Safety training effectively addresses the inexperience of and lack of knowledge among construction workers, which are some of the most significant contributors to workplace accidents on construction sites. This paper aims to understand the effectiveness of different extended reality (XR) technologies in imparting important construction safety training to construction workers in a virtual environment compared to conventional classroom training sessions. A group of experts were engaged to understand the most effective learning criteria and the impact of XR visualizations, and their responses were analysed using the interval type-2 fuzzy Delphi (IT2FD) method. Following this, a cohort of engineering students were subjected to construction safety training in traditional, augmented reality (AR) and virtual reality (VR) environments. Their feedback was collected using an online questionnaire and the responses were analysed using the interval type-2 fuzzy analytic hierarchy process (IT2F–AHP). The results revealed that addressing the virtual interface design of the training to maintain the attention of trainees and ensuring the virtual environment’s resemblance to the actual site and task were the most important factors in ensuring effective knowledge retention by the trainees. AR visualizations were most effective at imparting knowledge, and their interactive nature allowed trainees to retain the learned knowledge. Full article

Several types of fibers have enhanced the structural response of reinforced concrete-filled steel tubes (CFSTs). This article presents a state-of-the-art review of studies done on the axial compressive behavior of steel and glass fiber-reinforced CFSTs. The aim of using fibers is to improve the response of the CFSTs. This research indicates the findings of experimental programs and analytical evaluations of the effects of the fiber incorporation on the behavior of the CFSTs. The results of this research work demonstrate that steel fibers (SFs) have enough evident improving effects on the failure mode and load-carrying capacity of the CFSTs. The SFs greatly increase the ductility of the CFSTs. To enhance the compressive strength and ductility of the CFSTs, adding the SFs by 1% to the concrete mix is more effective than adding by 1.5%. The use of the SFs mixed with expansion agent considerably increases the yield and ultimate loads of the CFSTs. More glass fiber-reinforced polymer (GFRP) sheets reduce buckling and develop the compressive strength of the CFSTs. The implementation of the GFRP jackets not only enhances the load-carrying capacity of the CFSTs, but also increases their ductility. The GFRP reinforcement techniques for the CFSTs are also effective in improving their structural stiffness and energy absorption capacity. Full article

In residential buildings, air infiltration impacts energy, indoor air quality, and thermal comfort considerably. While air infiltration in residential buildings has been the focus of many studies, most published field-testing results pertain to developed countries, with little or no data on air infiltration in developing nations. This paper presents the results of one of the first field investigations into envelope infiltration in the residential buildings of the hot-arid climatic area of Egypt. To analyze the air permeability of the building envelope, the fan pressurization method, often known as the blower door test (BDT), is used, following ISO 9772. The study focuses on 20 residential dwellings built with heavy construction materials and subjects them to extensive characterization and testing. The average air leakage and the air permeability rate for the tested sample were 6.14 h⁻¹ and 17.3 m³/(h∙m²), respectively. However, significant variations in airtightness were observed across the dwelling, leading the team to test several building-related parameters statistically to study their impact on airtightness. Fenestration quality appeared to be a critical factor in determining air infiltration, showing a strong correlation with the air change and leakage. A further investigation underscored that the specific aperture factor and the fenestration quality can predict the infiltration rates to a large degree. Thus, we recommend further investigation of these characteristics in heavy construction material building. Finally, we strongly recommend that building codes in developing countries such as Egypt include minimum performance requirements for fenestration. Full article

The pupillary light reflex, which has been seen as an important noninvasive and objective indicator of autonomic nervous system function, can be used for evaluating the impact of different lighting conditions in buildings on circadian behaviors, assessing ipRGC function in healthy and diseased retinas, and explaining luminance adaptation. However, the mechanism by which the intrinsic and extrinsic signals of ipRGCs regulate the steady-state pupil size under continuous lighting stimuli is still not clearly understood after decades of exploration. This paper presents a new experimental protocol with a large hemisphere LED screen as the stimulation device, allowing for a more realistic and comprehensive study in architectural spaces, which can potentially inform the design of lighting systems in buildings that promote healthy vision and comfort. Results reveal that both intrinsic and extrinsic signals participated in the process of regulating pupil size under continuous lighting conditions. Based on the findings, a new mathematical model was further proposed to calculate the contribution of these two signal sources to the changing intensity of melanopic radiance. The research outcomes also provide new insight into the mechanism of visual perception and adaptation and the nonvisual effect of eyes under different light conditions. Results suggest that the contribution of extrinsic signals may have been underestimated in previous studies since the extrinsic signal increases with reducing intensity in photopic conditions with lower melanopic radiance. Full article

