Light Steel Frame Research Articles

Using a decision-making tool to select the optimal industrial housing construction system in Tehran

ABSTRACT Industrial dwelling construction (IDC) combines offsite and onsite construction methods. The current work proposes a multiple-criteria decision-making assistant system (DMAS) approach for evaluating home buildings, selecting decision agents, and determining acceptable IDC types and characteristics for large-scale housing enhancement. Using the analytical hierarchy process (AHP), a multicriteria DMAS was planned. Literature reviews and expert interviews were used to assess thirty decision agents. To validate the procedure, five IDCs were analyzed as case studies. Thirty professionals analyzed decision agents' and housing systems' priority vectors using questionnaires. Three decision agents were identified: (1) user needs, (2) the building industry, and (3) the supply chain. Consequently, Prefabricated Reinforced Concrete Slab, Beam, and Column Blocks (PRCSBCB) and Light Steel Frame Wall Panels (LSFWP) can be used to construct suitable dwellings. These construction options are low-cost, lightweight, and easy to install. They also use inexperienced local workers. Results showed the method's potential and usefulness with so many choices and decision agents. This research examines knowledge and skill gaps in Iran's IDC and encounters a shortage of IDC specialists and mass-construction variants. The study identifies key decision-agents and housing options for quick, appropriate, and cost-efficient mass housing and helps professionals, entrepreneurs, and decision-makers make better decisions.

A Hybrid Fuzzy MCDM Methodology for Optimal Structural System Selection Compatible with Sustainable Materials in Mass-Housing Projects

The present paper aimed to propose a new support approach to choosing the optimal structural system in accordance with sustainable materials in mass-housing projects. To this end, an integrated fuzzy multi-criteria-decision-making (fuzzy MCDM) method was used to identify the criteria affecting sustainable material selection. The proposed approach consists of a three-phase protocol: In phase I, the literature was used to create a database encompassing 42 factors affecting the selection of materials. These factors were classified as four indicators (economic, environmental, socio-cultural, technical-executive) in accordance with the sustainable development aspects. In phase II, the fuzzy Delphi method (FDM) was used to screen the key factors. In phase III, an integrated fuzzy SWARA–ARAS method was used to prioritize the optimal structural system for a case project: evidence from Iran. The results of selecting the structural systems based on 14 efficient key factors showed that the Light Steel Frame (LSF), Insulation Concrete framework (ICF), and the Prefabricated Reinforced Concrete System (PRC) systems have the highest priority to achieve the goals of sustainable material selection, respectively.

Analysis of the critical temperature on load bearing LSF walls under fire

Light Steel Frame (LSF) walls are widely used in building structures, used as partition walls and load bearing walls. The LSF is usually protected by layers of homogeneous plates or composite plates, with or without insulation materials in the cavity. This investigation presents the simulation results of composite LSF walls in reduced scale and full scale, based on variable load levels (20 to 80%). The numerical model uses a hybrid model approximation, based on the experimental tests to accurately determine the temperature field. The numerical model is validated with experimental results, at reduced and full scale, both at room temperature and under fire conditions. This modelling technique can follow the thermal and mechanical degradation of the protection layers of the LSF wall and determine the fire rating for load bearing (R) and insulation (I). The fire resistance (R) decreases with the increase of the load level. The insulation ability is also predicted for different protection materials. Relevant conclusions are presented to increase the insulation ability of LSF walls, especially when using non combustible double protection layers. The insulation ability to sustain fire usually increases with the number of studs and with the application of insulation material in the cavity region. The ability to sustain the load under fire also increases with the number of studs, especially for higher load levels. The ability to sustain the load also increases with the number of protection layers, changing from 16% at 20% load level, to 42% at 50% load level.A new proposal is presented for the critical temperature of the LSF, based on the maximum temperature of the LSF during the fire, allowing the calculation of the critical temperature, based on the load level of the specimen. This relation can predict the fire resistance time, based on the preliminary thermal analysis of the specimen. The reduced scale specimens present higher critical temperatures when compared to the full scale specimens, due to the typical failure mode (local modes for the reduced scale and global modes for the large scale).

