Buildings

The dilation of concrete in the radial direction is crucial in understanding the failure process and the key to predicting the confining level of passively confined concrete. To better understand this problem, we established a mesoscale model of concrete by considering the random distribution of coarse aggregate and the different properties between mortar and concrete. The model’s validity was demonstrated by comparing with the stress–strain curves in code and the lateral–axial strain curves in test. The simulation results show that the lateral dilation is non-uniformly distributed along the specimen height and the circumferential direction of sections. Moreover, the deformation mainly occurs in the middle part of the specimen ranging from 3/8 to 5/8. The strength of concrete influences the stress ratio at maximum compressive strain, while it slightly influences the stress ratio at zero volumetric strain. The secant strain ratio is about 0.5 as the compressive stress reaches the strength of concrete. Compared with the simulation, the relationship between lateral strain and axial strain proposed by Teng and Binici shows excellent performance on the dilation trend prediction of plain concrete. Full article

The OSS (acronym of the Italian “Osservatorio Sismico delle Strutture”) is a network of permanent seismic monitoring systems installed on about 150 buildings in Italy. Each system consists of a number of sensors sufficient to completely describe the dynamic response of the structure. Structural typologies have been selected according to their representativeness of the public building stock and to their importance for emergency management. Data available for each building include: structural survey and in situ tests on materials, experimental modal analysis, finite element models and model updating. In the above framework, a school building located in Amatrice, a small town in the meizoseismal area heavily impacted by the 2016 Central Italy earthquake, is one of the buildings instrumented by the OSS; thus, its monitored dynamic response, including that under the main shock, is available. The building showed diffused huge damage with partial collapses. Firstly, a linear finite element model is used in the interpretation of small amplitude vibrations in order to give a reliable dynamic characterization of the initial conditions of the structure. Some relevant quantities of the recorded structural motion under seismic excitation are used to describe the experimental dynamic behaviour. The recorded displacements are then applied to a nonlinear finite element model, and the numerical results are compared with the experimental evidence. The main aim is to discuss the capability of the combined use of experimental response and computational tools in quantifying damage suffered by a structure on the basis of the measured response to an earthquake. Full article

The building envelope design constrains how much HVAC systems must work to provide comfort. High thermal mass in walls is preferable to delay heat gain, as well as reduce it. Phase Change Materials (PCMs) seem to proportionate more thermal mass without increasing wall thickness because of their high latent heat. Thus, this work studies various PCM-based envelope layouts in four case studies, H060, H100, H200, and OB, under the tropical climate of Panama City, via building energy performance simulation. Energy and thermal comfort performance were used as criteria to determine an optimal PCM-based layout for such a climate through optimization analysis and to compare PCM-based and non-PCM-based envelope layouts. Results showed that among the considered combinations, PCM-based roof configurations provide more optimum solutions than PCM-based wall configurations. The PCM layout with a melting temperature of 27 °C allowed completion of the PCM cycle throughout the year. Although other PCM layouts did not present a complete charge/discharge cycle, such as the most frequent options at H060, H100, and H200, it suggests that PCM on liquid or solid phase provides better thermal performance than other considered combinations. Full article

Recently, the requirements regarding the environment of nursing homes are high, because the elderly are a vulnerable group with limited adaptive capacity to respond to transient environmental change. This paper presents a field investigation on the influence of transient thermal comfort changes between the indoor and outdoor spaces (i.e., air temperature (T_a), solar radiation (SR), relative humidity (RH), wind speed (WS), and the thermal comfort indices of Universal Thermal Index (UTCI)) on the willingness of the elderly to use outdoor spaces of the Wanxia nursing home of Chengdu City. Results indicated that, in summer, the mean UTCI values of indoor and corridor spaces corresponded to the level of moderate heat stress, while those of road and garden corresponded to the strong heat stress level. Road and garden spaces even showed moderate heat stress in spring. Approximately 28.93% (139) of the elderly living here used outdoor spaces every day. The morning period (from 9:00 a.m. to 10:00 a.m.) was the elderly’s favorited period for using outdoor spaces in seasons. The microclimatic transient differences between indoor and outdoor spaces ranged from 0.47 °C to 2.93 °C (|ΔT_a|), from 86.09 W/m² to 206.76 W/m² (|ΔSR|), from 5.29% to 14.76% (ΔRH), from 0.01 m/s to 0.07 m/s (|ΔWS|), and from 0.25 °C to 2.25 °C (ΔUTCI). These big microclimate differences could cause enormous health risks for the elderly in the process of indoor and outdoor space conversion. The minimal transient change occurred between corridors and indoors. Pearson correlation analysis indicated ΔT_a and ΔRH between indoor and outdoor spaces were the primary meteorological factors that influenced the elderly’s willing to use outdoor spaces. The elderly preferred to live in a constant Ta and RH environment. Only when the ΔT_a and ΔRH are small enough to resemble a steady-state (ΔUTCI ≤ 0.5 °C), ΔWS and ΔSI could affect the elderly’s choice of using outdoor space. Optimal design strategies were put forward for reducing the transient differences between indoor and outdoor microclimates to inspire the elderly to use outdoor spaces safely, including improving outdoor canopy coverage and indoor mechanical ventilation. Full article

