Buildings, Volume 11, Issue 11 (November 2021) – 73 articles

In Pakistan, data for household electricity consumption are available in the form of monthly electricity bills only, and, therefore, are not helpful in establishing appliance-wise consumption. Further, it does not help in establishing the relationship among the household electricity consumption and various driving factors. This study aimed to unlock the household electricity consumption in Pakistan by analyzing electricity bills and investigating the impact of various socioeconomic, demographic, and dwelling parameters and usage of different appliances. The methodology adopted in this study was survey-based data collection of the residential sector. For this purpose, data were collected from 523 dwellings through surveys and interviews in Mirpur city. The results of the data analysis revealed that the average household electricity consumption is 2469 kWh/year with an average family size of seven and an average floor area of 78.91 m². Based on possession of various appliances, the households were categorized into four types and their consumption patterns were established and compared. Air Conditioned (AC) houses consume 44% more electricity compared to the non-AC houses, whereas an Uninterrupted Power Supply (UPS) consumes electricity equivalent to an AC. The research findings are useful for policy makers and building designers and are discussed in the conclusion section. Full article

As one of the most prominent industries in developed and developing countries, the construction industry has had substantial impacts on different aspects of the environment, society, and economy. In recent years, sustainable construction has been introduced as an approach to evaluate the various construction phases based on environmental, economic, and social dimensions, also known as the triple bottom line (TBL). To conduct a sustainability analysis of the buildings in Tehran, the capital city of Iran, two conventional construction frames were selected, namely steel frame and concrete frame. In this research, three conventional approaches for the evaluation of the TBL, namely the life cycle assessment (LCA), life cycle cost (LCC), and social life cycle assessment (SLCA), were, respectively, used for the study of environmental, economic, and social impacts. The main results of the study are summarized as the following: Overall, based on the LCA results, the concrete frame led to almost 38% more environmental pollution than steel frame. In terms of the total prices of the buildings, considering their LCC and with respect to the present value (PV) method, the steel frame was almost 152,000 USD more expensive than the concrete frame. The quantified results of the social dimension by the SLCA method showed that concrete and steel buildings had a score of 0.199 and 0.189, respectively, which indicates that concrete had a slightly better social performance based on expert opinions. A multi-criteria assessment and sensitivity analysis of the results were conducted by a graphical tool, namely the mixing triangle, and showed that the overall preference of each alternative depends mainly on the importance weights given to each aspect of the assessment. However, one of the main findings of the research was that overall, giving a high importance weight to environmental dimension leads to sustainability preference of steel over concrete frame, while giving high importance weights to economic or social dimensions leads to sustainability preference of concrete over steel frame. Findings of the study are beneficial to decision-makers in the construction industry since they can decide on the best alternative among concrete and steel frames based on their strategies. Full article

The main aim of this study is to analyze fiber-reinforced polymer (FRP) bridge decks according to their material, cross-section, and shape geometry. Infill cell configurations of the decks (rectangular, triangular, trapezoidal, and honeycomb) were tested based on the FRP cell units available in the market. A comparison was made for each cell configuration in flat and curved bridge shapes. Another comparison was made between the material properties. Each model was computed for a composite layup material and a quasi-isotropic material. The quasi-isotropic material represents chopped fibers within a matrix. FE (finite element) analysis was performed on a total of 24 models using Abaqus software. The results show that the bridge shape geometry and infill configuration play an important role in increasing the stiffness, more so than improving the material properties. The arch shape of the bridge deck with quasi-isotropic material and chopped fibers was compared to the cross-ply laminate material in a flat bridge deck. The results show that the arch shape of the bridge deck contributed to the overall stiffness by reducing the deformation by an average of 30–40%. The results of this preliminary study will provide a basis for future research into form finding and laboratory testing. Full article