The impact of the exterior green wall on the summer regime in the building – energy simulation

The analysis is based on the results of computer simulation by using DesignBUILDER software. In the analysis is the multi dwelling house assessed. There are standard building constructions used like as the brick wall with polystyrene thermal insulation, Windows with plastic frame and double glazing and the flat roof with thermal insulation from polystyrene without the gravel layer. In this thermal simulation is considered with so called green walls, that are localized at eastern, southern, and western facade of the building. The light steel frame construction with the net from thin steel ropes creates the area for the climbing plants like a ivy. The function of the used green walls with climbing plants is to shade the external walls of the building in order to reduce the impact of solar radiation on the building facade during the hot summer days. We can these green walls in combination with external blinds consider like a effectively solution in order to reduce the energy consumption for cooling system in the building. By the way the used green walls help to reduce the air temperature surrounding the buildings and so they create the better town climate for their citizens.

Evaluation of a residential project in light steel framing according to leed for homes

The construction industry is responsible for high energy consumption, high carbon dioxide emissions, high extraction of non-renewable materials, and large generation of solid waste in the world. The use of prefabricated, industrialized, and technological construction methods can reduce environmental impacts generated. Aiming to confirm its environmental benefits, the research proposal was to analyze the sustainability of a residential project in Light Steel Framing (LSF), according to the requirements of the environmental certification Leadership in Energy and Environmental Design (LEED) for Homes of the Green Building Council (GBC) Brazil Homes. For this, it was necessary to apply the Technical Quality Regulation for the Energy Efficiency Level for Homes, achieving the A-level classification in this analysis, with 5.06 final points. Therefore, it was considered the constitution of the building wrap in LSF, the energy efficiency of the materials used, the water heating and lighting systems. In order to obtain the highest level of LEED certification, the project has received suggestions for improvements. The project obtained 60 final points in the analysis, which would allow the achievement of the gold certification seal. The total score in the Materials and Resources topic demonstrates the great benefit of the system in LSF in environmental preservation.

Development of Lightweight Steel Framed Construction Systems for Nearly-Zero Energy Buildings

Light steel frame (LSF) building systems offer high structural resilience, lower costs due to fast prefabrication, and high ability to recycle and reuse. The main goal of this paper was to provide state-of-the-art main components for such systems with the intention to be implemented for use in nearly-zero energy buildings (NZEBs). A brief historical outline of the development of LSF systems was given, and the key parameters affecting the design and use of LSF systems were discussed. The influence of the individual components of the LSF system (steel studs, sheathing boards, and insulation materials) was then thoroughly discussed in light of relevant research on energy efficiency and other important properties (such as sound protection and fire resistance). Web of Science and Scopus databases were used for this purpose, using relevant key words: LSF, energy efficiency, sheathing boards, steel studs, insulation, etc. Several research gaps were identified that could be used for development and future research on new LSF systems. Finally, based on the analysis of each component, an innovative LSF composite wall panel was proposed which will be the subject of the authors’ future research. Conducted preliminary analysis showed low thermal transmittance of the system and indicates the path of its further research.

