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Buildings, Volume 11, Issue 9 (September 2021) – 48 articles

Cover Story (view full-size image): We present an approach to automatically generate a dynamic energy simulation model for an existing building. It can be used for the preparation of energy retrofits to optimize effort and costs. Starting with a photogrammetrically generated polygon envelope model, we adapt and apply open-source tools for data enrichment and model generation. In a case study, the resulting model can accurately reproduce internal air temperatures. Heat transfer coefficients, heat demand, and accuracy implications of different parameter variations are analyzed and discussed. We conclude that that the presented workflow is suitable for enabling quick estimations of possible savings after a refurbishment. View this paper
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21 pages, 1719 KiB  
Article
Ductility of Concrete Beams Reinforced with FRP Rebars
by Tvrtko Renić and Tomislav Kišiček
Buildings 2021, 11(9), 424; https://doi.org/10.3390/buildings11090424 - 21 Sep 2021
Cited by 11 | Viewed by 7367
Abstract
Concrete beams reinforced with FRP rebars have greater durability than standard steel reinforced elements. The main disadvantage of using FRP rebars is the low ductility of elements which may be unacceptable in certain situations. There are several different ways of increasing the ductility [...] Read more.
Concrete beams reinforced with FRP rebars have greater durability than standard steel reinforced elements. The main disadvantage of using FRP rebars is the low ductility of elements which may be unacceptable in certain situations. There are several different ways of increasing the ductility of concrete elements, which are analyzed in this paper. They are compared based on efficiency, influence on durability and ease of construction. Less analyzed and tested methods are given more attention to try and expand the current knowledge and possibilities. For methods that lack experimental data, theoretical analysis is undertaken to assess the possible influence of that method on the increase in ductility. Ductility was obtained by calculating bending moment–curvature diagrams of cross sections for different reinforcement layouts. One method that lacks experimental data is confining the compressive area of beams with tensile FRP reinforcement. Theoretical analysis showed that confining the compressive area of concrete can significantly increase the ductility and bending capacity of beams. Since experimental data of beams reinforced with FRP rebars in tension and confined compressive area is sparse, some suggestions on the possible test setups are given to validate this theoretical analysis. Concrete beams reinforced with FRP can be detailed in such a way that they have sufficient ductility, but additional experimental research is needed. Full article
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19 pages, 3160 KiB  
Article
Shear Behavior of Steel-Fiber-Reinforced Recycled Aggregate Concrete Deep Beams
by Nancy Kachouh, Tamer El-Maaddawy, Hilal El-Hassan and Bilal El-Ariss
Buildings 2021, 11(9), 423; https://doi.org/10.3390/buildings11090423 - 21 Sep 2021
Cited by 23 | Viewed by 3543
Abstract
Results of an experimental investigation aimed at studying the effect of steel fibers on the shear behavior of concrete deep beams made with a 100% recycled concrete aggregate (RCA) are presented in this paper. The study comprised testing of seven concrete deep beam [...] Read more.
Results of an experimental investigation aimed at studying the effect of steel fibers on the shear behavior of concrete deep beams made with a 100% recycled concrete aggregate (RCA) are presented in this paper. The study comprised testing of seven concrete deep beam specimens with a shear span-to-depth ratio (a/h) of 1.6. Two beams were made of natural aggregates (NAs) without steel fibers, two beams were made of a 100% RCA without steel fibers, and three beams were made of RCA-based concrete with steel fibers at volume fractions (vf) of 1, 2, and 3%. Two of the beams without steel fibers included a minimum shear reinforcement. Test results showed that the beam with a 100% RCA without steel fibers exhibited a lower post-cracking stiffness, reduced shear cracking load, and lower shear capacity than those of the NA-based control beam. The detrimental effect of the RCA on the shear response was less pronounced in the presence of the minimum shear reinforcement. The addition of steel fibers significantly improved the shear response of the RCA-based beams. The post-cracking stiffness of the RCA-based concrete beams with steel fibers coincided with that of a similar beam without fibers containing the minimum shear reinforcement. The use of steel fibers in RCA beams at vf of 1 and 2% restored 80 and 90% of the shear capacity, respectively, of a similar beam with the minimum shear reinforcement. The response of the RCA specimen with vf of 3% outperformed that of the NA-based control beam with the minimum shear reinforcement, indicating that steel fibers can be used in RCA deep beams as a substitution to the minimum shear reinforcement. The shear capacities obtained from the tests were compared with predictions of published analytical models. Full article
(This article belongs to the Section Building Structures)
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22 pages, 11315 KiB  
Article
Utilization of Corn Cob Ash as Fine Aggregate and Ground Granulated Blast Furnace Slag as Cementitious Material in Concrete
by Naraindas Bheel, Montasir Osman Ahmed Ali, Yue Liu, T. Tafsirojjaman, Paul Awoyera, Nadhim Hamah Sor and Lenin Miguel Bendezu Romero
Buildings 2021, 11(9), 422; https://doi.org/10.3390/buildings11090422 - 21 Sep 2021
Cited by 33 | Viewed by 6264
Abstract
Cementitious and recycled materials that have the potential to improve various properties of concrete have attracted the attention of many researchers recently. Different types of cementitious and recycled materials seem to possess certain unique properties to change cement concrete. This experimental study aims [...] Read more.
Cementitious and recycled materials that have the potential to improve various properties of concrete have attracted the attention of many researchers recently. Different types of cementitious and recycled materials seem to possess certain unique properties to change cement concrete. This experimental study aims to investigate the impact of ground granulated blast furnace slag (GGBFS) and corn cob ash (CCA) as a partial replacement material for Portland cement (PC) and fine aggregate (FA), respectively, on fresh and hardened concrete properties, as well as the embodied carbon of concrete. The concrete mix was blended with 5–20% of GGBFS and 10–40% of corn cob ash, both individually and combined. A total of 300 concrete specimens were made to achieve the targeted strength of 25 MPa at a 0.50 water/cement ratio and cured at 28 days. It is observed that the workability of fresh concrete is lowered as the dosages of GGBFS and CCA increase in the mixture. Moreover, the compressive and split tensile strengths are augmented by 10.94% and 9.15%, respectively, at 10% of GGBFS by the weight of PC at 28 days. Similarly, the compressive and split tensile strengths are augmented by 11.62% and 10.56%, respectively, at 30% of CCA by the weight of FA at 28 days. Moreover, the combined use of 10% of GGBFS as a cementitious ingredient along with 30% of fine aggregate replaced with CCA in concrete provides the highest compressive and splitting tensile strength, with 16.98% and 13.38% at 28 days, respectively. Furthermore, the density and water absorption of concrete were reduced with increasing dosages of GGBFS and FA in concrete at 28 days. In addition, the embodied carbon and energy were also reduced as the replacement content of GGBFS along with CCA increased in concrete. It is concluded that 10% of GGBFS and 30% of CCA are the optimum percentages for structural applications to reduce the use of cement as well as the cost of the project. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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30 pages, 4855 KiB  
Article
Passive Energy-Saving Optimal Design for Rural Residences of Hanzhong Region in Northwest China Based on Performance Simulation and Optimization Algorithm
by Teng Shao, Wuxing Zheng and Zheng Cheng
Buildings 2021, 11(9), 421; https://doi.org/10.3390/buildings11090421 - 21 Sep 2021
Cited by 11 | Viewed by 2808
Abstract
The rural residences of Northwest China are characterized by a state of high energy consumption and low comfort due to the limited economic level and awareness of energy-saving compared with the urban residences. To remedy this, appropriate passive design strategies should be adopted [...] Read more.
