Journal of Architectural Engineering

Currently, most descriptions of low-energy buildings assume that the envelope acts as a barrier against energy loss. However, this approach does not focus on the potential exploitation of favorable contributions from the surrounding environment that could lead to additional improvements in performance. Adaptive building envelopes (ABEs) offer a number of different options for this. However, many of them require the supply of a certain energy amount to operate. A viable alternative is offered by self-sufficient solutions that adopt responsive materials-based actuators, which are capable of modifying some of their properties in response to environmental stimuli (e.g., temperature, humidity, light, and others), which determines the dynamic behavior of the envelope without requiring additional energy inputs and minimizing technical complexity. The research field into self-sufficient adaptive envelopes (SSAEs) has received a significant boost recently. Given the heterogeneity of the proposed solutions, this paper will report on a taxonomical investigation that will be performed on the available studies that deal with SSAEs, which highlight their role in innovation and will provide a systemic classification for applications to support future research.

Compared with conventional buildings, the design of interconnections in multistory modular buildings requires special attention, due to different load distribution mechanisms, level of redundancy, integration strategies, and the stability requirements, in particular under accidental load conditions. In this paper, the robustness of corner-supported modular steel buildings, subject to various sudden loss scenarios, is studied through investigating the collapse-resisting capacities and the probable gravity-induced progressive collapse mechanisms. The aim is to evaluate the minimum requirements and special considerations for the design of interconnections for robustness. To that end, archetypal precast room-sized volumetric modules with different heights are analyzed using the finite-element macromodelling method and the alternate load path approach. The load redistribution mechanisms are inspected, nonlinear dynamic responses are determined, and probable collapse mechanisms are identified for buildings with different heights and configurations. The dynamic increase factors are computed and compared with the values suggested by the design codes. Given that the individual modules are mainly made of inherently robust structures, the focus of this study is on the performance of interconnections and interactions between an assemblage of units. The results indicate that due to high redundancy in these systems, there is great reserve strength against gravity-induced progressive collapse scenarios, triggered by instantaneous removal of components.

This paper presents the findings of an experimental and numerical study on the system identification of modular steel frames in a laboratory environment. The project is a part of a broad study about the structural response of modular steel buildings. For this purpose, an experimental program is conducted on a full-scale volumetric prefabricated steel module, which is designed based on Australian standards. The module is fixed on a strong floor, instrumented with sensitive accelerometers, and its ambient and free vibration responses are captured and recorded. The output-only algorithms of operational modal analysis procedure, that is, direct fast Fourier transform, enhanced frequency domain decomposition, and stochastic subspace identification, are employed for extracting the main dynamic properties of the module, including natural frequencies, mode shapes, and modal damping ratios. Then the numerical finite-element models of the module are generated in micro and macro levels with continuum solid and beam elements, respectively. The numerical models are verified with the results of the experimental program and the discrepancies are discussed. The findings of this study are be used as a basis for research on the fundamental behavior of steel module assemblies and their interaction for the design of multistory modular buildings.

The objective of this research is to support sustainable architecture where renewable materials (such as plant-based materials and soil) are used for construction. The use of renewable materials and earthen building techniques in structural design represent important construction practices to mitigate the associated carbon footprint. In this study we propose structural systems that will be constructed using renewable materials such as bamboo, that probably is the most well-known renewable material and has long been valued as an alternative to wood. The main goal of the study is to design tree-shaped structural systems using the advanced characteristics of Guadua angustifolia, a clumping variety of bamboo chiefly native to South America, and to test its effectiveness by means of a structural parametric design optimization approach. For this purpose, an elliptical and a quadrangular structural system is parametrized and optimized to effectively support the design loads imposed by the roof that is supported by the proposed structural systems.

