Steel Stud Wall Research Articles

The results and uses of a New Interlaboratory Study for ASTM E90 for frequently constructed wall types

How does one compare test reports from two different labs? How do we improve our standard test methods? How does a lab prove they get the same results over time? Every ASTM standard method is required to include a precision and bias statement. The precision statement is based on interlaboratory studies where multiple labs do repeated tests on the same sample. That data was only relevant when it is similar to the type of sample usually tested. The last interlaboratory study to establish the precision for ASTM E90 was completed over 20 years ago on low-STC steel panels. This presentation covers the initial results of a new study that included over 80% of North American accredited labs using higher-performing, commonly used, steel stud wall assemblies. The authors will present the uncertainty determined by the study along with sources of variation between the labs including opening size, microphone type, and room volumes. The presentation will also discuss how consultants can use this information to better evaluate laboratory test data, and the industry as a whole can use it to improve the reliability of acoustic testing.

Stability of cold-formed steel stud walls subjected to vertical compression

Cold-formed steel (CFS) stud walls are the primary vertical load-bearing units in CFS residential systems. These walls need to meet both strength requirements and good stability. In this study, a CFS stud wall was simplified into a mechanical model of an orthotropic plate rib system using the orthotropic plate (OP) method. A formula for calculating the equivalent stiffness of the stud wall was obtained, and the correctness of the simplified calculation model and equivalent stiffness calculation formula was verified by finite element analysis. Various factors that affected the equivalent stiffness of the wall were investigated. Additionally, the stability of the stud walls under a vertical load was derived by considering the stability theory of the plate. The results indicated that the stability of the stud walls was mainly related to the height-thickness ratio of the walls. Finally, the correction factor of the allowable height-thickness ratio of the walls was obtained by analyzing the parameters of the wall thickness, stud spacing, sheathing materials, and wall opening, and a case study was used to illustrate the procedure of this simplified method.

Effect of solid blocking on lateral bracing requirements for cold-formed steel wall studs

The effectiveness of horizontal bracing in increasing the strength of cold-formed steel (CFS) load-bearing walls has been widely acknowledged. However, while significant research has been conducted regarding the bracing requirements for CFS bearing walls, the effect of solid blocking, which prevents columns (studs) within the wall from rotating, has not been fully explored. In this study, we propose an analytical method to quantitatively assess the effect of solid blocking on bracing requirements for CFS load-bearing walls. This method is comprehensive as it can be applied to systems with different bracing patterns, load patterns, or non-identical columns (studs), and it accounts for the columns’ initial curvature and semi-rigid end connections. It has been verified that considering the solid blocking always decrease the bracing requirements because the existence of solid blocking increases the system’s stiffness and subsequently decreases the additional displacement as well as the brace force, as expected. An example consisting of 23 CFS studs is presented to illustrate how the effect of solid blocking on bracing requirements is influenced by the location and interval of solid blocking, the stiffness of column end connections, and the characteristics of tie bracing. The results indicate that the effect of solid blocking on bracing requirements increases when the location of solid blocking is closer to the anchor and the solid blocking interval is smaller. Moreover, a modification to the equation in AISI S100 is proposed to account for the effect of solid blocking on the strength requirement of tie bracing. Overall, this research contributes to a better understanding of the role of solid blocking in CFS load-bearing walls and provides insights for optimizing bracing design in practice.

Thermal insulation performance of non-load-bearing light gauge slotted steel stud walls

Light gauge steel stud walls have been widely used in buildings as load-bearing members. But if used as non-load-bearing walls, more rows of perforations can be placed on stud webs and then the thermal bridge effect can be reduced. Experiments on six non-load-bearing light gauge slotted steel stud walls were conducted using a calibrated hot box. The temperatures of the steel studs and gypsum plasterboard were monitored for subsequent analysis of thermal bridging. The effects of parameters (number of rows of perforations, stud web height, and the ratio of window area to wall area) on the insulating capacity of the wall were identified and analyzed. Thermal transmittance decreases by 18.5% and 29.6% for specimens with 3 and 7 rows of perforations in comparison with the specimen without perforations, while it decreases by 29.8% and 42.7% respectively for 150 mm and 200 mm thick walls compared with that of the 100 mm thick wall. However, thermal transmittance increases obviously for the wall with a window opening relative to the wall without a window opening, reaching 14.7% in this test since more studs are placed around the window opening. A three-dimensional finite element (FE) model of the wall was developed and validated against experimental results, and then was used for parametric studies. A general method of calculating the thermal transmittance of the light gauge slotted steel stud wall was suggested based on the experiment and the FE model results, which can consider influences of wall thickness, web perforations, window openings, and thermal properties of materials.