The rural residences of Northwest China are characterized by a state of high energy consumption and low comfort due to the limited economic level and awareness of energy-saving compared with the urban residences. To remedy this, appropriate passive design strategies should be adopted first, in order to provide a design mode with low energy consumption and low cost for rural residences under the premise of thermal comfort. In this paper, taking Hanzhong region (Shaanxi Province, China) as an example, we establish a benchmark model based on a field survey and develop an optimization process by combining EnergyPlus simulation software, the MOBO optimization engine, and weighted sum method. The action mechanisms of passive design parameters, including the building orientation, length–width ratio, building envelope parameters, external shading system, and window–wall ratio, on heating, cooling, and total energy consumption are analyzed, and the quantitative relationships between single-parameter and energy consumption are established. Then, the mutually restricted indices of total energy consumption and initial investment cost are taken as optimization objectives, and 17 design parameters are selected as the optimization variables. The NSGA-II algorithm is adopted to conduct the multi-parameter, multi-objective optimization design for rural houses in Hanzhong area, through coupling of the EnergyPlus and MOBO software. In this way, Pareto solutions are obtained and the value distributions of the multi-objectives and design parameters are analyzed. Based on the actual requirements of decision-makers and using the weight method, three design schemes focusing on different performance tendencies are proposed. The results indicate that by using the proposed optimization process, the building energy consumption can be significantly reduced while taking initial investment costs into account, where the energy-saving rate is in the range of 31.9–61.5%. When the EC/IC ratio is 1:1, 2:1, and 1:2, the energy-saving rate can reach 51.5%, 57.8%, and 43.5%, respectively. It can provide a beneficial pattern for the energy-saving design and renovation of rural residences in Hanzhong area of China. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
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16 pages, 4608 KiB  
Article
Test and Evaluation of the Flexural Properties of Reinforced Concrete Beams with 100% Recycled Coarse Aggregate and Manufactured Sand
by Changyong Li, Tongsheng Liu, Hao Fu, Xiaoyan Zhang, Yabin Yang and Shunbo Zhao
Buildings 2021, 11(9), 420; https://doi.org/10.3390/buildings11090420 - 19 Sep 2021
Cited by 8 | Viewed by 2278
Abstract
Although studies have been performed on the recycled aggregate made of waste concrete for the production of new concrete, the new concrete with 100% recycled coarse aggregate and manufactured sand (abbreviated as RAMC) still needs to be researched for structural applications. In this [...] Read more.
Although studies have been performed on the recycled aggregate made of waste concrete for the production of new concrete, the new concrete with 100% recycled coarse aggregate and manufactured sand (abbreviated as RAMC) still needs to be researched for structural applications. In this paper, an experimental study was performed on seven groups, including fourteen reinforced RAMC beams under the simply supported four-point loading test, considering the factors of the strength of RAMC and the reinforcement ratio of longitudinal tensile rebars. Based on the test results, the cracking resistance, the bearing capacity, the crack width, the flexural stiffness and the mid-span deflection of reinforced RAMC beams in bending are discussed and examined by using the formulas of conventional reinforced concrete beams. Results show that an obvious effect of reinforcement ratio was present, while less so was that of the strength of RAMC. With the comparison of predicted values by the formulas of conventional reinforced concrete beams, the reinforced RAMC beams decreased cracking resistance by about 20%, increased crack width by about 15% and increased mid-span deflection by about 10%, although the same bearing capacity can be reached. The results directly relate to the lower tensile strength of RAMC which should be further improved. Full article
(This article belongs to the Collection Advanced Concrete Structures in Civil Engineering)
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21 pages, 7470 KiB  
Article
Plug and Play Modular Façade Construction System for Renovation for Residential Buildings
by Jorge Torres, Roberto Garay-Martinez, Xabat Oregi, J. Ignacio Torrens-Galdiz, Amaia Uriarte-Arrien, Alessandro Pracucci, Oscar Casadei, Sara Magnani, Noemi Arroyo and Angel M. Cea
Buildings 2021, 11(9), 419; https://doi.org/10.3390/buildings11090419 - 18 Sep 2021
Cited by 17 | Viewed by 8823
Abstract
The present paper focuses on the architectural and constructional features required to ensure that building envelope renovation are safe, functional, and adaptable to the building stock, with particular focus on “plug and play” modular facade construction systems. It presents the design of one [...] Read more.
The present paper focuses on the architectural and constructional features required to ensure that building envelope renovation are safe, functional, and adaptable to the building stock, with particular focus on “plug and play” modular facade construction systems. It presents the design of one such system and how it addresses these issues. The outcome of early-stage functional test with a full-scale mock-up system, as well as its applicability to a real construction project is presented. It is found crucial to obtain high quality information about the status of the existing façade with the use of modern technologies such as topographic surveys or 3D scans and point cloud. Detailed design processes are required to ensure the compatibility of manufacture and installation tolerances, along with anchor systems that deliver flexibility for adjustment, and construction processes adapting standard installation methods to the architectural particularities of each case that may hinder its use or require some modification in each situation. This prefabricated plug and play modular system has been tested by reproducing the holistic methodology and new technologies in the market by means of real demonstrators. When compared to more conventional construction methods, this system achieves savings in a real case of 50% (time), 30% (materials) and 25% (waste), thus achieving significant economic savings. Full article
(This article belongs to the Section Building Materials, and Repair & Renovation)
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19 pages, 16996 KiB  
Article
Measuring the Impact of Museum Architecture, Spaces and Exhibits on Virtual Visitors Using Facial Expression Analysis Software
by Linda Nubani and Aslıhan Öztürk
Buildings 2021, 11(9), 418; https://doi.org/10.3390/buildings11090418 - 18 Sep 2021
Cited by 3 | Viewed by 3287
Abstract
Since the launch of online video portals in 2005, museums have encouraged visitors to upload and share their visits online. Although much has been written about visitors’ experiences in museums, very little exists on the impact virtual visits have on viewers. In this [...] Read more.
