Journal of Architectural Engineering

Mass timber is gaining popularity in the North American architectural, engineering, and construction (AEC) industry as a viable and sustainable building material. Owing to the water storage potential of mass timber, durability is of concern as a result of long-term exposure to moisture during building construction and service. The importance of monitoring mass timber subjected to moisture degradation during construction and occupancy of a building is critical in determining the longevity and viability of mass timber products. In situ moisture monitoring deployment techniques are currently inconsistent across building case studies. The objective of this review is to investigate: (1) relevant types of moisture content (MC) sensors and their applications in mass timber construction; and (2) practices for deploying MC sensors in mass timber construction. Cross-laminated timber (CLT), nail-laminated timber (NLT), and glue-laminated timber (Glulam) are typical mass timber products, each of which varies in thickness, manufacturing processes, and species composition. In addition, MC sensors have a range of applications, installations, and accuracies. The variability of mass timber products and MC sensors lead to multiple combinations of moisture monitoring techniques. Mass timber moisture monitoring installation and deployment practices have been recommended based on the literature review and case study analysis performed.

In the last century, a modern seismic design concept has emerged, which is based on different mechanisms, such as reducing and dispersing the seismic input concerning the building or active interaction with the movement of the building. From the past to the present, a wide variety of seismic control methods have been found and applied, together with the modern understanding of seismic design. Using seismic control in buildings increases the functionality of the building and prevents extra structural requirements. This philosophy constitutes an alternative to the conventional seismic design approach, which relies on consuming earthquake energy on its own. With the changing approach, the concepts of seismic design philosophy have changed, and architectural design has been affected from many points by these concepts. Therefore, architects/designers should examine how the decision to use seismic control methods that concern building design decisions from the preliminary design phase will affect the architecture. This study, starting from the historical development of base isolation and energy damping systems, which are widely used among seismic control methods, focuses on new buildings, and new concepts emerging with the modern seismic design approach and their effects on architectural design are discussed in detail. The study’s methodology involves evaluating data from existing literature works, building codes, professionals, and practices. As a result, the architectural design of new buildings in the context of base isolation and energy-damping systems is evaluated in terms of the seismic device–building form relationship, planning and location, architectural details, aesthetics, and user comfort, and knowledge and recommendations are presented to architects/professionals.

Abstract

Selecting the appropriate delivery method is of paramount importance, especially in sustainable construction projects that have unique characteristics that are different from their traditional counterparts. A new decision-support model is proposed to assist decision-makers in this selection process. Thirty-six key selection criteria were first identified, through literature review, and then divided into traditional and sustainability-specific categories. The relative weights of these selection criteria were then assessed using an analytic hierarchy process through a survey administered to construction professionals. The results indicated that the three most important groups of selection criteria were level of integration, technology, and innovation, in addition to scope-related criteria. Another questionnaire survey was administered to evaluate the effectiveness of the three common delivery methods––design–bid–build (DBB), design–build (DB) and construction management at risk (CMR)––in achieving the 36 identified selection criteria. The results revealed that the traditional DBB delivery method was outmatched by the heightened needs of sustainable construction projects for collaboration and integration that can only be achieved through alternative delivery methods, such as DB and CMR. The proposed model consists of four functions––strategic alignment, screening of the comprehensive selection criteria, evaluation of the three project delivery methods, and final selection. The proposed model provides a comprehensive list of selection criteria for helping decision-makers produce a defensible rationale for choosing the appropriate delivery method for their sustainable construction project. A case study is also presented to demonstrate the application of the proposed decision-support model.

Practical Applications

Sustainable construction is significant in mitigating environmental impacts and promoting better health and quality of life. But it has unique characteristics that are different from conventional construction. To address these characteristics, there is a need for updating project management practices to satisfy the demands of sustainable construction projects. Among the significant project management decisions is the selection of the appropriate project delivery method (PDM) for sustainable construction projects. The practical relevance of this study is the development of a comprehensive multicriterion decision-support model that incorporates both sustainability-specific and traditional selection criteria to help owners choose the most appropriate delivery method for their sustainable construction projects. The model offers owners an invaluable tool for producing a defensible rationale to justify choosing a specific PDM. The easy-to-follow model allows owners to readily use the model without needing expertise in performing arduous mathematical tasks. Once the required selection criteria are fed into the model, it automatically and instantaneously sorts and ranks the alternative delivery method options. The owner then selects the most appropriate PDM that strategically aligns with the sustainable project’s goals. This model provides owners with a time- and resource-efficient technique for selecting the most appropriate delivery method. Selecting the appropriate PDM for sustainable construction projects enhances the chances of their successful completion and the achievement of the desired goals. This, in turn, encourages the execution of more sustainable construction projects, with their clear and established benefits to society, the economy, and the environment.