This paper investigates the effect of using near-surface mounted carbon fiber-reinforced polymer (NSM-CFRP) on the shear strengthening of rectangle beams with low strength concrete (f′c = 17 MPa), medium strength concrete (f′c = 32 MPa), and high strength concrete (f′c = 47 MPa). The experimental program was performed by installing NSM-CFRP strips vertically in three different configurations: aligned with the internal stirrups, one vertical NSM-CFRP strip between every two internal stirrups, and two vertical NSM-CFRP strips between every two internal stirrups. All tested beams were simply supported beams and tested under a three-point loading test. The experimental results were compared with the theoretical capacities that were calculated according to the ACI 440.2R-17 and finite element analysis (FEA) that was conducted using ABAQUS software to simulate the behavior of all beams. The experimental results indicated that using NSM-CFRP limited the failure mode of all beams to pure shear failure with no debonding or rapture of the carbon strips. Moreover, the use of NSM-CFRP proved its efficiency by increasing the shear capacity of all beams by a range of 4% to 66%, in which the best enhancement was recorded for the case of using two unaligned NSM-CFRP strips. In general, the experimental shear capacities increased with the increase in the compressive strength of all beams. On the other hand, the ACI 440.2R-17 was conservative in predicting the theoretical shear capacities, and the FEA results agreed well with the experimental results. Full article

The ductility and capacity of reinforced concrete beam-column connections depend mainly on the concrete’s strength and the provided reinforcements. This study investigates numerically the role of low-strength concrete in beam-column joints utilizing ABAQUS software. In this simulation, a newly developed stress-inelastic strain relationship for both confined and unconfined low-strength concrete is used. This study recommended a specific value of the concrete dilation angle for both substandard and standard joints. Also, stirrups’ yield strength value was found to play an insignificant role in improving the shear resistance of such joints with low-strength. In addition, the joint shear strength prediction using empirical models that implicitly consider the stirrups contribution in improving joint resistance was found to be better than the prediction of other models that explicitly consider the stirrups’ presence. The numerical results also showed that the use of a diagonal steel haunch as a joint retrofitting technique significantly increases the joint shear capacity and changes its brittle shear failure into a ductile beam flexural failure. Full article

This study sought to uncover (1) the disagreement of spatial conflict between urban heritage and surrounding urban structure using two case studies from Korea—the main gate of the royal palace (Gwanghwamun) and the urban park containing celebrity graves (Hyoch’ang Park)—and (2) whether digital heritage restoration may mediate spatial conflict. A historical literature review and field surveys were conducted, with three main findings. First, the place identity of Gwanghwamun and Hyoch’ang Park, rooted in the Josŏn Dynasty, was seriously damaged during the Japanese colonial period. Although there were national attempts to recover the place identities of these sites during the modern period, limitations existed. Second, the restoration of Gwanghwamun’s Wŏltae (podium) and the relocation of Ŭiyŏlsa (the shrine of Hyoch’ang Park), which involved spatial transformation based on heritage, emerged in conflict with their surrounding urban structures—we identify a spatial conflict between local residents and stakeholders’ memories and the histories of these sites. Third, Donŭimun (the west gate of the city wall of the Josŏn Dynasty) digital restoration is a case mediating the conflict by restoring a sense of place in a virtual space and activating the cultural memory of the public by showcasing properties. Full article

Blockchain can be introduced to use cases in the built environment where reliability of transaction records is paramount. Blockchain facilitates decentralised, cryptographically secure, trustworthy, and immutable recordkeeping of transactions. However, more research is urgently required to understand the process and complications in implementing blockchain solutions in the built environment. This paper demonstrates a methodology for developing a blockchain system starting from problem analysis, selection of blockchain platform, system modelling, prototype development, and evaluation. The evolutionary prototyping model was selected as the software development methodology for the use case of property transactions. A systematic process protocol involving the multi-criteria decision-making method, Simple Multi Attribute Rating Technique (SMART), was used to select Hyperledger Fabric as the most suitable blockchain platform for the prototype. The system architecture facilitates a simplified, lean property transaction process implemented through chaincode (smart contract) algorithms and graphical user interfaces. System evaluation through test cases allowed iterative improvements, leading to an incubation-ready software prototype. The contribution to knowledge of this paper is in the demonstration of the process to follow to implement a blockchain solution for a specific domain. The findings provide the foundation for developing proofs of concept for other potential applications of blockchain in the built environment. Full article

