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.

The largest tornado outbreak in the United States occurred on April 25–28, 2011. The outbreak resulted in widespread destruction across the southeastern United States and was responsible for over $5 billion in property loss. Although tornadoes cause significant damage every year in the United States, they are not currently included in building codes because the annual likelihood of an individual building being struck is quite small. However, catastrophic damage following large-scale tornado outbreaks has resulted in inquiry into the benefit of the use of stricter wind-design provisions in residential construction. Using the results of a fragility analysis based on the performance of a wind-induced vertical load path, property loss to wood-frame residential construction from tornadoes was estimated for residential buildings designed using locally adopted building codes at the time of the outbreak. The analysis was performed a second time, but this time using the stricter wind provisions of a state residential code applied across a portion of the southeastern United States. This allowed for an estimate of the reduction of property loss to wood-frame residential construction from large tornado outbreaks by using strengthened construction methodologies. Results indicate a reduction in residential property loss of up to 40% for the April 2011 outbreak.

The optimization of structures is a tricky process that involves strategies and mathematical algorithms in which the design parameters—introduced in terms of variables, constraint conditions, optimization functions, penalty conditions, and so forth—play very important roles. Their selection and introduction in the optimization process could influence the characteristics and the level of optimization of the derived solutions. This paper describes the roles of design parameters used in different optimization strategies. Moreover, an efficient optimization approach, which combines form-finding (FF), sizing-optimization (SO), and topologic-optimization (TO) strategies in a multilevel process for which design variables and constraint conditions are opportunely selected, is proposed. Numerical analyses referring to some canopy case studies derived from the current literature are also presented in the paper. The comparisons among optimization approaches, featuring FF, SO, and TO optimization strategies performed singularly or in combination throughout a simple sequence of phases, emphasize the effectiveness of the proposed approach for obtaining light structural solutions for grid shells.

This study focused on lifecycle assessment (LCA) and evaluation of the sustainable performance of structures retrofitted by adding stiff diaphragms or by using seismic isolation systems. To analyze the mitigation measures, methodological options addressing LCA uncertainties were used. For this purpose, a two-stage, nested, mixed, and balanced ANOVA test was applied. The following four cases were evaluated: nonretrofitted building (baseline), use of concrete diaphragms for strengthening, application of high-damping rubber bearings, and use of seismic isolation columns. Four natural ground-motion records were used for analysis: El Centro, Kobe, Hachinohe, and Northridge. The reduction in environmental damage, relative to the nonretrofitted alternative, was evaluated. It was found that the environmental impact of the four mitigation measures was approximately 10% of the total building impact. According to the results obtained in the frame of the present study, the use of seismic isolation columns resulted in damage reduction of approximately three times more than that achieved by high-damping rubber bearings.

People with Down syndrome have a wide range of capabilities but generally need support to achieve their potential. Some require very little, while others need a high level of support. Most people with Down syndrome work and lead full lives as productive and respected members of their communities. The research group investigated the opportunity of a smart apartment home equipped with assistive devices for supporting young people with Down syndrome in specific activities of daily living (ADLs) to improve their quality of life and independent living. The participants were three young people with Down syndrome who needed different levels of support. Using an assessment grid based on a 5-point intensity scale divided according to type of support needed, the researchers conducted a pilot study to verify improvements in the quality of performance of five ADLs without and with assistive devices. The results showed trends of improvement in two of the five ADLs investigated both without and with assistive devices. A larger controlled study would confirm the efficacy of this promising training apartment.

Lightweight, transparent, long-spanned, and high-rise constructions characterize the vision of many architects. Glass is at present the best-performing material where high transparency and durability are the main requisites, but its brittleness limits its ability to provide structural engineered solutions. Large-spanned glass beams are most often built with multiple splice lamination, but this technique presents some problems, such as increased dead load and lack of redundancy, ductility, structural hierarchy, and economy. An alternative strategy has been developed in the form of multiple segmented bolted beams, but the holes this requires inevitably weaken the glass. Using the results of a 10-year-long theoretical and experimental study carried out at the University of Pisa and following the principles of fail-safe design, the main purpose of this work is to present a new static concept for hybrid, segmented, esogen–endogen-compressed, and buckling-restrained glass structures. This concept represents the latest evolution of both the Travi Vitree Tensegrity (TVT) and the Solidi Vitrei Tensegrity (SVT) constructional systems. Finite element models (FEM) calibrated on the experimental findings demonstrate the feasibility of the new concept and its good performance at the ultimate and serviceability-limit states.