Facade-rendering mortars and their painting layers are constantly exposed to weather and, therefore, influence the hygrothermal behavior of buildings. The characterization and assessment of coating materials is fundamental, seeking adequacy in their selection, especially regarding moisture and temperature. Considering the exposure conditions of the facades, risks of damages, such as mold development, may be avoided by an assertive evaluation and selection among different types of paints. In this context, this paper experimentally determined essential properties related to the hygrothermal behavior of painted mortars and simulated their resulting performance when applied on exposed facades in three Brazilian cities in distinct bioclimatic zones. Hygrothermal simulations were carried out using the software WUFI Pro 6.6. Six different types of paints were studied, among which satin acrylic paint (SAP) led to the lowest water vapor permeability and matte polyvinyl acetate (PVA), silicate (SIL), lime (LP), and hydrated lime with white glue (HLG) paints led to the highest. Matte acrylic paint (MAP), PVA, SIL, LP, and HLG had similar impacts on the vapor transmission of mortar renderings. In the simulations, reference (REF) and LP specimens generally resulted in the highest water contents throughout the year, followed by SIL and HLG. SAP led to the lowest water content and a more homogeneous curve than the other paints. Among the studied cities, Macapá, which has the highest annual normal rainfall sum and mean relative humidity, also had the highest mean total water content values over time, followed by Porto Alegre and Petrolina. In general, no probable mold development is expected. However, caution should be taken when extrapolating the results for climate or construction conditions different than the simulated ones.

Three-dimensional (3D) printing applied in architectural engineering is profoundly changing building technologies and construction processes. Indeed, the wide scope of metamaterials and components manufactured with 3D printing provides unprecedented adaptability and customizability in construction. One of the promising applications of such novel technology concerns metamaterial noise barriers that protect buildings from environmental noise. More specifically, sonic crystal noise barriers (SCNBs) are effective solutions with good sound insulation characteristics (with the advantage of letting air/light pass through). Conversely, the limitations of SCNB are related to their design and manufacturing (new complex design approaches are required to maximize the performance of such devices). To overcome such drawbacks, this research proposes a novel methodological approach to design and customize the topology of SCNBs made achievable with additive manufacturing. First, parametric modeling affords design flexibility and adaptability. Second, iterative performance simulations are set to adjust parameters considering target frequencies. Third, 3D printing allows the prototyping of customized barriers. The methodology is applied to the case of train brake noise. A novel SCNB is designed, simulated, and prototyped through 3D-printing technology. Finally, experimental validation is executed according to current international standards.

Abstract

Ultrahigh-performance concrete (UHPC) is a new class of concrete with far superior mechanical and durability properties compared to conventional concrete. Recently, its use has been growing in both civil and architectural applications, especially in the precast industry. This paper presents the application of UHPC to the production of precast concrete sandwich wall panels commonly used in Northern regions and known as insulated wall panels. Using UHPC in the panel wythes allows for a significant reduction in wythe thickness and, consequently, panel weight, in addition to the elimination of longitudinal and transverse reinforcement, which simplifies production. In this study, four 2.44 m × 1.22 m × 203 mm composite UHPC sandwich wall panels were fabricated by a local precast producer using a nonproprietary UHPC mixture. Panels were tested in flexure to evaluate the degree of composite action when wythe thickness of 32 mm and glass fiber–reinforced polymer (GFRP) shear connectors are used. These panels do not contain any conventional rebars or prestressing strands as they are fully dependent on the presence of random steel fibers in UHPC to provide the tensile resistance. Test results have shown that this new system can achieve a flexural capacity of 92% of that of a fully composite panel while being more flexible and lighter than conventional concrete sandwich wall panels. The composite UHPC sandwich wall panels have a great potential in architectural and structural applications, such as exterior load-bearing walls and cladding panels.

Practical Applications

This paper investigates the structural behavior of a new system of sandwich wall panels utilizing reduced wythe thicknesses made of ultrahigh-performance concrete (UHPC) and achieving high degree of composite action. Structural performance and production efficiency of this system can have significant impacts on energy-efficient building construction. This new system can achieve a degree of composite action up to 92%, which makes the design efficient for large cladding panels and load bearing exterior walls. A design example is presented comparing a conventional concrete sandwich wall panel made of two 76-mm-thick concrete wythes and 51-mm-thick insulation to a UHPC panel with the same overall thickness of 203 mm but with 32-mm-thick concrete wythes and 140-mm-thick insulation. Both panels are 2.44-m wide and 9.14-m tall and subjected to unfactored wind pressure of 1.44-kPa, which is considerably higher than the typical values used in wall design for midwest states. The significant increase in the insulation thickness of the UHPC panel results in significantly less weight and higher R-value than those of the conventional concrete panel. In addition, the UHPC panel does not have either longitudinal prestressing strands or transverse reinforcing bars, which simplifies panel fabrication.