Steel formworks are widely used in prefabricated buildings thanks to their good characteristics. With the rapid development of engineering construction in China, steel formwork concrete structures, characterized by convenient construction, good seismic performance, and high strength, are expected to be more extensively applied in engineering practice. However, the bearing capacity of different forms of steel formwork concrete is still unclear. Two prefabricated columns with different internal diaphragm styles were set up for axial compression tests to investigate the performance of steel formwork columns. This study conducts monotonic static loading tests on six prefabricated steel tube column specimens and performs finite element analysis by taking steel tube thickness, rebar diameter, and internal diaphragm style as the influencing parameters. The results show that the prefabricated specimens can work in the test process, and the ultimate bearing capacity is consistent between the tests and numerical simulation. Moreover, the nephograms obtained from numerical simulation also conformed to the failure mode of the specimens in the test process. Therefore, the finite element model proposed in this study can accurately predict the stress performance of steel formwork concrete stub columns. These results offer guidance for future engineering practices. Full article

Ultra-high-performance concrete (UHPC) is a kind of structural material with ultra-high strength, extremely low porosity, and excellent durability, which has extremely broad application prospects. In order to promote the application of UHPC constrained by carbon fiber-reinforced polymer (CFRP) sheets as strengthening material in practical engineering, a total of nine specimens were designed, and two kinds of UHPC strengthening layer thickness (35 mm and 45 mm, respectively) were designed. By changing the constraint form of the UHPC strengthening layer (longitudinal reinforcements and ordinary stirrups, longitudinal reinforcements and spiral stirrups, and CFRP sheets, respectively), the axial compression performance of the strengthened column was explored. The study shows that compared with the without strengthened column, the uplift of carrying capacity of the strengthened test column is 277–561%. The reinforcement form of the strengthening layer has little influence on the lifting capacity. Among the three different strengthening methods, the wrapped CFRP has the best improvement effect on carrying capacity and ductility, followed by longitudinal reinforcements and spiral stirrups in the strengthening layer. With the increase of CFRP layers from two to five layers, the maximum carrying capacity increases by 21.3%. The carrying capacity of three different types of UHPC-strengthened columns is theoretically calculated, and the accuracy of the theoretical calculation method is verified by comparing the test value with the theoretical value, which provides a theoretical basis for the application of UHPC-strengthened columns in the future. Full article

Cities are the engines of economic growth, but they are also the source of many environmental and social challenges [...] Full article

Production efficiency is a critical research topic in the field of construction economics and management. It reflects the developmental potential and competitiveness of the economy or an economic system. An objective and reasonable assessment framework of the production efficiency in the construction industry is essential to promote the industry’s high-quality development. This study aims to propose a scientific and holistic framework to examine the production efficiency in the construction industry and to investigate evolution patterns from a macroeconomic perspective. Input and output indicators were identified through the value-added and the fuzzy Delphi methods. In addition, the production efficiency in the construction industry was examined via the bootstrap-DEA and Malmquist exponential decomposition models. A case study in China was conducted at the end of this research. The panel data of 31 provinces from 2010 to 2020 were applied in the case study. The results reveal the following: (1) The bootstrap-DEA model results show that the trends of production efficiency before and after rectification are similar, but the difference is largest at the peak. Moreover, the production efficiency value after correction is evidently lower than that which is obtained by the traditional DEA model. (2) The Malmquist index decomposition results show that the change trend of technical efficiency in the construction industry is contrary to that of the scale efficiency. In addition, the improvement of scale efficiency cannot bring a melioration of management efficiency or the accumulation of production experience. (3) There is no direct correlation between production efficiency and economic development. High-value areas and median areas are contiguous, and they are mainly distributed in the central and eastern provinces. The findings accurately reflect construction industry productivity, providing practical data for developing policy recommendations for bridging regional construction development gaps. Full article