Numerous constraints affect construction projects, and lack of management may lead to schedule deviation. In the execution phase of the project, due to the lack of timely access to the required resources and the existence of uncertainty, the project activities do not progress following the schedule, and as a result, schedule deviation occurs. The scheduling addresses resource constraints by the critical chain method and deals with delays in activities by placing buffers that have emerged as a method for scheduling construction projects. This paper presents a new bi-objective mathematical model which aims to reduce delay and increase quality, based on the critical chain method and resource constraint for scheduling construction projects. In the proposed model, the activities have been considered multi-mode ones. Moreover, this paper has assumed each activity to be executed in a normal or crashing way. Due to the uncertainty in real-world problems, the duration of the activity is expressed using triangular interval-valued fuzzy numbers. A new interval-valued fuzzy solution process is presented in this paper using a two-step approach. First, the equivalent crisp model is given; then in the second step, a goal programming approach is applied for transforming the bi-objective model into the single-objective one. Finally, the mathematical model is implemented on a case study adapted from the literature, and sensitivity analysis of the results is conducted. Full article

Heat island effects raise the ambient air temperature in metropolitan areas by 4–5 degrees Celsius and can reach 10 degrees Celsius at their maximum. This phenomenon magnifies cities’ energy difficulties while reducing comfort. Mitigation strategies have been developed and recommended to deal with the issue. Methods to increase albedo and the utilisation of vegetation appear to be the most promising, with a reasonably high heat island reduction capacity. This paper examines the heat mitigation techniques and their effectiveness under Sydney’s climate conditions and compares strategies. We implement two perspectives, namely urban greening (green roofs, green pavements) and albedo (street, roof), and characterise urban surface structures, and Envi-met software is employed for our simulation method. Mitigation strategies show a cooling potential of 4.1 °C in temperature along this precinct during the heatwave period. Scenarios that increase high-albedo material on the road, pavements and rooftops and full mitigation show the maximum cooling potential. The mitigation strategies have higher predicted cooling potential on the peak ambient temperature, up to 1.18 °C, while having no or little impact on minimum ambient temperature. The outdoor thermal comfort based on PMV indices varies between a minimum of −0.33 in scenario seven in large layout areas to 3. However, the mitigation scenario presents more acceptable outdoor thermal comfort, but large layouts are predicted to have a hot condition. Full article

Rapid transformation across all sectors through Saudi Arabia’s vision 2030 initiatives led to an increase in construction activities. However, the construction industry has been already facing huge cost and time overruns, affecting all stakeholders. The aim of this study is to identify and explore the influential risk factors that lead to completion delays and cost overruns of government-funded building construction projects in Saudi Arabia, all of which have been subjected to a traditional type of procurement method (Standard Public Works Contract). The literature examined in this study identified a total of 83 risk factors, which have been grouped into nine categories. A questionnaire-based survey was conducted to determine the participants’ perspectives on the degree of probability of occurrence (P) of each risk and its potential impact on a project in terms of time (IT) and cost (IC). The questionnaire survey was distributed to 200 experts and professionals associated with Saudi building construction projects, which were grouped into four categories: clients, designers, consultants, and contractors. Fifty-five acceptable questionnaires were returned and analysed. The relative importance index (RII), and Risk Importance (RI) were used to identify the most influential risk factors, and an agreement test was conducted. The results of the survey revealed that the most significant risks factors contributing to the delay of building construction projects’ completion are contractor’s financial difficulties, owner’s delay in making progress payments for completed works, contracts awarded to the lowest bidder, change orders during construction, ineffective project planning and scheduling by the contractor, shortage of manpower, and contractor’s poor site management and supervision. In addition, change orders during construction and contracts awarded to the lowest bidder are the most significant risks factors of exceeding budgets. Based on the results, it is concluded that for achieving sustainable development, client, contractor, and labour-related risks must be effectively managed. Full article

