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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AISI to Develop New Unified Cold-Formed Steel Seismic Design Standard
This chapter, Analysisprescribes that the structural analysis should be done in accordance with the applicable building code and AISI S Cold-formed steel special bolted moment frame.
The 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:.
Detailed guidance on how to determine the expected strength is provided in the standard. Safety and resistance factors: Sheathed shear wall analysis models.
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. 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.
In the absence of an applicable building code, the design requirements must follow accepted engineering practice for the location under consideration, as specified by ASCE This chapter discusses Quality Control and Quality Assurance.
This standard focuses on the design and construction aiis cold-formed steel members and connections in seismic-force-resisting systems SFRS and diaphragms in buildings and other structures.
Seismic Design Of Cold-Formed Structural Systems Covered In New AISI S Standard
The expected strength of this SFRS equals 1. The diaphragm stiffness needs to be taken into consideration in determining the iasi strengths of both the SFRS and the diaphragm itself since the stiffness directly affects the force distribution.
Aisii expected strength of the SFRS can be derived by simple mechanics based on the strap expected strength. Seismic energy is dissipated through sliding and bearing deformations in the bolted connections between the beams and columns.
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 braced wall should be designed to resist this force. Seismic energy is dissipated through the connections between the steel sheet and the cold-formed steel structural members. Chapter C This chapter, Analysisprescribes that the structural analysis should aiso done in accordance with the applicable building code and Qisi S This consolidated seismic design standard brings together all North American cold-formed steel seismic-force-resisting systems SFRS into one standard, adding a consistent capacity-based design philosophy to each.
The designated energy dissipating mechanism and methods for determining the expected strength of the various SFRS are included in Chapter E, as discussed below.
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. Unique to cold-formed steel, an additional yield stress increase must be considered due to the cold work of forming and inelastic reserve capacity: 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.
This standard currently provides the design provisions for cold-formed steel-framed diaphragms sheathed with wood structural panels. Chapter D This chapter, General Member and Connection Design Requirementsreferences Chapters E and F for specific member and connection design and is reserved for future development.
The standard also provides Canadian seismic design provisions where the seismic force modification aixi, R d R oare taken as greater than or equal to 1. Chapter A, Scope and Applicability This standard focuses on the design and construction aiisi cold-formed steel members and connections in seismic-force-resisting systems SFRS and diaphragms in buildings and other structures.
This first edition of AISI S represents a merging of the following previously published standards: Unique to cold-formed steel, an additional yield stress increase must be considered due to the cold work of forming and inelastic reserve capacity:.
Section 2210 Cold-Formed Steel
Additional system requirements must be met as further detailed in Section E3. Leave a Comment Click here to cancel reply. The nominal shear strength, V ncan be determined:. A design guide for the seismic design of cold-formed steel framing will be published in The nominal asi 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.
This system is formed by cold-formed channel beams and HSS columns with bolted moment connections, as detailed in Figure 3. Yielding also occurs in the tension fields across the steel sheet. Your message Submit Comment.
For this SFRS, the expected strength equals 1. This chapter, General Member and Connection Design Requirementsreferences Chapters E and F for specific member and connection design and is reserved for future development. For instance, it is limited to single story structures no higher than 35 feet. To ensure the shear wall performs as intended, additional system requirements must be met as further detailed in AISI S, Section E2.
Acting to collect and distribute seismic forces to the SFRS, diaphragms must be designed to resist the forces specified by the applicable building code. Shear wall sheathed with wood structural panels. Chapter B This chapter, General Design Requirementsoutlines fundamental seismic asii requirements.
Aisl ratio shear wall height, h, divided by length, w limits for the various assemblies are also provided. Determine the nominal shear strength of the strap braced wall, as illustrated in Figure 4aand the expected strength of the system.
Future editions are expected to expand on analysis methods and their implementation for cold-formed steel SFRS. 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.
Future d110 may be extended to include other common diaphragm systems. Braced shear wall design example. Two types of shear walls are included within the section:.