The evolution of long-span timber structures during the last centuries has been driven by technological developments that are associated with materials, joints, and manufacturing. Many extraordinary structural solutions have been developed, some of which have been very advanced in their time and have been replaced by new ones, typically because of the advent of new manufacturing methods or, at times, due to new technological innovations. This study examines the Hilding Brosenius (HB) system, which was developed in the 1940s as a versatile wooden frame solution for medium-to-long spans. The HB system is based on an I-shaped cross section where the web consists of two diagonal board layers, and the flanges are assembled from boards by nailing and gluing. This study presents and discusses the main structural components of the system from the perspective of structural mechanics, current design requirements, and manufacturing technologies. As a practical application example, the structural system will be examined in the renovation project of an HB portal frame from the 1950s. The main findings of this study are: (1) the HB system has certain features that would make it worthwhile modernizing and reusing it more widely; and (2) the HB system design principles lead to a safe and robust yet light and optimal structure.

Space exploration fosters great strides in research and provides innovative solutions that contribute to advancements in different fields. The discipline of space architecture represents the connecting point where space exploration and architecture meet. It pushes the boundaries of architecture and grants the possibility to develop new strategies and design methods in this field. Designing a resilient and sustainable infrastructure for human missions on Mars is a new challenge that requires new conceptual design approaches. Architecture in Space relies on some fundamental pillars that are intrinsically interconnected: space sciences, engineering, robotics, industrial design, ergonomics, medicine, psychology, and last but not least, art. The extreme environmental conditions are a major technological challenge but also an opportunity to explore new construction techniques using alternative materials, enabling architecture to update its traditional methods. In this paper, we designed a habitat on Mars, E.L.L.E., an Extreme Livable Lightweight Environment, for six astronauts and a mission of 600 days within a cross-disciplinary environment at different scales, from architecture to interior design. This challenges both space and terrestrial architectures to consider the relationships between human activities and the resources that support them. The E.L.L.E. habitat solution will be built with lightweight materials as they are particularly suitable for space exploration purposes. A computational design approach was applied to perform multiobjective optimization and form-finding analysis to support the decision-making process for E.L.L.E., identifying the optimal design configuration among several optimized solutions that maximize compactness, floor area, internal layout effectiveness, and structural integrity. This process could easily be applied to several future Mars habitats and settlements.

Reciprocal frame structures are nonhierarchical stable systems formed by elements that are simply connected to each other by tangency with no interpenetration. They are systems composed of elementary spatial self-supporting interlocking units or reciprocal nodes of mutually supporting beams placed in closed structural circuits. Those nodes can be designed as transformable by allowing the modification of the position of the tangency or supporting points. This article addresses the characterization and geometric definition of surfaces of variable geometry (bidimensional objects in three-dimensional space that can transform its geometrical form) by means of meshes, with cylindrical equal beams, arranged by the repetition of a pattern consisting of three transformable nodes of $n_A$, $n_B$, and $n_C$ elements around a triangular one (transformable homogeneous ABC reciprocal meshes). The objective of this analytical study is to define the topological and geometrical characteristics of these types of meshes. In addition, the study aims to parameterize them, taking into account their transformability, so they can be applied to the design of surfaces of variable geometry by using a newly created geometric software. To do so, we use analytical and optimization methods to develop a new form-finding approach of transformable reciprocal frame structures with elements of given fixed dimensions and a parameterization of a given mesh based on the moving capability of each of the elements of the system considering them as part of a whole transformable entity and making it possible to transform the geometry of the mesh by modifying the numerical value of the parameters.

The study described here analyzed natural ventilation techniques, operated in a real building in the United Arab Emirates (UAE), to assist passive cooling. The assessment has been conducted by comparing digital simulation results and field measurements. Computational fluid dynamics (CFD) was used to retrospectively understand and quantify the monitored contribution of natural ventilation toward cooling the building. After calibrating the model with the field monitored data, the CFD simulations showed that the predicted ventilation strategies (buoyancy and stack effect to remove indoor heat; “wind catcher” effect to provide indoor passive cooling) contribute to lower the indoor temperature by an average of 0.7°C throughout the day. The outcomes of the study contributes to assist early stage design, with special regard to passive cooling via natural ventilation, to achieve more sustainable buildings. Nevertheless, while it is quite reliable to plan for main air flow and direction, in a real building alternative behavior might occur that is difficult to control and might affect the ventilation purpose and efficiency.

