Buildings, Volume 13, Issue 12 (December 2023) – 240 articles

The architectural heritage directly related to the refugees from Europe who came to the USA as a result of World War II is still an under-researched topic. New post-war arrivals from the displaced persons camps resulted in a sizeable growth of the already well-established Lithuanian community, infusing it with highly educated professionals. This also included many architects who needed to adapt and continue their practice in a different environment while also finding a way to be useful for the objectives of their national group. The aim of this paper is to examine the architectural legacy of the Lithuanian community in the post-war decades in the USA, emphasizing buildings that were designed with a specific aspiration to implement national character. Research finds that buildings built for the Lithuanian community carried a strong symbolical language that was a peculiar, yet enriching case, in regard to the then-dominant mid-century modernist trends. These structures show the determination of the national group to use their built environment as a medium to reinforce their identity and use architecture as a political statement. The paper proposes to interpret this politically motivated and stylistically distinctive architecture as monuments testifying to the political atmosphere of the Cold War. In this way, the heritage value of these buildings is linked not to avant-garde architectural styles, but to the political needs of a specific community in exile. Full article

Epoxy resin concrete has superior mechanical properties compared to ordinary concrete, and will play an increasingly important role in urban construction. In this paper, the application effect and prospect of epoxy resin concrete in precast composite frame structures are discussed. Taking the joint surface of the old and new concrete at the end of the composite beam as the research object, three specimens were devised and fabricated. Subsequently, a horizontal cyclic load test was conducted, and the seismic performance indices were analyzed. Multiple finite element models were established to assess the influence of precast concrete strength, the diameter of the longitudinal bar of the beam, the shear span ratio, and the epoxy resin concrete post-cast area, among other factors, on the seismic performance of the beam end. Four findings indicate the following: Firstly, epoxy resin concrete, characterized by its high performance attributes, can be used as a post-cast material in precast concrete structures. Secondly, when the strength of the post-cast epoxy concrete approximates or slightly exceeds that of the precast concrete, and the ratio of longitudinal reinforcement and shear span ratio are appropriately balanced, the operational performance of the composite beam frame structure is enhanced. In addition, when post-cast epoxy resin concrete is employed in the beam-column joint area, the mechanical performance of the composite beam end in the joint area matches or even surpasses that of the structure that was cast in situ. And subsequently, the expansion of post-cast area resulted in better mechanical performance. Finally, when the area of post-cast epoxy resin concrete is a non-node area, the mechanical properties of the composite beam end are worse than the former. However, the amount of epoxy resin concrete used will be greatly reduced, and as the precast node area expands, the bearing capacity of the beam end will increase and gradually approach the cast-in situ structure, indicating that this construction scheme also has advantages. Full article

“Context” holds a broad meaning in architectural discourse, and its definition and components have evolved over time. A comparison between contemporary parametric design and overall architectural practices reveals a contradictory connotation of context in these discourses. In parametric design, as it is currently practiced, the concept of “context” appears to have shifted primarily toward energy considerations and quantifiable parameters, neglecting the broader range of site forces. However, it raises the question of whether parametric design can still be considered contextual and sustainable design when it overlooks compatibility with broader contextual dimensions such as cultural, social, and historical forces. To answer this question, we establish a clear and comprehensive definition of “context” in overall architectural practices by exploring the different meanings and epistemologies of “context” in cultural, social, historical, physical, environmental, political, and economic domains. This process helps us determine which context components can be incorporated into parametric architecture and which cannot, thereby aiding in the integration of sustainability principles into parametric design. The results show that while physical and environmental components can be included in parametric architecture, intangible parameters such as cultural, historical, social, economic, and political aspects cannot be easily quantified and thus are difficult to incorporate. Full article

Although an increase in walking is recommended to improve physical activity and public health, especially among older adults, the frequency of outdoor pedestrian activities, including walking, should be reduced when there is increased air pollution. There is limited understanding of the inter-relationships between two research fields, namely, older adults walking behavior and air pollution. This study investigates these factors and identifies their relationships with associated built environment factors. More than 200 peer-reviewed journal articles that met the selection criteria were analyzed. The factors pertaining to air pollution in the built environment were classified based on the scale of the urban environment. Comparing the built environment factors related to both fields of study, several common features such as the type of street enclosure (urban spatial), sky view factor (urban spatial), percentage of front gardens (urban design), and land use patterns were identified. Furthermore, we found that it is important to understand how the subjective/objective measures of the urban-design-related factors identified on the street are linked to air pollution at both street and neighborhood scales. A wide range of urban vegetation factors (pattern, size, and density) in both fields of study at a street scale were also identified. These inter-relationships need to be examined by future studies to get a clearer picture of the factors which might improve walking behavior among older adults while reducing the air pollution in urban environments. Full article

