Journal of Architectural Engineering

Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal.

Light-frame wood construction is the most common construction method used for single- and multifamily residential structures in the United States. Shear walls made with engineered wood structural panels are the primary lateral force resisting system in these structures. Although shear walls are expected to be protected from prolonged or severe exposure to moisture, situations such as flooding and compromised building envelopes have the potential to expose shear walls to high levels of moisture and subsequently alter their properties. The specific contribution of moisture degradation in engineered wood structural panels on shear wall performance was investigated in this study by subjecting oriented strand board (OSB) and plywood to accelerated weathering prior to shear wall assembly. Shear walls ($2.44\times 2.44\mathrm{m}$) were tested by using a monotonic loading protocol to compare performance between walls produced with standard sheathing and those produced after sheathing had been weathered and dried. Statistically significant losses in yield load, shear capacity, and energy dissipation from moisture degradation during accelerated weathering were determined for OSB walls, while none were present for plywood walls. In addition, localized strain in the sheathing near fasteners in the uplift corner was monitored by using digital image correlation, which showed differences in strain distribution for both OSB and plywood walls constructed with weathered sheathing.

To facilitate the initial stress design of three-dimensional (3D) curved hollow structural steel (HSS) steel (i.e., helicoidal) beams and rapid early-stage topology decisions, a series of design charts and closed-form equations are presented that incorporate the effects of coupled forces and helicoidal geometry on stresses. These design aids were motivated by structures with extreme curves, featuring nonprismatic structural systems and nonplanar facades, which increasingly require the design of helicoidal elements. To establish these design aids, a converged beam model was developed for parametric studies of 71 different cross sections and a range of plan angles, lead angles, and beam radii. The results were curve-fitted, providing simplified stress utilization design equations expressed in terms of beam cross section ($S_x$ and $S_y$). Results for the design equations and simplified design charts were within 1.5% and 5% of detailed finite-element analysis (FEA), respectively. The design aids were compared to two-dimensional (2D) projection methods and 3D helicoidal slab equations showing that the projection methods were able to be nonconservative by up to 34%, whereas the design aids were overconservative by up to 5% compared with the detailed FEA.

This paper describes the use of a system dynamics (SD) computational method to evaluate initial designs or upgrades of security measures to protect a building and its occupants from bioterror attacks. The paper identifies variables to be modeled in regard to security measures, explains the SD model for use in decision making, and provides a detailed description of the steps needed to develop a meaningful framework for collecting the diverse types of data needed to apply a model of this type. Every attempt was made to obtain meaningful experimental, simulated, or surrogate data that could be used to model performance in quantitative terms, allowing comparisons to be made between potential security measures. Results are presented as time-histories of specific performance attributes of the building or as the influence of different levels of mitigation strategies over a selected time period. Results show that different types of mitigation strategies are indicated for different levels of protection and resource availability. This information can be used to inform design and operation decisions in a risk-averse and resource-constrained building industry.

Glass exhibits brittle failure behavior. Therefore, redundancy is a fundamental design requirement when using glass as a main structural material. On this basis, a novel structural concept has been developed for hybrid glass-steel posttensioned triangulated structures, where the two materials collaborate. In forming such lattice structure, local fracture must be avoided. This paper presents a parametric study that highlights the influences of mechanical and geometrical parameters on the in-plane and out-of-plane static behaviour of laminated triangular glass panels. The resulting data set constitutes a useful source for the designer to select the most appropriate component. The main sensitivity parameters are panel length, laminate thickness, and interlayer stiffness.

