percentages. The results demonstrate that polypropylene fibers and bacteria cultures could substantially enhance the strength, durability, and self-healing percentage of geopolymer mortars. The findings present the potential of a bio-based self-healing approach for sustainable construction and repair materials. Full article

In this study, an experiment was conducted to innovate a new design of interlocking concrete blocks (ICBs) containing recycled aggregates (RAs) by reducing the consumed time and cost in construction using an environmental approach. Accordingly, the designed ICBs were produced manually using RAs, and wallettes were easily built with a mortarless mechanism by stacking the blocks without any mortar layers. In the experiments, besides the individual compression tests of the two types of ICB with natural and recycled aggregates, the wallette samples that were produced using ICBs, containing either 100% natural aggregates or 100% Ras, were tested under axial compressive loading. The experimental results were assessed considering the compressive strength, displacement, and failure mode. In the obtained results, we noticed that the average compressive strengths of the wallettes that were produced with natural or recycled aggregate ICBs were large enough to meet the standards of Syrian regulations, which are considered an example reference. The resulting displacement values were acceptable and could be negligible in some wallette specimens. It was concluded that the innovative ICBs with both normal or recycled aggregates could be a good alternative to traditional blocks, especially in post-disaster or post-war areas. Full article

This paper presents the key mechanical properties of PVC fiber-reinforced concrete. Six concrete mixtures were produced using plastic fibers obtained from clear PVC sheets. Three concrete mixtures were made using 20 mm long PVC fibers, whereas the other three were prepared with 40 mm long PVC fibers. The fiber content was varied in the range of 0–1.5 wt.% of cement for each length of fiber. The fresh concrete mixtures were tested for workability in terms of the slump. The hardened concretes were tested for their compressive and splitting tensile strengths, flexural strength and toughness, static elastic modulus, and impact resistance and toughness. The effects of the fiber content and fiber length on the workability and above-mentioned mechanical properties were observed. In addition, the correlations between various mechanical properties were sought. The test results revealed that the workability of concrete was reduced for both fiber lengths as the fiber content increased. The compressive strength, flexural strength and toughness, elastic modulus, and impact resistance and toughness increased at up to 1 wt.% fiber content, then decreased for 1.5 wt.% fibers. A similar trend was also noticed for the splitting tensile strength, particularly in the case of 20 mm long PVC fibers. Compared to the fiber length, the fiber content exhibited a more pronounced effect on the mechanical properties of concrete. The optimum fiber content was 1 wt.%, which produced the best performance in this study. Furthermore, excellent correlations were observed for the tested mechanical properties of concrete, except for splitting tensile strength, which was not well-correlated with compressive strength. Full article

Hydropower, a renewable energy resource, underpins China’s economic and social advancement, gaining prominence amidst the country’s energy structure metamorphosis. Enhancing the performance of hydropower development projects is imperative, with the mechanisms of learning and innovation wielding a substantial impact. The extant literature on how learning and innovation affect hydropower project performance remains nebulous, lacking a systematic model to elucidate these impact mechanisms. This investigation melds theoretical analysis with the idiosyncrasies of hydropower project development, forging a theoretical model to decipher the interplay of learning, innovation, and project performance. Employing a mixed-methods approach, we probe the influence of organizational learning orientation and individual learning on participant capabilities, engineering innovation magnitude, and overall project performance. Path analysis divulges that organizational learning orientation catalyzes individual learning, jointly enhancing engineering innovation and project performance directly, although the effect on each participant’s capability necessitates mediation through the engineering innovation level. This pioneering study establishes the links and influence trajectories between learning, innovation, and project performance, systematically delineating them. It fills a scholarly void in exploring learning and innovation mechanisms within hydropower project development, propounding strategies to augment project efficiency and furnishing pragmatic, constructive insights for better engineering practice outputs. Full article