This study aims to investigate the cost surcharges of green buildings. In this study, the green construction cost surcharge (GCCS) is defined as the additional capital costs associated with sustainable building features and practices. More specifically, this study intends to (1) identify the green cost surcharge difference on a global scale; (2) identify the green cost surcharge differences across building types; and (3) gain a basic understanding of the causes of cost differences. A literature survey on green building surcharge costs was performed, resulting in a total of more than 1,300 cases from 11 countries. The cases included both residential and nonresidential units. The results show that there is a regional difference among green cost surcharges; however, the median and mean green cost surcharges are 7%. Furthermore, there is a cost difference among building types, with school buildings having the highest cost surcharge. Varied cost estimation and collection methods also lead to different green cost surcharge results; the differences between industry findings and academic research are very apparent. Lastly, 11 cost variables are identified as well.

The endeavor toward eco-friendly building materials has led to the development of dowel laminated timber (DLT), a product in which sawn timber boards are laminated using hardwood dowels. DLT reduces the need for metallic fasteners and synthetic adhesives, however, its application as a beam element is challenged by the relatively low bending stiffness resulting from the low composite action. In this research, we evaluated the effectiveness of replacing hardwood dowels with connectors made from salvaged engineered wood products to improve the bending stiffness and further enhance the environmental benefits of DLT beams. 60 push-out shear tests were performed on three-layer connections laminated using dowels and tenons from salvaged plywood, salvaged laminated veneer lumber, and solid Oak as a reference. From selected connectors, three-layer beams were then fabricated and tested under a four-point bending load. The results indicated that beams laminated using salvaged plywood tenons have significantly lower end slips. The composite effect was more than two times higher compared to the conventional Oak dowels, resulting in about 40% higher bending stiffness. Thus, the use of salvaged plywood tenons could be an alternative option to improve the bending stiffness and sustainability of DLT beams.

Building science employs student–professional interactions to increase the learning and engagement of domain topics. Although these interactions are beneficial to students, labor shortages and automation trends will create barriers to expose students to professionals in the future. One solution is to utilize virtual situated learning contexts for students to experience simulated interactions with virtual professionals. Within these simulations, virtual humans are often used as a vehicle to preserve knowledge and deliver it to students. However, the impact of the fidelity of virtual human appearance on providing knowledge to the students within the building science domain remains unexplored. This paper presents a virtual reality (VR) educational system integrated with digital storytellers and grounded in the building science electrical career path context to explore how virtual human appearance fidelity affects student learning and engagement. A between-subject study was conducted with 42 construction management participants to explore the impact of 3 virtual human appearance fidelity conditions (realistic, modeled, and abstracted virtual human) in terms of student learning, social presence, virtual human persona factors, and topic interest. The findings of this study demonstrated that successful educational outcomes could be achieved with low virtual human appearance fidelity due to the lack of significant differences observed across experimental conditions. Furthermore, the study results did not detect significant differences in students' engagement by increasing the virtual human appearance fidelity. However, students across all experimental conditions reported engagement increments in the topic learned. The increments in student engagement suggest that the virtual human's age and gender are important factors to consider when designing educational interventions. These results contribute to the understanding of how to create virtual humans for building science educational interventions.

Applying the concepts of sustainability to reduce energy waste and environmental pollution in architecture has created a topic called sustainable architecture with an environmental approach. In recent years, the demand for adopting methods to promote environmental sustainability has increased. The construction industry, by introducing the Building Information Modeling (BIM) method, has provided an opportunity for professionals to achieve the goals of sustainable development more effectively. This study was carried out to investigate which attributes of BIM are of most contribution to improving the most important criteria of environmental sustainability. For this purpose, after collecting BIM attributes and environmental sustainability criteria, they were evaluated in the form of two questionnaires and the research data were analyzed through structural equation modeling (SEM) technique in Smart PLS software. The results of the study demonstrated that the BIM attributes such as virtualization of buildings, energy efficiency analysis and simulation maintenance or the retrofit process play an instrumental role in the overall promotion of environmental sustainability. Moreover, the most important criteria based on which BIM implementation can have the most impact on their improvement are in the field of materials and resources, energy and atmosphere, and innovation.