Engineering design review is the process of assessing a design against codes and standards requirements to validate the accuracy and quality of the design and detecting problems before manufacturing and assembly begin. Building design regulations are normally in the form of texts, charts, tables, and mathematical expressions. These regulations and guidelines usually have legal status. Nevertheless, the cognitive and logical ability of the people is dissimilar to anything executed in computing machines. Consequently, the computerization of this process represents an actual challenge to the architecture, engineering, and construction (AEC) industry. Most of the cited methods for automated rules compliance auditing are either based on proprietary, domain-specific, or hard-coded rule-based representations, which may be useful in their specific applications. However, these methods have the disadvantages of being costly to maintain, cumbersome to modify, and lacking a comprehensive schema of rules and regulations modeling that can adapt to different domains, and thus don’t support an open data standard. They are often denoted as black box or gray box methods. This work offers a new comprehensive framework that reduces the deficiencies of the current approaches. The primary goal is to tackle the problem by concentrating on establishing a generalized adaptive framework (GAF) for a neutral data standard [such as the Industry Foundation Classes (IFC)] that enables automation of building design review processes to achieve design accuracy and efficiency.

The National Research Council of Canada (NRC), as part of a consortium with members from vegetated roof industries and roofing associations, established a national wind resistance standard for modular vegetated roof assemblies (MVRAs), named CAN/CSA A123.24, “Standard Test Method for Wind Resistance of Modular Vegetated Roof Assembly.” Currently, this standard is widely used on a voluntary basis by the Canadian roofing industry for wind performance compliance of MVRAs. CAN/CSA A123.24 was developed based on extensive data collected on various MVRAs by simulating wind in laboratory conditions. Toward codification of CAN/CSA A123.24, the consortia members decided to validate such collected data with in situ performance data. This paper presents and discusses the validation process. Different MVRAs were installed on the rooftop of a Humber College building, located in Toronto. The validation was conducted by comparing the three wind performances of MVRAs as follows: (1) pressure equalization (between the top and bottom of the vegetated system); (2) coefficient of lift, $C_L$; and (3) estimated overturning wind speed, $U_{\mathrm{OT}}$, at different wind conditions. Data comparisons (laboratory versus field) showed consistent agreement in the global trend. Some discrepancies in the absolute values were observed; however, these discrepancies are due to the inherent variability of the field wind conditions and the limited amount of field data. The forecasting of the overturning wind speed provides a valuable tool to adequately evaluate MVRA design alternatives for acceptable wind resistance compliance in accordance with the National Building Code of Canada.

Structural optimization techniques are being usefully employed for the design of large grid shell structures. Indeed, thanks to the use of innovative strategies and mathematical algorithms, it is possible to combine different design parameters and structural requirements in a global process finalized to obtain solutions optimized for structural and architectural aspects. In the case of grid shells, a relevant role is played by the joints, which particularly influence both the local and the global stability. Nevertheless, few studies specifically concerning the role of joints in the optimization of grid shell structures are currently available. The aim of the study here presented is to carry out efficient optimization strategies for grid shell structures that specifically account for the role of joints. In particular, considering the possibility of having joint configurations able to offer different constraint conditions for members, the proposed strategies combine the common sizing optimization technique of members with the possibility to vary the configuration of joints. As shown in the paper, the proposed optimization strategies allow obtaining lighter solutions with respect to the ones obtained by only using the sizing optimization technique, particularly when global stability represents the governing phenomenon.

Existing buildings, especially aging ones, often are in urgent need of upgrading to improve their sustainability and environmental performance. Building owners often seek to identify and implement building upgrade measures to improve building sustainability as well as to achieve green certifications such as the leadership in energy and environmental design (LEED) within available budgets. To support building owners and operators as well as building managers in this vital goal, this paper presents two optimization models that are capable of (1) maximizing LEED points for existing buildings within a user-defined upgrade cost, and (2) achieving a user-defined LEED certification level for existing buildings with minimum upgrade cost. These optimization models are developed in two main steps: (1) a formulation step which identifies the model decision variables and formulates objective functions and constraints; and (2) an implementation step which performs the model computations using genetic algorithms and generates results in both tabular and graphical formats. A case study of a large existing building located at University of Colorado Denver was used to illustrate the capabilities of the optimization models and demonstrate their use. The results of the case study showed strong support to building owners and operators to identify the optimal use of their upgrade budgets to achieve LEED certification. The optimization model was designed to generate an action report that can be used by building owners and operators, listing building fixtures and equipment that need to be upgraded, their location in building, expected energy and water reduction, and expected annual savings. The primary contribution of this research is the innovative approach for identifying optimal upgrade measures for large existing buildings to maximize their sustainability using the LEED rating system.