One way to improve a structure’s total load-bearing capacity during an earthquake is to apply fiber-reinforced polymers (FRP) to unreinforced walls. The study discusses the use of FRP to strengthen unreinforced masonry (URM) structures. Although, many studies were conducted on the FRP strengthening of URM buildings, most of them were experiments to investigate the success of retrofitting approaches, rather than developing a successful design model. A database of 120 FRP-reinforced wall samples was created based on the current literature. Various approaches for calculating the bearing capacity of FRP-reinforced masonry are presented and detailed. The findings of the experiments, which were compiled into a database, were compared to those derived using formulas from the literature and/or building codes, and the model’s limitations are discussed. Full article

The fundamental notion of ‘smart’ in building materials discourse is responsiveness—the ability of materials to react to environmental stimuli by manifesting a noticeable physical change when there is a difference in the conditions of their immediate surroundings. This notion, however, is also interchanged with ‘intelligence’, which involves an array of control protocols. Notwithstanding, both notions are used synonymously and as occupant comfort and energy efficiency strategies in buildings. The current study aimed to underscore the fundamental issues in the conceptualization of both notions in building materials colloquy by systematic review of published literature following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 checklist. The review revealed that while smart responses are direct, predictable and reversible, requiring no external control system, computer systems and networks which require a constant supply of energy are essential for intelligence. In fact, the relationship between intelligent systems, energy efficiency and occupant comfort depends on external computer control and machine components of learning, resulting in complex systems with longer payback times, whereas smart materials and systems respond directly and immediately without additional energy or occupant control. The discussions present an attempt towards promoting zero additional energy demand for buildings using smart materials. Full article

Air filters are crucial components of a building ventilation system that contribute to improving indoor air quality, but they are typically associated with relatively high pressure drops. The purpose of the study is to evaluate the effect of additives on ultrathin electrospun filters, the pressure drop, and the particle removal efficiency of uniformly charged particles. The fibres were electrospun under optimised conditions that resulted in a fast-fabricating process due to the properties of the cellulose acetate solution. Different ultrathin electrospun fibre filters based on cellulose acetate (CA) were fabricated: a pure CA electrospun fibre filter, two filters based on CA fibres separately doped with activated charcoal (AC) and titanium dioxide (TiO₂), respectively, and a composite filter where the two additives, AC and TiO₂, were embedded between two CA fibres layers. The ultrathin filters exhibited a low pressure drop of between 63.0 and 63.8 Pa at a face velocity of 0.8 m s⁻¹. The filtration performance of uniformly charged particles showed a removal efficiency above 70% for particle sizes between 0.3 and 0.5 μm for all filters, rising above 90% for larger particles between 1 and 10 μm, which translates to the average sizes of pollens and other allergenic contaminant particles. Due to the positive impact on the fibre morphology caused by the additives, the composite filter showed the highest filtration performance among the produced filters, reaching 82.3% removal efficiency towards smaller particles and a removal of up to 100% for particle sizes between 5 and 10 μm. Furthermore, cellulose acetate itself is not a source of microparticles and is fully biodegradable compared to other polymers commonly used for filters. These ultrathin electrospun filters are expected to be practical in applications for better building environments. Full article

This study investigated students’ attitudes towards the use of outdoor open space in universities, identifying the most comfortable conditions and favourable factors, including urban layout, physical features, and outdoor thermal conditions, as well as the students’ needs and behaviour. A quasi-experiment was used to assess the quality of the outdoor spaces. Three outdoor open spaces on the university’s campus were used for the case study. A spatial analysis employing space syntax was used to determine the integration, agent, and connection factors. For the microclimate conditions, simulations were conducted. The students’ actions were recorded, and a questionnaire concerning their preferences was disseminated. According to the respondents, the key advantages of campus open spaces are that they provide places in which to socialise and rest and to pass by. The data revealed a correlation between microclimate conditions and the use of outdoor spaces. However, the students use outdoor venues even in unfavourable microclimates. The visual factor and spatial configuration of the site have a significant impact on the use of open spaces; hence, visibility is an important feature in campus layouts. This study established a baseline of data to integrate social and contextual factors for the creation of meaningful spaces in universities. Full article