This paper presents an integrated methodology for the assessment of inhabited built heritage, referred to as metodologia de avaliação de património edificado habitado (MAPEH), which emerges from the need to solve gaps resulting from the existence of fragmented studies that do not take into consideration the complex interaction of the different aspects involved in the interventions on built heritage. In particular, it incorporates a multidisciplinary analysis that combines three dimensions: patrimonial, technical, and social, which are associated with criteria such as identification of characteristics and values; assessment of safety and housing conditions; and recognition of residents’ profile, expectations, and basic needs. The paper also presents the results of the application of MAPEH to a case study: the inhabited old residential buildings of Porto, Portugal, underlining the interaction and importance of the three dimensions and the need for flexible and proportional criteria in the application of building codes and legislation, offering new input for establishing better-oriented intervention procedures on built heritage.

An innovative composite flat roof was developed to resist hurricane wind forces for industrial, commercial, and low- to midrise residential building applications. Combining two advanced materials, ultra-high-performance concrete (UHPC) and high-strength steel (HSS), the proposed engineered system is superlight, with only 83 kg/m² (17 lb/ft²) self-weight; low profile, with an overall depth of only 102 mm (4 in.); and ultra-thin-walled, with webs and flanges only 19 mm (3/4 in.) thick; additionally, it requires no transverse and shear reinforcement. Experimental work was conducted on two groups of specimens—single-cell and multicell specimens—under positive and negative bending configurations. Analysis based on the test results confirmed that the proposed system can withstand hurricane wind speeds of 336 km/hr (209 mph) for a span of 6.1 m (20 ft) (i.e., a span-to-depth ratio of 60:1). Test specimens showed flexural failure with considerable ductility and a strong panel action with a distribution factor of 0.33 among adjacent box-cells. Despite lack of any shear reinforcement, no shear crack was observed. Multicell specimens showed an improved performance in cracking and ductility over single-cell specimens, in part as a result of their transverse ribs. The proposed section showed optimal performance, as evident from similar capacity/demand ratios in positive and negative bending.

Waste, a non-value-added activity or process, is among the issues in every project that directly influence its main objectives, including time, cost, and quality. Lean thinking, following its success in the manufacturing industry, has been introduced to the construction industry, with the reduction of waste as its main purpose. The objective of this study is to develop an approach for developing and validating a lean construction plan (LCP). An LCP is developed through a systematic approach, specifying non-value-added processes and choosing appropriate lean techniques. To validate the developed plan, an evaluation of the progressive improvement of repetitive subprojects is utilized as an effective approach. The validation process is necessary for the support of top management its commitment to implementing an LCP; this is especially true in large construction projects that are associated with higher risks, due to changes in existing management approaches. A real project, used as an example of an application, is studied to illustrate the use of the approach and demonstrate its capabilities in construction projects.

Although industrialized construction methods, such as modular and manufactured buildings, have evolved over decades, core techniques used in prefabrication plants vary only slightly from those used in traditional site-built construction. With the focus of energy efficiency in modular construction, this research presents the development of a simulation, measurement, and optimization system for determining energy consumption (EC) in the manufacturing process of modular construction. The system uses the principles of a loosely coupled system operation to identify the nonvalue-added tasks and possible causes of low energy efficiency. The system includes value stream mapping (VSM), discrete optimization, and system dynamics (SD) for the demonstration and calculation of EC in modular construction. The benefits of implementing this system include the quantity analysis of possible waste factors, reductions in the EC, decrease of energy cost, and increase of profit. In addition, the research reveals the relationships between relocatable workers, energy efficiency, and operation flexibility. This system should provide superior performance over existing operation evaluation systems, enabling decision-making based on reliable quantities and delivery of true EC models to facility construction practitioners.

