An official website of the United States government
Abstract Use of cold‐formed steel (CFS) framing as load‐bearing system for gravity and lateral loads in buildings is becoming increasingly common in the North American construction industry, notably in high seismic regions where light‐weight construction is an attractive option. Buildings framed with closely spaced and repetitively placed CFS members can be detailed to develop lateral resistance using a variety of sheathing options. A relatively new option involves the use of steel sheet as sheathing. Steel sheet sheathed CFS shear walls offer high lateral strength and stiffness, and provide ductility courtesy of tension field action within the steel sheet. Despite their acceptance, gaps in the understanding of their behavior do exist, notably, behavior under dynamic loading, the contribution of nonstructural architectural finishes, and the behavior of wall‐lines: shear walls placed inline with gravity walls. To this end, a two‐phased experimental effort was undertaken to advance understanding of the lateral response of CFS‐framed wall‐line systems. Specifically, a suite of wall‐lines, detailed for mid‐rise buildings, were evaluated through simulated seismic loading imposed via shake table and quasi‐static cyclic tests. Damage to the wall‐lines was largely manifested in the form of damage to fastener connections used for attaching the sheathing and gypsum panels, and separation of exterior finish layer. This paper documents and quantifies the progressively incurred physical damage observed in the tested wall‐line assemblies, and correlates it with the evolution of dynamic characteristics and hysteretic energy dissipated across a spectrum of performance levels.
more »
« less
Cold-formed steel framed shear wall test database
Many monotonic and cyclic tests have been conducted on cold-formed steel framed shear walls in the last 20 years. Cold-formed steel framed shear wall provisions in AISI S240, AISI S400, and ASCE 41 are supported by the data obtained through these tests. The main objective of this article is to introduce a recently compiled cold-formed steel framed shear wall test database, to reveal the database structure, and to explain how to access and present the data. Most recently, the database has been standardized and expanded to include additional tests, complete cyclic information from tests, limit states, and code prediction information. The database structure incorporates a central Excel spreadsheet that includes descriptive information; ordered plain text files for each individual test; and custom MATLAB codes, which can read, process, and plot designated database subsets. The provided database can advance the understanding and modeling of cold-formed steel framed shear walls.
more »
« less
- Award ID(s):
- 1663348
- PAR ID:
- 10471316
- Publisher / Repository:
- SAGE Publications
- Date Published:
- Journal Name:
- Earthquake Spectra
- Volume:
- 40
- Issue:
- 1
- ISSN:
- 8755-2930
- Format(s):
- Medium: X Size: p. 871-884
- Size(s):
- p. 871-884
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Mass timber is a sustainable option for building design compared to traditional steel and concrete building systems. A shake table test of a full-scale 10-story mass timber building with post-tensioned mass timber rocking walls will be conducted as part of the NHERI TallWood project. The rocking wall system is inherently flexible and is expected to sustain large interstory drifts. Thus, the building’s vertically oriented non-structural components, which include cold-formed steel (CFS) framed exterior skin subassemblies that use platform, bypass, and spandrel framing, a stick-built glass curtain wall subassembly with mechanically captured glazing, and CFS framed interior walls, will be built with a variety of innovative details to accommodate the large drift demands. This paper will describe these innovative details and the mechanisms by which they mitigate damage, provide an overview of the shake table test protocol, and present performance predictions for the non-structural walls.more » « less
-
To advance understanding of the multihazard performance of midrise cold-formed steel (CFS) construction, a unique multidisciplinary experimental program was conducted on the Large High-Performance Outdoor Shake Table (LHPOST) at the University of California, San Diego (UCSD). The centerpiece of this project involved earthquake and live fire testing of a full-scale 6-story CFS wall braced building. Initially, the building was subjected to seven earthquake tests of increasing motion intensity, sequentially targeting service, design, and maximum credible earthquake (MCE) demands. Subsequently, live fire tests were conducted on the earthquake-damaged building at two select floors. Finally, for the first time, the test building was subjected to two postfire earthquake tests, including a low-amplitude aftershock and an extreme near-fault target MCE-scaled motion. In addition, low-amplitude white noise and ambient vibration data were collected during construction and seismic testing phases to support identification of the dynamic state of the building system. This paper offers an overview of this unique multihazard test program and presents the system-level structural responses and physical damage features of the test building throughout the earthquake-fire-earthquake test phases, whereas the component-level seismic behavior of the shear walls and seismic design implications of CFS-framed building systems are discussed in a companion paper.more » « less
-
Cold-formed steel assemblies are commonly used for partition walls in buildings, playing a critical role for fire compartmentation, and are also increasingly used as load-bearing structural systems due to their high strength-to-weight ratio and suitability for off-site prefabrication. This evolution leads to a need to characterize the behavior of these systems under the combined action of loading and fire. The objective of this paper is to provide a review of experimental studies on cold-formed steel members and assemblies at elevated temperatures. A comparative overview of testing methods is presented with a focus on the heating and loading procedures, temperature distributions, and end boundary conditions. The review covers experimental tests on lipped channels and built-up sections in compression and flexure, and wall and floor assemblies. The impact of elevated temperature on material properties and member strength is explored. Drawing on data from 30 experimental studies, the review examines the effects of end boundary conditions, section shape, temperature distribution, gypsum sheathing, and internal insulation on the stability and strength of the thin-walled members. Recommendations for future research include member experiments with non-uniform section temperatures and under localized fires, comparisons of steady-state and transient tests, and studies on lipped channel joists. By synthesizing key findings and identifying research gaps, this review aims to guide future experimental studies and support the advancement of building codes and performance-based fire design methods for cold-formed steel structures.more » « less
-
An accurate quantification of the displacement capacity of a reinforced masonry shear-wall system is of critical importance to seismic design because it has a direct implication on the seismic force modification factor, which is the R factor in ASCE 7. In spite of the shear capacity design requirement in TMS 402, special reinforced masonry walls within a building system could still develop shear-dominated behavior, which is perceived to be far more brittle than flexural behavior. These walls have a low shear-span ratio either because of the wall geometry (i.e., a low height-to-length ratio) or the coupling forces introduced by the horizontal diaphragms, which are often ignored in design. Although shear-dominated walls appeared to be very brittle in quasi-static tests conducted on single planar wall segments, reinforced masonry structures survived major ground shaking well in past earthquakes. This could be partly attributed to the beneficial influence of wall flanges as well as the over-strength of the system. Flanged walls are common in masonry buildings, but their behavior is not well understood because of the lack of laboratory test data. Furthermore, other walls or columns that are present in the structural system to carry gravity loads could enhance the lateral resistance of the shear walls and the displacement capacity of the system by providing axial restraints as well as alternative load paths for gravity loads. A research project is being carried out with shake-table tests to investigate the displacement capacity of shear-dominated reinforced masonry wall systems. This paper presents results of the first shake-table test conducted in this project on a full-scale single-story coupled T-wall system. The structure was tested to a drift ratio exceeding 15% without collapse.more » « less