Since the launch of online video portals in 2005, museums have encouraged visitors to upload and share their visits online. Although much has been written about visitors’ experiences in museums, very little exists on the impact virtual visits have on viewers. In this qualitative pilot study, a total of 2035 emotional reactions were recorded and analyzed after visiting 14 online museums using a facial expression recognition software. Following open and axial coding techniques, themes and subcategories emerged. Findings showed that while the background of the participant mediated how one experiences a museum online, certain architectural and exhibit attributes, if present, triggered similar emotions to those experienced in an in-person visit. Findings suggest that experiencing museums through online video portals may be as engaging as visiting museums in person—only if the creator captures a significant proportion of architectural details, transitioning of spaces and exhibits details. Further findings showed that facial expression software reveals what captures virtual visitors’ emotions, and what architectural and exhibit features keep them curious and engaged. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
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30 pages, 2459 KiB  
Review
3D Tree Reconstruction in Support of Urban Microclimate Simulation: A Comprehensive Literature Review
by Han Xu, Cynthia Changxin Wang, Xuesong Shen and Sisi Zlatanova
Buildings 2021, 11(9), 417; https://doi.org/10.3390/buildings11090417 - 17 Sep 2021
Cited by 17 | Viewed by 4575
Abstract
The negative climate change induced by rapid urbanization has become a global environmental issue. Numerous studies have been devoted to microclimate regulation functions performed by urban vegetation. Digital city information modeling provides a powerful tool for various simulations and data analytics for the [...] Read more.
The negative climate change induced by rapid urbanization has become a global environmental issue. Numerous studies have been devoted to microclimate regulation functions performed by urban vegetation. Digital city information modeling provides a powerful tool for various simulations and data analytics for the sustainable development of urban areas. However, the method reconstructing urban trees is still in its early stage compared to the relatively mature building modeling. Most prior studies on tree reconstruction focused on retrieving geometric features, while other factors related to urban microclimate simulation were rarely addressed. This paper presents a comprehensive literature review and in-depth analysis covering two distinct research directions in relation to urban microclimate simulation. The first one is set on the identification of key factors related to trees’ impact on urban microclimate. The second one is dedicated to approaches for three-dimensional (3D) tree reconstruction. Based on the findings, the paper identifies information including trees’ geometric, physiological characteristics and relation to the surroundings required for 3D tree reconstruction in the context of urban microclimate simulation, and further assesses the potential of the 3D tree reconstruction approaches to accommodate these pieces of information. An appropriate 3D tree reconstruction approach, which allows for the supply of the required information for urban microclimate simulation, is recommended. Full article
(This article belongs to the Collection Cities and Infrastructure)
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23 pages, 26776 KiB  
Article
Transport Properties and Resistance Improvement of Ultra-High Performance Concrete (UHPC) after Exposure to Elevated Temperatures
by Yunfeng Qian, Dingyi Yang, Yanghao Xia, Han Gao and Zhiming Ma
Buildings 2021, 11(9), 416; https://doi.org/10.3390/buildings11090416 - 17 Sep 2021
Cited by 8 | Viewed by 2651
Abstract
Ultra-high performance concrete (UHPC) has a high self-healing capacity and is prone to bursting after exposure to high temperatures due to its characteristics. This work evaluates the damage and improvement of UHPC with coarse aggregates through mechanical properties (compressive strength and ultrasonic pulse [...] Read more.
Ultra-high performance concrete (UHPC) has a high self-healing capacity and is prone to bursting after exposure to high temperatures due to its characteristics. This work evaluates the damage and improvement of UHPC with coarse aggregates through mechanical properties (compressive strength and ultrasonic pulse velocity), transport properties (water absorption and a chloride diffusion test), and micro-properties such as X-ray diffraction (XRD), Mercury intrusion porosimetry (MIP), and Scanning electronic microscopy (SEM). The result demonstrates that polypropylene (PP) fibers are more suitable for high temperature tests than polyacrylonitrile (PAN) fibers. The result shows that 400 °C is the critical temperature point. With the increase in temperature, the hydration becomes significant, and the internal material phase changes accordingly. Although the total pore volume increased, the percentage of various types of pores was optimized within 400 °C. The mass loss gradually increased and the ultrasonic pulse velocity gradually decreased. While the compressive strength first increased and then decreased, and the increase occurred within 25–400 °C. As for the transport properties, the chloride migration coefficient and capillary absorption coefficient both increased dramatically due to the higher sensitivity to temperature changes. The results of the property improvement test showed that at temperatures above 800 °C, the compressive strength recovered by more than 65% and the ultrasonic pulse velocity recovered by more than 75%. In terms of transport properties, compared to the results before self-healing, the chloride migration coefficient decreased by up to 59%, compared with 89% for the capillary absorption coefficient, after self-healing at 800 °C. With respect to the enhancement effect after exposure to high temperatures, the environment of a 5% Na2SO4 solution was not as good as the clean water environment. The corresponding changes in microstructure during the high temperatures and the self-healing process can explain the change in the pattern of macroscopic properties more precisely. Full article
(This article belongs to the Collection Advanced Concrete Materials in Construction)
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19 pages, 6594 KiB  
Article
Effects of Shear Tabs and High-Strength Bolts in Seismic Performance of Steel Moment Connections
by Chi-Ming Lai, Ching-Yu Yeh, Sin-Yu Kang and Heui-Yung Chang
Buildings 2021, 11(9), 415; https://doi.org/10.3390/buildings11090415 - 17 Sep 2021
Cited by 4 | Viewed by 3732
Abstract
A shear tab and high-strength bolts are often used to connect a steel H-beam to a column. The design demand and capacity of these elements vary from one standard to the other. To investigate the effect, this study applied a finite element method [...] Read more.
A shear tab and high-strength bolts are often used to connect a steel H-beam to a column. The design demand and capacity of these elements vary from one standard to the other. To investigate the effect, this study applied a finite element method (FEM) to develop models for two steel moment connections and validated the effectiveness by test data. The connections were characteristic of bolted-web-and-welded-flange details. The FEM models were then used to study the design of shear tabs and high-strength bolts in accordance with the U.S. and Japan standards and compared to the Taiwan practice. The result showed a small difference in the peak loads of the connections. However, the U.S. direct welded flange connection had flange buckling and strength degradation at a relatively smaller drift. The connection had a thinner shear tab and fewer high-strength bolts. The other two connections had very similar design results and loading responses. The increase in shear-tab thickness reduced the stress concentration and fracture potential of the connections. It is, therefore, recommended to design a shear tab with moment capacity greater than the beam web. This will reduce the stress concentration of the base metal surrounding the beam-flange groove welds, increasing the connection ductility. Full article
(This article belongs to the Section Building Structures)
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24 pages, 2405 KiB  
Article
The Influence of Different Scattering Algorithms on Room Acoustic Simulations in Rectangular Rooms
by Hanna Autio, Nikolaos-Georgios Vardaxis and Delphine Bard Hagberg
Buildings 2021, 11(9), 414; https://doi.org/10.3390/buildings11090414 - 17 Sep 2021
Cited by 3 | Viewed by 2181
Abstract
Raytracing is a widespread tool for room acoustic simulations, and one of its main advantages is the inclusion of surface scattering. Although surface scattering has been acknowledged as a central aspect of accurate raytracing simulations for many years, there is ongoing research into [...] Read more.