In this study, the energy consumption and generation characteristics, the operation status of a photovoltaic (PV) system, and the energy balance of a net-zero energy building (nZEB) in South Korea were analyzed based on the data collected over a 10-year period (2012–2021). The average annual power consumption of the nZEB was 101.3 MWh, 6.2% higher than the estimated power consumption. The PV system of the nZEB had an annual power generation capacity of 105.8 MWh, indicating an increase of 10.6% compared to the estimated value. The failure of PV systems such as module cracks, inverter failures, and performance degradation led to a decrease of 21.5% in the power generation. Energy balance analysis was conducted by comparing the energy consumption and generation data based on yearly, monthly, daily, and hourly time intervals. In addition, load coverage factor (LCF) and supply coverage factor (SCF) were used to evaluate the load matching rate. The nZEB achieved a net-zero energy status for 5 out of the 7 years of normal operation (2012–2018) based on average annual data. However, the energy balance analysis using hourly measured data showed that there was both a surplus and a shortage of power every year, and that the average annual power surplus and shortage were 56.4 MWh and 54.3 MWh, respectively. In addition, the load matching analysis showed that the annual LCF and SCF were approximately 0.36 and 0.32, respectively. Thus, the advanced nZEB design, hourly data-based energy analysis, fault diagnosis and maintenance, and the strategies enhancing the self-consumption rate should be considered to expand nZEB dissemination. Full article

Clay soil has poor engineering properties such as poor permeability and low shear strength. Waste steel slag is an industrial by-product formed in the furnace during the steelmaking process which has high quality, durability, anti-slip properties, gelling, high permeability and good particle interlocking properties. Therefore, in order to improve the engineering properties of clay and increase the utilization rate of waste steel slag, the steel slag was mixed into the clay. Steel slag clay mix was used for the straight shear test, cyclic shear test and post-cyclic straight shear test. To investigate the strength characteristics, damping ratio, shear stiffness variation and mixed soil displacement at the reinforcement-soil interface under different steel slag dosing, vertical stress, moisture content and shear amplitude conditions. The test results show that steel slag can significantly improve the shear strength of the clay tendon-soil interface, and the improvement effect is better than the conventional material sand improved clay. The steel slag mix has a large damping ratio and shear stiffness, suggesting that it has good damping and energy dissipation properties. In this case, the shear strength, damping ratio and shear stiffness of the soil mix at 40% steel slag admixture are better. The shear strength of the steel slag mix is increased after cyclic loading compared to straight shear before cyclic loading. In addition, the water content has a greater effect on the shear strength parameters, shear stiffness and damping ratio of the steel slag clay mix compared to the vertical stress and shear amplitude. The test results can provide a theoretical basis for the replacement of sand by steel slag in improving clay soils. Full article

The present study was conducted to clarify the flexural behaviors of the Composite Girders of a Prestressed Segmental Ultra-High-Performance Concrete (UHPC) Channel and a Reinforced Conventional Concrete Deck (PSUC-RCCD). The girders can be used as bridge superstructures with the advantages of structural efficiency, cost-effectiveness, and easy construction. A total of five specimens were tested. Three of them were PSUC-RCCD specimens, including two semi-segmental girders (the channel beams were composed of five segments with dry-joints) and one integral girder (the channel beams were integral ones without dry-joints). The two other specimens were P-UHPC girders composed of PSUC and UHPC deck slabs; one was semi-segmental and the other was integral. The flexural behaviors of the specimens were investigated, including the load-displacement curves, crack distribution, cracking moments, and ultimate flexural capacity. The study compared the influence of the segment number and deck material on the flexural behaviors of semi-segmental girders and introduced and validated methods for calculating the cracking moment and flexural capacity of both semi-segmental and integral sections in PSUC-RCCD and P-UHPC girders. The results show that the entire loading process of all the specimens can be classified into the elastic phase, the cracks development phase, and the failure phase. Compared to the integral girders, the number of segments has little effect on the flexural behavior of the semi-segmental girders, but it has a significant effect on the cracking moments. The cracking moments of the semi-segmental girders is only 0.58~0.60 of the integral girders. Reducing the strength of the deck slab by changing the material from UHPC to CC does not significantly affect their flexural behaviors. Based on the test results, this work proposes a method for predicting the cracking moment and flexural capacity of the semi-segmental girders, the results of which fit well with the test results, and it is applicable in the structural design of such members. Full article