In scholarly construction management, “program” denotes terminologies like “mega-project” and “infrastructure project”. Within this framework, the Construction Program Delivery (CPD) system is an indispensable mechanism affecting the entire lifecycle of these complex endeavours. The CPD system harmonises an arrangement of crucial delivery attributes to achieve successful outcomes, rendering the elucidation of these attributes a scholarly imperative. Numerous studies have identified multiple attributes that impact delivery strategies in the construction industry. However, only a limited number of studies have focused explicitly on the CPD attributes. Hence, the study aims to explore the main drivers of CPD methods based on a systematic review, including a bibliometric analysis over the current century in existing literature. It also addresses current research trends and gaps in the delivery context concerning mega projects. The two major-step research methodology involves a bibliometric assessment and determining key delivery attributes. A bibliometric analysis was conducted using 639 journal articles focused on CPD. Ultimately, the analysis of the findings and existing knowledge of the CPD literature have revealed that researchers, as well as construction agencies, have emphasised regulatory and technical aspects embedded within a socio-economic context conveying normative and cultural attributes when addressing CPD. These triple aspects of the delivery strategy have been considered by scholars simultaneously for a successful construction program. Full article

Power grids in the 21st century face unprecedented challenges, including the urgent need to combat pollution, mitigate climate change, manage dwindling fossil fuel reserves, integrate renewable energy sources, and meet greater energy demand due to higher living standards. These challenges create heightened uncertainty, driven by the intermittent nature of renewables and surges in energy consumption, necessitating adaptable demand response (DR) strategies. This study addresses this urgent situation based on a statistical analysis of recent scientific research papers. It evaluates the current trends and DR practices in buildings, recognizing their pivotal role in achieving energy supply–demand equilibrium. The study analysis provides insight into building types, sample sizes, DR modeling approaches, and management strategies. The paper reveals specific research gaps, particularly the need for more detailed investigations encompassing building types and leveraging larger datasets. It underscores the potential benefits of adopting a multifaceted approach by combining multiple DR management strategies to optimize demand-side management. The findings presented in this paper can provide information to and guide future studies, policymaking, and decision-making processes to assess the practical potential of demand response in buildings and ultimately contribute to more resilient and sustainable energy systems. Full article

The assessment of seismic risk for critical and strategic structures like schools and hospitals remains crucial, even in regions with low seismic activity. Presently, operational school buildings in Sri Lanka are primarily designed to handle gravitational loads without considering capacity-based design principles. Consequently, these structures may lack the necessary lateral resistance to mitigate potential damage or collapse during future earthquakes in Sri Lanka. Hence, conducting seismic risk assessments for such school buildings is imperative to ensure the safety of their occupants. In this research paper, we utilize a recently developed probabilistic seismic hazard map for Sri Lanka to evaluate seismic risk. We employ two nonlinear 3-D finite element models of school buildings created in OpenSees. Incremental Dynamic Analysis is conducted using a well-established set of ground motions, continuing until the structure approaches the point of collapse, to determine the probability of collapse prevention. Subsequently, we develop fragility functions for two limit states, immediate occupancy, and collapse prevention. These fragility curves are then used to compute the probability of exceeding these limit states, aiding in the assessment of the structural safety of the school buildings. A key outcome of this analysis reveals a general trend of increased damage probabilities as the number of stories in the buildings increases despite the distinct structural characteristics of each building. It is also important to note that the disparities between the immediate occupancy and more severe damage cases, such as collapse prevention, are notably pronounced in both two- and three-story school buildings. Full article

Straight-wall arch cross-sections are usually designed at the entrance and exit tunnels of subway stations, and dense underground pipelines often cross these cross-sections at close range. Among these pipelines, gas pipelines have the highest risk level. Therefore, it is necessary to reduce the deformation influence of underground crossing construction on existing gas pipelines. Based on the No. 2 entrance and exit tunnel project of Zhongshan Road Station of the Hohhot Metro Line 2, using the methods of numerical simulation and field monitoring, this paper has particularly investigated the influence of straight-wall arch tunnel construction by applying the pre-grouting reinforcement and double-side drift method to the deformation of existing gas pipelines. The research results show that the double-side drift method is an efficient and sustainable construction method for straight-wall arch tunnels, which can effectively reduce the crossing construction disturbance to overlying gas pipelines. The measured maximum settlement of the existing gas pipeline is 18.46 mm, and the maximum settlement of the new tunnel vault is 22.86 mm, with both values satisfying the requirements for deformation control. The simulation results are consistent with the measured results of gas pipeline settlement. This study shows that the safety control scheme employed in the field with a tunnel excavation step of 6 m, stratum reinforcement with upper semi-section grouting, and a grouting reinforcement range of 2.0 m is reasonable and effective. This scheme can provide a reference for the deformation control of similar underground gas pipelines in the crossing construction of straight-wall arch tunnels at close range. Full article