In recent years, urban communities in China have been continuously affected by extreme weather and emergencies, among which the rainstorm and waterlogging disasters pose a great threat to infrastructure and personnel safety. Chinese governments issue a series of waterlogging prevention and control policies, but the waterlogging prevention and mitigation of urban communities still needs to be optimized. The concept of “resilience” has unique advantages in the field of community disaster management, and building resilient communities can effectively make up for the limitations of the traditional top-down disaster management. Therefore, this paper focuses on the pre-disaster prevention and control of waterlogging in urban communities of China, following the idea of “concept analysis–influencing factor identification–evaluation indicators selection–impact mechanism analysis–resilience simulation prediction–empirical research–disaster adaptation strategy formulation”. The structural equation model and BP neural network are used by investigating the existing anti-waterlogging capitals of the target community to predict the future waterlogging resilience. Based on this simulation prediction model, and combined with the incentive and restraint mechanisms, suggestions on corrective measures can be put forward before the occurrence of waterlogging. Full article

Due to its special geographical conditions, Guangdong has absorbed the essence of the Central Plains Han culture and characteristics of foreign cultures, resulting in architecture in which traditional buildings exhibit unique regional cultural connotations. The architectural design is adapted to the needs of nature and ecology and the arts and humanities. This paper investigates the technical process of using local materials to obtain structural materials. Traditional Guangdong buildings use patios, cold alleys and doors as well as windows in a comprehensive manner to create an energy-saving and environmentally friendly ventilation design, which was analyzed here. In addition, we study the floor plans and artistic characteristics of traditional buildings in different regions of Guangdong. Traditional Guangdong buildings realize the harmonious coexistence of humans and nature, as well as embody the concept of sustainable development. Traditional buildings integrate benefits and efficiency while condensing the surpassing wisdom and rich experience of craftsmen from ancient times to the present. Thus, it is worthwhile to research the connotation of traditional buildings to develop modern architectures. Full article

The use of a genetic algorithm in evolutionary design is one of the major generative approaches for synthesis and evaluation during the design process. The process stimulates creativity in generating new, unexpected artifacts and aiding in their evaluation. We analyze the subject of the evolutionary design of building form styling following the aesthetic preferences of the designer. Component types and connection patterns characterize the building form and the rules of its composition. The designer using a graphics editor creates a 3D prototype model of a building form representative of his/her stylistic preferences by selecting different types of components and patterns of their connections. In the proposed evolutionary design, how the designer prototype model is organized, processed, and manipulated in generating buildings is based on the special graph structures. The research question addressed in this paper is, “How can a designer-defined 3D prototype model along with non-numerical graph calculations, influence computational creativity?” The main aim is to contribute to a better understanding of the non-numerical graph calculations describing the design process where visual perception is the driving force of creativity. Utilizing the developed formal description of the design synthesis, methodological contributions to generative and evolutionary techniques for computational creativity are presented. Full article

To identify hygrothermal transfer patterns of exterior walls is a crucial issue in the design, assessment, and construction of buildings. Temperature and relative humidity, as sensor monitoring data, were collected from the outside of the wall to interior bamboo and wood composite sheathing over the year in Huangshan Mountain District, Anhui Province, China. Combining the machine learning method of reservoir computing (RC) with agglomerative hierarchical clustering (AHC), a novel clustering framework was built for better extraction of the characteristics of hygrothermal transfer on the time series data. The experimental results confirmed the hypothesis that the change in the temperature and relative humidity of the outside of the wall (RHT12) dominated the change of the interior sheathing (RHT11). The delay time between two adjacent peaks in temperature was 1 to 2 h, while that in relative humidity was 1 to 4 h from the outside of the wall to interior bamboo and wood composite sheathing. There was no significant difference in temperature peak delay time between April and July. Temperature peak delay time was 50 to 120 min. However, relative humidity peak delay time was 100 to 240 min in April, whereas it was 20 to 120 min in July. The impact formed a relatively linear relationship between outdoor temperature and relative humidity peak delay time. The hygrothermal transfer patterns were characterized effectively by the peak delays. The discovery of the hygrothermal transfer patterns for the bamboo and wood composite walls using the machine learning method will facilitate the development of energy-efficient and durable bamboo and wood composite wall materials and structures. Full article

