Journal of Architectural Engineering

Current studies and performance labels focus mainly on the operational energy demand of buildings due to heating, cooling, ventilation, lighting, and hot water, but they rarely account for embodied impacts. Performing a life cycle assessment (LCA) on an entire building structure, let alone a building, requires time and data, both of which are often lacking for practitioners in the construction industry. Limited knowledge on the embodied carbon equivalent of building structures led to the benchmarking effort of the database of embodied quantity outputs (DEQO), developed by the first author over the last 6 years in close collaboration with industry and academia. DEQO collects material quantities for existing buildings in a robust way directly from industry. This paper presents the lessons learned from this database to define the next steps for structural engineers to lower the environmental impacts related to the material quantities in their projects. To create confidence and comparability in the results, recommendations are given such as implementing uncertainty analysis into practice to avoid inaccurate comparisons with a false sense of precision.

Energy efficiency measures in buildings, along with maintaining indoor thermal comfort, are increasingly drawing attention. The most widely accepted indices, Predicted Mean Vote (PMV) and Percentage People Dissatisfied (PPD), have been used in this study for evaluating thermal comfort of a small office room in Delhi. Various parameters influencing thermal comfort have been measured for two months and the observations have been used for assessing the PMV and PPD, which have then been compared with the simulation results from IDA ICE 4.7 Beta software, and found to be in agreement. Moreover, a comparison of the PMV values has been done with other indices such as Tropical Summer Index (TSI) and Corrected Effective Temperature (CET). Parametric study for the office room has also been performed to predict the shifts in the comfort levels by changing types and thicknesses of wall as well as roof insulations, provision of blinds, and types of window glazing, using which, the best possible solution to enhance the thermal environment of the office room has been proposed.

Due to their latent heat storage capacity, phase-change materials (PCM) incorporated in wallboards are an effective solution to reduce energy consumption inside buildings. This is achieved by incorporating PCM in construction elements made of cement-based materials. The purpose of this research is to evaluate both the thermal conductivity and the heat storage capacity of mortars and concretes with different amounts of PCM in order to evaluate their thermal performance. Therefore, a laboratory-developed transient plane source experimental setup was used to measure these properties. First, several mortar and concrete specimens including different amounts of PCM (0%, 4.5%, 9%, and 13% by total mass of cement) were manufactured. Then, the experimental setup was used to measure the temperature development on PCM-concretes and PCM-mortars for a period of 1,000 s. The collected data were analyzed to back-calculate the thermal characteristics using a numerical optimization procedure. Numerical findings using the finite-element method show that the testing procedure efficiently provides accurate estimations of the thermal properties of the tested specimens. It was found that cement-based materials incorporating PCM have lower thermal conductivity and higher heat storage capacity, which indicates the improvement of their thermal behavior.

Political conduct is a normal occurrence in every organization in today's business environment. The political environment in the construction industry is particularly problematic because of the engagement of many stakeholders with distinct expectations and agendas, along with the limited control of project personnel over influential stakeholders. Today, political skill and emotional intelligence are considered to be crucial skills in managing complex interpersonal relationships at work. Therefore, this research investigated the relationship between the two in the context of the construction industry. Data were collected from 273 project personnel working in construction projects in Australia and a Bayesian network was used to analyze the data. This research found that political skill was the precursor of emotional intelligence. Therefore, in the construction industry context, project personnel should exercise their political skill to improve the effectiveness of emotional intelligence when managing stakeholder relationships. Construction organizations could use this finding in their human resource management process when recruiting or promoting individuals to higher managerial levels.

This paper introduces a tessellated structural-architectural (TeSA) wall system concept with the potential for improving both resilience and sustainability of the built environment. Resilience requires fast recovery and restoration of building functionality after an extreme event, while sustainability seeks designs that facilitate building adaptability and reuse for long-term occupancy. TeSA wall systems are comprised of individual, interchangeable tile segments, which are arranged in tessellated (repetitive) patterns. TeSA walls provide a resilient and sustainable solution wherein tiles can be prefabricated, reconfigured, disassembled, and reused during the lifetime of a structure. This paper introduces the TeSA concept through preliminary physical and analytical studies. The physical test involved a beam made of interlocking tessellated acrylic tiles, which was loaded to failure. The analytical study featured two reinforced concrete TeSA shear walls under lateral loading. The physical test showed that damage can be localized within individual tiles that can be replaced to restore loadbearing capacity. The analyses showed that TeSA shear walls can provide ductility and localized damage in individual tiles. Recommendations for advancing the TeSA toward implementation are also discussed.