This article aims to improve the toughness of pre-packaged grouts (PPG) by incorporating crumb rubber. The mechanism for toughness of PPG with crumb rubber was analyzed based on the uniaxial compression model. Crumb rubber with surfaces treated by different methods (NaOH solutions or microwave treatment) was observed by scanning electron microscopy (SEM). The effects of mesh sizes, amounts, surface-treated methods of crumb rubber, and mixing procedures on the PPG’s mechanical strength and rheological properties were investigated. The results showed that, firstly, the addition of crumb rubber improves the PPG’s toughness, while its mechanical strength is reduced. Adding NaOH solutions or microwave-treated crumb rubber into PPG can weaken the negative effects of crumb rubber on the PPG’s mechanical strength; however, this function is limited. Secondly, the crumb rubber grouts’ rheological properties can be fully exploited by increasing the stirring rate and time so that the fluidity of crumb rubber grouts is improved, which fulfils the characteristics of no bleeding and micro-expansion. Finally, the optimal formula and mixing technique of crumb rubber grouts were proposed in this paper.The results of this paper can provide a significant reference for the application of scrap tires. Full article

The construction industry faces multiple challenges, where transition to circular production is key. Digitalisation is a strategy to increase the sector’s productivity, competitiveness, and efficiency. However, digitalisation also impacts environmental goals, such as those concerning more eco-friendly solutions, energy efficiency, products recycling, and sustainability certifications. These strategies rely on data, understood as digital, interoperable, incremental and traceable. Data related concepts, such as digital data templates (DDT) and digital building logbooks (DBL), contribute to “good data”. Despite some research focused on each one, little importance has yet been given to their combination. Relevant relationships and overlaps exist, as they partially share the exact same data through the built environment life cycle. This research aims to provide improved understanding on the role of these concepts and their contribution to a more circular industry. The review develops conceptualisations where DDT and DBL are complementary and framed within an incremental digital twin construction (DTC). Misconceptions or confrontations between these three solutions can therefore stand down, for the benefit of a data-driven priority. To increase understanding and reduce misconceptions, our study developed the “Digital data-driven concept” (D3c). This concept contribution is the ability to structure, store, and trace data, opening way to streamlined digital transformation impacting circular built environment concerns. Full article

Gender equality at work in male-dominated industries is conditioned by intrinsic systemic issues which established policies have, to a significant extent, failed to address, as women’s participation remains under-represented. This study argues for the reappraisal of the issue through a different lens and carries out a systematic and thematic review of the literature on women in construction in Australia through a women’s empowerment framework. Despite its usual application in gender inequality at work in development studies, the concept of empowerment lacks attention in the context of developed countries, particularly regarding the construction industry. Empowerment has been proved a useful overarching framework to analyse personal, relational, and environmental factors affecting women’s ability to be or do. In the examined studies, there is significant focus on external barriers to women in construction, such ‘organisational practices’ (environmental), ‘support’ and ‘others’ attitudes and behaviour’ (relational). There is, however, limited attention to more active stances of power, such as one’s attitude (personal), control and capacity, in shifting power dynamics. The paper draws seven major findings, covering personal, relational and environmental dimensions, supported and supplemented by some international studies, and suggests the way forward for empowering women in construction. Full article