In this paper, new prefabricated cold-formed light-gauge steel stud wall panels sheathed with fireproof phenolic boards, which are fabricated by connecting the steel studs and the boards by using structural silicone sealant, was proposed. The proposed prefabricated wall has a good fireproof performance and can be manufactured rapidly in a factory. Full-scale tests on the mechanical properties of the prefabricated wall system, consisting of the prefabricated wall and the connection between the wall and the surrounding steel structure under out-of-plane loading, were performed. A total of six specimens were tested considering the effects of the arrangement of the cold-formed light-gauge steel studs, the shape and thickness of the steel connector for jointing the prefabricated wall panel and the surrounding steel structure, and the number of self-tapping screws connecting the surrounding structure. The results show that the out-of-plane stiffness of the prefabricated wall system in the elastic stress state under out-of-plane loading can be increased by increasing the number of self-tapping screws, increasing the thickness of the steel connector, or adopting the symmetrical arrangement of the light-gauge steel studs. The out-of-plane stiffness of the prefabricated wall system and the stiffness contribution of a single special-shaped steel connector can both be increased by increasing the number of special-shaped steel connectors. Furthermore, the special-shaped steel connector is more beneficial to a greater out-of-plane stiffness than the L-shaped steel connector. In addition, the theoretical calculation methods for deflection of the proposed prefabricated wall and flexural stress of the CFS C-channel stud considering the fireproof phenolic board sheathing effect under elastic state were proposed. The predicted results using the proposed method are compared with test results and the predicted results by using other methods. It was found that the predicted results by using the proposed method agreed better with the test results compared with the predicted results using the transformed-section method or the reduced stiffness method, which demonstrates the acceptability and accuracy of the proposed mothed for calculating deflection of the proposed prefabricated wall and flexural stress of the CFS C-channel stud. Full article

In order to make full use of the advantages of PD (particle damper) and TLD (tuned liquid damper) technologies, a new kind of damping system combining these two already-existing dampers is proposed and was named as PDAL (tuned particle damper with additional liquid). A shaking table test of a steel frame structure with a PDAL system is conducted here for the purpose of vibration control analysis. The results of the test demonstrate well the reliability and effectiveness of the PDAL system under various seismic waves. Seismic responses (mainly acceleration value) are investigated thoroughly for parameter analysis based on the experimental data, and some suggestions are proposed for future designs, including the necessity for parameter optimization and awareness of the dynamic characteristic changes that might occur in actual structures if attached with a PDAL system. This paper constitutes a preliminary study for the PDAL system, and it can serve as a baseline and conceptual reference for future investigations. Full article

The study of the long-term behavior of the prestressed continuous beam is vital for the design and the appliance of wood structures in engineering. In this study, long-term experiments were first conducted to determine the long-term creep behavior. Afterward, the prestress of the long-term beam was regulated to the initial state, and we carried out short-term flexural experiments to explore the effect of prestressing regulation. The influences of prestressed value and the number of prestressed steel wires on the mechanical properties of the continuous beam were investigated and discussed. The experimental results demonstrate that the creep reduced the stress in the steel wires, weakened the effect of prestressing, and increased the tensile stress at the bottom of the beam, which led to a reduction in the bearing capacity of the beam. The prestressing regulation could increase the moment arm, so the bearing capacity of the beam was improved. Full article

Starting from historical environmental records of the Benicalap neighbourhood in Valencia, this paper presents an energy model contributing to the assessment of carbon-neutral city policies for several nature-based solution (NBS) pilots extended to the neighbourhood level and combined with building façade renovation proposals. Accurate monitoring of several NBS pilot strategies was studied to validate a computational-fluid-dynamic (CFD) microclimate flux (both storage heat flux and latent heat flux) model, allowing a joint understanding of humidity and heat dynamics for the pilots under study. When expanded at a neighbourhood level, the combined effect of NBSs and energy dynamics (from buildings and vegetation) on neighbourhood microclimates is used to assess the optimal combination of urban renovation policies for energy efficiency and consequently carbon footprint reduction. Full article

