Journal of Architectural Engineering

Current air-conditioning systems often rely on maximum occupancy assumptions and fixed schedules to maintain a sufficient comfort level. Having knowledge regarding the occupancy situation may lead to significant energy savings in a building. Therefore, the paper proposes a method to investigate an occupancy-driven HVAC control system that is based on thermal comfort analysis. Computational fluid dynamics (CFD) was used to evaluate thermal comfort through modeling of the indoor air distribution and flow. Air velocity and temperature were simulated in several scenarios and the predicted mean vote (PMV) and the predicted percentage dissatisfied (PPD) were computed. The simulation results were verified through a survey asking for occupants’ feelings, and the consequential thermal comfort profiles were identified, which were used for creating possible energy savings. Moreover, a predefined working schedule and the historical behavior of persons were used to develop a pattern for predicting personal occupancy situations. Finally, all variables were imported into an intelligence system to fulfill intelligent control of the air-conditioning system. The results show good potential to reduce energy consumption while meeting the comfort requirements of occupants.

Failures of the connections of thin-walled steel roof battens to rafters or trusses were increasingly observed in the form of a localized pull-through failure in the batten bottom flanges during recent extreme wind events. Therefore, an extensive research study was conducted to investigate this local connection failure, and suitable test and design methods were developed to accurately determine the design pull-through capacities of roof battens. The study also showed that optimizing the batten geometry is unlikely to increase the pull-through capacity of batten connections to rafters or trusses because they essentially depend on the diameter of the screw fastener head, batten thickness, and steel ultimate tensile strength. Hence, the study was extended to develop suitable strengthening methods to delay or prevent this critical localized connection failure and thus enhance the pull-through capacity. This article first presents the investigations of some current roof construction practices recommended and used by roof batten manufacturers and builders, then proposes the details of suitable strengthening methods. Detailed experimental investigations were undertaken for this purpose, and their results and discussions are presented in this article. In addition, suitable capacity-improvement factors are proposed for the strengthening methods to accurately determine the design pull-through capacities of roof batten connections to rafters or trusses.

Maintenance of existing structures requires a solid understanding of their structural behavior and their varying geometry, boundary conditions, and load cases. For the case of the masonry arches, this understanding is still lacking in the field, yet masonry arches are crucial parts of the railway and highway network systems in many countries. In this study, two-dimensional numerical models were prepared to simulate the nonlinear response of masonry arches under static loading without soil–structure interaction effects. A custom-made discrete-element method (DEM) software was employed for this research, such that the models represent a discontinuous medium of rigid blocks. Different scenarios were generated on a hypothetical masonry arch model to observe the influence of different parameters on the structural behavior of masonry arches. Investigated parameters include effect of backfill and spandrel walls, bond pattern at the arch barrel for double-layer arches, and boundary conditions. In addition, the discrete-element approach and the software were validated by an experimental work from the literature. The results of the analyses show that discrete-element modeling is a powerful technique for demonstrating the development of collapse mechanisms of masonry arch structures. Parametric analyses also indicated that backfill and spandrel walls, if intact, can have beneficial effects on the load-carrying capacity of arches. Based on the results of this study, the bond pattern between arch layers does not make a significant difference in the overall behavior. As expected, boundary conditions matter, and they should be taken into careful consideration for each masonry arch bridge through detailed observations on site.

The objective of the study presented in this paper was to determine the racking performance of a four-side structural glazing tape curtain wall system. An EN-WALL 7250 (EN-Wall, Las Vegas, NV) unitized curtain wall system was tested using 3M VHB Structural Glazing Tape G23F (3M, St. Paul, MN). Specimens were planar and single story in configuration, features that align with most commercial unitized systems. Racking tests followed a published stepwise protocol to characterize the performance of the system for both unrestrained and restrained end-boundary conditions. Air leakage tests were also performed during to evaluate the wall system serviceability performance with respect to air leakage. Results of these tests on two full-scale specimens are presented herein. In summary, the full-scale specimens did not sustain any damage to the 3M VHB Structural Glazing Tape G23F or the glazing system. Some framing derailment occurred under very high drifts when certain boundary conditions were imposed. A complete description of the unitized system design is presented along with observations of potential serviceability issues.

High-performance buildings, such as zero-energy buildings (ZEBs), are an important step toward a reduction in greenhouse-gas emissions. Because ZEBs may exhibit large differences between demand and on-site generated electricity, residual electrical loads imposed by the building may fluctuate between positive and negative values. Furthermore, such buildings can be characterized by large temporal changes in residual load, commonly caused by clouds passing on a sunny day. Today, electricity grid operators can easily deal with a single ZEB with this behavior. But what happens if large portfolios of ZEBs have the same behavior? In this study, a highly efficient office building with a total floor area of 8,355 m² located in Denver, Colorado, was designed and simulated using a detailed building energy modeling approach. Combining the building energy model with a photovoltaic model showed that the building reached net positive status on an annual basis. Further analysis of residual loads and strategies for their reduction revealed the limited potential of demand-side management in ZEBs and the high flexibility of batteries. Using a multiple-objective optimization approach for optimizing several simplified electric and thermal storage systems allowed the comparison of different strategies for residual load reduction. Although electrical storage may not yet be economical given today’s system costs, results show that the residual loads can be effectively managed and reduced, and at the same time, an increase in photovoltaic self-consumption can be achieved. The analysis concludes with the presentation of a multiple-objective optimal solution (Pareto front) for a battery storage model, indicating what utility incentives would be required to achieve cost-effectiveness for a range of price scenarios for battery systems.

