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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Specifically, the available strength of the SFRS must be greater than or equal to the required strength determined from the applicable aisu combinations to ensure adequate performance in a design-level seismic-event. The nominal shear strength and detailed requirements are provided in Section E6 of the standard.
STRUCTURE magazine | AISI S/S
The designated energy dissipating mechanism and methods for determining the expected strength of the various SFRS are aiso in Chapter E, as discussed below. Additional system requirements must be met as further detailed in Section E3.
This chapter discusses Quality Control and Quality Assurance. Safety and resistance factors: 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.
AISI to Develop New Unified Cold-Formed Steel Seismic Design Standard
To ensure the shear wall performs as intended, additional system requirements must be met as further detailed in AISI S, Section E2. 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. Expected strength is used to estimate the maximum forces the SFRS is anticipated to resist prior to dissipating energy through yielding.
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:. Unique to cold-formed steel, an additional yield stress increase must be considered due to the cold work of forming and inelastic reserve capacity:.
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Yielding also occurs in the tension fields across the steel sheet. Future editions may be extended to include other common diaphragm systems.
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.
This standard currently provides the design provisions for cold-formed steel-framed diaphragms sheathed with wood structural panels. Cold-formed steel special bolted moment frame. 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.
Acting to collect and distribute seismic forces to the SFRS, diaphragms must be designed to resist the forces specified by the applicable building code.
This standard focuses on the design and construction of cold-formed steel members and connections in seismic-force-resisting systems 1s10 and diaphragms in buildings and other structures. Shear wall sheathed with wood structural panels. In the absence of an applicable building code, the design requirements must follow accepted engineering sisi for the location under consideration, as specified by ASCE Determine the nominal shear strength of the strap braced wall, as illustrated in Figure 4aand the expected strength of the system.
Chapter C This chapter, Analysisprescribes that the structural analysis should be done in accordance with the applicable building code and AISI S The shear wall strength is determined by the nominal strength of the strap as follows:.
Seismic energy is dissipated through the connections between the steel sheet and the cold-formed steel structural members.
This chapter, Analysisprescribes that the structural analysis should be done in accordance with the applicable building code and AISI S This chapter outlines requirements for Diaphragms. This first edition of AISI S represents a merging of the following previously published standards: 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.
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 limit states such as fracture at the strap ends and buckling of the chord studs e110 avoided. A design guide for the seismic design of cold-formed steel framing will be published in 1s10 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.
Type I shear walls Figure 2 a are fully sheathed and require hold-downs and anchorage at each end of the shear wall. Seismic energy is dissipated through sliding and bearing deformations in the bolted connections between the beams and columns. Aspect ratio shear wall height, h, divided by length, w limits for the various assemblies are also provided. The diaphragm stiffness needs to be taken into consideration in determining the required strengths of both the SFRS and the diaphragm itself since the stiffness directly affects the force distribution.
The expected strength of the SFRS can be derived by simple mechanics based on the strap expected strength. wisi
Chapter B This chapter, General Design Requirementsoutlines fundamental seismic design requirements. 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. To ensure the shear wall performs as intended, additional system requirements must be met as further detailed in AISI S, Section E1.
First Name Last Name. If an opening exists, details must be provided for load transfer around the opening. Unique to cold-formed steel, an additional yield stress increase must be considered due to the cold work of forming and inelastic reserve capacity: