Buildings

Creep properties are determined in design standards by measuring the creep coefficient, noted φ, as a function of time, t, and the age of the concrete at loading, t₀. The work aims to study the validity of the analytical models proposed in the most used international standards and to check the possibility of their extension to estimate the creep of recycled aggregates concrete (RAC). A database was built from experimental results available in bibliographic references including 121 creep curves divided into 73 curves for natural aggregates concrete (NAC) and 48 curves for RAC. The comparison between the experimental and predicted values showed a significant dispersion for NAC and RAC. For the remediation of this dispersion, a new analytical model was developed for NAC. The parameters being the conventional creep coefficient, φ₀, the power of the ageing function, named α, and β_h, which accounts for the relative humidity and the compressive strength in the ageing function, were identified by inverse analysis. It was found that the power of the ageing function is 0.44 and not 0.3, as fixed by Eurocode 2 (EC2). Moreover, new expressions were proposed for φ₀ and β_h. The presence of recycled aggregates was considered through the equivalent replacement ratio. Full article

The structural design of glass curtain walls and facades is a challenging issue, considering that building envelopes can be subjected extreme design loads. Among others, the soft body impact (SBI) test protocol represents a key design step to protect the occupants. While in Europe the standardized protocol based on the pneumatic twin-tire (TT) impactor can be nowadays supported by Finite Element (FE) numerical simulations, cost-time consuming experimental procedures with the spheroconical bag (SB) impactor are still required for facade producers and manufacturers by several technical committees, for the impact assessment of novel systems. At the same time, validated numerical calibrations for SB are still missing in support of designers and manufacturers. In this paper, an enhanced numerical approach is proposed for curtain walls under SB, based on a coupled methodology inclusive of a computationally efficient two Degree of Freedom (2-DOF) and a more geometrically accurate Finite Element (FE) model. As shown, the SB impactor is characterized by stiffness and dissipation properties that hardly match with ideal rigid elastic assumptions, nor with the TT features. Based on a reliable set of experimental investigations and records, the proposed methodology acts on the time history of the imposed load, which is implicitly calibrated to account for the SB impactor features, once the facade features (flexibility and damping parameters) are known. The resulting calibration of the 2-DOF modelling parameters for the derivation of time histories of impact force is achieved with the support of experimental measurements and FE model of the examined facade. The potential and accuracy of the method is emphasized by the collected experimental and numerical comparisons. Successively, the same numerical approach is used to derive a series of iso-damage curves that could support practical design calculations. Full article

The public housing built under the Franco regime in Spain (1939–1975) brought about the largest urban growth in the country’s recent history. It shares similar characteristics with other public housing built in Europe during the 20th century, and today it houses a predominantly multicultural and socioeconomically precarious population. This study analyses and evaluates three estates that make up a new urban axis in the city of Murcia. The objective is to evaluate the benefits and shortcomings of these developments in order to establish rehabilitation plans, which will seek to improve the lives of their inhabitants and enhance their experience of the urban area from environmental, functional and interactive perspectives. The methodology used for this study is based on the application of three systems of indicators in order to obtain a quantitative and qualitative evaluation of each neighborhood. The quantitative analysis evaluates the urban area in terms of environmental sustainability, while the two qualitative systems explore the neighborhoods’ functionality and ability to instil a sense of attachment, and therefore responsibility, among their inhabitants. In its conclusions, the article provides concrete lines of action for updating and regenerating these residential areas that form a significant part of the city of Murcia. Full article

The majority of cultural heritage is stored in archives, libraries and museum storage spaces. To reduce degradation risks, many archives adopt the use of archival boxes, among other means, to provide the necessary climate control and comply with strict legislation requirements regarding temperature and relative air humidity. A strict ambient indoor climate is assumed to provide adequate environmental conditions near objects. Guidelines and legislation provide requirements for ambient indoor climate parameters, but often do not consider other factors that influence the near-object environment, such as the use of archival boxes, airflow distribution and archival rack placement. This study aimed to provide more insight into the relation between the ambient indoor conditions in repositories and the hygrothermal conditions surrounding the collection. Comprehensive measurements were performed in a case study archive to collect ambient, local and near-object conditions. Both measurements and computational fluid dynamics (CFD) modeling were used to research temperature/relative humidity gradients and airflow distribution with a changing rack orientation, climate control strategy and supply as well as exhaust set-up in a repository. The following conclusions are presented: (i) supplying air from one air handling unit to multiple repositories on different floors leads to small temperature differences between them. Differences in ambient and local climates are noticed; (ii) archival boxes mute and delay variations in ambient conditions as expected—however, thermal radiation from the building envelope may have a large influence on the climate conditions in a box; (iii) adopting night reduction for energy conservation results in an increased influence of the external climate, with adequate insulation, this effect should be mitigated; and (iv) the specific locations of the supply air and extraction of air resulted in a vertical gradient of temperature and insufficient mixing of air, and adequate ventilation strategies should enhance sufficient air mixing in combination with the insulation of external walls, and gradient forming should be reduced. Full article

Construction projects and cities account for over 50% of carbon emissions and energy consumption. Industry 4.0 and digital transformation may increase productivity and reduce energy consumption. A digital twin (DT) is a key enabler in implementing Industry 4.0 in the areas of construction and smart cities. It is an emerging technology that connects different objects by utilising the advanced Internet of Things (IoT). As a technology, it is in high demand in various industries, and its literature is growing exponentially. Previous digital modeling practices, the use of data acquisition tools, human–computer–machine interfaces, programmable cities, and infrastructure, as well as Building Information Modeling (BIM), have provided digital data for construction, monitoring, or controlling physical objects. However, a DT is supposed to offer much more than digital representation. Characteristics such as bi-directional data exchange and real-time self-management (e.g., self-awareness or self-optimisation) distinguish a DT from other information modeling systems. The need to develop and implement DT is rising because it could be a core technology in many industrial sectors post-COVID-19. This paper aims to clarify the DT concept and differentiate it from other advanced 3D modeling technologies, digital shadows, and information systems. It also intends to review the state of play in DT development and offer research directions for future investigation. It recommends the development of DT applications that offer rapid and accurate data analysis platforms for real-time decisions, self-operation, and remote supervision requirements post-COVID-19. The discussion in this paper mainly focuses on the Smart City, Engineering and Construction (SCEC) sectors. Full article

Currently, unmanned aerial vehicles are increasingly being used in various construction projects such as housing developments, road construction, and bridge maintenance. If a drone is used at a road construction site, elevation information and orthoimages can be generated to acquire the construction status quantitatively. However, the detection of detailed changes in the site owing to construction depends on visual video interpretation. This study develops a method for automatic detection of the construction area using multitemporal images and a deep learning method. First, a deep learning model was trained using images of the changing area as reference. Second, we obtained an effective application method by applying various parameters to the deep learning process. The application of the time-series images of a construction site to the selected deep learning model enabled more effective identification of the changed areas than the existing pixel-based change detection. The proposed method is expected to be very helpful in construction management by aiding in the development of smart construction technology. Full article

Construction and demolition (C&D) activities generate a large amount of waste and have significant impacts on the environment. Thus, it is necessary to implement C&D waste management (WM), which requires the involvement of stakeholders and is influenced by a variety of factors. This study aims to undertake a systematic review of the stakeholder-associated factors influencing C&D WM. The Scopus search engine was used in a literature search, and two rounds of screening were performed. Only journal articles or reviews that were published in English after 2000 were used in this study. A total of 106 journal articles were reviewed. The review identified 35 stakeholder-associated factors influencing C&D WM and categorized them into six groups: regulatory environment, government and public supervision, advances in technologies, recycling market, knowledge, awareness, attitude, and behaviour of stakeholders, and project-specific factors. All the 35 factors are discussed in detail with considerations into relevant stakeholders. Although there have been studies focused on the factors influencing C&D WM, few have attempted to take stakeholders’ perspectives into consideration. This study expands the C&D WM literature by mapping the influential factors with relevant stakeholders and enables the practitioners to clearly understand their roles and responsibilities and make better informed decisions in the C&D WM process. Full article