Quantifying the environmental impacts of buildings is a key step in realizing resilient and sustainable buildings. Buildings are vulnerable to natural hazards during their functional life, and the structural performance of the building affects its environmental impacts due to repair of hazard-related damage. This study presents a rational probabilistic approach to quantify the life-cycle environmental performance and functional life of buildings located in regions threatened by seismic hazards. The approach simulates multiple discrete earthquake event scenarios used to estimate the functional life of the building: an important metric for assessing the sustainability and resilience of buildings. It also calculates the hazard-related life-cycle environmental impacts directly from the materials needed to repair different components while accounting for uncertainty in each phase of the analysis. The approach is demonstrated on a case-study steel building, with illustrative results showing the impact of component groups on the overall environmental performance of the building. The building performed well structurally, but with considerable impacts due to damage to nonstructural components. The approach can be used to study a variety of building designs.

A single table permits the designer of architectural glazing systems to select glazing constructions that will meet specified design wind loads. This simplification of the glazing construction selection process employs, as working elements, the minimum load resistance of commonly used glass thicknesses and opening areas. The process is based on two principal observations: (1) heat-treated lites (heat strengthened and fully tempered) with relatively large areas of approximately 4.6–6.5 m² (50–70 ft²) can carry relatively large design pressures in excess of 4.8 kPa (100 psf) acting alone, thus eliminating the need for load-sharing analysis in most common sizes of insulating glass units; and (2) the load resistances of commonly used monolithic and polyvinylbutyral-laminated lites with identical dimensions and designated thickness are close enough to be considered equal, within 140 Pa (3 psf).

Space exploration focuses on new technologies to search the unknown. It has been used to investigate possibilities for the creation of human colonies in extraterrestrial environments. Current projects concerning space architecture reflect two perspectives that differ from highly rationalized engineering solutions in that they are highly conceptual and abstract approaches. Although implemented for extraterrestrial environments, new technologies do not offer a comprehensive approach from an architecture perspective that can be implemented for different design and programmatic purposes by the use of in situ materials on Mars. This paper aims to propose a comprehensive approach in which the form generation process is driven by environmental conditions, specifically the dune fields on Mars. A set of architectural geometry, described computationally, can respond to different spatial conditions, such as shell structures, from fully enclosed to semiopen surfaces. In this approach, in situ materials are used with robotic fabrication; more specifically, three-dimensional (3D) printing is used on Martian land. A material system, which creates a titanium-dioxide-based shielding layer, was developed against high radiation levels on the Martian surface. The interconnected structural modules were considered similar to the brick material called T-brick. The system was assessed structurally by selecting an enclosed geometry: a dome structure. Hence, the efficiency factor was calculated. The results proved that the proposed T-brick shell is an efficient solution considering the payload constraints of the system. The method can be potentially implemented on Earth and extraterrestrial environments in addition to Mars.

The method for determining load resistance of insulating glass in ASTM standards uses a load-share factor equation based only on glass-lite thicknesses to estimate the load carried by each lite. This paper presents an experimental investigation of load sharing of double- and triple-glazed insulating glass units. The major factors varied in the investigation include unit rectangular dimensions, glass-lite thicknesses, and initial airspace volumes. Pressure versus deflection curves are presented for select insulating glass unit configurations. A second testing procedure explores the measured change in pressure within the sealed airspaces while simultaneously measuring applied pressure and associated deflections. Changes in pressures in the sealed airspaces are directly compared to the ASTM standard load-share factors. Figures in this paper show the load-sharing trends of various similarly loaded insulating glass units, and the results presented in this paper suggest many of the neglected factors significantly influence load sharing in insulating glass units.