Sound transmission loss through steel-framed building partitions

Load-bearing steel-stud walls pose a unique acoustical challenge because both the spacing and the mil thickness of the studs can significantly affect the acoustical performance of these walls. A single wall type in a load-bearing steel building may actually include many acoustically distinct walls as the stud spacing and mil thickness change from floor to floor in the building due to the different loads. This can be especially challenging on delegated design projects where the final selection of the steel studs is left to the framing contractor and may not be included in the project documents supplied to the acoustical consultant, if there even is one on the project. In prior ASA presentations, Ben Shafer has clearly documented the effects of steel stud spacing and mil thickness on acoustical performance. This presentation adds to Ben’s prior work by investigating the effects of resilient sound isolation clips on wall performance. Clips are a unique application because the spacing of both the clips, and the hat channels does not change with changing stud spacing and because the low stiffness of the rubber isolators should reduce the effect of stud stiffness. This presentation will present the results of recent lab tests of walls with resilient sound isolation clips and compare the results to the data previously presented by Mr. Shafer.

Numerical modelling and investigation of CFS built-up stud walls in fire

Cold-formed steel (CFS) stud walls with the studs made of BC (built-up back-to-back CFS channel) and NC (built-up nested CFS channel) members are likely to be utilised in many applications in CFS building structures. However, the knowledge and understanding related to the thermal and structural behaviour of these improved CFS stud walls under fire exposure and their FRLs (fire resistance levels) are still limited. Although standard fire tests of real-sized walls could show the behaviour and FRL of some BC and NC stud walls, their results are limited because of their high cost and time-consuming nature, and are applicable to only the tested configurations. In this study, thermal and sequentially coupled structural finite element models were established. The validation of these models was achieved using the standard fire test results of real-sized BC, NC and channel stud walls. Later, parametric investigations based on the established models were undertaken to investigate the behaviour and FRLs of load-bearing BC, NC and channel stud walls with or without cavity insulation under varying load ratios. The outcomes from these investigations clarified the superiority of cavity insulated NC stud walls. Details of this study and its outcomes are presented in this paper.

Finite element analysis of cold-formed steel stud wall subjected to blast load and validated using artificial neural network combined with response surface method

Finite element analysis of cold-formed steel stud wall subjected to blast load and validated using artificial neural network combined with response surface method

The booming party walls being constructed in the skyscrapers of Toronto

With eight new 300 m or higher buildings and another ninety shorter skyscrapers either under construction or proposed for the booming Toronto real estate market, there is no shortage of work for acoustic consultants in Toronto at the moment. Most of the high-rise buildings allocated for residential use include concrete floors and ceilings, glass curtain walls, and lightweight, steel stud gypsum board interior walls. A party wall design that has become popular among architects is a double steel stud wall with one or more layers of gypsum board attached to the studs in the gap between the rows of studs in addition to the gypsum board attached to the exterior of the studs. Typically, the transmission loss values for the wall designs used to demonstrate compliance with the building code are those for single stud walls with equivalent stud gauges and numbers of exterior layers of gypsum board. Due to the lack of available data, the National Research Council of Canada measured the transmission loss of many of these wall designs and found that adding the gypsum board in the cavity between the rows of studs has a significant effect on the transmission loss below 200 Hz.

Experimental investigation of the behaviour and capacity of sheathed cold-formed steel stud walls under inward flexural loading

A comprehensive experimental programme was designed and executed with the aim of investigating the out-of-plane bending behaviour and capacity of cold-formed steel (CFS) stud walls sheathed with wood-based boards. The influence of key design variables, including the screw spacing, the board material and thickness, the stud and track thicknesses, the board configuration (single-sheathed, double-sheathed and unsheathed) and the presence/absence of longitudinal seams, noggins and track sections, was investigated and quantified. A total of 15 stud walls sheathed with either Oriented Strand Board (OSB) or plywood were tested under four-point bending. Ancillary material tests, and push-out and pull-out connector tests were also performed. The results revealed a surprising richness in failure modes, given the initial geometric simplicity of the system. Simultaneous crushing of the OSB and distortional buckling failure of the studs, with either full or partial shear interaction, was a commonly observed failure mode. However, rotational and lateral–distortional deformations of the studs, often accompanied by longitudinal cracking of the boards, were also observed as a cause of failure.