Biophilic design as a new design approach promotes the integration of natural elements into the built environment, leading to a significant impact on human health, well-being, and productivity. On the other hand, scholars have explored Virtual Environment (VE) to create virtual nature and provide a complex experience of exposure to natural elements virtually. However, there is a lack of understanding about such studies in general, which use VE as a reliable tool to support biophilic design. Thus, the authors conducted a literature review on the applications, capabilities, and limitations of VE for biophilic design. The literature review shows that VE is capable of supporting critical features of biophilic design studies such as representing combinations of biophilic patterns, providing multimodal sensory inputs, simulating stress induction tasks, supporting required exposure time to observe biophilic patterns, and measuring human’s biological responses to natural environment. However, factors affecting user’s experience of a virtual biophilic environment exist, such as VE experience dimensions, user-related factors, cybersickness, navigational issues, and possible limitations of VE sensory input. Overall, biophilic design studies in VEs are still limited. Nevertheless, there are many opportunities for further research in this field. Full article

Performance-based design plays a significant role in the structural and earthquake engineering community to ensure both safety and economic feasibility. Its application to masonry building design/assessment is limited and requires straightforward rules considering the characteristics of masonry behavior. Nonlinear static procedures mainly cover regular frame system structures, and their application to both regular and irregular masonry buildings require further investigation. The present paper addresses two major issues: (i) the definition of irregularity in masonry buildings, and (ii) the applicability of classical nonlinear static procedures to irregular masonry buildings. It is observed that the irregularity definition is not comprehensive and has different descriptions among the seismic codes as well as among researchers, particularly in the case of masonry buildings. The lack of global language may result in the misuse of the procedures, while adjustments may be essential due to irregularity effects. Therefore, irregularity indices given by different codes and research studies are discussed. Furthermore, an overview of nonlinear static procedures implemented within the framework of the performance-based approach and improvements proposed for its application in masonry buildings is presented. Full article

This paper presents a preliminary assessment of road tunnel safety issues among respondents—specifically, real and potential users of road tunnels. We recruited a group of respondents to study their knowledge of evacuation procedures and awareness of safety issues in road tunnels. We conducted surveys with 504 participants, 12.7% of whom had previously participated in real-scale evacuation experiments in a road tunnel. Analysis of respondents’ answers reveals that their knowledge of safety procedures is unfortunately not sufficient. On average, the respondents selected the most recommended answer for approximately 5.35 out of 15 questions. Only 16% of respondents correctly answered more than 50% of the survey questions; moreover, no respondent provided the correct answers for 12 or more questions. Interestingly, most respondents were convinced that they had a better knowledge of road tunnel safety issues than was actually the case. The results of the survey demonstrate a significant educational role of evacuation exercises. Individuals who have participated in an evacuation have better knowledge, allowing them to apply the correct rules of road tunnel safety procedures. Various aspects addressed in this paper can be taken into consideration in an information campaign regarding safety in road tunnels during a fire. Full article

The purpose of this paper was to examine the community consultation practices carried out by implementing agencies when managing post-disaster housing reconstruction (PDHR) projects, identify the obstacles they face, and evaluate the effect these obstacles have on the quality of information obtained in relation to achieving a high level of beneficiary satisfaction. The aim was to develop a framework for community consultation in PDHR, which ensures that the needs of beneficiaries are more accurately reflected in the housing produced. A qualitative research methodology was adopted with data first being obtained through a literature review of relevant publications and implementing agency reports as a means of establishing common themes among community consultation practices and identifying indicators that influence beneficiary satisfaction. This was followed by a case study analysis to further an understanding of how these indicators were affected by the community consultation practices undertaken in a real-world context. The results of the research indicate that community consultation often forms a central role in the planning and delivery of PDHR projects, however, despite the implementing agencies’ best intentions, there are often obstacles that prevent the process from achieving the desired result. The community consultation framework proposed here has been developed to address the identified obstacles with the aim of ensuring that beneficiary requirements are included in housing design as a means of improving the level of beneficiary satisfaction in the housing provided. Full article