Sustainability and resiliency against hazards are two important factors in building design. Sustainability parameters or attributes can be evaluated through Leadership in Energy and Environmental Design (LEED) ratings (scores) and lifecycle assessment (LCA), with respect to energy and material usage, whereas resiliency attributes can be assessed by ductility, wind-borne debris resistance, fragility analysis, and parameters from structural analysis, such as elastic and inelastic drifts under seismic and wind loads. This article presents a multiple-attribute decision-making (MADM) method for choosing a building design that reconciles building design parameters that may conflict with each other when both sustainability and resiliency are considered together. For example, some building materials used may be beneficial for withstanding fire hazards but harmful to the environment at the end of their lifecycle. The main novelty of the proposed MADM method is that it can reconcile various conflicting attributes and provide sensitivity analysis information on winning designs when some of the design parameters/attributes are uncertain at the time of making design decisions. Simulation techniques were used to determine a distribution of final design rankings, and a case study of the selection of an office building was conducted to demonstrate the proposed method. The numerical example shows that the proposed framework was able to handle the conflicting attributes applied for the selected case study.

Human health can be affected adversely by a number of conditions in built environments, from materials and techniques used in the construction process, from activities within those spaces, and from connections to the external environment. Some groups, including children, pregnant women, and limited-resource households, are at a higher risk than others for experiencing negative health impacts from indoor pollutant exposures. Limited-resource households, in particular, do not have the resources necessary to test for the presence of indoor air pollutants and to mitigate them. This paper (1) provides a review of exposure by vulnerable populations, especially children, to indoor air pollutants; (2) demonstrates the feasibility of an inexpensive smart phone app and attached hardware that can detect indoor air pollutants; and (3) illustrates a simple ventilation system for improving the quality of air that children breathe.

Rammed-earth constructions are present all over the world and are common in Portugal, especially in the southern part of the country. In recent years, several research works published on this topic focused on characterizing the mechanical properties and understanding the structural behavior of buildings through experimental and numerical works. Much of the work focused on the characterization of the seismic vulnerability of rammed-earth construction. The research presented in this paper offers another contribution on this topic, particularly in understanding the influence of construction elements in a vernacular seismic culture. On the basis of a simplified case study, derived from a real building, a set of numerical analyses was carried out to assess the influence of the geometry, layout, and different retrofitting solutions typical of vernacular rammed-earth constructions on behavior and seismic performance.

This article presents findings of an investigation, conducted in South Africa, on the influence of the beneficiaries’ participation in the formation of low-income housing residents’ satisfaction with their houses. The study was conducted among delivery practitioners of low-income housing and housing occupants. The research was conducted in municipalities in three metropolitan areas and one district in the Gauteng Province of South Africa. Data used in the study were obtained from a field questionnaire study. Using modeling software, the influence of beneficiaries’ participation on the satisfaction of low-income housing was investigated. The findings show that beneficiary participation on resident satisfaction was statistically significant and exacted a direct influence on the prediction of residents’ levels of satisfaction with their houses. However, because of the idiosyncratic data set used in the study, it remains to be seen if the evaluated relationships between beneficiary participation and resident satisfaction can be replicated to cross-cultural data sets. If the relationships can be replicated, the paper makes a significant contribution toward understanding residential satisfaction with subsidized low-income housing projects.

Lifecycle cost analysis (LCCA) is a tool to assess the costs associated with each phase of the building lifecycle. This study evaluated the lifecycle cost (LCC) of a prefabricated fiber-reinforced composite (FRC) building in comparison with a masonry one. The four lifecycle phases of construction, operation, maintenance, and demolition were taken into consideration, and buildings in the American cities of El Paso, Los Angeles, and San Francisco were analyzed. First, the contribution of different building components to construction cost was defined. Consequently, the operation costs to supply cooling and heating-energy demands and lighting and home appliances were calculated. After determining the maintenance and demolition costs, the total LCC of both building types were compared through net present value (NPV). Finally, sensitivity analyses were carried out to assess the impact of influential parameters. The results highlight the significance of construction cost for both structures and the higher maintenance and lower demolition costs of the prefabricated building. Moreover, the prefabricated building was found to have higher cooling costs despite its lower U-value. The prefabricated building had a higher total LCC in all locations. The results also demonstrate the importance of location by indicating substantial variations in construction, maintenance, and demolition costs among the studied cities. Furthermore, the prefabricated building was found to have lower operating costs in Los Angeles and San Francisco but higher costs in El Paso. The sensitivity analyses show significant impacts of the discount rate and lifetime, moderate influence of the inflation rates of maintenance and demolition costs, and limited impact of the inflation rate of electricity cost.