Building Affordable Homes with Mass Timber Construction

With the explosion in increased population migration to metro cities, housing infrastructure poses to be one of the biggest challenges in India as well as other countries. Housing in-equality, affordability and homelessness are persistent and complex challenges in our society. United Nations in the year 2015 has adopted Sustainable Development Goals or Global Goals to facilitate people to enjoy peace and prosperity, allow balanced social, economic and environmental sustainability. The need for a safe space to live which transforms the quality of life of individuals and families is a basic necessity. Thus, providing sustainable cities and communities along with good health and well-being of the citizens are priorities which needs to be addressed along with providing affordable clean energy, furthering actions to mitigate climate change. According to a United Nations report, (17) by 2050, more than 7 billion people will move to cities. The rapid growth of cities due to rising population has resulted in increased number of slums which are becoming a feature of urban life. To accommodate the rising urban poor, affordable homes have to be envisioned and built faster. The delay in construction time required by conventional construction methods is resulting in squatter, un- organized settlements as well as contributing largely to global carbon emissions. The need to provide affordable, sustainable homes with healthy benefits using better construction technology is the need of the day. Conventional method of construction which involves concrete and steel are a disastrous method of construction as they are dependent on energy generated from fossil fuels to process materials. As per a United Nations report (17), globally our cities occupy 3 percent of Earth’s land but account for 60 to 80 percent of energy consumption and 70 percent of carbon emissions. Hence, the need for alternative sustainable method of construction which can be built in the smallest amount of time, is a necessity. The technology adopted must be a big leap in reducing the carbon emissions, reducing the construction time and providing a healthy environment for the habitants. Presently in India, to reduce the construction time of mass housing, the Government is adopting ‘light gauge steel frame’ structures in which constructions are faster compared to the conventional buildings. However, this method is still dependent on burning of fossil fuels and other non-renewable resources still resulting in a sizeable carbon footprint. The need to adopt sustainable ways of construction, with less environmental disruption, while ensuring quality and to build faster, led to study of various construction practices adopted globally. Amongst the various solutions, Mass Timber Construction is believed to be one of the most effective solution, characterized by pre-fabricated components manufactured offsite and assembled on site in a shorter period of time and reduced dependency on workers, all the while using a renewable resource, timber. To move towards accomplishing the Sustainable Development Goals set by the United Nations, our future cities have be built to be safe, sustainable and inclusive. For achieving this we have to change and relook the way we build.

Influence of heat-conducting elements on temperature amplitude of inner surface of frame-supporting buildings

The paper considers the heat stability of enclosing structures of frame-supporting buildings. These buildings are characterized by a significant heterogeneity of enclosing structures. The supporting structures have a large number of uprights, beams, lintels, connectors, and heat-conducting elements such as building corners, balconies, window and door jambs, and plinth nodes. Two typical junctions are considered for a frame-supporting building with light gauge steel framing and wooden frames. The Simulation module of the SolidWorks software is used to analyze the obtained minimum and maximum temperature on the inner surface. The diagram of the temperature distribution is suggested for two design solutions, i.e., the outer corner and floor junction, and the light gauge steel framing and wooden frame-supporting structure. It is found that near the heat-conducting elements, the maximum allowable value is exceed by 5 and 3 times for the light gauge steel and wooden framing respectively, which does not meet the standard requirements. The temperature fluctuations are observed in the junction between the floor and wall. Thus, for the light gauge steel framing, the temperature fluctuations occur at a distance of ~200 mm in the room, while in wooden-frame building, this distance is ~100 mm.

The Impact of Thermal Inertia on the Indoor Thermal Environment of Light Steel Framing Constructions

Typically, reinforced concrete and brick masonry construction is the most common construction system of the majority of the southern European residential building stock. However, the lightweight steel framing (LSF) construction system has been progressively assuming a relevant position in the residential sector. Since LSF is not the traditional construction system, the indoor thermal environment of these buildings has not been widely studied and discussed considering the southern European climate context. The low thermal inertia of this construction system is commonly pointed to as a possible weakness in warmer climates. The present work aims to address this research gap by evaluating and comparing the LSF and masonry construction systems in terms of the indoor thermal environment focusing on the level of thermal inertia. The considered methodology lies in a long-term experimental campaign based on the construction and monitoring of two identical experimental test cells, differing only in the construction system. The test cells are in the central region of Portugal. The monitoring period elapsed over an entire year. Dynamic simulations are also carried out with a model experimentally validated to consider a wider range of climatic conditions. It is shown that internally insulating the ground floor has an impact on the indoor thermal environment of the LSF test cell by accentuating the indoor air temperature fluctuations and magnitude of the extreme peak values. However, the results also reveal that the faster and closer response to the outdoor conditions may be beneficial for LSF buildings during the heating season.