There has been growing interest in how to foster collaborative relationships between facility managers and end-users to obtain user-centred post-occupancy data for improving design and user satisfaction. Despite this attempt, there is little understanding on how facility managers respond to user feedback and its impact on user post-feedback behaviours. Drawing from theoretical insights from organisational justice, organisational response, and service quality studies and using a case study of higher education facilities in Australia, how facility managers manage user feedback to drive collaboration between facility managers and users during occupancy is explored. Various methods were used in this case study research, including document analysis, interviews, and observations. The research findings indicate that facilitation, timeliness, redress, apology and explanation, and attentiveness and efforts are applicable to facilities management (FM) services and could influence user post-feedback behaviour. Current responses to user feedback are not satisfactory, resulting in a poor relationship between facility managers and users that negates service acceptance and the engagement in a positive word-of-mouth. To foster more facility manager–user collaborative relationships in post-occupancy evaluation, and position FM as a service organisation, there is a need for improvements in current FM responses to user feedback and the effective management of user post-feedback behaviours. Full article

The test results obtained for reinforced concrete columns by several studies have revealed that the peak displacement and cumulative hysteresis energy are important parameters for evaluating the damage of columns under horizontal bidirectional and unidirectional loading. Therefore, the seismic parameters related to the nonlinear peak displacement and cumulative hysteresis energy with regard to horizontal bidirectional seismic input should be investigated. In this study, the bidirectional seismic input to an isotropic nonlinear one-mass two-degree-of-freedom system was evaluated. First, a dimensionless parameter γ, which controls the low-cycle fatigue effect, was formulated as a function of two energy input parameters (the maximum momentary input energy and total input energy) and a nonlinear system (ductility and normalized hysteresis energy absorption during a half cycle). Then, the maximum momentary input energy and total input energy were evaluated according to the ground motion characteristics (Fourier coefficient of horizontal ground motion components) and system properties. Finally, the nonlinear peak displacement and parameter γ of the nonlinear system were evaluated on the basis of the maximum momentary input energy and total input energy. The results revealed that the nonlinear peak displacement and parameter γ can be properly evaluated using two energy parameters. Full article

Comprehensive methodologies based on a fully probabilistic approach (i.e., the performance-based earthquake engineering approach, PBEE), represent a refined and accurate tool for the seismic performance assessment of structures. However, those procedures are suitable for building-specific evaluations, appearing extremely time-consuming if applied at the urban scale. In the proposed contribution, simplified loss assessment procedure will be applied at the urban scale with reference to the residential building stock of the center of Potenza. After the identification of the main reinforced concrete (RC) structural typologies and the definition of specific archetype building numerical models, the direct estimation of expected annual loss (DEAL) methodology will be applied to derive the EAL (i.e., expected annual loss) of RC buildings, deriving information on the effectively seismic quality (or seismic resilience) of the aforementioned built heritage at urban scale. Similarly, the monetary losses associated with downtime are evaluated. Preliminary considerations on the socio-economic effects of seismic scenarios on the territorial scale are also proposed. Full article

Plastic materials are increasingly becoming used in the building envelope, despite a lack of investigation on their effects. In this work, an extruded Acrylonitrile-Butadiene-Styrene panel has been tested as a second-skin layer in a ventilated facade system using a full-scale facility. The experimental results show that it is possible to achieve performances very similar to conventional materials. A numerical model has then been developed and used to investigate the performances of plastic and composite polymer panels as second-skin layers. The experimental data has been used to verify the behavior of the numerical model, from a thermal point of view, showing good reliability, with a root mean square error lower than 0.40 °C. This model has then been applied in different refurbishment cases upon varying: the polymer and the manufacturing technology (extruded or 3D-printed panels). Eight refurbishment case studies have been carried out on a typical office building located in Napoli (Italy), by means of a dynamic simulation software. The simulation results show that the proposed actions allow the reduction of the thermal and cooling energy demand (up to 6.9% and 3.1%, respectively), as well as the non-renewable primary energy consumption (up to 2.6%), in comparison to the reference case study. Full article