Rubberised concrete has emerged as a material of interest to the research community with the mission of creating sustainable structural members and decreasing the burden of waste tyre rubber. The potential benefits of replacing natural aggregates with rubber particles to obtain greater energy absorption and ductility are proven in the literature. To negate the reduction in capacity due to the addition of rubber particles, single- and double-skin confinements were proposed and successfully tested by researchers. Hybrid rubberised double-skin tubular columns (RuDSTCs) were recently trialled and tested by the authors. Each of these hybrid RuDSTCs had a filament-wound carbon fibre-reinforced polymer (CFRP) outer tube and an inner steel tube with rubberised concrete as the sandwich material between the two tubes. To explore the axial behaviour of such a column, this paper develops a finite element modelling strategy and carries out a comprehensive parametric study of the hybrid RuDSTC with 0%, 15%, and 30% combined aggregates replaced with rubber particles. This methodology is validated by experimental results, and a good agreement is found. Hybrid RuDSTC models are developed in four groups with different material and geometric parameters, in addition to those corresponding to the experimentally tested column, to explore the effects of the thickness ratio, hollow ratio, steel tube yield strength, and CFRP tube diameter with a special focus on the transition of the characteristic bilinear stress–strain curve of the hybrid RuDSTCs. The results show the smooth transition of the stress–strain curve with increasing rubber content after the yielding of steel, which indicates better ductility of the rubberised columns. The novel hybrid RuDSTCs can provide a promising sustainable solution with greater capacity compared with their unconfined counterparts. Better strain and enhanced ductility of the hybrid RuDSTCs compared with non-rubberized hybrid DSTCs enable their use in seismic-prone regions and mining infrastructure. Full article

Risk management practices are critical for construction companies to prevent any problems caused by uncertainties in the projects. This study examines how risk management is practiced in construction projects of the Somali Regional State in Ethiopia. It also identifies the most influential risk factors in the region which need to be given a higher consideration when practicing risk management. Within this context, a questionnaire survey was conducted among construction professionals in the Somali region. Based on the findings, there is a deficient practice of risk management in Somali Regional State construction projects due to a lack of knowledge or budget. Risk factors like design errors, top management changes, insufficient experienced staff, and delays in payment are found to have the highest probability of occurrence in Somali Regional State construction projects. Findings from this study can help construction managers to better understand the risk factors influencing construction projects in the Somali region in the context of improving project performance. Full article

Structural health monitoring (SHM) is critical to maintaining safe and reliable civil infrastructure, but the optimal design of an SHM sensing system, i.e., optimal sensor placement (OSP), remains a complex challenge. Based on the existing literature, this paper presents a comprehensive review of OSP strategies for SHM. It covers the key steps in OSP, from evaluation criteria to efficient optimization algorithms. The evaluation criteria are classified into six groups, while the optimization algorithms are roughly categorized into three classes. The advantages and disadvantages of each group of methods have been summarized, aiming to benefit the OSP strategy selection in future projects. Then, the real-world implementation of OSP on bridges, high-rise buildings, and other engineering structures, is presented. Based on the current progress, the challenges of OSP are recognized; its future development directions are recommended. This study equips researchers/practitioners with an integrated perspective on state-of-the-art OSP. By highlighting key developments, persistent challenges, and prospects, it is expected to bridge the gap between theory and practice. Full article

Recent advancements in virtual reality (VR) technology have enabled its integration into learning diverse aspects of spatial components and relationships in the field of spatial design, as well as designing, communicating, collaborating, and managing complex building projects. With the growing interest in incorporating VR technology in spatial design, examining whether people understand, perceive, and perform spatial tasks in the same way in VR as they do in static modes is essential. Thus, the purpose of this study was to compare spatial ability performance in a conventional static paper–desktop mode and an interactive VR mode. Thirty students completed the Architecture and Interior Design Domain–Specific Spatial Ability Test in both modes. Their visual cognitive style was measured with the Object–Spatial Imagery Questionnaire, and their responses to the usability of the VR mode were analyzed. The results revealed: (a) significant difference in performance between static and VR modes, including better performance in three spatial visualization subconstructs in static mode than in VR; (b) no gender difference in VR mode; (c) a tendency of spatial visualizers to benefit from VR mode; and (d) a tendency of people with high spatial ability to be more susceptible to test mode. Overall, the results contribute to expanding our understanding of spatial ability performance in different test modes and provide insights concerning the integration of VR into the development of spatial ability tools and education. Full article