Numerical and analytical investigations on cold-formed steel stud wall system using FEA and validation using ANN and RSM

Numerical and analytical investigations on cold-formed steel stud wall system using FEA and validation using ANN and RSM

Lateral performance of cold‐formed steel OSB‐sheathed stud wall panels

AbstractOriented Strand Boards (OSB) are currently one the most widely used cladding options in cold‐formed steel (CFS) stud wall panels. The sheathing generates significant resistance to lateral loads owing to its diaphragm stiffness, which is however typically not fully exploited in design. This paper aims to investigate the lateral inplane behaviour of CFS OSB‐sheathed stud wall panels and provide insight into their failure mechanisms and seismic characteristics. Detailed finite element (FE) models of CFS OSB‐sheathed wall panels were developed, featuring material nonlinearity, detailed connection behaviour and geometric imperfections, and their accuracy was validated against previously conducted experiments. The validated FE models were then employed in a parametric study to investigate the effects of key design variables, including the OSB and CFS element thicknesses and the board configuration, on the structural performance parameters and seismic characteristics of the walls. The results demonstrate that using thinner OSB sheathing resulted in lower lateral strength, initial stiffness and energy dissipation, but increased the ductility and ultimate displacement by up to 40%. It was also shown that the presence of horizontal/vertical seams significantly reduces the lateral load capacity and initial stiffness.

A field study of the relationship between sound insulation and noise annoyance, activity disturbance and wellbeing in multi-unit residences

Impact and airborne noise are often an issue for occupants in multi-unit residential buildings (MURBs). Despite minimum sound insulation requirements in building codes, occupants still complain about the impact and airborne noise which suggests that there is a lack of understanding of the relationship between sound insulation and occupants’ perceptions of their acoustic environment. To enhance existing knowledge on the relationship between sound insulation and occupants’ perception of noise, a field investigation was carried out in five Canadian MURBs with heavy-weight floor construction and concrete shear and steel stud walls. Airborne and impact sound insulation were measured, and surveys were conducted to assess subjective annoyance levels and effects on occupants’ various daily activities. The study found a significant correlation between airborne sound insulation and annoyance. However, there was no significant relationship between impact sound insulation and annoyance. The results showed no significant difference in impact noise annoyance between occupants in a building with high impact insulation (AIIC 62) compared to occupants in buildings with low impact insulation levels (AIIC 31–32). However, a significant correlation was found between impact sound insulation and reported effects of noise on work performance at home suggesting that disturbance of work or other activities might be a better indicator of occupants’ perception and acoustic comfort compared to annoyance ratings. In addition, the analysis revealed that occupants in suites located at the most exposed façade facing a major roadway report lower annoyance levels. The results indicate that the masking effects of outdoor or other noise sources should be considered when investigating occupants’ perception of impact and airborne noise.

Behaviour and performance of OSB-sheathed cold-formed steel stud wall panels under combined vertical and seismic loading

This paper investigates the in-plane lateral behaviour and capacity of cold-formed steel (CFS) stud wall panels which are sheathed with Oriented Strand Board (OSB). Detailed nonlinear FE models of the panels were developed, accounting for nonlinear material properties, geometric nonlinearity, realistic fastener behaviour and geometric imperfections. The models were validated against available experimental data and subsequently employed to conduct comprehensive parametric studies into the effects of key design variables, including the screw spacing, the OSB and CFS element thicknesses, the board layout configuration, the intensity of the gravity loading and the number of boards (single- vs. double-sheathed systems). The structural performance of the studied panels was compared in terms of their lateral load capacity, initial stiffness, failure mechanisms, deformation capacity, ductility, and energy dissipation. Lateral capacity, initial stiffness and energy dissipation were positively influenced by a reduced screw spacing, thicker OSB and an absence of seams in the boards. Ductility and deformation capacity were generally promoted by increased screw spacing, thinner OSB and vertical seams. High vertical load ratios have the potential to dramatically reduce lateral strength, ductility and energy dissipation.