This study focuses on determining the possible interaction of organics like kadukkai (terminalia chebula) and jaggery (unrefined sugar) with an inorganic lime mortar using chemical analysis, organic analysis, and analytical techniques such as XRD, FT-IR, TGA, and SEM. It is due to the materials present in organics that various properties of lime mortar are enhanced. The results of kadukkai (LM-K), jaggery (LM-J), and jaggery-kadukkai hybrid (LM-JK) lime mortars were compared with the reference mortar (LM-R). Results show that the presence of carbohydrate in the organics boosts the carbonation process in the lime matrix. The thermal gravimetric analysis (TGA) results illustrate that the total weight loss of organic modified lime mortar was higher for LM-K, LM-J, and LM-JK with 14.36%, 14.23%, and 15.58% whereas mortar without organic modification was 8.05%. The addition of kadukkai and jaggery in the lime mortar separately has enhanced the carbonation rate of lime mortar whereas the kadukkai-jaggery hybrid modified lime mortar increased the calcium oxalate minerals in the lime mortar, which helps to increase the durability of mortar.

The traditional design approach for the improvement of outdoor comfort involves a static solution, typically simple-plane canopy shading. This often does not suit every type of climate and the changing of weather boundary conditions throughout the day. It can also be a visually invasive solution. A kinetic component, such as an origami surface, is adaptable to the various climatic conditions during a day and could be folded up when not needed. Despite its potential, application is limited by the lack of outdoor comfort-based methodology and simulation workflows to control their operations. This study is a contribution to the field of simulation of adaptive components that fulfil the maximum degree of outdoor comfort. In particular, a parametric optimization methodology is presented to find the best dynamic configuration based on the Universal Thermal Comfort Index. It is considered key to have a workflow in the parametric environment, as this is the environment where dynamic components are conceptualized, and movement programmed. The optimization workflow of different simulation parametric tools is demonstrated in the case study of the origami surfaces for a shading shelter in an archaeological area.

In the United States, commercial buildings consume 18% of the total primary energy, which is predicted to increase by 1.2% per year from 2006 to 2030 due to population and economic growth. Windows in commercial buildings are also responsible for 34% of commercial space conditioning energy use and 1.5% of total energy use in the United States. Therefore, controlling the heat gain and loss from windows in commercial buildings would save a significant amount of energy and subsequently reduce the carbon footprint. As the main function of shading is to moderate light rays, whether intercepting or allowing them to enter, having well-designed shading can improve building energy performance. However, shading should be designed carefully since decreasing the cooling load may result in increased heating load and vice versa. In addition, in designing window shading, achieving a balance between energy load reduction and light energy consumption is always challenging. This study proposes a new approach to designing kinetic exterior window shading for small commercial buildings, which changes the geometrical parameters of the exposed glazing area (EGA) of existing windows. To achieve this, first an optimization code was developed based on the hill climbing algorithm. The developed optimization code was then coupled with EnergyPlus software to determine the optimum area of the EGA, its optimum width to height ratio, and its optimum location in an existing window. To illustrate the application of the proposed shading and evaluate building energy performance a model was designed and presented in DesignBuilder software. The study showed the significant amount of energy saved by applying the proposed shading.

Practitioners and educators alike see technologies and delivery methods changing the fundamental way in which we approach and execute building design. As such, these same items will require changes in how we educate future generations. Over the past nine years, a student-driven capstone was implemented that had an open-ended scope in regard to assignments to simulate cutting-edge industry conditions. This study provides original contributions in creating an open-ended design project where multidisciplinary teams are expected to self-develop project-specific goals, and then select proper technologies, processes, and infrastructures to achieve those goals. This capstone course is distinguishable from other capstones in that the level of knowledge gained is relatively independent by the student teams (versus teaching by the faculty). Here, teams put their collective goals above individual goals that utilize a design competition modeled on real projects where many of the student deliverables are iterative. The results indicate that properly constructed foundations for the course will provide ample opportunities for students to engage more deeply in multidisciplinary interactions by developing more-complex and integrated designs. This paper describes successes observed throughout nine years of this approach to assist other educators in implementation of similar offerings in their programs.