In recent years, Sweden has promoted prefabricated buildings supporting the increasing of prefabricated rates in buildings with precast components, in order to reduce the environmental problems caused by the construction sector. This study, focusing on the construction activities, examines how the increasing prefabricated rate could influence the environmental impacts of the construction sector. This study conducts a cradle-to-gate life cycle assessment (LCA) of a reference building with a prefabricated rate of 26% in the Stockholm Royal Seaport, and compares nine scenarios with prefabricated rates, ranging from 6% to 96%. The results indicate the water footprint decreases, but the total energy footprint and carbon footprint increase as the prefabricated rate increases. Among other impacts, terrestrial ecotoxicity shows the biggest increase with an increase of the prefabricated rate. This study reveals that material extraction is the largest influencing factor, causing a water footprint when the prefabricated rate increases. The impact changes in the energy footprint, carbon footprint, and terrestrial ecotoxicity, and are primarily determined by transport and are sensitive to transport distance and vehicle types. Full article

The thermal comfort requirements of disabled people in healthcare buildings are an important research topic that concerns a specific population with medical conditions impacted by the indoor environment. This paper experimentally investigated adaptive thermal comfort in buildings belonging to the Association of Parents of Disabled Children, located in the city of Troyes, France, during the winter season. Thermal comfort was evaluated using subjective measurements and objective physical parameters. The thermal sensations of respondents were determined by questionnaires adapted to their disability. Indoor environmental parameters such as relative humidity, mean radiant temperature, air temperature, and air velocity were measured using a thermal microclimate station during winter in February and March 2020. The main results indicated a strong correlation between operative temperature, predicted mean vote, and adaptive predicted mean vote, with the adaptive temperature estimated at around 21.65 °C. These findings highlighted the need to propose an adaptive thermal comfort strategy. Thus, a new adaptive model of the predicted mean vote was proposed and discussed, with a focus on the relationship between patient sensations and the thermal environment. Full article

This study investigates the dynamic characteristics of a smart PZT interface mounted on a prestressed anchorage to verify the numerical feasibility of the admittance-based anchor force monitoring technique. Firstly, the admittance-based anchor force monitoring technique through a single-mount PZT interface is outlined. The admittance response of the PZT interface-anchorage system is theoretically derived to show the proof-of-concept of the technique for anchor force monitoring. Secondly, a finite element model corresponding to a well-established experimental model in the literature is constructed. The effect of anchor force is equivalently treated by the contact stiffness and damping parameters at the bottom surface of the anchorage. Thirdly, the admittance and the impedance responses are numerically analyzed and compared with the experimental data to evaluate the accuracy of the numerical modelling technique. Fourthly, the local dynamics of the PZT interface are analyzed by modal analysis to determine vibration modes that are sensitive to the change in the contact stiffness (i.e., representing the anchor force). Finally, the admittance responses corresponding to the sensitive vibration modes are numerically analyzed under the change in the contact stiffness. The frequency shift and the admittance change are quantified by statistical damage indices to verify the numerical feasibility of the anchor force monitoring technique via the smart PZT interface. The study is expected to provide a reference numerical model for the design of the single-point mount PZT interface. Full article

For a practical structural health monitoring (SHM) system, the traditional single objective methods for optimal sensor placement (OSP) cannot always obtain the optimal result of sensor deployment without sacrificing other targets, which creates obstacles to the efficient use of the sensors. This study mainly focuses on establishing a bi-objective optimization method to select the sensor placement positions. The practical significance of several single-objective criteria for OSP is firstly discussed, based on which a novel bi-objective optimization method is proposed based on the Pareto optimization process, and the corresponding objective functions are established. Furthermore, the non-dominated sorting genetic algorithm is introduced to obtain a series of the Pareto optimal solutions, from which the final solution can be determined based on a new defined membership degree index. Finally, a numerical example of a plane truss is applied to illustrate the proposed method. The Pareto optimization-based bi-objective OSP framework presented in this study could be well suited for solving the problem of multi-objective OSP, which can effectively improve the efficiency of the limited sensors in SHM system. Full article