The following work evaluates the acoustic performance of different sound-absorbing materials and balcony configurations used in the facades of urban street canyons in the Valle de Aburrá (AV) Colombia. The main insertion loss in the urban canyons was achieved by placing materials such as pumice stone and refractory brick on 16.7% and 8.3% of the facade surfaces. This obtained an environmental noise mitigation of up to 5.1 dB at a 5 kHz frequency and up to 3.6 dB at a frequency of 1.25 kHz. With other materials such as cork wood and metal wool, mitigations of up to 3.9 and 3.7 dB were achieved at the frequencies of 5 and 1.25 kHz, respectively. However, balconies caused an increase in ambient noise levels on pedestrian walkways with increases of up to 4.7 and 3.6 dB at a frequency of 1.6 kHz, regardless of whether materials such as pumice stone or cork wood were adhered to their surface. In recent decades, noise has become one of the most harmful pollutants for urban residents. Among the different sources of noise, car traffic has been identified as the main contributor. This can be aggravated by conditions commonly found on city streets, where tall, hard, close-spaced facades increase noise due to the different reflections that these conditions cause. This work shows the benefits that certain materials such as pumice stone, refractory brick, cork wood, and metal wool can provide in mitigating urban noise when placed in strips along the facade of a building. These materials stood out among others under conditions that might have resistance to weather. However, balconies projecting onto walkways could be counterproductive for pedestrians, since these features tend to increase the noise generated by cars circulating on the road. The potential application of this work is to mitigate noise pollution on urban street canyons.

Abstract

Car parks are essential for every new development, but they often result in inefficient use of space. To save space, basement car parks are adopted. However, their capacity is limited by the building footprint and immovable vertical structural elements. Current research on basement car parks mainly focuses on ventilation under extreme situations such as fires. The impact of specific design factors unique to basement car parks on capacity has not been fully studied yet. Therefore, this paper investigates the impact of basement car park design factors on capacity by studying three design aspects: parking aisle network, building footprint, and column positions. A parking lot placement algorithm is proposed to help model and automate the car park design process. Parking lots are optimized using a genetic algorithm (GA). A series of impact analyses have been conducted for three selected design factors. Four design principles from prior research were used to analyze and compare the impact of design factors on parking lots. It was found that the proposed design optimization method can automate basement car park design and facilitate the impact analysis of design factors. Based on the impact analysis, the increase in parking lots for each layout is not strictly positively correlated with the perimeter of the parking aisle. The long rectangle building footprint can have a larger capacity compared with other shapes. Adjusting column positions can provide more space for parking lots and further optimize car park capacity.

Practical Applications

This research has practical implications for the field of architectural engineering, benefiting architects, engineers, and designers. Architects and designers working on basement car park projects can utilize the research findings to optimize the layout of parking spaces. By considering nonadjustable column positions and vertical obstructions, they can make more efficient use of available space, thereby increasing car park capacity. The systematic analysis of design factors, including parking aisle networks, building footprints, and column positions, empowers professionals to make informed decisions during the design phase. They can tailor car park designs to meet specific needs, while adhering to structural constraints. The introduction of a novel parking lot placement algorithm with optimization capabilities offers a practical tool for architects and designers. It streamlines the process of positioning parking lots to maximize capacity, particularly in basement car parks with fixed columns and obstacles. The research provides valuable guidance for basement car park design, enabling architects to apply design principles derived from surface and single-use multistory car park design to basement configurations. In practice, these applications result in more efficient and flexible car park designs, addressing the unique challenges of basement car parks, while optimizing their capacity and functionality.

Abstract

Sustainable development and the preservation of the natural environment are two concepts that are becoming increasingly important in the construction sector, leading to a growing interest in the development of ecofriendly building solutions. In this regard, the use of waste polyethylene terephthalate (PET) bottles as a construction material is an interesting alternative that can help to reduce the environmental impact of the building activity at little or no cost, while providing a second life to a material that is one of the main sources of pollution. The present study analyses the mechanical behavior of PET bottles for their use as construction materials, carrying compression tests to assess the elastic properties of PET bottles filled with sand or plastic waste, both alone and embedded in a concrete matrix. In a second part of the study, a finite-element method model of an existing water tank built with PET bottles in Tanzania is developed and tested. The results obtained show the suitability of the composite bottle-and-concrete samples as a sustainable construction technique.