Numerous studies have examined the responses of various structures to the mainshock–aftershock (MS–AS) ground motion, and the MS–AS ground motions are very important as the input. Therefore, in the absence of aftershock information, it is particularly critical to construct a reasonable MS–AS seismic sequence. This paper aims to provide a new reasonable method for generating the target aftershock response spectrum, which can be used to select or artificially simulate aftershock ground motion, given the seismic information of the main shock. Firstly, the magnitude, fault size, and location of the aftershock are determined. Then, other parameters required for the aftershock ground motion prediction equation (GMPE) are calculated. Subsequently, the correlation of the spectral shape to the MS–AS ground motion is used to modify the response spectrum predicted using the GMPE to obtain the conditional mean spectrum of aftershocks (CMS_A). Finally, the relative errors of the predicted spectrum via the ASK14 model and CMS_A are compared for four different assumptions. The results show that the simulated aftershock parameters and the actual ones accord well, and the relative errors of the CMS_A can be controlled within 20%. Meanwhile, the discrete property of the target aftershock response spectrum is closer to the real recorded response spectrum. Full article

The accurate distribution of solar energy on indoor walls is the basis of simulating the indoor thermal environment, and its specific distribution changes all the time due to the influence of solar azimuth and altitude angle. By analyzing the assumptions of each model, the existing solar energy distribution models are eight kinds in all and are divided into three categories. The solar radiation models in TRNSYS, EnergyPlus, and Airpak software all use the absorption-weighted area ratio method, which assumes that a single interior surface is a whole, but the detailed assumptions of the models used in the three software are different. In the Radiosity-irradiation method, the indoor surfaces are discretized into small surfaces for calculation. The calculation accuracy of solar radiation distribution indoors can be controlled by the number of discrete small surfaces. The Radiosity-irradiation method is implemented by using Matlab software programming in this paper. Through the numerical calculation and analysis of typical cases, the solar distribution results of the absorption-weighted area ratio method and the Radiosity-irradiation method all show the asymmetry. The asymmetrical ratio of direct solar radiation varies during the time between 7.96–9.89, and the minimum turns up at 11:30 in the summer solstice. The asymmetrical ratio of diffuse solar radiation is 3.23 constantly. The asymmetrical ratio of total solar energy is mainly influenced by the direct and diffuse solar feat gain and its value changes in the range from 3.4 to 4.45 in the summer solstice. Calculation comparison and error analysis on the solar radiation models used in TRNSYS, EnergyPlus, and Airpak software are conducted. There are significant errors in the simulation results of all three software. TRNSYS has the highest error among the three software as its results do not change over time. For EnergyPlus, the distribution ratio of floor 1 is too large. Airpak has the smallest error, but the solar radiation distribution ratios of the indoor surfaces near the south glazing facade are underrated, especially the indoor surfaces that have not been exposed to direct solar radiation. Full article

The building sector accounts for a significant proportion of global energy usage and carbon dioxide emissions. It is important to explore technological advances to curtail building energy usage to support the transition to a sustainable energy future. This study provides an overview of emerging and sustainable technologies and strategies that can assist in achieving building decarbonization. The main technologies reviewed include uncertainty-based design, renewable integration in buildings, thermal energy storage, heat pump technologies, thermal energy sharing, building retrofits, demand flexibility, data-driven modeling, improved control, and grid-buildings integrated control. The review results indicated that these emerging and sustainable technologies showed great potential in reducing building operating costs and carbon footprint. The synergy among these technologies is an important area that should be explored. An appropriate combination of these technologies can help achieve grid-responsive net-zero energy buildings, which is anticipated to be one of the best options to simultaneously reduce building emissions, energy consumption, and operating costs, as well as support dynamic supply conditions of the renewable energy-powered grids. However, to unlock the full potential of these technologies, collaborative efforts between different stakeholders are needed to facilitate their integration and deployment on a larger and wider scale. Full article