Topology optimization has recently been investigated as a technique for the conceptual design of efficient structures during the early stage of the design of buildings to tackle the design challenges. The use of this technique, which leads to optimum structures, mostly results in esthetic, lightweight, and best performance from the perspective of engineers or architects. However, the topology optimization results are not usually known for direct realization in practice, and the engineer and architect should be able to choose the best solution among numerous choices in close cooperation. This paper has focused on defining a parametric framework of continuous optimum design of lateral bracing systems for tall buildings considering wind and gravity loads. The bidirectional evolutionary structural optimization (BESO) method was employed, considering the main optimization parameter, loading scenarios, and constraints. In order to show the effectiveness of the suggested topology optimization framework for minimizing compliance (maximizing stiffness) and minimum consumption of materials in the design of lateral bracing systems, 2D and 3D systems have been discussed. According to the obtained results, this framework could employ topology optimization during the conceptual design to seek a new definition of the optimum layout of lateral bracing systems with high structural performance, elegant geometries, and other characteristics considered by architects and engineers.

Advances in materials, design, and control, as well as increasing concerns about the sustainability of the built environment, have provided a background for the development of deployable tensegrity and scissor-like systems, which are often limited between a closed and an open state. In cases where more versatile reconfigurations are aimed at, the systems rely on embedded computation and mechanical actuators. Such mechanisms often lead to energy-inefficient operation and complex kinematic behavior. Toward providing multiple possible target configurations of the structure, as well as flexibility and controllability, the effective crank–slider and effective 4-bar methods have been proposed and applied to planar multibar linkage systems. The underlying kinematics principle refers to the reduction of a multi-DOF system to an externally actuated 1-DOF system in each reconfiguration step of the control sequence while adjusting the system joints from an initial to a target position. The present paper reviews related aspects with regard to the two basic reconfiguration approaches and exemplifies their combined implementation through a case study concerning a closed-chain linkage system with eight bars.

This paper presents an explicit finite-element (FE) model formulated using the continuum shell element to examine the behavior of unreinforced and externally strengthened masonry walls. Masonry is modeled as a homogenized material capable of producing elastic and inelastic behavior with distinct directional properties. The macroscopic properties of masonry are defined using a Hill-type and a Rankine-type yield surface to model its behavior under compression and tension, respectively, which are embedded in a VUMAT user material subroutine developed using the ABAQUS Explicit algorithm. Alongside the mechanical properties of masonry, the thickness direction properties of the continuum shell element are defined through the input file to ensure compatibility between the algorithm used in the VUMAT and the continuum shell formulation. The parameters of the FE model have been validated with the test data sets of a total of six out-of-plane and in-plane loaded masonry walls taken from three separate experimental programs reported in the literature. A close match between the experimental and FE model failure mode and load–displacement relation was observed. The model is extended to predict the behavior of externally strengthened walls, which experienced the debonding of the carbon fiber-reinforced polymer (CFRP) layers from the masonry substrate. A significant increase in the in-plane capacity of the strengthened walls was observed.

Several thermal comfort indices have been proposed over the years and studies have shown that these models do not work universally. This study compares eight thermal comfort indices with results of occupant-perception survey during May and December of a hot–humid climate of the southeast coast of the Indian Peninsula. A 14-story naturally ventilated apartment building with cruciform planform provided living rooms located at different orientation and height for the study. A week-long occupant’s comfort survey along with measurement of temperature, relative humidity, and indoor air velocity in the living rooms (located at different heights and orientations) during both in May and December were used for evaluating the thermal performance using predicted mean vote (PMV), e-PMV, a-PMV, TSI, SET, PTS ASHRAE–adaptive, and IMAC comfort scales. These indices were brought into a common seven-point scale, and the comparison was done in two stages: building level and then an in-depth comparison of shortlisted comfort indices by considering the microclimatic variation between living rooms located at different heights and directions. The indices that can predict the perception survey-based actual mean vote (AMV) closely under these variations are highlighted.