Raytracing is a widespread tool for room acoustic simulations, and one of its main advantages is the inclusion of surface scattering. Although surface scattering has been acknowledged as a central aspect of accurate raytracing simulations for many years, there is ongoing research into its effects and how to implement it better. This study evaluates three different algorithms for surface scattering in raytracers, referred to as on–off scattering, perturbation scattering, and diffuse field scattering. Their theoretical foundation is discussed, and the physical accuracy of the resulting simulations is evaluated by comparing simulated room acoustic parameters to measurements. It is found that the choice of surface scattering algorithm has a significant impact on the simulation outcomes, both in terms of physical accuracy and in terms of usability. Additionally, there are differences in the parametrization of surface scattering depending on the algorithm chosen. Of the three tested algorithms, the most commonly used algorithm (on–off scattering) seems to have the best properties for simulations. Full article
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20 pages, 6812 KiB  
Article
Improving Comfort and Health: Green Retrofit Designs for Sunken Courtyards during the Summer Period in a Subtropical Climate
by Gang Han, Yueming Wen, Jiawei Leng and Lijun Sun
Buildings 2021, 11(9), 413; https://doi.org/10.3390/buildings11090413 - 16 Sep 2021
Cited by 15 | Viewed by 4282
Abstract
The sunken courtyard has long been used in underground spaces and provides an important outdoor environment. It introduces natural elements to create a pleasant space for human activities. However, this study measured a typical sunken courtyard and found potential problems of excessive solar [...] Read more.
The sunken courtyard has long been used in underground spaces and provides an important outdoor environment. It introduces natural elements to create a pleasant space for human activities. However, this study measured a typical sunken courtyard and found potential problems of excessive solar radiation and accumulated air pollutants in summer when at an acceptable outdoor temperature for human activities. To improve the comfort and health of a sunken courtyard, this research proposes some green retrofit designs. Firstly, compared with green wall, water and a tree, sunshade is a primary measure to improve thermal comfort. Combining sunshade, a green wall and water reduces the temperature by up to 5.6 °C in the activity zone during the hottest hour. Secondly, blocking/guiding wind walls can effectively improve the wind environment in a sunken courtyard, but only when the wind direction is close to the prevailing wind. A blocking wind wall was better at affecting velocity and uniformity, while the guiding wind wall was more efficient at discharging air pollutants. This study initially discusses the climate-adaptive design of underground spaces in terms of green, thermal comfort and natural ventilation. Designers should generally integrate above/underground and indoor/outdoor spaces using natural and artificial resources to improve comfort and health in underground spaces. Full article
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22 pages, 3722 KiB  
Article
Onsite Quality Check for Installation of Prefabricated Wall Panels Using Laser Scanning
by Mudan Wang, Cynthia Changxin Wang, Sisi Zlatanova, Samad Sepasgozar and Mitko Aleksandrov
Buildings 2021, 11(9), 412; https://doi.org/10.3390/buildings11090412 - 16 Sep 2021
Cited by 15 | Viewed by 3502
Abstract
Prefabricated construction has gained increasing popularity to meet the needs of rapid city development in recent years. Installation quality check is a critical task in prefabricated construction, and currently mostly still carried out manually, which is slow and ineffective. To provide an efficient [...] Read more.
Prefabricated construction has gained increasing popularity to meet the needs of rapid city development in recent years. Installation quality check is a critical task in prefabricated construction, and currently mostly still carried out manually, which is slow and ineffective. To provide an efficient and practical quality check method to replace the current manual method, this paper elaborates on an approach for checking prefabricated wall panels using laser scanning. The approach is validated in an actual case study. A common laser scanner BLK 360 is adopted to collect onsite 3D scenes after panel installation. The point clouds collected are co-roistered, classified, and segmented. Geometric parameters such as angles and distances allow for determining whether the installation meets the quality requirement. The outcome is compared with the quality check results using the conventional manual method. The results show that the panels, which need rectification, are correctly identified by the proposed approach. The major contribution of this study is determining the set of segmentation parameters to be adopted in similar quality check-up procedures. A practical and efficient quality check process is also proposed and can be readily implemented for certain prefabricated elements in many construction cases. Full article
(This article belongs to the Collection Cities and Infrastructure)
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22 pages, 4436 KiB  
Review
Industry 4.0, Disaster Risk Management and Infrastructure Resilience: A Systematic Review and Bibliometric Analysis
by Mahyar Habibi Rad, Mohammad Mojtahedi and Michael J. Ostwald
Buildings 2021, 11(9), 411; https://doi.org/10.3390/buildings11090411 - 16 Sep 2021
Cited by 32 | Viewed by 5504
Abstract
The fourth industrial era, known as ‘Industry 4.0’ (I4.0), aided and abetted by the digital revolution, has attracted increasing attention among scholars and practitioners in the last decade. The adoption of I4.0 principles in Disaster Risk Management (DRM) research and associated industry practices [...] Read more.
The fourth industrial era, known as ‘Industry 4.0’ (I4.0), aided and abetted by the digital revolution, has attracted increasing attention among scholars and practitioners in the last decade. The adoption of I4.0 principles in Disaster Risk Management (DRM) research and associated industry practices is particularly notable, although its origins, impacts and potential are not well understood. In response to this knowledge gap, this paper conducts a systematic literature review and bibliometric analysis of the application and contribution of I4.0 in DRM. The systematic literature review identified 144 relevant articles and then employed descriptive and content analysis of a focused set of 70 articles published between 2011 and 2021. The results of this review trace the growing trend for adoption of I4.0 tools and techniques in disaster management, and in parallel their influence in resilient infrastructure and digital construction fields. The results are used to identify six dominant clusters of research activity: big data analytics, Internet of Things, prefabrication and modularization, robotics and cyber-physical systems. The research in each cluster is then mapped to the priorities of the Sendai framework for DRR, highlighting the ways it can support this international agenda. Finally, this paper identifies gaps within the literature and discusses possible future research directions for the combination of I4.0 and DRM. Full article
(This article belongs to the Collection Cities and Infrastructure)
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22 pages, 7059 KiB  
Article
Improving Energy Performance of Historic Buildings through Hygrothermal Assessment of the Envelope
by Alexander Martín-Garín, José Antonio Millán-García, Jon Terés-Zubiaga, Xabat Oregi, Iñigo Rodríguez-Vidal and Abderrahmane Baïri
Buildings 2021, 11(9), 410; https://doi.org/10.3390/buildings11090410 - 15 Sep 2021
Cited by 15 | Viewed by 4114
Abstract
The intervention on historic buildings through building energy retrofitting has become one of the current challenges of improving energy efficiency. Nonetheless, this building typology presents certain complexities. Among them, one of the most relevant is the protection on their façades due to the [...] Read more.
