Abstracts:This study used multicriteria decision analysis to quantitatively compare two prototype buildings, both designed using equivalent mass timber and steel structural systems across four decision criteria of seismic resiliency, global warming potential, superstructure cost, and durability. The 5-story and 12-story prototype buildings were both located at an arbitrary site in Seattle, WA. The first three decision criteria were quantitatively measured for each prototype building and durability was assumed to be equivalent between the alternatives. Seismic resiliency was measured using the median expected annual loss calculated using as a percentage of predicted building replacement cost using a procedure in line with FEMA P-58. The global warming potential was measured over the production, construction, and end-of-life stages using the life-cycle analysis program Athena Impact Estimator for Buildings (IE4B). The superstructure cost was calculated as the average cost per square meter using 10 estimating variations that attempt to account for uncertainty in market rates of material, labor, and mass timber design efficiency. Five decision-maker scenarios were analyzed that span the practical range of decision-maker priorities, as informed by discussions with architects and engineers active in the Pacific Northwest. Results from this study showed that for decision-maker cases where the global warming priority was low, steel buildings were the preferred choice. For cases with moderate to high global warming priority and low priority on cost, mass timber buildings were the preferred choice. However, for decision-maker scenarios with moderate priority on both global warming potential and cost, the steel and mass timber buildings were approximately equivalent. Finally, a hybrid steel–timber alternative was presented as a possible sweet-spot solution that merged the benefits of each building material and minimized their drawbacks, making it the most-preferred solution for the case of moderate priority on both cost and global warming potential. The hybrid case was also close second in ranked choice for all other scenarios examined.

Abstracts:Architects and designers have employed angulated structures for kinetic architectural design due to their formal esthetics, geometry, and light weight. The arrangement of these structures within a regular repetitive (modular) layout forms a kinetic skin. Geometric patterns are repeated in angulated structures based on particular orders as happens in girih patterns in Iranian historical architecture. This similarity forms the base of this study. Given the importance of revitalizing these motifs due to the gap between the modern and traditional architecture and their modernization using up-to-date technologies, the authors propose a process for implementing these patterns on generated lattice structures. This study is organized into two parts to achieve the mentioned goals: in the first part, the effect of changing parameters on the ultimate form of lattice structure is evaluated. In the second part, changes are applied to the structural form according to the patterns through two strategies (i.e., implementing the pattern of girih components on the central opening of the structure and implementing the form of girih components on structural elements), focused on the Islamic girih patterns and the importance of their implementation on the structure. The outcome of this study is kinetic skins containing forms dominantly shapes of Iranian patterns repeated regularly throughout the structure; it represents the beauty and identity of the traditional Iranian architecture and can adapt to changing conditions according to the purposes of sustainable architecture. Finally, a designed structure is modeled and analyzed using the Ansys software in order to investigate the constructability of a full-scale structure and evaluate it under loads in the climate of Tabriz; the results of the analysis indicate that the structure can withstand loads applied in the climate of Tabriz with a thickness of more than 3 mm.

Abstracts:Commercial rooftops provide extensive areas representing the desired platform for installing photovoltaic (PV) systems. The combination of roofing assembly and PV system is called photovoltaic roofing assembly (PVRA). Currently, there is a shortage of information about building codes on PV system and roofing assembly integration. The National Research Council of Canada (NRC) developed an industry consortium project to generate codifiable research data on the wind and thermal performances of photovoltaic roofing assemblies. This paper examines the thermal bridging of the PV mounting attachments and its impact on the overall thermal resistance of the roofing assembly. Seven different types of PV mounting fixed attachments were tested in this study. Thermal bridging evaluation of PV mounts was done on the component level as individual mounts were installed through a section of a roofing assembly. The roofing assemblies were designed for a prescriptive thermal resistance of RSI 5.46 m² K W⁻¹ (R-31 h ft² °F BTU⁻¹) as per current standard and requirements for Climate zones 4–6. The thermal bridging experiments were conducted on a 1.2 m by 1.2 m guarded hot box at a mean temperature of 24°C. The measured data indicated a decrease in the effective thermal resistance of the PVRA, ranging from 3.3% to 50.0%, compared to the opaque roofing assembly devoid of any thermal bridging. Furthermore, it was found that among fastener-designed PV mounting attachments, the greater the number of fasteners, the more significant the decrease in effective thermal resistance. From the experimental data, chi factors (χ) were developed to support the calculation of point thermal bridging effects on the thermal performance of low-sloped roofing assemblies. Toward codification, efforts are underway to potentially implement these chi factors in the energy codes that could enhance the thermal design of both retrofit and new roof constructions installed with photovoltaic systems.

Abstracts:Equipping unmanned aerial systems (UASs) with light detection and ranging (lidar) has been made possible with recent advancements, which has made these sensors compact and gradually more cost-effective. Despite the increased proliferation of UAS-lidar in several fields, the geometric accuracy of lidar-generated point clouds, together with their visual qualities, needs to be explored for building surveying applications. Considering that red−blue−green (RGB) cameras are the most prevalent UAS sensors in building surveying, a lidar- and an RGB camera-equipped UAS was deployed on a mixed infrastructure to simultaneously collect data and generate corresponding point clouds. Different geometric features from both RGB and lidar point clouds were measured and compared quantitatively against benchmark field observations. A qualitative analysis on the point clouds’ visual qualities was also performed and a sensor recommendation matrix was proposed based on desired application accuracy. Lidar has proven to be a viable alternative, providing better geometric accuracy, data quality, and clarity in all three dimensions.