Rental properties make up approximately 37% of the US residential building stock and are responsible for 23% of the total energy consumption in this sector. Although this market has great potential for energy efficiency, the implementation of energy savings measures in this market faces numerous challenges. In particular, one of the main challenges cited is the split incentive, limiting the potential motivation of rental property owners and tenants to invest in energy-efficient technologies. Smart thermostats have gained substantial interest and adoption in the past decade and have been the subject of numerous studies. However, their adoption and use in the context of the rental housing market has not been considered. In this study, reviews posted on an online retailer’s website (Amazon) were used as an unstructured source of information to evaluate the attitudes of landlords and tenants toward smart thermostats. In total, 31,790 reviews were collected for 14 commercially available smart thermostats; from these, 173 reviews were identified as directly associated with rental units. These selected reviews were then analyzed and categorized based on the unique opportunities and challenges that were expressed. The majority of reviewers focused on usability aspects and expressed an interest in the advanced remote-control functions of their purchased devices. Furthermore, our findings indicated that occupancy pattern learning capabilities were not of particular interest among this user group. These findings can inform product manufacturers and policy makers in their future interactions with stakeholders in the rental housing market and potentially increase adoption and hence energy efficiency.

Investments in the architectural, engineering, and construction (AEC) sector can be used by governments to introduce desired changes in the economy, which gives an indication of the future trends of the economy. In addition, the stock market—as reflected by the Standard and Poor 500 (S&P 500)—creates a sense of confidence about the direction of the US economy. Many studies have shown that stock prices in multiple international industries could be considered as leading economic indicators. Nevertheless, this was not researched within the AEC sector in the United States. This paper addresses this knowledge gap by investigating whether the stock prices of AEC companies in the United States could be used to inform strategic, proactive decision making. First, time series data were collected for the stock prices of 16 large AEC companies as well as for the S&P 500 index. Second, multivariate time series analysis was conducted to examine the type of relationship between the response variable—S&P 500—and all other input variables. Two econometrics models were developed: a linear, statistical vector autoregression model and a computational, deep learning model based on long–short-term memory (LSTM) networks. Third, the two developed econometrics models were tested on unseen data. Fourth, the best econometrics model was verified using another leading economic indicator which is the Purchasing Managers’ Index. The results reflected that the computational LSTM model outperformed the linear statistical model. The findings showed that the stock prices of AEC companies could be considered as an additional and complementing leading economic indicator to the American Institute of Architects’ Architecture Billings Index to provide a broader perspective of the business ecosystem. This paper adds to the body of knowledge by providing an econometrics model for helping in optimal investment opportunities, taking informed strategic management and business judgments, and predicting changes in the economy.

The utilization of building information modeling (BIM) to support various tasks of building lifecycle management (BLM) has been reported in a range of studies. However, during its lifetime, a building is an important part of its immediate surroundings; hence, its lifecycle must not be managed in isolation as a single entity without considering its participation in the immediate surroundings. BLM must consider in what way surroundings influence lifecycle and how a building impacts its surroundings. The use of geographic information system (GIS) has been reported in a range of studies for supporting various tasks of building lifecycle in which BIM is lacking. Understanding the participation of a building in its surroundings is also done by using GIS, however potential use of GIS in the entire lifecycle of a building has not yet been investigated. The review of literature produced a list of application areas of BIM and GIS which may possibly improve existing BLM processes, specifically, the possible ways to consider surroundings, site constraints, locational effects, and services of nearby facilities/utilities. An interactive and collaborative practical framework has been developed by using the main application areas of BIM and GIS seamlessly in various stages of BLM, enabling data reuse in all stages, developing efficient designs and plans, and making sustainable decisions. The developed framework was used for the lifecycle management of the building project taken as a case study. It has been established that the application areas of both BIM and GIS have a coordinated solution to makes BLM a multidisciplinary perspective.