The intervention on historic buildings through building energy retrofitting has become one of the current challenges of improving energy efficiency. Nonetheless, this building typology presents certain complexities. Among them, one of the most relevant is the protection on their façades due to the historical and/or artistic values of a given façade and, therefore, the addition of external thermal insulation is restricted. However, at the same time, in several of those buildings indoor surfaces do not present that architectural value, and then internal thermal insulation becomes a promising strategy for improving their thermal performance. Nevertheless, its application must be carefully evaluated to avoid possible pathologies caused by moisture problems. This paper aims to identify constructive solutions for interior insulation of walls free from moisture problems. For this purpose, a comprehensive analysis of a series of constructive solutions based on internal insulation has been carried out through hygrothermal simulations. The results show how the application of water-repellent impregnation becomes essential to guaranteeing the integrity of the envelope. In addition, the combination of insulations with or without inner membranes, such as smart vapor retarders or vapor diffusion barriers, has been evaluated detecting the solutions that best fit the objective. Finally, taking advantage of the great potential of 2D simulation tools, the post-processing of the data has been performed to apply the wood decay model, and thus assess the behavior of a very conflictive point in this type of intervention, i.e., the wooden beam-ends. The results in this critical point have shown how the application of the proposed constructive solutions becomes essential to guarantee the integrity of the element and how the application of traditional solutions could lead to a hazard that must be avoided. Full article
(This article belongs to the Special Issue Energy Efficiency of Historical Buildings)
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28 pages, 6176 KiB  
Review
Applications of Computer Vision in Monitoring the Unsafe Behavior of Construction Workers: Current Status and Challenges
by Wenyao Liu, Qingfeng Meng, Zhen Li and Xin Hu
Buildings 2021, 11(9), 409; https://doi.org/10.3390/buildings11090409 - 14 Sep 2021
Cited by 30 | Viewed by 5892
Abstract
The unsafe behavior of construction workers is one of the main causes of safety accidents at construction sites. To reduce the incidence of construction accidents and improve the safety performance of construction projects, there is a need to identify risky factors by monitoring [...] Read more.
The unsafe behavior of construction workers is one of the main causes of safety accidents at construction sites. To reduce the incidence of construction accidents and improve the safety performance of construction projects, there is a need to identify risky factors by monitoring the behavior of construction workers. Computer vision (CV) technology, which is a powerful and automated tool used for extracting images and video information from construction sites, has been recognized and adopted as an effective construction site monitoring technology for the identification of risky factors resulting from the unsafe behavior of construction workers. In this article, we introduce the research background of this field and conduct a systematic statistical analysis of the relevant literature in this field through the bibliometric analysis method. Thereafter, we adopt a content-based analysis method to depict the historical explorations in the field. On this basis, the limitations and challenges in this field are identified, and future research directions are proposed. It is found that CV technology can effectively monitor the unsafe behaviors of construction workers. The research findings can enhance people’s understanding of construction safety management. Full article
(This article belongs to the Special Issue Application of Computer Technology in Buildings)
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18 pages, 2773 KiB  
Article
Evaluation for Low Temperature Performance of SBS Modified Asphalt by Dynamic Shear Rheometer Method
by Tao Wang, Xuelei Wei, De Zhang, Hai Shi and Zhiqiang Cheng
Buildings 2021, 11(9), 408; https://doi.org/10.3390/buildings11090408 - 13 Sep 2021
Cited by 15 | Viewed by 2503
Abstract
Finding an alternative or supplementary test method to evaluating the low temperature performance of asphalt is an area of considerable interest. This paper tries to explore the possibility of using the dynamic shear rheometer (DSR) method for assessing the low temperature properties of [...] Read more.
Finding an alternative or supplementary test method to evaluating the low temperature performance of asphalt is an area of considerable interest. This paper tries to explore the possibility of using the dynamic shear rheometer (DSR) method for assessing the low temperature properties of styrenebutadienestyrene (SBS) modified asphalt. In the study, 60/80 and 80/100 pen grade asphalt binders, named binder A-70, binder B-70 and binder C-90, are used to produce the SBS modified asphalt samples. After that, the low temperature performance of the asphalt binders is characterized by using bending beam rheometer (BBR) test. The results indicate that the low temperature performance of the different binders is related to the source of the binder. The low temperature performance of asphalt could be improved with the addition of the SBS. The DSR test is used to develop the complex modulus master curves for binders. Based on the principle of time–temperature conversion, the glass transition temperature of asphalt is calculated by the Williams–Landel–Ferry (WLF) equation. The glass transition temperatures (Tg) of base asphalt and the SBS modified asphalt are determined by the viscoelastic parameters of the master curve and the WLF equation coefficients based on the time–temperature superposition principle. By establishing the relationship between the critical temperature and the Tg of the asphalt binder, the effectiveness of the method established in this paper is verified. The advantage of this method is the ability to use the DSR test for the rapid evaluation of the low temperature performance of asphalt, which is able to reduce testing materials and save testing time as well. The glass transition temperature of the SBS modified asphalt is closely associated with aging degree, asphalt source and the SBS content. Full article
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17 pages, 7989 KiB  
Article
The Effect of Waste Plant Oil on the Composition and Micro-Morphological Properties of Old Asphalt Composition
by Zhi Suo, Lei Nie, Fanrong Xiang and Xu Bao
Buildings 2021, 11(9), 407; https://doi.org/10.3390/buildings11090407 - 12 Sep 2021
Cited by 11 | Viewed by 2109
Abstract
At present, the regeneration agent with mineral oil as the main component is widely used. However, its strong volatility, nonrenewability, and other shortcomings restrict the development of regeneration technology. In this study, waste vegetable oil was used as the main component of the [...] Read more.
At present, the regeneration agent with mineral oil as the main component is widely used. However, its strong volatility, nonrenewability, and other shortcomings restrict the development of regeneration technology. In this study, waste vegetable oil was used as the main component of the regeneration agent to prepare regenerated aging asphalt. The change in microstructure of aging asphalt was explored with the change in waste vegetable oil content and regeneration time. The results showed that the addition of waste vegetable oil could effectively supplement the contents of saturates and aromatics, and inhibit the oxidation of saturates and aromatics into asphaltene and resin. When the regeneration time was 60 min and the regeneration content was 7.0%, the effect was best. The correlation between the component composition of regenerated aging asphalt and the micro-morphological characteristics was in the order of saturates, asphaltene, resin, and aromatics. Full article
(This article belongs to the Special Issue Advanced Eco-Friendly Cementitious Materials)
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25 pages, 8034 KiB  
Article
Parametric Investigation on the Effectiveness of FRM-Retrofitting in Masonry Buttressed Arches
by Corrado Chisari, Daniela Cacace and Gianfranco De Matteis
Buildings 2021, 11(9), 406; https://doi.org/10.3390/buildings11090406 - 11 Sep 2021
Cited by 10 | Viewed by 1988
Abstract
Buttressed arches represent some of the most vulnerable elements in historical masonry buildings under seismic actions. Given their structural, architectural and often artistic importance, it is paramount to investigate effective retrofitting measures which satisfy reversibility and compatibility requirements for historical heritage. Among these, [...] Read more.