Many researchers are developing heating construction materials to remove black ice from roads, addressing the scientific challenges associated with this issue. The use of carbon-based nanomaterials in concrete is of great interest due to the excellent electrical and thermal conductivity of this material. In this study, the incorporation of multi-walled carbon nanotubes (MWCNTs) into concrete compositions results in the formation of MWCNT bridge networks. MWCNTs exhibit a low specific heat and possess the ability to promptly generate raised temperatures with minimal power input. This characteristic has the potential to induce temperature variations in concrete. The heat generation test parameters for MWCNT concrete included the mixing concentration of the MWCNTs, the mixing ratio of coarse aggregate, the water/cement (W/C) ratio, and the presence or absence of superplasticizers. The heating performance of concrete was found to improve as the mixing concentration of the MWCNTs increased, while a heating performance decrease was observed as the mixing ratio of coarse aggregate increased, owing to the reduced dispersibility of the MWCNTs. Conversely, the heating performance improved when the W/C ratio increased due to the enhanced dispersibility of the MWCNTs. Moreover, superplasticizers assist in dispersing MWCNTs, thereby improving the heating performance. Additionally, field emission scanning electron microscopy revealed that MWCNTs form a bridge network between the cement hydrates. As a result of this study, the maximum temperature variation of concrete mixed with MWCNTs was up to 73.6 °C. Therefore, by mixing MWCNT aqueous solutions with concrete and using an appropriate W/C ratio and superplasticizer, a new construction material capable of enhanced heating performance was developed. Full article

Project sustainability has become a research hotspot in the construction industry and a crucial driving force for the successful delivery of projects. How enterprises can improve project sustainability performance and realize sustainable development by applying BIM has become an important research topic. In this study, based on the resource-based view and institutional theory, a relationship model of BIM application affecting project sustainability performance is constructed, and data from 449 questionnaires with electric power construction industry practitioners obtained by the two-stage data collection method are used to explore the relationship between BIM application and project sustainability performance, and to investigate the mediating role of green innovation and the moderating role of institutional pressures. The study found that: (1) BIM application has a significant positive impact on project sustainability performance; (2) BIM application has a significant positive predictive effect on green innovation, and green innovation plays a mediating role in the relationship between BIM application and project sustainability performance; and (3) under a high degree of institutional pressures, the positive relationship between BIM application and green innovation is strengthened, and, in this case, the mediating role of green innovation is enhanced. The study results help to expand the theoretical analysis of the relationship between BIM application and project sustainability performance and provide practical guidance for improving project sustainability. Finally, the data in this study only come from the power construction industry and do not differentiate between the types of green innovations, and further research could be conducted on these two aspects in the future. Full article

Nowadays, heat exchangers find widespread use across various applications in different fields, particularly in the field of heat recovery. This paper provides a detailed explanation of a plate heat exchanger counter-flow model developed in Simulink/Matlab. Water was employed in simulations for both circuits, although the thermal properties of other fluids can be investigated by modifying them. The “Tanks in series” method was used for simulation purposes. The developed model enables users to explore the impact of various parameters on heat exchanger functionality, such as altering the number of plates, the material or thickness of the plates, and the nature of thermal agents (gaseous or liquid). These models play a crucial role not only in simulating and sizing heat exchangers but also in achieving parametric optimization. Parameter variations can be employed to examine the operation of existing equipment under conditions different from their design specifications. The Simulink/Matlab proposed model, featuring a variable number of finite volumes to ensure high accuracy, was compared to the classical design method for plate heat exchangers. The results revealed good accuracy, with relative errors for heat transfer rate remaining below 2.6%. This research also considered the study of the number of finite volumes necessary for achieving accurate results. For the 40 finite volumes model, the relative error for heat transfer rate is less than 10%. Dividing the mesh into 50 finite volumes along the fluid flow direction resulted in relative errors ranging from 1.6% to 1.7%, indicating that a finer mesh was not necessary. To validate the conceived model, experimental data from the literature were compared. The relative errors for heat transfer rate between the Matlab/Simulink model’s results and experimental data ranged from 1.58% to 11.92%, demonstrating a strong agreement between the conceived model and the experimental values. Full article