Electric water heaters represent 14% of the electricity consumption in residential buildings. An average household in the United States (U.S.) spends about USD 400–600 (0.45 ¢/L–0.68 ¢/L) on water heating every year. In this context, water heaters are often considered as a valuable asset for Demand Response (DR) and building energy management system (BEMS) applications. To this end, this study proposes a model-free deep reinforcement learning (RL) approach that aims to minimize the electricity cost of a water heater under a time-of-use (TOU) electricity pricing policy by only using standard DR commands. In this approach, a set of RL agents, with different look ahead periods, were trained using the deep Q-networks (DQN) algorithm and their performance was tested on an unseen pair of price and hot water usage profiles. The testing results showed that the RL agents can help save electricity cost in the range of 19% to 35% compared to the baseline operation without causing any discomfort to end users. Additionally, the RL agents outperformed rule-based and model predictive control (MPC)-based controllers and achieved comparable performance to optimization-based control. Full article

In the ISO 16283 series for field measurement of sound insulation, a low-frequency procedure is specified for determining indoor average sound pressure level, which is the so-called corner method. In the procedure, additional measurements are required in the corners in addition to the default measurements in the central zone, and the indoor average level is corrected with the highest level in the corners. However, this procedure was empirically proposed, and its validity is not fully examined for façade sound insulation. In this paper, detailed experiments were performed in a mock lightweight wooden house for validating the low-frequency procedure for façade sound insulation measurement. The results suggest that a correction with energy-averaging level of all corners is more reliable than with the maximum level, and the uncertainty in the default procedure is sufficiently improved with additional measurements in four non-adjacent corners. Moreover, the effect of the detailed position of the microphone around the corner was clarified for a more specific instruction. Full article

What is the future of virtual reality (VR) in the built environment? As work becomes increasingly distributed across remote and hybrid forms of organizing as a result of the COVID-19 pandemic, there is a need to rethink how we use the set of collaborative technologies to move toward a sustainable world. We propose a new vision of VR as a discipline-agnostic platform for an interdisciplinary integration of the allied design, social, and environmental disciplines to address emerging challenges across the building sectors. We build this contribution through the following steps. First, we contextualize VR technologies within the changing digital landscape and underlying tensions in the built environment practices. Second, we characterize the difficulties that have arisen in using them to address challenges, illustrating our argument with leading examples. Third, we conceptualize VR configurations and explore underlying assumptions for their use across disciplinary scenarios. Fourth, we propose a vision of VR as a discipline-agnostic platform that can support built environment users in visualizing preferred futures. We conclude by providing directions for research and practice. Full article

Microbial-induced carbonate precipitation (MICP) is a bio-inspired solution where bacteria metabolize urea to precipitate. This carbonate acts as a bio-cement that bonds soil particles. The existing framework has focused mainly on applying MICP through infiltration of liquid bacterial solutions in existing soil deposits. However, this technique is inefficient in soils with high fines content and low hydraulic conductivity, and thus few studies have focused on the use of MICP in fine soils. The main objective of this study was to evaluate the effect of MICP applied to compaction water in soils containing expansive clays and sandy silts. This approach searches for a better distribution of bacteria, nutrients, and calcium sources and is easy to apply if associated with a compaction process. In soils with expansive minerals, the effect of MICP in swelling potential was explored at laboratory and field scales. In sandy silts, the evolution of the stiffness and strength were studied at the laboratory scale. The treatment at the laboratory scale reduced the swelling potential; nevertheless, no significant effect of MICP was found in the field test. In sandy silts, the strength and stiffness increased under unsaturated conditions; however, subsequent saturation dissolved the cementation and the improvement vanished. Full article

Many studies have been conducted to measure the experiential qualities of historical streets using the standards and principles released by many global organizations. However, little attention has been paid to the effect of spatial characteristics of historical heritage. This study proposes a space syntax-based methodology, first developed by Bill Hillier and Julienne Hanson with colleagues from the Bartlett School of Architecture, while introducing factors such as complexity, coherence, ‘mystery’, and legibility from the work of environmental psychologist Stephen Kaplan and the urban designer Gordon Cullen. Our intention is to help inform urban designers in understanding people’s spatial cognition of historical streets, and thereby assist designers and managers in identifying where cognitive experiences can be improved. The proposed method is applied to Nanxun, which is a developed canal town currently in decline in Zhejiang Province, China. This will be treated as the case study in order to explore the implication of the space syntax analysis. The impact from spatial characteristics on the evaluation is indirect and largely determined by the road-network of the canal town. As for Nanxun, the findings of this research suggest that the government’s priority is to solve current negative tourist perception based on a conservation restoration plan. The findings of this research provide a reference for policymakers to better understand the experiential qualities of historical streets in townscapes. Full article