Turkey, which is a country with rapid population growth, has a housing problem with low-income groups, that particularly emerged due to urbanization. Different solutions have been used in an attempt to solve this problem, within the scope of social housing policies that the local or central governments have produced. However, social housing policies have been insufficient to solve the rapidly changing housing problem due to the social, political, and economic dynamics of Turkey. Some social housing policies have succeeded; however, some have accelerated the formation of illegal settlements. Although the most important component of this multidimensional process is generally the government, actors, such as users, architects, and construction companies, whose expectations and effects are different from each other are the components of the process. It is uncommon for the user to have a say in the design, or production, or both of a house. This is true for Turkey and many countries worldwide. This paper aims to achieve a centralized view of the production of housing for low-income groups in Turkey, which is quite complicated and problematic; and to draw attention to the potential of user participation that has not previously had a place in this process and to open the issue to discussion. First, a literature review will be conducted that focuses on discourses in the late 1960s and early 1970s, where user participation in low-cost housing production was on the agenda. Later, to revise the existing large framework in the context of Turkey, social housing policies that were developed by the governments to solve the housing demands of low-income groups will be briefly reviewed. Finally, the effect of user participation in the process of social housing for low-income groups in Turkey will be discussed through the best practices believed to be from three practical experiments. The aim is to raise awareness about user participation in low-cost housing production in Turkey which is not currently on the agenda.

Despite alarming injury and fatality rates, construction workers continue to neglect the appropriate use of personal protective equipment (PPE). This research explores safety outcomes concerning knowledge, attitude, and practice in PPE use on Trinidad's construction sites. A questionnaire survey of 100 respondents and 20 interviews with site workers revealed that knowledge of action and attitude were better predictors than practice on the propensity of construction workers to be involved in near-misses and accidents. The research explains why there were no significant differences between safe work practices and the occurrence of near-misses or accidents. In addition, it was found that workers' attitudes toward PPE use were not mediated by on-site experience, but they were more related to their age and if they believed their safety was the responsibility of their supervisor. The research concludes that knowledge of action varied among educational groups; however, there was no significant difference between PPE training and workers with knowledge of PPE usage and calls for changes in the current educational program content and delivery. This research identifies accident causation factors and recommends measures for construction companies to achieve improved safety performance and reduce the risk of accidental injury or death.

This paper describes the 3-credit summer internship course, AE 8050 Internship in AE. AE 8050 Internship in AE is a required course in the ABET-Accredited Master of Architectural Engineering curriculum at the University of Nebraska. During their internship, students are required to conduct 10 interviews with company employees on specific topics associated with the business aspects of the company. The course culminates in student internship presentations prior to the Durham School of Architectural Engineering and Construction Career Fair in the fall. This paper discusses the motivation, history, current practice, assessment, and further development and expansion of the Internship in AE course in the Durham School.

This paper aims to reveal more of the hidden secrets of the Cheops Pyramid in terms of the descending rays of the sun during the equinox falling upon the azimuth of the diagonal secant position at the solar successions. The methodology used to complete this investigation project is based on the collection and analysis of data related to the erection principles practiced when the pyramid was constructed during the era of the Fourth Dynasty Egyptian Pharaoh Khufu. These principles are the key for the geometrical representations of the balanced states across the residual depictions of the sun's position relative to the Cheops Pyramid during the equinox. This research has found that the apex is an inevitable predetermined inclusion within the theorem of universal expansion. Moreover, the inclinations of the pyramid were set to predetermine the location of its plumb line, thereby serving as a guiding factor in erecting the blocks of the Cheops Pyramid. The main conclusion is that there is a strong relationship between the Cheops Pyramid geometry, the erection of its steps, and the solar equinox.