Alkali-activated materials (AAMs) result from the dissolution process and polycondensation of precursors in high pH solutions. This material is considered alternative cement with similar properties and lower environmental impact than Portland cement. However, AAMs are subjected to the same standardization applied to cement-based materials since no formal methods exist to characterize this material and/or the precursor reactivity. Therefore, this work aims to develop a method to characterize the reactivity of the main precursors used to produce AAMs. Hence, the precursors were assessed in two steps after chemical, physical, and mineralogical characterization. The first step evaluated the crystallinity change of the material after the acid attack by mixing 1 g of each material in 100 mL of 1% HF solution for 6 h at ambient temperature. The crystallinity change was evaluated by comparing the X-ray diffraction of the materials before and after the acid attack. The second step involved evaluating the formation of geopolymerization products in the pastes of studied precursors through FTIR test. The pastes were produced with Na₂SiO₃ and NaOH as activators. After 28 days of curing, the pastes were submitted to a FTIR test for structural analysis. This method was tested evaluating the reactivity of traditional precursors for alkali activation (i.e., silica fume (SF), blast furnace slag (BFS), and metakaolin (MK)), in addition sugarcane bagasse ash mechanically treated (SCBAM) and sugarcane bagasse ash mechanically and heat treated (SCBAMH) since SCBA is a promising precursor for alkali activation. Considering the crystallinity change of precursors (step 01), the formation of geopolymerization products (step 02), and the chemical composition of precursors (preliminary characterization), it could be concluded that: (i) surface area is not relevant to materials with small particle size (<23 µm); (ii) amorphous area is only relevant if the material exhibits the optimal chemical composition; and (iii) the chemical composition is a crucial parameter for alkali activation. In addition, the potential precursors for alkali activation should have a significant amorphous halo and a SiO₂/Al₂O₃ ratio of 2 to 5. Also, it could be concluded that SF and SCBAMH do not exhibit adequate reactivity while BFS, MK, and SCBAM can be classified as reactive precursors. Full article

Raising the final contract cost (FCC) is a significant risk for project owners. This study hypothesizes that the factors that cause owner’s cost estimation (OCE) accuracy and FCC changes share the same causes, and a case study confirmed that the two variables (OCE and FCC) could be correlated. Accordingly, this study aims to develop a forecast model to predict FCC on the basis of the initial OCE, which has not been studied previously. This study utilized data from 34 Saudi Arabian projects. Two linear regression models developed the data, and the square root function transformed the data. Moreover, the artificial neural network (ANN) model was developed after data standardization using Zavadskas and Turskis’ logarithmic method. The results showed that the ANN model had a MAPE smaller than the two linear regression models. Using Zavadskas and Turskis’ logarithmic standardization method and elimination of data that had an absolute percentage error (APE) of more than 35% led to an increase in ANN model accuracy and provided a MAPE value of less than 8.5%. Full article

This study first provides an overview of the development of a novel tube anchor system for the seismic strengthening or repair of reinforced concrete (RC) shear walls with carbon fibre-reinforced polymer (CFRP) sheets. The new anchor system can significantly improve the load transfer mechanism between the CFRP and supporting RC structural elements, resulting in ductile behaviour of the strengthened shear walls with increases of lateral load capacity and ductility by up to 2.6 and 8.3 times, respectively. The study then presents a new finite element modelling technique capable of capturing the complete cyclic response, i.e., from the elastic behaviour to the ultimate collapse of CFRP-strengthened RC shear walls with the newly developed tube anchor system. Two different modelling approaches are proposed to consider the effects of the tube anchor system. Additionally, other important CFRP- and RC-related mechanisms, including CFRP debonding effects, confinement enhancement, tension stiffening, compression softening, and strength and stiffness degradation under cyclic loads, are also considered in the model. By comparing the analytical and experimental results, it is demonstrated that the proposed modelling approach can accurately replicate the complex behaviour of CFRP-strengthened shear walls with a wide range of aspect ratios, from the ductile flexural behaviour of slender walls to the brittle shear failure of squat walls, without requiring detailed modelling of the anchor system. Full article