With the development of engineering technology, engineering has higher requirements for the accuracy and the scale of simulation calculation. The computational efficiency of traditional serial programs cannot meet the requirements of engineering. Therefore, reducing the calculation time of the temperature control simulation program has important engineering significance for real-time simulation of temperature field and stress field, and then adopting more reasonable temperature control and crack prevention measures. GPU parallel computing is introduced into the temperature control simulation program of massive concrete to solve this problem and the optimization is carried out. Considering factors such as GPU clock rate, number of cores, parallel overhead and Parallel Region, the improved GPU parallel algorithm analysis indicator formula is proposed. It makes up for the shortcomings of traditional formulas that focus only on time. According to this formula, when there are enough threads, the parallel effect is limited by the size of the parallel domain, and when the parallel domain is large enough, the efficiency is limited by the parallel overhead and the clock rate. This paper studies the optimal Kernel execution configuration. Shared memory is utilized to improve memory access efficiency by 155%. After solving the problem of bank conflicts, an accelerate rate of 437.5× was realized in the subroutine of the matrix transpose of the solver. The asynchronous parallel of data access and logical operation is realized on GPU by using CUDA Stream, which can overlap part of the data access time. On the basis of GPU parallelism, asynchronous parallelism can double the computing efficiency. Compared with the serial program, the accelerate rate of inner product matrix multiplication of the GPU asynchronous parallel program is 61.42×. This study further proposed a theoretical formula of data access overlap rate to guide the selection of the number of CUDA streams to achieve the optimal computing conditions. The GPU parallel program compiled and optimized by the CUDA Fortran platform can effectively improve the computational efficiency of the simulation program for concrete temperature control, and better serve engineering computing. Full article

The Leadership in Energy and Environmental Design for Existing Buildings (LEED-EB) version 3 (v3) and version 4 (v4) gold-certified office space certification strategies in Spain have not yet been studied. The two purposes of this study were to evaluate (1) the impact of high or low achievements in the energy and atmosphere (EA) “optimize energy performance” credit (EAc1 for v3 and EAc8 for v4) on the compensation strategy for LEED “compensation group” credits and (2) the impact of EAc1-v3 or EAc8-v4 on the monotonic change in LEED “compensation group” credits. Data on a total of 77 LEED-EB v3 and 43 LEED-EB v4 gold-certified office space projects were collected. In the v3 group, 26 LEED-certified projects had the highest EAc1 achievements (v3 group 1), and 26 LEED-certified projects had the lowest EAc1 achievements (v3 group 2). In the v4 group, 15 LEED-certified projects had the highest EAc8 achievements (v4 group 1), and 15 LEED-certified projects had the lowest EAc8 achievements (v4 group 2). The exact Wilcoxon–Mann–Whitney test and Fisher’s exact 2 × 2 with Lancaster’s correction test were used to estimate the difference between groups 1 and 2. Spearman’s rank-order correlation was used to assess monotonic change in LEED credits. The results show that v3 and v4 group 1 outperformed v3 and v4 group 2 in EAc1 and EAc8 (p < 0.0001, respectively). However, v3 and v4 group 2 outperformed v3 and v4 group 1 in “renewable energy” (EAc4 for v3 and EAc6 for v4, p = 0.0039 and 0.0088, respectively) and “building commissioning” (EAc2.2 for v3, p = 0.0015; EAc3 for v4, p = 0.0560, respectively). EAc1-v3 and LEED v3 “compensation group” credits showed a moderate negative correlation (r_s = −0.53 and p < 0.0001). EAc8-v4 and LEED v4 “compensation group” credits showed a strong negative correlation (r_s = −0.74 and p < 0.0001). As a result, increasing the share of renewable energy and performing building commissioning in LEED-EB v3- and v4-certified projects occurred only as a compensation strategy in response to the low achievement in the “optimize energy performance” credit. Full article

This research centers on the implementation of photovoltaic systems in residential applications, coupled with battery-based energy storage, and evaluates their efficiency in generating energy, specifically for lighting in buildings. The methodology hinges on detecting interharmonic signals to characterize potentially disruptive frequencies and identify the origins of various failures. Multiple case studies are presented to validate the method’s efficacy, including one involving fluorescent lamp circuits and another examining variations in solar radiation during the summer season. Real-world experiments are conducted in a residential setting, and the results are thoroughly analyzed. Various types of interharmonic generation behaviors are demonstrated, which are influenced by fluctuations in solar radiation and the appropriate installation of solar panels. The findings reveal that the absence of solar radiation below 300 W/m² in a photovoltaic system relying on energy storage adversely affects interharmonics in luminaires installed within a residential space. Full article