An important challenge for acoustic engineers in room acoustics design is related to the acoustic performance of multi-purpose auditoriums, which are typically designed to suit several performance requirements. With this intent, the analysis of several scenarios is usually performed individually, and then an acceptable solution, that may be adapted to several situations, is selected. One way of providing a more appropriate acoustic performance for each function of the auditorium is using variable sound absorption techniques to control reverberation and other relevant acoustic phenomena associated to sound perception. In this paper, the acoustic behavior of a perforated system that may be suitable for achieving a variable acoustic solution for room acoustic design is addressed. In the design of a cost-effective solution, the surface appearance is kept unchanged, while variable acoustic behavior is achieved either by closing the holes in the back face of the perforated panel or by placing a porous material in varying positions inside the backing cavity, thus accomplishing different acoustic requirements within a multipurpose auditorium. An analytical approach, based on the transfer matrix method is employed for preliminary acoustic sound absorption assessment provided by the system and to develop optimized solutions. Diffuse sound absorption is then computed and used to simulate, by the ray-tracing method, the acoustic behavior of a multipurpose auditorium to demonstrate efficient acoustic performance for different types of use. Full article

Design–build (DB) projects have become increasingly popular for construction projects in developing countries due to the cost and scheduling advantages and their design optimization ability. As a result, much research has been conducted on improving DB efficiency in terms of cost, scheduling, risk management, etc. However, the existing studies have mainly focused on the owner’s roles, whereas general contractors (GCs) must also take many risks on behalf of owners in DB projects. The adequate identification and assessment of risks before engaging a contractor can increase the likelihood of a project’s success, at least from a DB contractor’s perspective. Therefore, this study interviewed procurement experts to conduct a survey at the local level, then analyzed, developed, and proposed an additional risk management process (RMP) for use by GCs during the bidding process of DB projects. A case study was conducted with a large Vietnamese GC to evaluate the effectiveness of the process and find ways to optimize it in the future. The results of the study showed that risk management during a DB project is imperative. Nevertheless, preparing bids is time-consuming and increases the contingency costs, reducing the competitiveness of the bid prices for contractors. Therefore, depending on the specific project and risk management objectives, an RMP is recommended for adjusting the risk management target to reduce the risk, while still maintaining the competitiveness of the bid prices. Full article

Buildings’ outdoor thermal comfort influences environment quality and human behavior in urban neighborhoods. The Universal Thermal Climate Index (UTCI) has been broadly applied to the study of buildings’ outdoor thermal comfort in urban areas. However, complex environmental conditions in climate-sensitive urban areas can make UTCI assessment complicated and ineffective. This paper introduces digital techniques into buildings’ outdoor thermal comfort analysis for the improvement of the urban habitant environment. A digital simulation system is generated to facilitate the analysis procedure for buildings’ outdoor thermal comfort assessment in urban neighborhoods. The analysis addresses the research question: “Can digital simulation techniques provide a modeling system to assess buildings’ outdoor thermal comfort continuously and effectively?” Methods include a case study of neighborhoods in Beijing, qualitative and quantitative analysis based on digital processes, and parametric modeling. The results indicate that digital simulation techniques and tools have the capability to support the analysis of buildings’ outdoor thermal comfort by providing three-dimensional models, algorithm-based analysis, and visual simulation. The findings include a critique of digital simulation as applied to architecture study and insights on potentially improving buildings’ outdoor thermal comfort through human–computer interactions. Full article