Buttressed arches represent some of the most vulnerable elements in historical masonry buildings under seismic actions. Given their structural, architectural and often artistic importance, it is paramount to investigate effective retrofitting measures which satisfy reversibility and compatibility requirements for historical heritage. Among these, Fibre-Reinforced Mortar (FRM), characterised by enhanced ductility, has recently emerged in the scientific literature. In this paper, a numerical investigation aimed at exploring the effectiveness of this seismic retrofitting technique, when applied at intrados or extrados of various typologies of buttressed arches, is presented. An automatic tool for limit analysis is described and validated against a nonlinear Discrete Macro-Element modelling approach. This precedes an extensive parametric analysis, which has highlighted the effect of various geometrical features of the system on both collapse mechanism and maximum acceleration in the unreinforced configuration, and the high increase in seismic capacity provided by the retrofitting. This is particularly remarkable in case of local mechanism, i.e., wholly within the arch, in which case the FRM may be responsible of an overall shifting to a semi-global failure type. Full article
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17 pages, 5827 KiB  
Article
Comparison of Different Procedures for Progressive Collapse Analysis of RC Flat Slab Structures under Corner Column Loss Scenario
by Andrey Nikolaevich Dmitriev and Vladimir Vladimirovich Lalin
Buildings 2021, 11(9), 405; https://doi.org/10.3390/buildings11090405 - 10 Sep 2021
Cited by 4 | Viewed by 4061
Abstract
Progressive collapse is the failure of the whole structure caused by local damage, which leads to significant economic and human losses. Therefore, structures should be designed to sustain local failures and resist subsequent nonproportional damage. This paper compared four procedures for a progressive [...] Read more.
Progressive collapse is the failure of the whole structure caused by local damage, which leads to significant economic and human losses. Therefore, structures should be designed to sustain local failures and resist subsequent nonproportional damage. This paper compared four procedures for a progressive collapse analysis of two RC structures subjected to a corner column loss scenario. The study is mainly based on the methods outlined in the current Russian standard (linear static (LS) pulldown, nonlinear static (ND) pulldown, and nonlinear dynamic), but also includes LS and NS pushdown procedures suggested by the American guidelines and linear dynamic procedure. We developed detailed finite element models for ANSYS Mechanical and ANSYS/LS-DYNA simulations, explicitly including concrete and reinforcement elements. We applied the Continuous Surface Cap Model (MAT_CSCM) to account for the physical nonlinearity of concrete. We also validated results obtained following these procedures against known experimental data. Simulations using linear static pulldown and linear dynamic procedures lead to 50–70% lower results than the experimental because they do not account for the nonlinear behavior of concrete and reinforcement. Displacements obtained from the NS pulldown method exceed the test data by 10–400%. It is found that correct results for both RC structures can only be found using a nonlinear dynamic procedure, and the mismatch with the test data do not exceed 7%. Compared to static pulldown methods, LS and NS pushdown methods are more accurate and differ from the experiment by 28% and 14%, respectively. This relative accuracy is provided by more correct load multipliers depending on the structure type. Full article
(This article belongs to the Section Building Structures)
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25 pages, 8592 KiB  
Article
Intervention Strategies for the Seismic Improvement of Masonry Buildings Based on FME Validation: The Case of a Terraced Building Struck by the 2016 Central Italy Earthquake
by Maria Rosa Valluzzi, Luca Sbrogiò and Ylenia Saretta
Buildings 2021, 11(9), 404; https://doi.org/10.3390/buildings11090404 - 10 Sep 2021
Cited by 13 | Viewed by 4114
Abstract
Residential masonry buildings represent a large stock among highly vulnerable structures in medium–high seismic hazard areas, often built without any anti-seismic provisions. Their rehabilitation and/or strengthening according to optimised intervention strategies is topical and may contribute to revaluating zones characterized by depopulation phenomena. [...] Read more.
Residential masonry buildings represent a large stock among highly vulnerable structures in medium–high seismic hazard areas, often built without any anti-seismic provisions. Their rehabilitation and/or strengthening according to optimised intervention strategies is topical and may contribute to revaluating zones characterized by depopulation phenomena. In this paper, a terraced building struck by the 2016 Central Italy earthquake is analysed through a frame by macro element (FME) model. The building is composed of six two-storey units made of stone and clay block masonry walls and semi-rigid diaphragms. The numerical model was calibrated based on the damage pattern caused by the earthquake and then used to carry out parametric analyses on the strengthened conditions by simulating both one unit and the entire terrace. The effects of interventions applied to either vertical or horizontal components, both singularly and in combination, were analysed in terms of nonlinear static analyses, and quantified by a performance factor, according to the upgraded seismic code in Italy. Kinematic analyses also completed the assessment of the building. Results compared the capacity of interventions in attaining the targets defined for improvement at both local and overall levels. Full article
(This article belongs to the Section Building Structures)
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14 pages, 271 KiB  
Article
Contextual Communicative Competence in Multinational Infrastructure Projects
by Anna-Therése Järvenpää, Anthony Pavlik and Tina Karrbom Gustavsson
Buildings 2021, 11(9), 403; https://doi.org/10.3390/buildings11090403 - 10 Sep 2021
Cited by 4 | Viewed by 1966 | Correction
Abstract
Communication is dynamic, social, challenging, and a key quality factor for construction projects. This is especially the case in multinational and inter-organizational infrastructure projects where factors like culture and language differ among the involved actors. As infrastructure projects usually extend over longer periods [...] Read more.