Lateral load capacity of the common steel stud wall framing braced bays in Australia's Northern Territory

Construction within Australia's northern coastal region has undergone many changes over the years to adapt to its tropical climate, which is prone to devastating cyclonic events. Steel stud wall framing (SSWF) is used as a standard construction method for many residential and commercial structures within the Northern Territory. The stability of SSWF structures is primarily achieved by utilising several braced bays for external and internal shear walls to resist wind loading, which is often a critical design factor. However, the lateral load capacity of these SSWF braced bays is estimated as a value based on conservative and fundamental static analysis, which does not account for the complexity of analysing cold-formed channel and welded thin wall steel sections. This paper investigates lateral load capacity, modes of failure, and lateral deflection of a common SSWF braced bay configuration used in NT through full-scale experimental testing. Finite element simulations then have been conducted to compare the experimental results with theoretical capacities and failure modes. After calibration, the simulation model is used to determine the lateral load capacity of other SSWF braced bay configurations. The common failure modes were found to be the tensile failure of the stud flange and failure of the weld between the tensile stud and bottom plate. Results also provide a reliable evaluation of the lateral resistance of the common SSWF configurations in NT housing.

Mechanical Properties of Prefabricated Cold-Formed Steel Stud Wall Panels Sheathed with Fireproof Phenolic Boards under Out-of-Plane Loading

In this paper, new prefabricated cold-formed light-gauge steel stud wall panels sheathed with fireproof phenolic boards, which are fabricated by connecting the steel studs and the boards by using structural silicone sealant, was proposed. The proposed prefabricated wall has a good fireproof performance and can be manufactured rapidly in a factory. Full-scale tests on the mechanical properties of the prefabricated wall system, consisting of the prefabricated wall and the connection between the wall and the surrounding steel structure under out-of-plane loading, were performed. A total of six specimens were tested considering the effects of the arrangement of the cold-formed light-gauge steel studs, the shape and thickness of the steel connector for jointing the prefabricated wall panel and the surrounding steel structure, and the number of self-tapping screws connecting the surrounding structure. The results show that the out-of-plane stiffness of the prefabricated wall system in the elastic stress state under out-of-plane loading can be increased by increasing the number of self-tapping screws, increasing the thickness of the steel connector, or adopting the symmetrical arrangement of the light-gauge steel studs. The out-of-plane stiffness of the prefabricated wall system and the stiffness contribution of a single special-shaped steel connector can both be increased by increasing the number of special-shaped steel connectors. Furthermore, the special-shaped steel connector is more beneficial to a greater out-of-plane stiffness than the L-shaped steel connector. In addition, the theoretical calculation methods for deflection of the proposed prefabricated wall and flexural stress of the CFS C-channel stud considering the fireproof phenolic board sheathing effect under elastic state were proposed. The predicted results using the proposed method are compared with test results and the predicted results by using other methods. It was found that the predicted results by using the proposed method agreed better with the test results compared with the predicted results using the transformed-section method or the reduced stiffness method, which demonstrates the acceptability and accuracy of the proposed mothed for calculating deflection of the proposed prefabricated wall and flexural stress of the CFS C-channel stud.

Seismic Performance of Modular Structures with Novel Steel Frame: Light Gauge Slotted Steel Stud Walls

Modular structures are premanufactured off-site and assembled on-site, leading to reduced on-site works and construction periods and improved quality compared to conventional prefabricated steel structures and reinforced concrete structures. Meanwhile, steel frame-light gauge slotted steel stud (LGSS) walls have been considered to be assembled into the modules due to their excellent thermal- and sound-insulation properties. These structural components will also contribute to the resistance of the modular system when subjected to lateral loads/actions, especially seismic actions. A finite element model was developed to investigate the seismic performance of high-rise modular steel structures with LGSS shear walls. Then, parametric studies were conducted to investigate the influences of the layouts of the LGSS shear walls and structure heights on the lateral stiffness, the deformation modes, and the stress states of the modular steel structures. Observed from the results of a ten-storey modular steel structure infilled with LGSS shear walls, the maximum storey drift reduced by 50.1–79.50% compared to the corresponding pure steel frame structure under the selected high-intensity seismic waves. The results indicate that the studied modular steel structure with LGSS shear walls possesses good seismic resistance and could be a practical and economical choice for future modular constructions.