Megaproject social responsibility (MSR) is a critical factor regarding the sustainable delivery of megaprojects and MSR behavior to implement MSR. However, the questions of which factors effectively promote MSR behavior and how these factors work remain underexamined. Thus, this study aims to examine how the external institutional pressure and internal factors composed of relational behavior and pure altruistic values affect MSR behavior. On the basis of a conditional process analysis conducted on a set of survey data from various organizations involved in megaprojects in China, the results revealed that the higher the degree of mimetic pressure, the higher the degree of MSR behavior. Concurrently, relational behavior mediates the relationship between normative pressures and MSR behavior. Relational behavior also drives MSR behavior, and pure altruistic values moderate the relationships between institutional pressures and MSR behavior. These findings also provide practical suggestions for policymakers on the implementation and governance of MSR. Full article

Construction is a hazardous industry. The project-based nature and fragmentation in the industry lead to change and uncertainty requiring special expertise. To handle those, construction firms must develop strategies and action plans along with the experience gained from lessons learned. Among the risks, safety risks are of critical importance leading to accidents. Hence, firms need to strengthen their safety programs, review their strategies for safety management, and develop effective safety training sessions to protect their workers. This study focuses on the success factors promoting safety performance. In this respect, a questionnaire was designed and administered to the Engineering News-Record (ENR) 2020 Top 400 Contractors. The questionnaire data was utilized in conducting a factor analysis to group and name the factors considering the total variance. The analysis of the factors resulted in six-factor groups; namely, project and firm-related factors, demographic factors, practical factors, motivational factors, organizational factors, and human-related factors. Project and firm-related factors were found to be the most essential factor group in terms of promoting the effectiveness of safety training. The results of this study are expected to guide industry practitioners in terms of reviewing and revising their safety training programs. Full article

Façades, as the most external building envelope component, are subject to different ex-ternal environmental loads, such as: Temperature, precipitation, damp, and wind. Therefore, the contribution of environmental actions to the occurrence of defects in façades claddings is an important subject of study since these actions strongly affect the degradation process and natural ageing of these components during their service life. In this study, a methodology to support decision-makers in the process of selecting a façade cladding system and the maintenance strategy to implement is presented and discussed. This methodology covers the performance of four façade claddings (ceramic tiling systems (CTS), natural stone claddings (NSC), external thermal insulation composite systems (ETICS), and architectural concrete façades (ACF)) over time, according to three environmental exposure variables (exposure to damp, distance from the sea, and orientation). The databases were established based on the diagnosis of the degradation condition of these claddings in-service conditions, in Portugal. The results reveal that the environmental exposure variables have a significant impact on maintenance requirements and costs. For all the categories of the environmental exposure condition variables, under all scenarios, ETICS is the least favorable constructive solution while CTS is the most advantageous solution. Furthermore, the results show that properly implemented maintenance activities enhance the performance level of building components, which positively affects their degradation behavior over time. Full article

The recent growth of cooperative housing in Spain questions existing design standards and regulations as well as cultural norms of ownership, management and current housing typologies. This paper analyzes the design opportunities and challenges emerging from this. It studies the transformative capacity of housing cooperatives and how the realization of new social, spatial and economic demands is restricted by regulatory and administrative frameworks that limit collective ownership and use. Based on a case study analysis of recent projects in Barcelona, the paper discusses how regulations condition housing design, but also why changing ideas of ownership, household and dwelling structures require a review of how regulations are formulated and implemented. It examines this in the context of designing with housing cooperatives and their ethos defined by engagement in and responsibility for all decision-making processes and self-management. In cooperative housing, architecture is a process, not a product, one that extends beyond the completion of a building. This gives credibility to the claim of cooperative housing not just as a grassroots response to housing failures, but also as a political project of democratization and social transformation. Full article