BARRASIM4P – A Digital Platform for the Structural Design of Cold‐Formed Steel Elements from the Company Barraferros

AbstractThe use of cold‐formed steel sections as secondary structural elements (purlins) and primary elements of light steel framing (LSF) solutions has had a strong increase in recent years, presenting a high degree of specialization, with specific and optimized geometries for different applications, implying an increased effort for the design of steel structures. This article presents BarraSim4P – a digital platform to support structural design based on Eurocode and developed in partnership between Barraferros and Politécnico de Leiria. The platform aims to support the user in choosing sections considering specified design conditions and code actions in the structure. The platform was also validated with several tests on Barraferros sections with known results.

Power-actuated fasteners in single shear-An experimental investigation and proposed design rules

This paper presents the results of 81 experimental tests on the design strength of power-actuated fasteners (PAFs) in single shear connections for a light gauge steel framing (LGSF), as an alternative to self-drilling screws for selective uses. This type of connection can be employed to install a reinforcing plate on one or both sides of the frame, to connect steel strap cross bracing to framing, as well as for many other applications. These power-actuated fasteners present a very efficient and practical solution which can increase productivity and work quality by replacing time consuming screw connections. In this study, two different steel grades (G300 and G550), along with three different steel sheet configurations were investigated. Modes of failure for both the PAFs and the connected material were examined so to provide an understanding of the structural performance of nailed single lap connections and develop design recommendations and proposed formulae. The investigation covers a wide range of steel gauges (0.75 mm, 0.95 mm and 1.15 mm), commonly used in LGSF residential and commercial applications. Two groups of tests were performed. The first group of tests was conducted to determine the shear strength of connectors with two types being tested. The second tests series were carried out in various steel grade and gauge configurations for assembled connections. The results of this research and the proposed design formula can be used to establish the strength prediction model for power-actuated fasteners (PAFs) embedded into LGSF.

A Comparative Study on the Life Cycle Assessment of New Zealand Residential Buildings

In New Zealand, housing is typically low density, with light timber framing being the dominant form of construction with more than 90% of the market. From 2020, as a result of the global pandemic, there was a shortage of timber in New Zealand, resulting in increased popularity for light steel framing, the main alternative to timber for housing. At the same time, the New Zealand government is committed to sustainability practises through legislation and frameworks, such as the reduction of whole-of-life carbon emissions for the building industry. New Zealand recently announced reducing its net greenhouse gas emissions by 50% within 2030. Life cycle assessment (LCA) is a technique for assessing the environmental aspects associated with a product over its life cycle. Despite the popularity of LCA in the construction industry of New Zealand, prior research results seem varied. There is no unified NZ context database to perform an LCA for buildings. Therefore, in this paper, a comprehensive study using LCA was conducted to quantify and compare the quantity of carbon emissions from two commonly designed houses in the Auckland region, one built from light timber and the other from light steel, both designed for a lifespan of 90 years. The cradle-to-cradle system boundary was used for the LCA. From the results of this study, it was found that the light steel house had 12.3% more carbon in total (including embodied and operational carbons) when compared to the light timber house, of which the manufacturing of two houses had a difference of 50.4% in terms of carbon emissions. However, when the end-of-life (EOL) analysis was included, it was found that the extra carbon could be offset due to the steel’s recyclability, reducing the amount of embodied carbon in the manufacturing process. Therefore, there was no significant difference in carbon emissions between the light steel and the light timber building, with the difference being only 12.3%.

Seismic resistance of frame-cladding buildings with a cold-formed galvanized steel profile framing

Building structural systems with light gauge steel framing technology are steadily gaining popularity due to their huge advantages over traditional technical solutions. As a result of the competitiveness inherent in LGSF technology, its application is gradually increasing in the manufacture of both bearing and nonbearing structures. At the same time, the actual absence of national standards for seismic design requires the development of programs and the implementation of research and development work to study the behavior of LGSF buildings in the conditions of seismic impact. The article touches upon the main problems of antiseismic construction of LGSF buildings and presents the results of domestic and foreign research.