A more efficient attention recovery of workers during their break time is essential for achieving higher productivity and wellness. In recent years, the biophilic design that introduces indoor plants has become one of the solutions to these problems. This study aims to determine the impact factors and corresponding levels related to indoor planting design concerning workers’ attention recovery. Firstly, the volume ratio, layout, and leaf size of indoor plants and the corresponding levels were put forward by a focus group study with ten participants. Secondly, the orthogonal experiment method established nine virtual recovery scenarios based on characteristics extraction of staff break areas in the factory. Thirdly, eighteen participants were guided to feel fatigued by experiencing the sustained attention to response test to measure the baseline attention level of participants. Then, participants rested in the virtual scenarios. Lastly, the attention test was conducted again to observe participants’ attention recovery degree. The difference values of participants’ sensitivity, reaction times, and the number of correct responses between the two detection targets were applied to evaluate the attention recovery. Results showed that the volume ratio of indoor plants had the most significant effect on workers’ attention recovery; 3% by volume ratio, mixed floor and wall plants and floor planting with large leaves were demonstrated as the optimal indoor planting design for attention recovery. Full article

A building curtain wall is an outer protective structure of a building composed of a panel and a supporting structure system. As the main materials of a building curtain wall, the optimization of the keel and panel is a problem that has attracted much attention from decoration enterprises. In order to reduce the cost of constructing a single building curtain wall and improve the economic benefits of decoration enterprises, in this study, the keel is taken as the key optimization objective, and a comprehensive optimization scheme is proposed for the deepening design stage of a single building curtain wall. This scheme firstly reduces the cost of the keel by optimizing the radius of the keel and then considers the overall degree of fit between the panel and the keel while optimizing the keel. Finally, in order to improve the processing efficiency of the keel, a reverse-cutting method is proposed based on the traditional forward-cutting method and then combined with the forward-cutting method to form a comprehensive cutting method. The feasibility of the optimization of both design and driving cost is verified with practical cases. The results show the following: Firstly, compared with the theoretical scheme, the average rate of cost saving for the keel when using the comprehensive optimization scheme is 9.56%. Secondly, the overall degree of fit between the optimized keel and the panel is evaluated, which effectively reduces the discontinuity of panel installation. Finally, the comprehensive cutting method proposed here is shown to improve the material utilization rate compared with the single forward-cutting method. Full article

Building costs play a significant role in determining the affordability of a housing project, and these depend to a large extent on design choices. This paper is based on the premise that collaborative design processes, or co-design, used in collaborative housing (CH) in Europe reduce building costs and consequently increase the affordability of these housing projects. However, research remains scarce on the extent to which CH is an affordable solution from a design perspective compared to affordable mainstream housing (MH), in which no co-design is used. Therefore, this paper aims to fill this knowledge gap by assessing the impact of design choices on building costs in CH and MH. To this end, we developed a simulation model to compare the building costs of CH with MH based on their design choices. Findings indicate that CH represents a more affordable and space-efficient solution when compared to MH, if we look at the building costs per unit. This is because CH provides less expensive units while it includes larger common spaces and extra quality. These results help to refute existing claims about the unaffordability of CH design solutions. Full article

The construction and demolition sectors are among the world’s most critical activities, generating large amounts of waste. Thus, these sectors’ waste accumulation problem is related to the environmental protection system and proper waste management. On the other hand, it is well known that proper waste disposal can increase its value. In this way, the economic potential of the trash can be raised again. Therefore, this article will examine the economic potential of construction and demolition (C & D) waste. Different waste management processes will be analyzed to better understand the topic from a financial perspective in this area underway in Spain. Therefore, data from other regions of Spain were collected. This data led to results where the most expensive rooms were Pais Vasco and the Balearic Islands, where disposal of C & D waste had the highest prices, exceeding EUR 30 per ton. Conversely, the lowest prices are found in regions such as Navarre and Andalusia, where prices per ton are EUR 8 and EUR 6, respectively. The values show a direct relationship between the treatment price and the amount of C & D waste disposed of. Therefore, this article will look at different factors influencing sustainable waste management. Such activities have a positive impact, as waste needs to be recycled and reevaluated by waste management operators. The cost of construction waste is an integral part of the budget because it represents the monetary value of the cost of collecting and recycling construction waste. Construction waste is an essential resource for economic and social development, as it contributes to job creation, education and culture, and the protection and preservation of the environment. Full article