Views, drawings, and data extracted from building information modeling (BIM) constitute essential deliverables throughout the lifecycle of an architecture, engineering, and construction project, offering crucial insights for comprehending the design. Nevertheless, many employers evaluating BIM deliverables lack standardized criteria for the specific intended use of each BIM outcome, which hampers the practical utility of BIM results. This study introduces a quantitative evaluation method for the management of BIM-based two-dimensional (2D) deliverables. The BIM outcome measurement index for 2D deliverables (BOMI-2D) is formulated to provide a quantitative assessment of BIM data, focusing on their composition, structure, data readiness, and consistency. Pilot tests validated the efficacy of BOMI-2D, revealing an impressive 88.3% reduction in additional work required for 2D deliverables when data readiness increased by 25% and consistency improved by 32%. BOMI-2D is poised to play a pivotal role as an evaluation index for BIM data and outcomes, ultimately enhancing their utilization and productivity. Full article

This paper addresses the deep renovation and enhancement of energy efficiency in existing urban areas, aiming to transform them into zero energy districts, utilizing renewable sources. This transformative process is essential to align with contemporary models for new buildings and to elevate existing structures to meet environmental housing standards mandated by current regulations. The proposed densification strategy is motivated by the necessity to augment the real estate value and enhance the architectural and performance quality of the existing building stock, all while minimizing additional land occupation. Its efficacy has been rigorously tested and demonstrated within the European Horizon 2020 project “ABRACADABRA”. The key actions advocated for in this approach revolve around the incorporation of renewable energies, volumetric expansion, and completion volumes (urban infill), within the Positive Energy District. The validation of this process occurs on a district scale in a social housing urban block located in Bologna (Italy), with currently poor environmental performance. A multi-criteria analysis was employed to examine the architectural, climatic, and energy context. The meta-design phase successfully attained the energy and economic targets set by the project and by local and European regulations settings, offering an optimized design solutions for reshaping the built environment. Full article

Relationship management among different stakeholder groups plays an increasingly important role in construction innovation, which could explain the growing interest in stakeholder relationship studies of construction projects (SRCP) over the last two decades. However, most of the recent literature review studies have focused on stakeholder management, and there are very few studies systematically describing what types of relationships actually exist in construction projects. To fill the gap, a mixed-methods review is conducted to explore the state-of-the-art work on SRCP. 312 relevant peer-reviewed journal articles published between 2000 and 2022 were examined and analyzed using data from the Scopus and Web of Science databases. A follow-up systematic review of the identified literature was conducted with three main objectives: identifying the main research category, summarizing the main research topics, and proposing future research directions. It was found that over the past 20 years, SRCP has been extended to a greater variety of research topics, such as information technology, which needs to take into account the multi-dimensional research agendas. Overall, this study contributes to the research field in the SRCP domain by offering insightful information on the current state of SRCP and proposing potential future directions for research. Full article

Source location identification methods are typically applied to steady-state conditions under pure indoor or outdoor environments, but under time-varying wind conditions and coupled indoor and outdoor environments, the applicability is not clear. In this study, we proposed an improved adjoint probability method to identify the pollutant source location with time-varying inflows in street canyons and used scaled outdoor experiment data to verify the accuracy. The change in inflow velocity will affect the airflow structure inside the street canyons. Outdoor wind with a lower temperature will exchange heat with the air with a higher temperature inside the street canyon, taking away part of the heat and reducing the heat of the air inside the street canyons. Moreover, the room opening will produce some air disturbance, which is conducive to the heat exchange between the air near the opening and the outdoor wind. Furthermore, the fluctuations of the upper wind will influence the diffusion of the tracer gas. We conducted three cases to verify the accuracy of the source identification method. The results showed that the conditioned adjoint location probability (CALP) of each case was 0.06, 0.32, and 0.28. It implies that with limited pollutant information, the improved adjoint probability method can successfully identify the source location in the dynamic wind environments under coupled indoor and outdoor conditions. Full article