Heat transfer analysis of the vertical closing system in light steel framing using the isothermal planes method and finite element method

The use of steel in construction is an alternative that has changed the panorama of this sector, contributing to an increase in productivity, and a reduction in waste and construction time. The Light Steel Framing (LSF) system, introduced in Brazil at the end of the 1990s, is undergoing a process of technical development and acceptance in the national civil construction market, but there are still shortcomings regarding the design, itemization and implementation of the complementary closing systems, and also regarding its thermal performance. This study employs an analytical approach that uses the isothermal planes method to calculate the resistance and thermal transmittance, and a numerical approach that uses the ANSYS software (version 15) to verify and compare these analyses. Multi-layer closures are considered, with the outer layer being made up of cement board and the inner layer of gypsum board, brokered by fiber glass insulation and air, with studs formed by C-section profiles in galvanized steel. The isothermal planes method revealed the value of 0.77 (m2.K)/W for the equivalent thermal resistance, 1.3 W/(m2.K) for the thermal transmittance, and 13.04 W/m2 for the heat conduction flux. The difference of the results when comparing the isothermal planes and numerical solution methods was 9% for thermal resistance and 8% for heat conduction flux. The obtained results showed that the heat flux is equivalent to a value around 54% greater than the heat flux value for a closure without the presence of steel profile.

Energy consumption in intermittently heated residential buildings: Light Steel Framing vs hollow brick masonry constructive system

The hollow brick masonry and reinforced concrete construction is the most common and technically known constructive system in southern European countries. However, more industrialised alternatives have arisen, such as the Light Steel Framing (LSF). Nevertheless, an important research gap concerning the performance of this constructive system and its comparison with the brick masonry buildings was found. The shortage of available experimental data hinders the optimisation of these buildings towards high energy efficiency standards and indoor comfort. In this sense, the primary aim of this research is to assess the opportunities and limitations of each constructive system in terms of minimising energy consumption and providing a comfortable indoor environment during the heating season, considering an intermittent heating pattern. The novelty of the present work is the long-term experimental campaign involving the construction and monitoring of two identical test cells, differing only in the constructive system. The test cells are located in the Aveiro district (Portugal) and were monitored over an entire year. The results revealed a lower energy consumption of LSF test cell in every monitored month. On the other hand, this test cell is more responsive to the external weather stimulus and, therefore, more susceptible to the nocturnal temperature drop and overheating during warmer conditions. The present work intends to achieve a long-term value by providing the scientific community with original data within a research scope where this information is not abundant.

Indoor Thermal Environment Challenges of Light Steel Framing in the Southern European Context

Over the past decades, Southern European residential architecture has been typically associated with heavyweight hollow brick masonry and reinforced concrete construction systems; however, more industrialised alternative systems have been gaining a significant market share, such as the light steel framing (LSF). Regardless of the proliferation of LSF buildings, a lack of experimental research studies have been performed on this construction system in terms of the indoor thermal environment and thermal comfort in the Southern European climate context. Moreover, a research gap also exists regarding experimental comparisons with typical brick masonry buildings. The present study focused on this research gap by characterising and comparing the performance of these two construction systems. A long-term experimental campaign was carried out, involving the construction and monitoring of two identical test cells, differing only by construction system. The test cells were located in Portugal and were monitored over an entire year. The results revealed that the LSF experimental test cell presented higher daily indoor air temperature fluctuations, leading to more extreme maximum and minimum values, closely following the outdoor dry bulb temperature variations. The more responsive behaviour was also reflected in the indoor thermal comfort analysis, with the LSF cell presenting slightly worse performance; however, some advantages were also observed regarding the LSF construction system, which could provide benefits during intermittent residential occupation, especially in mild climates, in which overheating is not a major concern.

What is the potential for prefabricated buildings to decrease costs and contribute to meeting EU environmental targets?