Prefabricated residential construction forms a large portion of the European building stock and needs to be upgraded to current living standards and, if applicable, to current seismic resistance requirements. In fact, as indicated by the European Union in 2011, the refurbishment of the structures built during the second half of the twentieth century is priority for the entire construction sector. However, this process is affected primarily by the lack of knowledge of the material and construction aspects of prefabricated buildings, which makes the development of economic and efficient refurbishment interventions difficult. Based on this need, this paper focuses on the assessment of the seismic structural behavior of residential buildings built using the prefabrication procédé Camus, widely used in France and in many European countries, including Italy, during the 1960s. The analysis was carried out on a typological building placed in the city of Bologna, as this region concentrates an important number of prefabricated structures that had been recently affected by several earthquakes. Results show that due to the building layout, the analyzed structure has significantly higher lateral stiffness and better structural performance in the transverse direction than in the longitudinal direction. In fact, it was observed that the structural prefabricated walls located in the longitudinal direction will need to be strengthened in order to fulfill current requirements for shear strength and the combined effect of axial loads and bending moments.

Environmental impact studies within the built environment rely on predicting building lifespan to describe the period of occupation and operation. Most life cycle assessments (LCAs) are based on arbitrary lifespan values, omitting the uncertainties of assessing service life. This research models the lifespan of American residential housing stock as a probabilistic survival distribution based on available data from the American Housing Survey (AHS). The log-normal, gamma, and Weibull distributions were fit to demolition data from 1985 to 2009 and these three models were compared with one another using the Bayesian information criterion. Analysis revealed that the estimated average housing lifespan in the United States is 130 years given model assumptions, although a probabilistic approach to lifespan can yield higher accuracy on a case-by-case basis. Parameters for modeling housing lifespan as log-normal, gamma, and Weibull survival functions are published with the intent of further application in LCA. The application of probabilistic housing lifespan models to community-wide turnover and integration with existing simulations of natural disaster are proposed as potential ways to achieve community sustainability and resilience goals.

A multioccupancy environment (e.g., classroom, open office space, auditorium) typically features unbalanced ambient conditions such as temperatures, humidity, CO₂ levels, noise levels, and lighting conditions. It is also occupied by a large number of occupants with varying comfort requirements and preferences, making it extremely challenging to provide a collectively satisfactory environment to accommodate the comfort needs of this diverse population. This challenge is due to a lack of understanding and modeling of how to define group comfort levels based on individual comfort levels. This paper proposes a social-welfare-based human comfort aggregation model for quantifying the comfort levels of a group of occupants based on their individual comfort levels. The model accounts for the factors such as “inequality of human comfort” and “poverty of human comfort,” both of which have an impact on occupants' group comfort. A set of hypothetical and real case studies were conducted to illustrate how the proposed model can be applied in measuring the comfort levels of building occupants in different indoor environmental conditions. This research contributes to the body of knowledge by providing a new model for measuring group occupants' comfort. It provides a more explicit understanding of the relationships between group comfort and individual comfort in indoor environments. It could serve as the foundation for human-centered design and operation of buildings that offer more comfortable, healthier, and more inclusive indoor environments to building occupants.

To promote the development of the regeneration of old industrial buildings and reasonably evaluate the effects of regeneration projects, we propose an evaluation model for the regeneration of old industrial buildings based on the multilevel extension method. First, we construct an evaluation index system that includes economic, technical, social, ecological, and sustainability through field research and expert consultation. Second, a combination weighting method is used to determine the index weight, weaken the influence of human subjective factors on the evaluation results, and make the determination of index weight more simple and reasonable. Third, a multilevel extension method is used to determine the project evaluation grade, an actual regeneration project is used to verify the validity and practicability of the model. The research shows that the model is an organic combination of combination weighting method and multilevel extension method, and can evaluate the effects of the regeneration of old industrial buildings scientifically and reasonably.

During their early development, deployable structures were constructed using translational and polar scissor units. The discovery of angulated units revolutionized the field and popularized radially deployable geometries. This paper presents a geometric design method for axisymmetric grid structures made of three-dimensional angulated scissor units on a regular polygonal base. The method is applied to a series of forms, namely: positive, zero, and negative curvature shapes, and validated using a graphical procedure. The paper also describes the kinematic analysis of deployable planar rings and three-dimensional axisymmetric grids. Position, velocity, and acceleration (PVA) analyses provided insights into the structures' motion characteristics and the influence of geometric parameters on their deployment and folding.

Wind design procedures for wood roof trusses of low-rise structures are evaluated in this paper using wind tunnel test data and two-dimensional finite-element frame models. The adequacy of the conventional and two alternative design procedures is determined by computing the combined stress index in the top chord and the reliability index, β conditioned on the occurrence of the design wind speed. For trusses with typical design dead loads and constructed with wood that exhibits a relatively low degree of variability in material design values, the results indicate that both the conventional and the alternative design procedures considered in this study meet a target reliability index equal to 3.0. Of the three procedures, replacing main wind force resisting system (MWFRS) loads on a chord segment with components and cladding (C&C) loads, while maintaining MWFRS loads on all other chord member segments, provides the closest match to the target β. For trusses constructed with wood that exhibits a relatively high degree of variability in material design values, the reliability index is lower for all design procedures.