Abstracts:In this paper, we present a proposal for a retrofit system for existing reinforced-concrete (RC) buildings consisting in the use of precast concrete panels, designed for improving both the structural and energetic performance. In particular, the proposed system is conceived to improve both the energetic efficiency, by ensuring high-performance thermal insulation, and the capacity of the structural elements under gravity and seismic loads. Firstly, a detailed description of the proposed technology is provided, which has been tested and assessed on a real-scale prototype. Then, the efficiency of the technique was explored by means of numerical simulations for both the energetic and structural performance. Although no experimental tests are available, the results of our numerical simulations and analyses on a real case-study building reveal interesting insights, highlighting the main pros and cons of the proposal and providing a possible retrofit solution for buildings that do not meet the current European code requirements.

Abstracts:Cross-laminated timber (CLT) panels are an innovative wooden product that has gained popularity in recent years because it has a high strength-to-weight ratio, improves construction efficiency, and it is a natural and renewable material. Therefore, the recently released 2021 International Building Code (IBC) include guidelines for CLT panels for the construction of buildings of up to 18 stories. The construction applications of CLT panels as well as the research initiatives have largely centered on softwood tree species such as laminates, and the application of hardwood species has yet to be investigated. This paper documents the structural behavior of several hardwood species abundant in the Appalachian region and demonstrates the promising feasibility of using these species in the construction industry with CLT panels considering the architectural and structural behavior and economic aspects. The hardwood tree species selected are abundant in the Appalachian region and this paper highlights their potential as a construction material and provides an insight for future development. Three hardwood species including red maple, sweetgum, and sycamore are considered for this study, and three- and five-ply panels are fabricated to evaluate their behavior. The samples are tested in three directions for compression to understand the orthotropic behavior. Considering the softwood species including southern yellow pine and Douglas fir as a baseline for comparison, a total of 120 samples are tested and evaluated based on ASTM standards. The results show an average higher compressive strength from sweetgum panels followed by red maple, sycamore, Douglas fir, and southern yellow pine in the main directions used for structural walls. The findings imply a potential market for the underutilized hardwood species in Appalachia, which may lead to future economic development in the region.

Abstracts:Owners, occupants, and society are constantly changing the demands and expectations placed on buildings. Design for adaptability (DfA) provides one approach for delivering buildings that serve current needs and that can be readily adapted to meet future demands. The benefits and strategies of DfA have been widely reported; however, there is a dearth of information on the costs of implementing DfA. This paper presents a case study evaluating the economic costs of applying select DfA strategies to a wood-framed multifamily residential building in Atlanta. Comparisons are made between the construction costs of a baseline non-DfA building and a series of adaptable buildings. DfA strategies in the adaptable buildings include increased floor live load, increased floor-to-floor height, and the use of post-and-beam framing instead of interior structural walls. When all three of these strategies were implemented in the same design, the estimated building construction cost increased by 14%. The cost increase ranged from 1% to 7% when only one of the DfA strategies was implemented in a design. These comparisons are intended to facilitate cost–benefit analyses by designers, owners, and contractors interested in intentionally designed adaptable buildings.

Abstracts:Remote teamwork has become critical to the communicative and collaborative operations of architectural practice and education in Australia. Consequently, building information modeling (BIM) processes, which are core to both sharing and producing architectural designs, are evolving in response. The aim of this paper is to examine and identify ways to improve BIM-enabled design collaboration processes in architectural practice and education. Using data from semi-structured open-ended interviews (n = 25) undertaken during the pandemic, this paper identified six thematic categories of BIM-enabled design collaboration processes: (1) representation, (2) communication, (3) coordination, (4) collaboration, (5) technical operation, and (6) nontechnical operation. These themes, along with 48 codes developed from the interviews, are then presented as an integrated BIM process model. This model contributes to a collective understanding of recent BIM processes and areas where improvements are needed to support BIM adoption and implementation in the new era of remote working.

Abstracts:Considering the significant amount of time and money wasted yearly in fixing errors caused by miscommunication and inadequate information on project sites, relaying the knowledge of field experts through design software may reduce communication-based conflicts in projects. This study aimed to create a model to integrate human field expertise in the construction process with building information modeling (BIM) software. This study is based on the premise of the significance of human involvement in construction. Basement construction in Fargo, North Dakota, was the construction scenario selected for scrutiny in this study. Surveys and in-person interviews were conducted with local contractors to ascertain valuable recommendations and views on basement construction in Fargo. Information from these contractors was coded into models to offer warnings and recommendations on the assessed basement construction activities to help architecture, engineering, and construction (AEC) professionals with design, planning, and other processes required before and during construction. Combining BIM (with all its proven strengths) with the human aspect of construction will significantly improve the construction process, especially in decision-making and risk mitigation.

Abstracts:Fuzzy techniques are approximations used to model phenomena or decisions for which mathematical precision is impractical or impossible. In this work, we have developed a new approach to modeling visual performance using fuzzy techniques. Fuzzy techniques allow us to include variables that are not included in the current visual performance model. We also introduce the term critical contrast, which we define as the contrast at which a change in the rating of visual performance occurs. The comparison between our fuzzy relative visual performance model and the relative visual performance model shows close agreement for most conditions. A digital tool was also developed and is available for use. This will make the proposed metric simple to use and implement.