With many natural hazards impacting coastal communities, the resilience of low-rise residential wood buildings (LRWBs) in the community has been critical. To better understand structural performance under extreme weather conditions, detailed finite-element analysis (FEA) was carried out by many researchers to perform fragility or vulnerability assessment of LRWBs under different types of loadings, such as wind, flooding, or wave or their combinations. In the current codes and specifications, structural and nonstructural components in LRWBs are differentiated from each other when evaluating their functions in terms of safety. Different important factors or different methodologies are proposed and used for the design or usage of structural and nonstructural structural components in LRWBs. In many detailed models for FEA, nonstructural components are usually simplified as mass, and their stiffness is usually ignored in the analysis. However, for existing LRWBs in coastal communities, after years of exposure and continuous operations, significant damage could have accumulated in the structural and nonstructural components or their connections. As a result, the loading path could have shifted differently compared with the original design. It could be very challenging to identify the loading path and differentiate the functions of these structural and nonstructural components in the loading path with changed stiffness contributions as more uncertainties are introduced in the deterioration process for these structural members or connections. The nonstructural systems, such as the interior walls, could possibly affect the loading path in extreme loading conditions. As a result, progressive failure could lead to different failure scenarios if the nonstructural components are not included in the analysis. In the present study, high-fidelity finite-element models for typical LRWBs were built including typical structural and nonstructural components to evaluate the functionality of the nonstructural walls under extreme loading conditions. For comparison purposes, two different finite-element models (FEMs) under different loading scenarios were evaluated and compared. The first model included only structural members, while the second model included both structural and nonstructural members, such as interior walls, which were simulated using shell and beam elements. Different wind loadings were applied on the models to assess the structural resilience. Vulnerability curves were obtained and compared for these two models. Discussions also include the applicable criterion for differentiating structural and nonstructural members in the typical LRWB.

Although acknowledged as a must in earthquake-prone countries, the introduction of seismic design principles in schools of architecture is often perceived by the students as a serious limitation to their design freedom. Hence, teaching methods where students are encouraged to devise architectural design strategies that embrace seismic principles and lessen students’ perceptions of reduced design freedom are required. The sawtooth method presented here allows the progressive introduction of seismic design guidelines consistent with the complexity involved in architectural design. This technique comprises an iterative sequence of short tasks or workshops, organized in a zoom-in or zoom-out explorative sequence and embedded within two major seismic-related frameworks: configuration and detailing phases. The sawtooth method has been implemented as a teaching and learning approach in a studio in a faculty of architecture in Izmir, Turkey. The assessment of four case studies reveals that the presented approach helps architecture students to integrate seismic design principles in their projects, facilitating the blending of conceptual approaches with highly realistic scenarios.

Buildings are complex systems whose energy consumption depends on the interplay of multiple physical and human factors. This paper explored the performance of single-family detached dwellings using the tools of data analytics. The goals of this work were to understand and eventually to predict electrical energy consumption in order to develop strategies to reduce both peak power consumption and annual energy consumption in the residential building sector. Results showed that the year in which a dwelling was built combined with primary heating source is a significant predictor of electricity use.

The importance and benefits of change and dependency management (CDM) and knowledge management (KM) have been increasingly recognized in the architecture, engineering, and construction (AEC) industry. In energy retrofits, traditional manual methods of managing changes are inefficient and do not fully engage all team members or adequately capture the rationale for changes. Given that knowledge has become a fundamental resource for organizations, it is imperative that any new knowledge generated from change and dependency management be captured and disseminated. This paper presents the development of the integrated change and knowledge management (ICKM) approach based on literature and case studies. The integrated approach establishes a systematic way to facilitate change and dependency management, capture lessons learned during CDM processes, and support information exchange between different disciplines in change and knowledge management activities. It has been evaluated and refined through two case studies.

