Find the most up-to-date version of AISI S at Engineering 2 to the North American Specification for the Design of Cold-Formed Steel Structural Members, Edition February ; AISI S/S ()AISI . Cold-Formed Steel─Special Bolted Moment Frame (CFS─SBMF) system in the proposed AISI Seismic Standard (AISI S) are developed.
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The nominal shear strength, V ncan be determined:. Asii beams and columns, therefore, need to be designed to resist the expected moment M e and shear V e at the bolted connections defined as:. Additional system requirements must be met as further detailed in Section E3.
Future editions may be extended to include other common diaphragm systems. The designated energy dissipating mechanism and methods for determining the expected strength of the various SFRS are included in Chapter E, as discussed below.
Yielding also occurs s110 the tension fields across the steel sheet. The expected strength of the SFRS can be derived by simple mechanics based on the strap expected strength. This standard currently provides the design provisions for cold-formed steel-framed diaphragms sheathed with wood structural panels. This chapter, Analysisprescribes that the structural analysis should be done in accordance with the applicable building code and AISI S Expected strength is used to estimate the maximum forces the SFRS aisk anticipated to resist prior to dissipating energy through yielding.
This first edition of AISI S represents a merging of the following previously published standards: To ensure the shear wall performs as intended, additional system requirements must be met as further detailed in AISI S, Section E1.
The nominal shear strength, V ncan be determined using the same equations provided in Section a except that values for v n and C a are tabulated separately in the standard. Shear wall sheathed with wood structural panels. Chapter B This chapter, General Design Requirementsoutlines fundamental seismic design requirements. Unique to cold-formed steel, an additional yield stress increase must be considered due to the cold work of forming and inelastic reserve capacity: The standard also provides Canadian seismic design provisions where the seismic force modification factors, R d R oare taken as greater than or equal to 1.
This chapter outlines requirements for Diaphragms.
Section 2210 Cold-Formed Steel
For this SFRS, the expected strength equals 1. The expected strength of steel-sheet sheathed shear walls is specified as 1. This system is formed by cold-formed channel beams and HSS columns with bolted moment connections, as detailed in Figure 3.
This chapter, General Design Requirementsoutlines fundamental seismic design requirements. First Name Last Name. This is intended to dovetail with ASCE 1s10 12, which aiis general guidance on this topic.
Leave a Comment Click here to cancel reply. To ensure the shear wall performs as aosi, additional system requirements must be met as further detailed in AISI S, Section E2. Aug, By Rob Madsen P. Safety and resistance factors: The modification coefficient for strength increase due to cold work of forming is determined as: The shear wall strength is determined by the nominal strength of the strap as follows:. Braced shear wall design example.
This chapter discusses Quality Control and Quality Assurance. Specifically, the available strength of the SFRS must be greater than or equal to the required strength determined from the applicable load combinations to ensure adequate performance in a design-level seismic-event.
For instance, provisions must be made to guard against loose strap bracing either by pre-tensioning the straps or through other similar methods of installing the tension-only strap bracing. Chapter C This chapter, Analysisprescribes that the structural analysis should be done in accordance with the applicable building code and AISI S Your message Submit Comment. Future editions are expected to expand on analysis methods and their implementation for cold-formed steel SFRS. Chapter A also provides the provisions for determining the material expected strength for steel.
Sheathed shear wall analysis models.
Collectors, strap connections, chord studs, other vertical boundary elements, hold-downs and anchorage connected to it and all other components and connections of the strap aisl wall should be designed to resist this force. Wisi the absence of an applicable building code, the design requirements must follow accepted engineering practice for the location under consideration, as specified by ASCE For instance, it is limited to single story structures no higher than 35 feet.
Seismic energy is dissipated through sliding and bearing deformations in the bolted connections between the beams and columns. The expected strength of this SFRS equals 1. In addition, a new effective strip method has been introduced in this edition, which can be used to determine the nominal shear strength of the shear wall analytically.
The nominal shear strength per unit length, v nis based on the values for Type I shear walls and C a is tabulated in the standard for a variety of shear wall geometries. This chapter, Use of Substitute Components and Connections in Seismic Force-Resisting Systemspermits the substitution of components or connections in any of the SFRS specified in Chapter E as long as they follow the applicable building code requirements and are approved by the authority having jurisdiction.
The expected strength of the SFRS, capped by the seismic load effects including overstrength, is to be used to design other components in the SFRS that are not part of the designated energy-dissipating mechanism, including any collectors.
To perform as intended in a design level seismic event, this common SFRS must be designed and detailed to ensure that the diagonal tension strap yields first, thus dissipating the seismic energy, while other z110 states such as fracture at the strap ends and buckling of the chord studs are avoided. If an opening exists, details must be provided for load transfer around the opening.
AISI to Develop New Unified Cold-Formed Steel Seismic Design Standard
Seismic energy is dissipated in wood structural panel shear walls through titling and bearing deformation in the screw connections between the wood structural panel sheathing and the cold-formed steel structural members, and in the wood structural panels themselves. Aspect ratio shear wall height, h, divided by length, w limits for the various assemblies are also provided. A design guide for the seismic design of cold-formed steel framing will be published in This standard focuses on the design and construction of cold-formed steel members and connections in seismic-force-resisting systems Asi and diaphragms in buildings and other structures.
Detailed guidance on how to determine the expected strength is provided in the standard. Type I shear walls Figure 2 a are fully sheathed and require hold-downs and anchorage at each end of the shear wall.