This paper analyzes the heritage values of lighthouses related to science, technology, and construction in the age they were built and launched throughout history. The implementation of a lighthouse requires the resolution of several technological and constructive problems of great complexity. Since the beginning of the 19th century, the construction of lighthouses represented an emerging international market once the scientific advances were transferred to the industry. Spain has a geostrategic advantage by possessing approximately 6,000 km of coastline, necessitating an extensive network of lighthouses for maritime navigational aid. An in-depth analysis of the 191 active lighthouses has been conducted, concluding that 130 of them have some particular historical value. These lighthouses represent a clear example of Industrial Heritage because they are authentic signaling factories that possess active technology within the building complex. The paper aims to establish a procedure to identify the heritage values of historical lighthouses. This article describes the technology implemented initially and proposes a typological classification of the architectural composition identified in Spanish lighthouses. It is the first work conducted in Spain of this scope and nature, constituting an initial attempt to establish a listing of the historic lighthouses of Spain.

The hybrid modular approach to architecture consists of a conceptual separation of permanent structural systems and removable living systems, in which a permanent, traditionally built structure hosts changeable modular living components. This way of conceiving buildings for residential purposes meets the emerging need for a high level of mobility among the global professional working class. A hybrid modular solution can provide dynamic and flexible housing services for a changing urban society. This paper aims to define the main guidelines and considerations for such hybrid modular buildings. Moreover, it develops possible technologies to fit the specific structural requirements of hybrid modular constructions, including random module interchangeability and fast plug-in and plug-out structural connections between the host structure and living modules. Such connection approaches further allow removable modules to be conveniently installed, disconnected, and relocated.

Historic buildings are regarded as a national heritage for their countries and therefore worthy of conservation. In an attempt to conserve them, various forms of intervention have been made over time. These interventions often lead to a problem when performed without adherence to architectural conservation principles. This paper aims to examine the compliance of reparations of historic buildings in Tripoli, Libya to architectural conservation principles and to discuss the main reasons that led to contradictions to these principles. The research demonstrated that about 40% of the observed works comply with architectural conservation principles. The main reasons that led to the contradictions are lack of knowledge and lack of proper repair materials in the local market in addition to security and safety. The findings have practical significance and provide lessons learned from successful and nonsuccessful experiences that should be passed into future repair works to avoid a repetition of mistakes.

In this paper, the history of the basilica of Santa Maria di Collemaggio for the last 10 years is outlined: from the damage occurred during the 2009 earthquake in L’Aquila, to the rehabilitation works and the main findings of the structural health monitoring (SHM) program carried out in 2018–2019. The restoration aimed at increasing the overall structural response by reducing the local collapse mechanisms (facade, apse, nave walls, etc.) observed after the seismic event. The vulnerability analysis, assessing the seismic capacity of the masonry structure before and after the restoration, throws light on the critical kinematic mechanisms, which are currently observed by a permanent monitoring system installed in 2017. First results concerning the dynamic identification of the basilica under both operational conditions and seismic events are developed and discussed. Furthermore, the maximum accelerations engaging each masonry macroelement during the last low-intensity earthquakes are discussed.

Delays in achieving projects' objectives according to the planned schedule are considered one of the main sources of conflicts in Iran's construction industry. A precise and structured methodology and baseline to properly evaluate the root causes of delays and present guidelines has not been established, to the best of the authors’ knowledge. Therefore, there are limited perspectives on the effects of delays on the projects, creating an inefficient approach to deal with construction delays. The purpose of this study is to identify the most significant causes of construction delays, categorize and rank them to determine the root of delays, and provide a suitable solution. After extracting the main causes of delays through a comprehensive literature review and interviews, a structured questionnaire was designed to rank the delays in terms of three indices of importance, occurrence probability, and impact. In addition, when the causes of delays were identified and classified, the causes were split into eight main groups including the contractor, owner, design, procurement, equipment, consultant, labor, and miscellaneous, and the results were depicted using a cause-and-effect diagram. The findings show that the fundamental group causing delays was the contractor category, and the most critical cause was the contractor's financial problems. The primary conclusion of this study is that financial matters play a critical role in project delays in Iran's construction industry, and it is recommended that owners should take more meticulous measures to choose the most qualified contractor with strong financial backgrounds and they need to define and phase the project to their financial resources and determine an efficient financial plan for payments.