Communication is dynamic, social, challenging, and a key quality factor for construction projects. This is especially the case in multinational and inter-organizational infrastructure projects where factors like culture and language differ among the involved actors. As infrastructure projects usually extend over longer periods of time, collaborative relationships need to be established in which the actors can develop, for example, mutual understanding, learning, and efficient working routines. By building on empirical data from contemporary infrastructure projects, we explore how international contractors and a large public client communicate in multinational infrastructure projects (i.e., what the challenges are and what competences are needed). The analysis is based on the linguistic framework of communicative competence, and we contribute to the development of collaborative models in construction project management by suggesting the concept of contextual communicative competence. Full article
(This article belongs to the Section Construction Management, and Computers & Digitization)
22 pages, 24395 KiB  
Article
Prediction of Shear Strength of Reinforced Recycled Aggregate Concrete Beams without Stirrups
by Monthian Setkit, Satjapan Leelatanon, Thanongsak Imjai, Reyes Garcia and Suchart Limkatanyu
Buildings 2021, 11(9), 402; https://doi.org/10.3390/buildings11090402 - 08 Sep 2021
Cited by 17 | Viewed by 2465
Abstract
For decades, recycled coarse aggregate (RCA) has been used to make recycled aggregate concrete (RAC). Numerous studies have compared the mechanical properties and durability of recycled aggregate concrete (RAC) to those of natural aggregate concrete (NAC). However, test results on the shear strength [...] Read more.
For decades, recycled coarse aggregate (RCA) has been used to make recycled aggregate concrete (RAC). Numerous studies have compared the mechanical properties and durability of recycled aggregate concrete (RAC) to those of natural aggregate concrete (NAC). However, test results on the shear strength of reinforced recycled aggregate concrete beams are still limited and sometimes contradictory. Shear failure is generally brittle and must be prevented. This article studies experimentally and analytically the shear strength of reinforced RAC beams without stirrups. Eight RAC beams and two controlled NAC beams were tested under the four-point flexural test with the shear span-to-effective depth ratio (a/d) of 3.10. The main parameters investigated were the replacement percentage of RCA (0%, 25%, 50%, 75%, and 100%) and longitudinal reinforcement ratio (ρw) of 1.16% and 1.81%. It was found that the normalized shear stresses of RAC beams with ρw = 1.81% at all levels of replacement percentage were quite similar to those of the NAC counterparts. Moreover, the normalized shear stress of the beam with 100% RCA and ρw = 1.16% was only 6% lower than that of the NAC beam. A database of 128 RAC beams without shear reinforcement from literature was analyzed to evaluate the accuracy of the ACI 318-19 shear provisions in predicting the shear strength of the beams. For an RCA replacement ratio of between 50% and 100%, it was proposed to apply a reduction factor of 0.75 to the current ACI code equation to account for the physical variations of RCA, such as replacement percentage, RCA source and quality, density, amount of residual mortar, and physical irregularity. Full article
(This article belongs to the Collection Advanced Concrete Materials in Construction)
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18 pages, 2989 KiB  
Article
Psychological Drivers of Hotel Guests’ Energy-Saving Behaviours—Empirical Research Based on the Extended Theory of Planned Behaviour
by Qian-Cheng Wang, Ke-Xin Xie, Xuan Liu, Geoffrey Qi Ping Shen, Hsi-Hsien Wei and Tian-Yi Liu
Buildings 2021, 11(9), 401; https://doi.org/10.3390/buildings11090401 - 08 Sep 2021
Cited by 21 | Viewed by 4263
Abstract
The hospitality industry is an important energy consumer and carbon emitter. Behaviour-driven energy conservation is a strategy with great promise to strengthen the energy efficiency of hotel buildings. The aim of this study is to explore the driving psychological factors of hotel guests’ [...] Read more.
The hospitality industry is an important energy consumer and carbon emitter. Behaviour-driven energy conservation is a strategy with great promise to strengthen the energy efficiency of hotel buildings. The aim of this study is to explore the driving psychological factors of hotel guests’ energy-saving intentions and behaviours. This paper constructs two extensions of the theory of planned behaviour (TPB) with personal norms, past behaviours, and self-determined motivation to explain the guests’ energy-saving behaviour in hotel buildings. This research compares the explanatory power of the original TPB and two extensions with structural equation modelling. The analysis is based on 530 valid, self-reported data from 827 surveyed hotel guests in Shanghai. The analysis suggests that the extended model gains greater explanatory power in predicting the behaviour patterns by employing the above three additional factors. In addition, self-determined motivation presents a more significant impact than other more developed TPB predictors, such as intention and perceived behaviour control. Aside from that, past behaviour replaces attitude as the most critical predictor of hotel energy-saving intention in the extended models. In addition to the existing interventions in office and residential buildings, the research highlights the role of self-determination in hotel energy conservation and further emphasises the long-term benefit of encouraging pro-environmental behaviours in hotel guests. The findings expand the existing research on pro-environmental behaviours and will contribute to energy-saving behaviour intervention in hotel buildings and policy formulations for sustainable hotel operation and maintenance. Full article
(This article belongs to the Special Issue Building Energy-Saving Technology)
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19 pages, 4861 KiB  
Article
Assessment of the Seismic Behavior of a Precast Reinforced Concrete Industrial Building with the Presence of Horizontal Cladding Panels
by Liana Ostetto, Romain Sousa, Hugo Rodrigues and Paulo Fernandes
Buildings 2021, 11(9), 400; https://doi.org/10.3390/buildings11090400 - 07 Sep 2021
Cited by 4 | Viewed by 2769
Abstract
The latest earthquakes in Europe exposed some critical problems in the connections of cladding panels in industrial precast reinforced concrete (PRC) structures. These connections did not perform as desired, causing the panels to fall, leading to significant nonstructural damage that resulted in the [...] Read more.
The latest earthquakes in Europe exposed some critical problems in the connections of cladding panels in industrial precast reinforced concrete (PRC) structures. These connections did not perform as desired, causing the panels to fall, leading to significant nonstructural damage that resulted in the loss of human life and significant socio-economic impacts due to the interruption of business. Furthermore, in addition to the behavior of the cladding system itself, it is still not clear to what extent it can influence the overall seismic performance of the main structure. Making use of a simplified macroelement, the present study assesses the seismic performance of commonly employed cladding-to-structure connections, as well as the interaction of cladding panels with industrial PRC buildings. The analyses were carried out considering a PRC building representative of a Portuguese industrial park, studied with and without cladding panels. The seismic behavior of the structure was assessed considering both nonlinear static and dynamic procedures. Full article
(This article belongs to the Collection Structural Analysis for Earthquake-Resistant Design of Buildings)
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14 pages, 987 KiB  
Article
The Primacy of As-Built Drawings in the Management of Underground Utility Operations: A New Zealand Study
by Sami Maree, Funmilayo Ebun Rotimi and James Olabode Bamidele Rotimi
Buildings 2021, 11(9), 399; https://doi.org/10.3390/buildings11090399 - 07 Sep 2021
Cited by 4 | Viewed by 2553
Abstract
There are increasing incidences of damages to underground utilities and services during maintenance and construction works. These have posed significant challenges to utility owners regarding the magnitude and costs associated with remediation works. Therefore, this study investigates the management activities for underground utility [...] Read more.