The European Union (EU-27) targets buildings' decarbonization by 2050, and prefabrication presents an opportunity to reduce buildings and construction sector impacts. A stock-based approach was developed to measure the influence of wide adoption of building prefabrication in the EU-27 building stock from 2020 to 2050. Impacts and costs of five typologies using conventional or prefabricated construction systems were assessed for three cities – Lisbon, Berlin, and Stockholm – and three insulation levels. Results were calculated at the building and country levels and then combined at the stock level. Global warming (GW) varies between 5kgCO2eq/m2 for prefabricated light steel framing (prefab_LSF) medium- or a high-rise in France and 85kgCO2eq/m2 for the conventional concrete single-family (SF) in Poland. Life cycle costs vary between around 900€/m2 for multi-family buildings in prefabricated LSF in Bulgaria and over 11 000€/m2 for an SF in conventional concrete in Luxembourg. Prefabrication can further decrease building stock burdens up to 6% and reduce building stock costs up to 10%. The developed building stock model has proven to be a fast and reliable tool to forecast the market dynamics when introducing a technological innovation, such as prefabrication. Prefabrication can contribute to achieving the EU-27 targets and reduce construction costs, increasing the construction sector's productivity and sustainability.

Applying a new systematic fuzzy FMEA technique for risk management in light steel frame systems

ABSTRACT Light Steel Frame (LSF) system is mainly used for construction of short and intermediate-height buildings in developed countries whereas considerable heed is not given to it in developing countries. Unfamiliarity to LSF risks is one of the main reasons for this averseness so risk management can remedy this challenge and develop its application. Hence, this paper investigates the risk management of LSF considering design, construction and operation phase. Three steps entailing risk identification, assessment and responding using fuzzy Failure Mode and Effect Analysis (FMEA) technique are suggested for risk management implementation and validation of responses, a novel index with respect to weighted combination of project quality, time and cost is calculated. The methodology is demonstrated on a pilot study in a developing country. By using interview, 29 significant risks are extracted in design, construction and operation and then evaluated by proposed fuzzy method. Results showed that the share of the risks in these steps are 21%, 31% and 48% respectively. The results revealed that the risks in the construction and operation phases are higher than those in the design phase. The results also show that involving safety as a project object in the risk management process could eventuate acceptable results.

Numerical study of LSF walls made of cold-formed steel hollow section studs in fire

Cold-formed steel square and rectangular hollow section (SHS/RHS) studs are often used to replace the conventional lipped channel section studs in light gauge steel frame (LSF) wall systems to meet the required high load demand. To ensure adequate structural fire resistance of SHS/RHS stud walls, four full-scale fire tests were previously completed under standard fire conditions. However, the full-scale fire tests are expensive and time-consuming, while the complex fire performance cannot be adequately explained through test observations and results alone. Hence, a numerical study was undertaken by developing simplified and sheathed stud finite element (FE) models of tested walls. This paper provides the details of the developed models of LSF walls made of SHS/RHS studs at both ambient and elevated temperatures and a comparison with experimental results. The validated models were used to highlight the advantage of using SHS/RHS studs in cavity insulated stud walls and further understand the factors that may affect the fire resistance of LSF walls, such as steel grade and stud depth. In addition to the simplified stud model, advanced modelling techniques were used to explore the effects of sheathing and localised plasterboard fall-off on the wall behaviour in fire. Overall, this paper presents a numerical study of SHS/RHS stud walls and the simplified stud model developed in this paper can be used to predict the fire performance of other SHS/RHS stud walls with similar wall configurations.

Opportunities of Light Steel Framing towards thermal comfort in southern European climates: Long-term monitoring and comparison with the heavyweight construction

In a climate such as the southern European, heavyweight buildings have been associated with improved indoor comfort conditions. The heavyweight reinforced concrete and brick masonry construction is the most widespread and technically known constructive system. However, alternative lightweight systems have been gaining market share, such as the Light Steel Framing (LSF). Experimental research focused on the comparison between the two constructive systems is yet scarce.The present work intends to focus on this research gap by analysing and comparing the performance of the two constructive systems in terms of indoor thermal environment and thermal comfort, considering an intermittent residential occupation. To this end, a robust experimental campaign was carried out, based on the construction and monitoring of two identical experimental test cells, differing only in the constructive system. The test cells are located in Portugal and were monitored for one full year.It is shown that the LSF constructive system presents higher daily indoor temperature fluctuation and more expressive peak values, following closer the outdoor dry-bulb temperature variations. The obtained results also evidence the opportunities of the LSF constructive system in terms of indoor thermal comfort, presenting, in general terms, a more promising scenario on the performed annual analyses.