To investigate the mechanical properties of plastic–concrete silo walls in practice, the mechanical properties and failure mechanism under the combined bending moment and water pressure were analyzed through the uniform loading test, water pressure test, and numerical analysis. The influence of the connecting plate spacing, radius, and the waterproof plate thickness on the water pressure-bearing capacity were analyzed. The test results show that the chemical adhesive force exists between the waterproof plate and concrete and can resist 20 kPa. The displacement and strain of the waterproof plate increases significantly with the increment in water pressure. When the water pressure reached 85 kPa, the specimen was damaged due to shear failure. The established numerical model was validated by the test results. The numerical analysis results show that the specimen failure mainly depends on the bolt strength when the thickness of the waterproof plate is greater than 14 mm or the radius of the connecting plate is greater than 60 mm. The relation between the design parameters and the water pressure-bearing capacity was proposed. Compared with the waterproof plate thickness, the connecting plate spacing and radius have greater influence on the water pressure-bearing capacity. Full article

High-rise apartment buildings, the preferred type of housing in South Korea, have very similar exteriors. Thus, apartment complexes tend to look similar with no unique identity of complex or city. This study aimed to identify the factors influencing the exterior design of high-rise apartment buildings in their 40-year history. I surveyed 50 apartment complexes from the 1970s to 2010, categorized important periods in Korean history, and analyzed corresponding changes in the exterior design of high-rise apartment buildings. I visited apartments in Seoul to take photos and conduct field surveys, and statistically analyzed the results by classifying the buildings’ external characteristics. I found correlations between the exterior design of the buildings and three major factors influencing their changes and development. The first is increasing institutional supply in the 1970s and developing landscapes in the 2000s. The second is an economic factor—economic growth. Third, as technology developed, apartment buildings transitioned from low-rise to high-rise, and their exterior design underwent many changes. This study reveals the relationship between changes in high-rise apartment buildings’ exteriors as they developed alongside South Korea’s growth and the influencing factors, and presents major factors that determine the direction of exterior design for high-rise apartment buildings in the future. Full article

Downburst is the main source of extreme wind speed in non-typhoon areas, which has caused a large amount of transmission line damage all over the world. In order to reveal the wind-induced vibration response characteristics of a transmission tower-line system under downburst, the nonlinear dynamic analysis of a single tower and tower-line system is carried out, and the amplification effect of tower-line coupling and fluctuating wind on the dynamic response is studied. Then, the effects of three wind field parameters closely related to the average wind profile on the wind-induced response of the tower-line system are studied. The results show that under the action of the downburst, the tower-line coupling weakens the dynamic response to a certain extent, and the dynamic amplification factor of a single tower and tower-line system is 1.1 ~ 1.3; for the self-supporting tower, when the height of the peak wind speed is close to the height of tower, the responses of the structure are more unfavorable. When the vector superposition method is used, the storm moving speed (V_t) has little effect on the wind-induced response of the tower-line system. For large-span structures such as tower-line systems, to ensure the safety of the structural design, the value of the characteristic radius (R_c) should not be too small. Full article

The indoor thermal environment has become a critical factor, due to its impact on the energy efficiency of a building and the health and performance of its occupants. It is particularly important for educational buildings, where students and teachers are exposed to these thermal conditions. This study assessed the impact of natural ventilation efficiency and university students’ thermal perception during the cold season. A field monitoring campaign and a questionnaire survey were conducted. A total of 989 students participated in this study. The results show that, although the CO₂ concentration in 90% of the evaluated classrooms was below the European recommended value (i.e., 800 ppm), only 18% of the classrooms were within the thermal comfort zone defined by national regulations. These thermal conditions caused 55% of the students surveyed to report that they were dissatisfied, and that this environment interfered with their academic performance. Significant differences were found between thermal sensation votes from female and male students (p < 0.001). The obtained neutral temperature was one degree higher for female students than for males. Our results suggest that ventilation protocols need to be modified by adjusting the window opening strategy, and these findings should be used as guidelines during their redesign. Full article