There are increasing incidences of damages to underground utilities and services during maintenance and construction works. These have posed significant challenges to utility owners regarding the magnitude and costs associated with remediation works. Therefore, this study investigates the management activities for underground utility maintenance works in New Zealand to establish the significance of as-built drawings as a mitigator of these challenges. Data for the analysis was obtained through a questionnaire survey of asset owners, consultants, and contractors based in three major city centres in New Zealand. The responses are analysed descriptively and inferentially for ease of understanding of the study findings. The findings established the challenges around the as-built records, which were significant to utility damages during construction operations in New Zealand. The study participants highlighted other factors such as poor project management, site records, communication, excavation operator competencies, and inadequate site inventory. Generally, more investment in asset documentation is recommended for asset owners. Innovative approaches to information capture, monitoring and updating of as-built drawings are also suggested to improve on current routine processes. Other solutions relate to skills acquisition and development in the management of underground utility maintenance projects. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
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31 pages, 6688 KiB  
Article
Experimental, Analytical and Numerical Studies of Interfacial Bonding Properties between Silane-Coated Steel Fibres and Mortar
by Yong Yao, Hui Zhang, Xin Zhang, Feifan Ren, Yaqi Li and Zhenjun Yang
Buildings 2021, 11(9), 398; https://doi.org/10.3390/buildings11090398 - 06 Sep 2021
Cited by 6 | Viewed by 2279
Abstract
A systematic investigation of the effects of silane coatings on steel fibre–mortar interfacial bond properties was conducted, combining pullout tests, analytical solutions, and meso-scale FE simulations. Nine silane coatings were tested, and their effects were evaluated by 30 single fibre pullout tests. They [...] Read more.
A systematic investigation of the effects of silane coatings on steel fibre–mortar interfacial bond properties was conducted, combining pullout tests, analytical solutions, and meso-scale FE simulations. Nine silane coatings were tested, and their effects were evaluated by 30 single fibre pullout tests. They were found to increase the peak force and energy consumption up to 5.75 times and 2.48 times, respectively. Closed-form analytical solutions for pullout load, displacement, and interfacial stress distribution during the whole pullout process were derived based on a tri-linear bond-slip model, whose parameters were calibrated against the pullout tests. Finally, the calibrated bond-slip models were used to simulate the pullout tests and complex failure of multi-fibre specimens in mesoscale finite element models. Such an approach of combining pullout tests, analytical solutions, and mesoscale modelling provides a reliable way to investigate the effects of fibre–mortar interfacial properties on the mechanical behaviour of steel fibre reinforced concrete members in terms of structural strength, stiffness, ductility, and failure mechanisms. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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20 pages, 4490 KiB  
Article
Numerical Study of Circular Concrete Filled Steel Tubes Subjected to Pure Torsion
by Khanh Ba Le and Vui Van Cao
Buildings 2021, 11(9), 397; https://doi.org/10.3390/buildings11090397 - 06 Sep 2021
Cited by 10 | Viewed by 3150
Abstract
This study numerically explored the torsional behavior of circular concrete-filled steel tubes (CFST) under pure torsion. Numerical models of CFSTs were developed in ABAQUS. The models were validated by comparing with the experimental results available in the literature; then, these models were used [...] Read more.
This study numerically explored the torsional behavior of circular concrete-filled steel tubes (CFST) under pure torsion. Numerical models of CFSTs were developed in ABAQUS. The models were validated by comparing with the experimental results available in the literature; then, these models were used for parametric study. Based on the obtained results, the mechanism of torsional moment transferring from steel plates to CFST was presented. The results obtained from the parametric study indicated that the compressive strength of concrete marginally improved the torsional moment capacity of the CFST while concrete prevented buckling and helped the steel tubes to work more effectively. The steel strength significantly affected the torsional moment capacity of the CFST. When the yield strength of steel increased from 235 to 420 MPa, the yield torsional moment of the CFST increased by approximately 50%. The yield torsional moment capacity of the steel tube had the strongest correlation with the yield moment of the CFST, followed by the ratio of diameter to thickness of the steel tube while the parameters related to the compressive strength of concrete exhibited a poor correlation with the yield torsional moment. Full article
(This article belongs to the Section Building Energy, Physics, Environment, and Systems)
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19 pages, 5794 KiB  
Article
Fire Spread Characteristics of Metal-Polyethylene Sandwich Panels
by Ru Zhou, Zhihao Chen, Yinke Fan, Zhengjiang Yu, Jianan Qian and Juncheng Jiang
Buildings 2021, 11(9), 396; https://doi.org/10.3390/buildings11090396 - 05 Sep 2021
Viewed by 2414
Abstract
An experimental study was conducted to determine the characteristics of the flame spread and droplets of metal-polyethylene (PE) sandwich panels during combustion. The mass-loss rate, average flame height, temperature, and fire spread rate were investigated. The results showed that the fire spread rate, [...] Read more.
An experimental study was conducted to determine the characteristics of the flame spread and droplets of metal-polyethylene (PE) sandwich panels during combustion. The mass-loss rate, average flame height, temperature, and fire spread rate were investigated. The results showed that the fire spread rate, mass change of the droplets, average flame height, and temperature increased with an increase in the sample length, except for the mass loss rate of the 40 cm-long sample. The time interval between the droplets decreased, and the flame pulsation frequency increased. The relationship between the flame height and sample length was determined. During the combustion process, bending deformation and top flame phenomena occurred due to the shrinkage of the PE, which increased the fire risk. The distance between the outer surface of the expanded metal aluminum layer and the insulation panel increased with an increase in the panel length. A schematic diagram of the fire spread of the metal sandwich panel was established based on the observations and theoretical analysis. The mechanism and combustion behavior of the metal sandwich panels were determined to provide references for the construction of metal sandwich panels of exterior walls. Full article
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11 pages, 3852 KiB  
Article
Learning Statics by Visualizing Forces on the Example of a Physical Model of a Truss
by Kajetan Sadowski and Szymon Jankowski
Buildings 2021, 11(9), 395; https://doi.org/10.3390/buildings11090395 - 04 Sep 2021
Cited by 4 | Viewed by 2696
Abstract
The article presents a new didactic tool helping in teaching the structures of students of the Faculty of Architecture. It is an attempt to solve the problem related to the difficulties in teaching structural systems among students of architecture. In the beginning, examples [...] Read more.
The article presents a new didactic tool helping in teaching the structures of students of the Faculty of Architecture. It is an attempt to solve the problem related to the difficulties in teaching structural systems among students of architecture. In the beginning, examples of Graphic-Statics tools supporting an intuitive understanding of the construction work are presented. Then a physical model of the truss was implemented, which responsively presents the values of internal forces using the colors of the luminous bars. The main part of the article describes the design elements of the truss model and presents how it works. Then, the influence of the model on the education of architecture students was checked by means of a questionnaire study. The results showed the great educational usefulness of the proposed solution. Full article
(This article belongs to the Special Issue Architecture, City, People, and Structure)
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