Design of cold-formed steel wall studs subject to non-uniform elevated temperature distributions

The current design rules for cold-formed steel studs used in wall systems subject to non-uniform elevated temperature distributions are complicated with iterations and different elevated temperature section properties. This paper first investigates the accuracy of the current effective width method (EWM) and direct strength method (DSM) based design equations, and then simplifies the calculation process without compromising the accuracy in calculating the load ratios (elevated to ambient temperature capacity ratio). It also improves the accuracy of the current DSM based design equations. It then investigates the possibilities of using uniform temperature based DSM design equations for non-uniform temperature distributions and identifies the possibilities of using hot flange mechanical properties and uniform temperature based DSM design equations. Hence, it proposes a simplified uniform temperature based DSM design method with hot flange mechanical properties and a correction factor based on hot and cold flange temperatures, yield strength, length and depth of studs.

Seismic behavior of light-gauge cold-formed steel stud walls under monotonic and cyclic loading

Light-gauge structures framed with cold-formed steel (CFS) are considered a suitable alternative to the traditional hot-rolled or built-up steel framing as a primary structural system. In this study, the seismic behavior of light-gauge CFS stud walls is evaluated through experimental tests on two stages to investigate the failure modes, load capacities, initial stiffness , ductility ratios and response modification factors. The first stage is testing specimens under monotonic load, while the second one is testing specimens under cyclic load conditions. The results revealed that using cement board and ferro-cement board sheathing had adverse effects on the loading capacity (up to 80% reduction in ultimate load capacity for specimen with ferro-cement board) as well as the initial stiffness, compared to specimens with steel sheathing. However, specimens with cement board and ferro-cement board sheathing exhibited lesser instability in their framing members at the ultimate load compared to specimens with steel sheathing. Furthermore, the screw connections between sheathing and steel framing members resulted in a significant reduction on the overall behavior, particularly for specimens with cement board and ferro-cement board sheathing. Meanwhile, the specimen with steel sheathing on both sides reported a higher loading and energy dissipation capacities. • Summary for existing experimental researches data regarding light-gauge cold-formed steel stud walls. • Experimental tests are conducted on full scale specimens. • Specimens are subjected to both monotonic and cyclic loading. • Loading capacities, ductility ratio, initial stiffness and response modification factors for each model are provided.

Enhancing static resistance of steel stud wall systems for blast design using new section geometries

Steel Stud Wall Systems (SSWSs) have been attractive structural alternative due to its merits. This research is mainly focused on enhancing static resistance of SSWSs to resist moderate blast events. Resistance function is considered an important item of data in calculating dynamic response of a system using Single Degree of Freedom model. Resistance function can be obtained by quasi-static experimental loading. Or alternatively, using FE modelling for finding the non-linear static response of a system. This research shows how combinations of the various in-lack parameters can be arranged to maximize efficiency of the system for performance as blast proof structures. This is performed by analyzing different section geometries from traditional ones with aids of FE software (ABAQUS 16). The solution is under quasi-static loading and the obtained toughness is used to hold comparison between the new geometries and the traditional stud section. Two validation models followed by a comprehensive parametric study are performed to investigate back-to-back cold formed sections efficiency in comparison to traditional system from blast point of view. For this purpose, two new introduced factors Material Utilization Factor (M.U.F) and (EF) are used to relate the various design variables and outputs to the amount of material used in the sections. The paper shows how using the new sections and changing parameters may maximize the system efficiency to raise toughness and elastic load limit up to 3.94 times and 3.78 respectively from the traditional system. Finally, important conclusions are withdrawn about the efficiency of the new sections. Withdrawn conclusions are emphasizing that using back-to-back cold formed sections with a certain arrangement is much beneficious than traditional used sections.

Fastener behaviour in sheathed light‐gauge steel stud walls under cyclic and monotonic actions

AbstractSteel framed buildings using digitally fabricated light‐gauge steel sections, combined with an offsite panelised fabrication approach, are becoming more widespread and contribute towards reducing cost and erection time without requiring a large workforce to assemble them. Currently, design standards mandate the use of K‐ or X‐bracing in these structures, thus neglecting the beneficial influence of the sheathing on the behaviour of the system, in particular its resistance to lateral loads. This composite behaviour is largely influenced by the performance of the fasteners, which may exhibit tilting, shear failure and fastener pull‐out. This paper takes a first step towards accounting for composite action between light‐gauge steel stud framing and calcium silicate board by focusing on the behaviour of the screws connecting both. Key failure modes are identified, based on direct pull‐out tests and monotonic and cyclic connector shear tests. Significant pinching behaviour was observed under cyclic excitations.