A major challenge in building energy renovation is to cost effectively achieve notable energy savings. This paper investigates cost-effective passive energy-efficiency measures for thermal envelope retrofit of a typical Swedish multi-apartment building from the 1970s. Here, the use of different types of insulation materials for the retrofits of roof, exterior walls, and ground floor are analyzed along with changing windows and doors with varying thermal transmittance values. The cost-effectiveness analysis is based on the net present value of the investment costs of the energy-efficiently measures and the achieved energy cost saving. Different economic scenarios and renovation cases are considered in techno-economic analyses to determine the cost-effective energy-efficiency retrofit measures. The results indicate that improved windows reduce energy demand for space heating by up to 23% and yield the highest final energy savings. However, additional mineral wool roof insulation is the most cost-effective measure under all economic scenarios. This measure gave the lowest ratio of cost effectiveness of about 0.1, which was obtained under the stable scenario. The final energy savings that can be achieved in a cost-effective manner vary between 28% and 61%, depending on the economic scenario and renovation case. This analysis emphasizes the influence of different renovation cases and economic parameters on the cost effectiveness of passive energy-efficiency measures. Full article

To prevent brittle damage and improve the post-earthquake rapid repair capability of beam-column connections, a precast reduced beam section (PRBS) connection joint that can be rapidly repaired under earthquake action was proposed in this study. Four specimens, including a repaired specimen, were subjected to a quasi-static test to investigate the seismic performance and repair ability of the connection. Seismic performance indices such as the failure mode, hysteresis curve, skeleton curve, strain distribution, and ductility were obtained through observations and analyses. The results indicated that the novel connection exhibited superior load-bearing, energy dissipation, and rotation capacities, compared to the welded flange-bolted web and traditional bone-weakened connections. This novel connection effectively relocated the plastic hinge to alter the failure mode and prevent brittle damage. Additionally, rapid post-earthquake repair was achieved by replacing the dog-bone-style splice section, maintaining a high load-bearing capacity and seismic performance. Finite element (FE) models were established to analyze the mechanical behavior of the specimens, and a parametric analysis was conducted to study the influence of different parameters on the load-bearing capacity of the connection. Based on the experimental and FE analysis results, the possible yield and failure modes of the connection were analyzed, and a calculation method for the bearing capacity of the PRBS connection was proposed. A comparative result demonstrates that the proposed calculation method can accurately predict the load-carrying capacity of a connection. Full article

This article presents the cracking and load-bearing behaviour of carbon-reinforced prismatic concrete tensile specimens. Grids with different geometries and impregnations were used as carbon reinforcement. In addition, the roving surfaces were partially coated with a fine sand to improve the bond between concrete and reinforcement. The article shows the influence of the different parameters on the developing cracks with respect to their width and spacing from each other. The material properties and tensile strengths of carbon concrete are also presented. These can be used for calculations. A fine-grained, commercially available shotcrete was used for the investigations. Based on the tests and results described in this article, an influence of the sanded carbon grids on the crack properties (crack widths, crack spacing) could be shown in comparison to unsanded carbon grids. Full article

Monitoring of non-structural elements is not usually implemented, despite the seismic vulnerability of these components and the significant cost associated with their replacement in case of damage. By exploiting the limited cost of commercial sensors, accelerometers were installed in an existing building to compare accelerations applied to non-structural elements in case of an earthquake with critical acceleration thresholds. The exceedance of these thresholds would indicate a possible danger for the occupants and the need for a more detailed inspection of the element, guiding prioritisation strategies in the aftermath of the earthquake. Furthermore, the real-time probabilistic assessment of potential damage to non-structural elements can serve to identify escape routes and facilitate rescue operations. Critical acceleration thresholds were defined from probabilistic considerations on the expected seismic performance of each typology of non-structural element, described by appropriately selected fragility curves. The feasibility of the proposed procedure was tested by comparing the identified acceleration thresholds with the design values of floor acceleration provided by the Italian Building Code. As a further application, critical acceleration values of the different non-structural elements were compared with a set of real floor acceleration values recorded at the top level of reinforced concrete buildings, highlighting critical non-structural element typologies. Full article