Practical Applications

Environmental sustainability is an increasingly important aspect in our society and all its productive sectors, and the construction industry is no exception. In this regard, diverse initiatives have been proposed to introduce waste polyethylene terephthalate (PET) bottles as a construction material, which provides three direct benefits: offering a low-cost construction material, reducing the consumption of new resources, and giving a second life to waste material that would otherwise end up in landfills or in the environment. However, to use these new sustainable materials in safety conditions, it is necessary to understand their mechanical and structural behavior and treat them with the same rigor as we treat conventional construction materials such as concrete or steel. In this sense, in the present study, a testing campaign is conducted to assess the compressive strength of PET bottles filled with sand or plastic, as well as their combined use with concrete to form walls in buildings or water tanks.

Abstract

Electric vehicles (EVs) are increasingly being adopted by homeowners as a replacement for gas-powered vehicles. As this transition continues, it is important to understand the charging behavior of electric vehicles, particularly in residential buildings where the majority of EV charging occurs. EV charging represents a newer and substantial residential electric load that parallels that of air conditioning in terms of electric demand. As the grid continues to become increasingly powered by renewable resources, it is important to understand the availability of EV loads for use in supporting demand-side management, that is, the ability to adjust demand to meet electricity supply in real time. The majority of prior studies have assessed EV charging using synthetic or hypothetical charging scenarios; there are limited studies that consider charging behavior of EVs based on field data collection. This research collects data on the EV charging patterns in 46 homes across a one-year period (2018). These data were cleaned and quality controlled, then used in combination with EV adoption data to develop EV charging potential estimates at the local and regional level. Results suggest that EV charging behavior is relatively consistent throughout the year, with most charging events occurring in the evening and night hours, likely linked to nonpeak hour-targeted smart chargers. From 6 a.m. to 7 p.m. the likelihood of a charging event generally increases, then slightly decreases from 7 p.m. to 10 p.m. Weekend charging generally also as smaller peaks in charging than weekdays. These load profiles demonstrate the consistency of EVs, in aggregate, as a source of DSM for supporting the increasingly renewable electric grid.

Practical Applications

With widespread adoption of electric vehicles (EVs), charging of EVs has become a frequent event at home. This new load added with the usual other residential loads such as heating, ventilation, and air conditioning (HVAC), dryer and other daily appliances will become a critical factor for power grid management in near future. This research provides an insight into the consistent charging behavior of EVs in residential buildings, primarily during evening and night hours. For those who involved in power distribution and grid management, this can be proved to be a good candidate for demand-side management, providing flexibility in the grid with more integration of renewable energy sources. In addition, this research also analyzes the total demand of EVs on power grid of the Midcontinent Independent System Operator (MISO) region throughout a typical day and the load reduction potential in relation to maximum peak demand. This will help utility providers and policymakers crafting EV-friendly infrastructure and regulations. Finally, this study will pave the way for a more sustainable and reliable grid with the rising integration of EVs in our daily life.

Numerous techniques and technologies exist to automate construction-related tasks, which include the latest three-dimensional concrete printing (3DCP) methodology. These automation techniques seek to solve the entrenched problems in construction, such as declining productivity, shortage of skilled workers, ineffectiveness in project management, unsustainability, and the increase in construction demand. The 3DCP has further benefits, such as quicker construction times, design freedom, and more predictability. However, there is resistance to adopting 3DCP in the industry and by the market. With experience from a 3DCP organization and a case study on a 3DCP villa, this paper presents the major challenges that hinder this technology’s adoption and use, important lessons learned from the villa construction, and highlights of the local community’s critical feedback.

This article presents a study on the capture velocity of local exhaust ventilation (LEV) using a specially designed workstation within a laboratory setting. The workstation featured a worktop with dimensions of 90 cm width and 45 cm depth, and the exhaust duct was positioned near the pollutant source, considering the intended operation of the LEV system. The worktop was divided into squares for precise documentation and remeasurement. A supply duct above the worktop provided controlled fresh airflow. Smoke was used to visualize airflow patterns. The measurements focused on air velocity and turbulence intensity, aiming to understand flow structures and vortices. Various capture rates were tested at specific measurement points. The study revealed that the central capture lines yielded the highest efficiency. To address air extraction from behind the exhaust duct, a back sheet panel was introduced. The results showed that installing a back sheet enhanced capture velocities. The findings contribute to understanding LEV efficiency and the importance of proper design and adjustments for effective containment of contaminants in the occupational environment.