Flat-to-slope roof retrofitting transforms the flat roofs of multistory buildings into the sloping roofs to improve the building function and landscape effect provided that the building structures and the foundation bearing capacity meet the requirements, which normally commits to improve the thermal insulation performance of the top layer and to solve the problems such as the top layer leakage. This study developed an optimal structural design protocol for flat-to-slope roof retrofitting through comparative analysis. The case study used an existing building in Hangzhou city and in the process of energy consumption simulation on flat-to-slope roof retrofitting, control variables were used to keep consistent building materials, building environments, and meteorological conditions such as the hourly temperature, monthly heat gain and loss, and monthly energy consumption. The indoor environment of the building top floor with different gradients settings was simulated in groups, and the hourly temperature, monthly heat gains and loss, and energy consumption of each model were analyzed. This study provided both theoretical and practical references for future flat-to-slope roof retrofitting projects in terms of building energy efficiency.

The leaders of construction innovation in China promote the integration of production best practices such as design for Excellence (DfX) in industrialized construction (IC) projects as a strategic path to leverage radical performance improvements in productivity, cost, quality, circularity, and sustainability. Despite its maturity in the manufacturing industry, the implementation of DfX methods in China's IC projects remains low. One widely cited reason for the sluggish interest is a poor understanding of the holistic business benefits that DfX methods could offer in IC projects. This study identified and evaluated 23 perceived benefits of DfX methods in IC projects in China. Quantitative data were collected using structured questionnaires administered to 229 IC academics and industry practitioners in China. Statistical analysis showed that all the benefits were perceived as significant. Based on mean significance indices, the top five perceived significant benefits include: “improves component design and production efficiency,” “facilitates standardization and customization,” “reduces labor requirements and improves productivity,” “reduces labor, inventory and development costs,” and “reduces material and construction wastes.” The study grouped the benefits into four clusters, namely, improved project design productivity, efficiency, and management; shortened design and construction time; life cycle cost savings; and improved flexibility, adaptability, and circularity. This study constitutes the first holistic evaluation of the benefits of DfX methods in IC projects. The evaluated benefits may serve as a basis for measuring the business benefits to justify investments in DfX in IC projects. The outcome constitutes a starting point for developing evidence-based DfX performance measurement metrics, indicators, and tools in the future.

In 2017, a moisture monitoring study was initiated on an eight-story, mass timber building located in Portland, Oregon. A detailed description of the monitoring program and initial monitoring results from the first year of the program were published previously. It was discovered that by the end of Year 1, some of the mass timber components had not dried below 19% moisture content (MC). This technical note is a follow-up to the original paper to examine how the building changed over its first 3 years after construction. All of the locations monitored over 3 years have reached stable moisture contents between 10% and 15%, which are acceptable for building functionality and performance. The main conclusion from this study is that mass timber buildings can naturally recover from construction wetting provided that such buildings are properly enclosed and further moisture intrusion is prevented.

Green walls, built structures covered with vegetation, are gaining momentum nowadays owing to the benefits imparted by the walls such as improved aesthetics, improved air quality, and noise reduction. Recent work has proven that green walls can be developed using pervious concrete made of cement and coarse aggregate with little or no fine aggregate. As this concrete has a void content of about 15% to 30%, an attempt has been made in this study to use this concrete to develop green walls. Voids in pervious concrete were filled with compost and used as a substrate for vegetational growth. Pervious concrete with 25% voids was made in this study with plain cement and a fly ash mix. Compost was made in the laboratory using vegetable and fruit peels and mixed with garden soil to fill in the voids of the pervious concrete. Selective plant varieties with lateral roots were first attempted to plant in the substrate. Two methods of planting, stem cutting and seed sowing, were attempted and both methods were found to be suitable. Further studies are in progress to improve the design of pervious concrete to use this substrate as integrated green walls for low-maintenance built structures.

A basic requirement of a building is to provide indoor thermal conditions to maintain good health and improve productivity. This can be achieved by optimizing the building envelope design. In building optimization problems, the objective function cannot be defined directly in terms of design variables. Hence, it cannot be solved effectively using traditional optimization techniques. Therefore, a simulation-based optimization technique was used for building envelope design optimization. The objective of this study is to present a novel methodology to calibrate a simulation model by correlating indoor and outdoor temperatures obtained from the simulation results and comparing it with the existing results obtained from actual field measurements.