The use of renewable building materials in construction is crucial to minimising the environmental impact of new buildings. Bio-based building materials have a wide range of positive properties, many of which are due to their hygroscopic behaviour. The purpose of this study is to investigate the hygrothermal performance of chopped straw, sheep’s wool, and cellulose insulated timber frame external wall assemblies in the presence of air leakage and high indoor relative humidity. For this purpose, tests with different moisture contents, overpressures, and defects in the airtight layer were carried out in an outdoor test stand over a period of 18 months. The results were compared with a conventional mineral wool insulated construction. Both sheep’s wool and cellulose are particularly fault-tolerant insulation materials in combination with timber frame constructions. All three bio-based insulations, despite defects in the airtight layer, showed no mould-prone moisture content. An installation level insulated with sheep’s wool can increase the fault tolerance of constructions with insulation made of hygric and more sensitive building materials. For chopped straw and cellulose, the measured U-value was lower than expected. Further in situ measurements of bio-based structures are important to gain confidence in their hygrothermal behaviour and to increase their use in multi-storey construction. Full article

The color of urban streets plays a crucial role in shaping a city’s image, enhancing street appeal, and optimizing the experience of citizens. Nevertheless, the relationship between street color environment and residents’ perceptions has rarely been deeply discussed, and most of the existing studies adopt qualitative methods. To accurately and effectively assess the connection between street color environment and residents’ emotional perceptions, this paper introduces a quantitative research framework based on multi-source data called “Color Emotion Perception with K-Means, Adversarial Strategy, SegNet, and SVM (CEP-KASS)”. By combining K-Means unsupervised machine learning and SegNet computer vision techniques, it captures and analyzes visual elements and color data from Baidu Street View Images (BSVI). It then employs a human–machine adversarial scoring model to quantify residents’ perceptions of BSVI and uses the support vector machine regression model to predict the final perception scores. Based on these data, a Pearson correlation analysis and visual analysis were conducted on the elements and color in the urban environment. Subsequently, the streets were classified based on perception frequency and perception scores by integrating multi-source data, and areas within the third ring of Xuzhou City were selected for validating the research framework. The results demonstrate that utilizing street-view images and the CEP-KASS framework can quantitatively analyze urban color perception and establish a connection with residents’ emotions. In terms of color perception, red, orange, and blue all have a strong positive correlation with the interesting score, whereas black is positively correlated with a sense of safety. Regarding color attributes, low-saturation bright colors result in higher fun perception scores in urban spaces; too low saturation and brightness can affect their attractiveness to residents; brightness has an inverse relationship with the perception of safety, and adjusting brightness inversely can improve the perceived safety experience in certain urban external spaces. The street classification criteria based on perception frequency and perception scores proposed herein can provide references for planners to prioritize color transformation decisions, with a priority on emulating HSHF streets and transforming LSHF streets. When formulating color planning, suggestions for color adjustment can be given based on the correlation study of color with visual elements and perception scores, optimizing urban residents’ spatial perception and their emotional experiences. These findings provide robust theoretical support for further enhancing the visual quality of streets and refining urban color planning. Full article

The construction sector is one of the leading global contributors to environmental footprint, with road infrastructures being a significant resource consumer. The traditional practice of using virgin raw materials and extracting natural aggregates has a significant impact, causing landscape alterations and disruptions to ecosystems. As result, the focus on achieving sustainable mobility through road networks is increasing. Companies operating in the civil sector must consider the environmental performance of roads to inform their decision making. Various assessment tools are available, with life cycle assessment being a commonly employed methodology in the industrial sector. However, its application to infrastructure projects has inherent challenges, primarily due to the complexity associated with inventory management. This complexity has resulted in a limited adoption of LCA within this sector. This research explores the suitability and compatibility of existing tools, methodologies, and databases, while establishing future requirements to adapt LCA and other types of environmental analysis to the life cycle of roads. To achieve this objective, a comprehensive analysis of the scientific and technical literature is conducted in this study. The findings highlight the need for more versatile impact analysis tools, including specialized databases tailored to the specifics of road infrastructure. Such enhancements would facilitate the application of procedures outlined in ISO 14040 and ISO 14044 standards. Full article