An in-depth understanding of the effect of cordierite/belite core–shell structure lightweight aggregate (CSLWA) on the mechanical performance of LWA concrete (LWAC) is critical for improving the failure resistance of LWAC. In this study, the stress distribution of the microregion in CSLWA was systematically investigated via a finite element analysis to explore its effect on the mechanical properties of LWAC. In detail, the material components, core–shell thickness ratio, porosity and width of interfacial transition zone (ITZ), and absence or presence of interfacial bonding zone (IBZ) were considered during the stress distribution analysis of the microregion of LWAC. The results showed that a reduction in the material components, with a high-elastic modulus in the core, a decrease in the core–shell thickness ratio, and the formation of the core–shell IBZ are beneficial for optimizing the stress distribution of the microregion and alleviating the stress concentration phenomenon of LWAC. Moreover, due to the continuous hydration of belite shell, the ITZ of CSLWA becomes increasingly dense, thus the stress distribution is more uniform than that of ordinary LWAC, indicating that CSLWA exhibits the potential to improve the failure resistance of LWAC. This study helps to develop an understanding of the role played by the core–shell structure in improving the toughness of LWAC, and provides a new solution and methodology for improving the brittleness of LWAC. Full article

The importance of green and sustainable materials in civil engineering is undeniable. Alongside modern practices that improve the properties of standard building materials, there are ways to revive forgotten techniques, including straw bale buildings. Straw bales are load-bearing structures, which are applied based on handed-down experience and lack standard approaches in testing, design, and application. Therefore, a goal ahead is to describe every aspect of the process in technical detail. The objective of this paper is to highlight practical ideas for testing straw bales on a hydraulic press machine and to provide a basic statistical investigation of the results obtained. Two basic series were prepared, one without a side barrier and the other with a side barrier. The reason for this was to delineate the limits of the real behaviour of the straw bale on the load bearing wall of the house. Due to the assumed slight embedment of adjacent bales, the real result were within these limits. The experimental plan, basic results, simplified correlations, and statistical evaluation are presented. Recommendations for a further testing and evaluation are provided. As expected, the results with and without the lateral barrier differ by almost 18% for the true strain. Full article

Effective maintenance of ancient buildings is paid more and more attention worldwide. Many ancient buildings with high inheritance value were gradually destroyed, especially for murals in the open tombs. The bioaerosol particles (BPs) are the major source of contamination in murals and visitor walking could increase this hazard. In order to study the impact of visitors walking on the air flow and the distribution of BPs in the typical tomb chambers, the k-ε and Lagrangian discrete phase model were adopted. The walking visitor was described by the dynamic mesh, and the concentration of BPs in the simulation was verified by experimental sampling. The distribution and migration mechanism of contamination in the chamber were dynamically analyzed. The results indicate that the denser vortex generated when a visitor was walking, and the concentration of BPs changed obviously. Therefore, the number of BPs deposited on some precious murals increased and the contamination location shifted in the direction of visitor walking. In addition, the deposition time of BPs was lagging which would cause potential risk. This research can provide scientific basis for reducing murals contamination during visitor visiting and a reference for the maintenance of ancient buildings. Full article

Cases of fire with highly flammable, combustible liquids and combustible gases with high potential heat emission at oil and gas facilities are assumed to develop as a hydrocarbon fire, which is characterized by the temperature rising rapidly up to 1093 ± 56 °C within five minutes from the test start and staying within the same range throughout the test, as well as by overpressure being generated. Although various fireproof coating systems are commonly used to protect steel structures from high temperatures, a combination of fire protection and cryogenic spillage protection, i.e., protection from liquefied natural gas (LNG), is rather an international practice novelty regulated by standards ISO 20088. Thanks to their outstanding features, i.e., ability to sustain chemical and climatic impact, these epoxy-based materials are able to ensure positive fireproof performance for steel structures in the case of potential cryogenic impact. The article discusses tests on steel structures coated with epoxy fireproof compounds, specifically PREGRAD-EP, OGRAX-SKE and Chartek 2218. The test records show the time from the start of cryogenic exposure to the said sample reaching the limit state, as well as the time from the start of heat impact to the sample reaching the limit state in case of hydrocarbon fire temperature. Full article