Building solar protection regulations is essential to save energy in hot climates. The protection performance is assessed using a shading factor computation that models the sky irradiance and the geometry of shadow obstructing the surface of interest. While Building Information Modeling is nowadays a standard approach for practitioners, computing shadow geometry in BIM authoring tools is natively impossible. Methods to compute shadow geometry exist but are out of reach for the usual BIM authoring tool user because of algorithm complexity and non-friendly BIM implementation platform. This study presents a novel approach, dubbed solid clipping, to calculate shadow geometry accurately in a BIM authoring tool. The aim is to enhance project delivery by enabling solar control verification. This method is based on typical Computer Aided Design (CAD) in BIM authoring tools. The method is generic enough to be implemented using any BIM authoring tool’s visual and textual API. This work demonstrates that a thermal regulation, here the French overseas one, can be checked concerning solar protection, thanks to a BIM model. Beyond automation, this paper shows that, by directly leveraging the BIM model, designs presently not feasible by the usual process can be studied and checked. Full article

In this study, the engineering properties of basalt aggregate used for asphalt road pavement on Jeju Island were evaluated, and the characteristics of the asphalt mixtures used were evaluated to assess the suitability of Jeju Island basalt as road construction material. Chemical composition and surface morphology analysis of the basalt and granite aggregate, engineering characteristics analysis, and filler property evaluation were performed. Mix design was performed, and the basic properties of three asphalt mixtures for the surface, intermediate, and base layers were evaluated. Permanent deformation resistance was evaluated through a wheel tracking test, and moisture resistance was evaluated through a dynamic immersion test and a tensile strength ratio test. The optimum asphalt contents of the asphalt mixture using low-porosity basalt aggregate and high-porosity basalt aggregate were determined to be 5.7% and 5.9% in the surface layer, 5.3% and 5.4% in the intermediate layer, and 4.7% and 5.1% in the base layer, respectively. It was found that the basic properties of the asphalt mixtures satisfied Korean quality standards. The dynamic immersion test results of low-porosity basalt aggregate and high-porosity basalt aggregate were 20% and 10%, respectively, which fall far below the quality standard of 50%. The tensile strength ratios of the basalt asphalt mixtures for the intermediate layer were 0.69 and 0.40, and they were found to increase significantly to 0.87 and 0.80 after the application of a suitable anti-stripping agent. Therefore, it was concluded that in order to apply Jeju Island basalt to asphalt pavement, an appropriate anti-stripping material must be applied. Full article

There are many problems in the development of urban space in China. Among them, urban tunnels generally pass through many sections with very complicated geological conditions, and the construction will encounter great difficulties, so the mechanical behavior of shield segments in different complex strata is worth discussing. In this paper, the axial force, bending moment and pore water pressure of shield tunnel segments in the soft and hard uneven stratum, clay stratum and fully weathered granite stratum of overlying buildings are studied by establishing a rectangular element mechanical model based on the field test method. The analysis shows that the mechanical properties of shield tunnels in different strata are quite different, but their mechanical properties change stages are the same. The earth pressure on the left and right sides of the test ring is asymmetric in the soft and hard uneven stratum, and the vault pressure is much greater than the vault bottom pressure. The distribution of earth pressure in each position of the segment ring in clay stratum is relatively balanced, and the earth pressure on both sides is relatively small; in the fully weathered granite layer of the overlying building, the segment ring of the test ring is subjected to greater additional stress, and the internal force of the segment is much greater than that without the overlying building. Exploring the similarities and differences of segment stress in these three complex strata can provide an important basis for the design and construction of shield segments in complex strata. Full article

Power construction projects (PCPs) consume a large amount of energy and contribute significantly to carbon emissions. There is relatively little research on carbon emission reduction in PCPs, especially in predicting carbon emission reduction from a dynamic perspective. After identifying the influencing factors that promote the carbon emission reduction effect of PCPs, this study adopted a dynamic analysis method to elucidate the relationship between the variables. A quantitative carbon emission reduction system for PCPs with 51 variables was established using the system dynamics model, and the system simulation was performed using Vensim PLE software. Finally, a sensitivity analysis was conducted on four key factors: R&D investment, the prefabricated construction level, the scale of using energy-saving material, and the energy efficiency of transmission equipment. The results show that: (1) The reduction in carbon emissions from PCPs continues to increase. (2) R&D investment is the most significant factor for improving the carbon emission reduction in PCPs. (3) The value of the above four influencing factors should be increased within a reasonable range so that the four factors can work better to promote the carbon emission reduction effect of PCPs. This paper creatively proposes a dynamic prediction model for carbon emission reduction in the PCP, and the research results provide the scientific basis for government supervision and enterprise decision-making. Full article