Addressing safety risks in construction is an ongoing priority, and integrating safety considerations into construction scheduling is a crucial aspect of this effort. A notable challenge is the safety risk posed by concurrent tasks, which has received limited attention in prior research. This study aims to address this research gap by introducing a novel Building Information Modeling (BIM)-based model that assesses the increased hazardousness resulting from overlapping construction activities. Historically, research has predominantly focused on individual task safety, with less emphasis on the risks associated with overlapping activities. Our innovative approach introduces the concept of a ‘source–target’ match, which evaluates the degree of hazardousness escalation when activities overlap. Drawing on data from the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) fatal accident reports, we extracted 11 hazardous and 9 susceptibility attributes to build a source–target match table. This table reveals the characteristics of activities that generate hazardous conflicts when overlapping. The key contribution of this research is the assessment, prioritization, and visualization of risk levels in a BIM environment. This framework empowers safety managers to proactively address safety risks resulting from overlapping construction activities, ultimately reducing accidents in the construction industry. By shedding light on this overlooked aspect of construction safety, our research highlights the importance of integrating safety considerations into construction scheduling and provides a practical tool for mitigating risks, enhancing workplace safety, and ultimately improving project outcomes. Full article

Shared bicycle systems play a crucial role in promoting sustainable urban transportation, addressing challenges such as traffic congestion and air pollution. Understanding the spatiotemporal patterns of shared bike usage is essential for optimizing bike-sharing infrastructure and improving transportation planning. In this study, we analyzed 2.4 million records of shared bicycle data to explore the spatial distribution, interaction patterns, and flow dynamics within Beijing’s urban central area. We found that bike distribution peaks during commuting hours, particularly in central regions with employment centers. Complex networks are an important method for studying travel flows. Through a spatial interaction network, we identified key streets with high node strength and popularity, often concentrated in central areas. They experience heavy shared bicycle use during peak hours due to their employment-centric location. Conversely, peripheral areas see increased usage in the evenings, reflecting distinct commuting patterns. The morning exhibits higher positive central values compared to the evening, while negative values show the opposite trend. Based on these findings, we recommend enhancing bike infrastructure in high-density areas with bike lanes and ample shared bikes during peak hours. Implementing mixed-use zoning policies in the central region can reduce traffic congestion. Expanding shared bike services to peripheral regions can promote equitable access. This research underscores the importance of considering spatial and temporal factors in urban transportation planning. Future work should incorporate additional data sources, explore environmental impacts, and analyze usage in different seasons and special events, further contributing to sustainable urban mobility development. Full article

A common strategy for studying the nonlinear vibrations of beams is to discretize the nonlinear partial differential equation into a nonlinear ordinary differential equation or equations through the Galerkin method. Then, the oscillations of beams are explored by solving the ordinary differential equation or equations. However, recent studies have shown that this strategy may lead to erroneous results in some cases. The present paper carried out the following three research studies: (1) We performed Galerkin first-order and second-order truncations to discrete the nonlinear partial differential integral equation that describes the vibrations of a Bernoulli-Euler beam with initial curvatures. (2) The approximate analytical solutions of the discretized ordinary differential equations were obtained through the multiple scales method for the primary resonance. (3) We compared the analytical solutions with those of the finite element method. Based on the results obtained by the two methods, we found that the Galerkin method can accurately estimate the dynamic behaviors of beams without initial curvatures. On the contrary, the Galerkin method underestimates the softening effect of the quadratic nonlinear term that is induced by the initial curvature. This may cause erroneous results when the Galerkin method is used to study the dynamic behaviors of beams with the initial curvatures. Full article

Both Tulous (土楼) and Weilong Houses (围龙屋) are important types of traditional Hakka (客家) dwellings whose architectural morphology is closely related to the historical origin, social organisation, and cultural values of Hakkas. Previous studies focused on the influence of Chinese traditional etiquette systems and ritual values on the physical morphology of Hakka traditional dwellings, where ancestral halls are often the core of the entire building. This article selects six typical case studies of Tulous and Weilong Houses and launches a comparative study on their spatial configurations through quantitative analysis of space syntax. This study found that compared to Tulous, Weilong Houses exhibit decentralisation and gridification in their spatial structure, in addition to a decrease in defence capability and an increase in residential privatisation. The ancestral hall of the Tulou is still the spiritual and living centre of Tulou residents, located in the geometric centre and possessing high spatial configurational values. However, although the ancestral hall of the Weilong House is still located in the geometric centre of the entire building, it does not exhibit the highest spatial configurational values, indicating that the increase in secularisation and the decrease in ritualisation of Hakka communities inhabiting Weilong Houses resulted in the separation of secular space and ritual space. It coincides with the “Centre–Periphery” distribution characteristics of Hakka communities related to Tulous and Weilong Houses, reflecting the different community existence paradigms of the Hakkas “landed” and “rooted” in the Guangdong–Fujian–Jiangxi border area. Full article