The authors characterized earthen wall materials and plasters in a mid-fourteenth-century Hohokam great house at Casa Grande Ruins National Monument (Arizona) and assessed the seismic susceptibility of its puddled earth walls. Characterization included determining the microstructure, microcomposition, porosity, aggregate mineralogy, and identification of phases in the binding matrix for each of 36 samples and reconstructing plaster technologies, including material selection, preparation, and application sequences. Findings support the ideas that earthen materials were manipulated to optimize their performance to suit the unique site conditions and needs of the ancient people using the structure and included finishes that were unusual in southwestern sites from this time period. By using a new set of tools that integrate the complicated geometry of individual wall segments as captured in light detection and ranging (LiDAR) scans (models were generated in Rhino version 5) with the dynamic analysis of rocking mechanisms (tools for this analysis were developed in Rhino), seismic collapse assessment was used to identify the most vulnerable parts of the building to earthquake loading and provided an initial evaluation of the seismic overturning capacity of these wall segments.

Linear-elastic finite-element analysis is sometimes used to assess masonry arch bridges under service loads, despite the limitations of this method. Specifically, linear-elastic analysis can be sensitive to material properties, geometry, and support settlements, while also allowing the development of tensile stresses that may be unrealistic for masonry structures. However, even though linear-elastic methods remain appealing for their simplicity, it is rare to evaluate their output against experimental data. In this paper, detailed strain and displacement monitoring data for a masonry arch viaduct are used to evaluate a series of independently developed linear-elastic simulations of this structure. Although uncertainties in input parameters mean the magnitude of modeling results cannot be presumed accurate, the simulated response pattern was found to agree reasonably well with monitoring data in regions of low damage. However, more damaged regions produced a markedly different local response. Comparisons between the simulations revealed useful conclusions regarding common modeling assumptions, namely the importance of modeling backing material, spandrels, and foundation stiffness, to capture their influence on the arch response.

Risks to communities arise due to their inability to adapt to the impacts of natural disaster, technological bottleneck, and knowledge and capacity constraints. In this situation it is important to learn from the good cases and enrich knowledge and capacity to build resilience. Post-disaster shelter strategy is an important attribute of resiliency development. Therefore, this paper examines India’s post-disaster shelter strategies by comparing them with equivalent practices in Japan and Indonesia. The objectives of this paper are to review the literature on definitions, challenges, and best practices of post-disaster temporary shelter and temporary housing, to examine the effectiveness of housing recovery through case studies from Japan (2011) and Indonesia (2004) and compare it with the Indian case (2004), and to explore future policy for better practice in Indian post-disaster housing strategies. The paper follows a case study approach for responding to the objectives.

The adobe mission church (circa 1801) at Tumacácori National Historical Park in Arizona was damaged in an intense winter storm in 2010. To mitigate the damage and to address building envelope vulnerabilities, investigators completed a study of the hygrothermal behavior of the dome, including characterization of soluble salts and environmental conditions that result in salt damage, identification of structural and seismic vulnerabilities, performance testing (lab and in situ) of lime-based renders for exterior surfaces of the church, and an assessment of structural wood. Hygrothermal modeling of the dome indicates that heavy rain events that occur every 5–10 years result in moisture infiltration and damage to the decorated plasters on the dome interior. The structural assessment identified conditions requiring repair, strengthening, and/or improvements that will result in improved ductility of building assemblies. The wood assessment identified species and grade of structural wood members that require repair, reinforcement, or replacement for developing seismic retrofit designs. Natural hydraulic lime (NHL)–based stuccos offer the best combination of performance properties, resistance to erosion, low absorption and debonding, and acceptable flexural strength and water vapor transmission.