Multiple energy-simulation programs have recently been developed. Most of these programs utilize thermodynamic equations and the mechanical characteristics, loadings, and temperature set points of the building to predict the total energy demand in a year. In addition, numerous building design parameters, including building envelope, window-to-wall ratio, and building orientation and shape, influence the level of energy consumption, which makes the design process complicated. Challenges that manifest within these systems are inherently complex and interdisciplinary in nature, and they often defy linear, cause-and-effect correlation, which makes the simulation of building energy performance even more complicated. In addition to the difficulty of determining the best design parameters, multiple numbers of objectives, such as the life-cycle cost and environmental emission of the project, increase the complexity of the problem. Therefore, a proper multiobjective optimization algorithm tool that is capable of eliminating a portion of trial-and-error process is needed. This article presents a framework for developing a multiobjective design optimization tool that is capable of identifying the designs with the lowest life-cycle cost, lowest life-cycle emission, and highest occupant thermal satisfaction. To demonstrate the application of this framework, the development of the design optimization tool using a C# program is presented. The building envelope, as the major barrier between the outdoor environment and inside conditioned zone, was considered as the main building component to optimize. To calculate the occupants' thermal satisfaction, a predicted mean vote method (PMV) was used. Even though the theoretical basis behind this tool is robust and accurate, the developed tool is simple, flexible, and user-friendly to encourage its use among designers and engineers. It is expected that the developed tool will ease the integration of energy efficiency in commercial buildings.

Compressed and stabilized earth block (CSEB) structural systems represent a sustainable low-cost alternative to other construction systems that are common in industrialized countries. The wide availability of suitable soils makes these structural systems attractive for building affordable housing worldwide. Currently, CSEB construction in the USA is mainly used in dry and arid regions and has rarely been used in humid climates. In this work, a structural, architectural, and economic feasibility study for CSEB structural systems in the U.S. Gulf Coast region is presented. The structural feasibility study presented in this paper included the identification of locally available soils for CSEB fabrication; experimental investigation of mechanical properties of CSEB and mortar as function of their composition; durability study for a CSEB wall with and without protective plastering; and calculation of wind resistance for a representative CSEB house. The architectural feasibility study investigated the use of CSEB systems in vernacular housing typologies of Southern Louisiana. Finally, the economic feasibility study compared the cost of a reference house built using CSEBs and other more common construction materials. The results obtained in this study suggest that CSEB systems have the potential to provide a modern, cost-effective, sustainable, hurricane-resistant housing construction system as an alternative to more common constructions systems in the U.S. Gulf Coast region.

In the majority of ordinary housing development projects, instead of using complex multicriteria decision-making systems, companies still rely on expert knowledge, checklists, or similar tools to decide on an appropriate level of modularization. Generally, in these types of projects the level of modularization is mainly driven by site constraints, such as accessibility and harsh weather conditions. Because of the lack of appropriate decision support tools, it is very hard for decision makers to include factors, such as lifecycle costs, quality, productivity, efficiency, and design complexity, into their decision, even if they are willing to do so. Simple decision support tools are required to provide practical assistance to the decision makers to adopt an appropriate level of modularization for such projects. This study, as a part of a broad ongoing research project on the optimum level of modularization in building construction, has compiled the expert knowledge for decision support that enables the decision makers to perform an easy initial feasibility study on the use of an appropriate level of modularization in their construction projects. First, a list of critical decision-making criteria is created. These criteria are obtained from an extensive literature review, qualitative survey questionnaires, and semistructured interviews with researchers and professionals in the construction industry as well as modular manufacturers. Then, using the results, a simple multicriteria decision analysis (MCDA) approach is developed as a practical decision support system to facilitate the decision-making process for selecting appropriate construction systems as well as determining the proper level of modularization for building construction projects. The validation of the study is demonstrated through a local actual case study.

The use of building information modeling (BIM) to create a building energy model (BEM) compared with traditional simulation practices offers significant timesaving potentials by minimizing efficiency issues, legal disputes, added costs, and delays. The BIM-BEM strategy avoids remodeling the building to create the BEM by exchanging architectural information to complete the energy analysis. However, most existing frameworks do not simultaneously describe the BIM-BEM process and related technical aspects to be followed during the design process. Therefore, this paper proposes a comprehensive BIM-BEM framework initially created based on theoretical and field investigations and then enhanced by a trial investigation using a testing case. The proposed framework is illustrated in an easy-to-follow process map that includes work/data flows and specifies data exchangers and information requirements. The framework is validated using a complex case study to demonstrate its applicability for different BEM tools. The proposed framework intends to provide the industry with a useful and generic process for BIM-BEM that enables professionals to create proper BIM and BEM to complete energy analysis during the design process.