This study presents the performance-based seismic assessment of low-rise reinforced concrete archetype buildings, considering repair costs for ordinary moment-resistant frames (OMF) and dual systems consisting of OMF plus special shear walls (SSW). Historically, the OMF systems, conceived for residential purposes in Ecuador resulting from informal construction, have reported poor responses under seismic forces. This study analyzes damage levels through fragility curves as a function of the maximum global drift reached through incremental dynamic analysis. For this, two archetypes with OMF and two with a similar configuration, including structural walls, are modeled to define a loss function and annual collapse probabilities. As a result, it is noted that systems with structural walls significantly reduce repair costs by between 75 and 90% of the total cost of the building, and prevent collapse. Systems with ordinary moment frames report total losses, implying their use should be limited in areas of high seismicity. Full article

The performance of self-compacting concrete (SCC) is gaining popularity in construction due to its exceptional strength and durability. However, the properties of combined steel and concrete at elevated temperatures lack experimental data from previous research. This study aimed to investigate the behavior of the SCC core with a steel tube at ambient and elevated temperatures varying from 100 °C to 800 °C with 100 °C intervals for each test specimen. Tests were conducted on circular steel tubes filled with SCC for different grades (M25, M30, and M40) under compression at elevated temperatures. Experimental observations revealed that the stress–strain curve increased with increasing the cross-sectional area and grade of concrete. However, increasing the temperature and length-to-diameter ratio reduced the stress–strain curve. At elevated temperatures, confined SCC experienced a smaller decrease in the overall modulus of elasticity when compared to unconfined concrete. Within the compressive elastic region (from 30 °C to 400 °C), there was a significant relationship between lateral strain and longitudinal strain, which was followed by a sudden increase beyond 400 °C. Equations for various design parameters were proposed based on the peak load and confinement factor of confined SCC-filled steel tubes (SCCFSTs) via multiple regression. Moreover, this study developed load–axial shortening curves, identifying significant properties such as the yield strength of confined SCCFSTs, including the load-carrying capacity. The predicted numerical analysis results were well aligned with the experimental results, and the findings contributed valuable insights for designing resilient and durable combined SCC and steel tube infrastructures. Full article

Deep-learning- and unmanned aerial vehicle (UAV)-based methods facilitate structural crack detection for tall structures. However, contemporary datasets are generally established using images taken with handheld or vehicle-mounted cameras. Thus, these images might be different from those taken by UAVs in terms of resolution and lighting conditions. Considering the difficulty and complexity of establishing a crack image dataset, making full use of the current datasets can help reduce the shortage of UAV-based crack image datasets. Therefore, the performance evaluation of existing crack image datasets in training deep neural networks (DNNs) for crack detection in UAV images is essential. In this study, four DNNs were trained with different architectures based on a publicly available dataset and tested using a small UAV-based crack image dataset with 648 +pixel-wise annotated images. These DNNs were first tested using the four indices of precision, recall, mIoU, and F1, and image tests were also conducted for intuitive comparison. Moreover, a field experiment was carried out to verify the performance of the trained DNNs in detecting cracks from raw UAV structural images. The results indicate that the existing dataset can be useful to train DNNs for crack detection from UAV images; the TransUNet achieved the best performance in detecting all kinds of structural cracks. Full article

The efficient and precise identification of cracks in masonry stone structures caused by natural or human-induced factors within a specific region holds significant importance in detecting damage and subsequent secondary harm. In recent times, remote sensing technologies have been actively employed to promptly identify crack regions during repair and reinforcement activities. Enhanced image resolution has enabled more accurate and sensitive detection of these areas. This research presents a novel approach utilizing deep learning techniques for crack area detection in cellphone images, achieved through segmentation and object detection methods. The developed model, named the CAM-K-SEG segmentation model, combines Grad-CAM visualization and K-Mean clustering approaches with pre-trained convolutional neural network models. A comprehensive dataset comprising photographs of numerous historical buildings was utilized for training the model. To establish a comparative analysis, the widely used U-Net segmentation model was employed. The training and testing datasets for the developed technique were meticulously annotated and masked. The evaluation of the results was based on the Intersection-over-Union (IoU) metric values. Consequently, it was concluded that the CAM-K-SEG model exhibits suitability for object recognition and localization, whereas the U-Net model is well-suited for crack area segmentation. Full article

One of the paths to CO₂ emissions reduction in the concrete industry is to use low-clinker cements, providing at the same time the performance of concrete that is adequate for application in concrete structures. This paper explores the impact of the clinker replacement with high amounts of limestone powder (21–70% in the powder phase) on concrete carbonation resistance. To quantify this impact, the empirical relationship between the carbonation resistance and the compressive strength of the high-volume limestone powder concrete (HVLPC) was established. For that purpose, the regression analysis was applied on the experimental results collected from the published research. The service life analysis based on the full probabilistic approach was performed using the fib Model Code 2010 prediction model and proposed empirical relationship. The first-order reliability method (FORM) was applied to solve the limit state function of reinforcement depassivation with a reliability index equal to 1.3. The obtained minimum concrete cover depths were 40–110% higher compared to those prescribed in the current European standard EN 1992-1-1:2004 for indicative strength classes. Based on the full probabilistic analysis, recommended cover depths are given for all carbonation exposure classes, commonly applied concrete strength classes, and service lives of 50 and 100 years. Full article

Air pollution is a rising environmental concern that has detrimental effects on human health and the environment. Building environment and urban green space features play a crucial role in the dispersion and accumulation of air pollutants. This study examines the impacts of building environment and urban green space on air pollution levels in the highly urbanized city of Hong Kong, focusing on their interaction effects and potential nonlinearity. For the analysis, this paper investigates how building density, building height, building types, urban green space size, and number of urban green space clusters, as well as their interplays, impact PM_2.5 concentrations using high-resolution, satellite-based PM_2.5 grids coupled with spatial analysis techniques. The findings reveal that a unit increase in the size of urban green space and the standard deviation of building height contribute to a 0.0004 and a 0.0154 reduction in PM levels, respectively. In contrast, air pollution levels are found to be positively associated with building density (0.1117), scatteredness of urban green space (0.0003), and share of commercial buildings (1.0158). Moreover, it has been found that building height presents a U-shape relationship with PM_2.5 concentrations. Finally, the negative association between the size of urban green space and air pollution levels tends to be enlarged in districts with more low-rise buildings. This study conveys important building environment and urban green space planning implications. Full article

The COVID-19 pandemic has catalyzed global efforts toward transitioning to a sustainable society, driving rapid innovation in building technologies, working practices, building design, and whole life cycle environmental impact consideration. In this pursuit, this study explores the enduring impact of these on an alternative ventilation approach for both existing building renovations and new building implementations. Comparing displacement ventilation to mixed-mode ventilation in a Finnish office building with varying occupancy densities, this study examines indoor air quality (IAQ), thermal comfort, total building energy performance, and embodied carbon. The findings reveal that the basic case of mixed ventilation has a specified system primary energy value of 38.83 kWh/m² (with 28 occupants) and 39.00 kWh/m² (with 24 occupants), respectively. With the displacement ventilation alternative, it reduces this by 0.3% and 0.1%, enhancing thermal comfort and decreasing turbulence as well as having a marginal decrease in embodied carbon. In general, the study offers three-fold contributions: insights into post-pandemic office mechanical ventilation design with an emphasis on sustainability and ecological footprint considerations, a concrete case study addressing climate action and human-centric IAQ design, and a multifaceted analysis using the Environmental, Social, and Governance (ESG) paradigm, contributing to the groundwork for associated future research and policy progress. Full article

An innovative approach for measuring wind fields in urban building clusters using Unmanned Aerial Vehicles (UAVs) is presented. This method captures the distribution of wind fields within clusters. The results indicate that building architecture has a significant influence on wind flow characteristics at 15 m and 25 m height levels. Particularly, areas adjacent to the buildings and the wake section exhibit notable variations in wind speed and turbulence intensity compared to the incoming flow. The regions most affected include the areas flanking the buildings on either side and the intermediate section of the wake. The flow separation and convergence of incoming wind from the windward sides of the buildings notably amplify the wind load, resulting in a significant shift in wind speed and turbulence intensity within pedestrian pathways. The use of UAVs for wind measurements enables a flexible and efficient assessment of urban wind fields. These findings pave the way for further research into wind field measurements in urban architecture and a better understanding of the interference effects of buildings. Full article