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 expected strength of the SFRS can be derived by simple mechanics based on the strap expected strength. The nominal shear strength, V ncan be determined:.
This chapter, Use of Substitute Components and Connections in Seismic Force-Resisting Systemspermits the substitution of components or connections in any of the SFRS aiisi in Chapter E as long as they follow the applicable building code requirements and are approved by the authority having jurisdiction.
Shear wall sheathed with wood structural panels. The modification coefficient for strength increase due to cold work of forming is determined as: To ensure the e110 wall performs as intended, additional system requirements must be met as further detailed in AISI S, Section E1.
STRUCTURE magazine | AISI S/S
Chapter B This aksi, General Design Requirementsoutlines fundamental seismic design requirements. The designated energy dissipating mechanism and methods for determining the expected strength of the various SFRS are included in Chapter E, as discussed below. 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.
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. 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 aisu wall analytically. Aspect ratio shear wall height, h, divided by length, w limits for the various assemblies are also provided.
Expected strength is used to estimate the maximum forces the SFRS is anticipated to resist prior to dissipating energy through yielding.
AISI to Develop New Unified Cold-Formed Steel Seismic Design Standard
Unique to cold-formed steel, an additional s1110 stress increase must be considered due to the cold work of forming and inelastic reserve capacity:.
The nominal shear strength and detailed requirements are provided in Section E6 of the standard. This standard focuses on the design and construction of cold-formed steel members and connections in seismic-force-resisting systems SFRS and diaphragms in buildings and other structures.
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. Sheathed shear wall analysis models.
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. Chapter D This chapter, General Member and Connection Design Requirements aisii, references Chapters E and F for specific member and connection design and is reserved for future development. The expected strength of steel-sheet sheathed shear walls is specified as 1.
Acting to collect and distribute seismic forces to the SFRS, diaphragms must be designed to resist the forces specified by the applicable building code. For instance, it is limited to single story structures no higher than 35 feet.
Two types of shear walls are included within the section:.
Section 2210 Cold-Formed Steel
For instance, provisions must be made to guard against loose strap bracing either by pre-tensioning the straps or through other ausi methods of installing the tension-only strap bracing. Leave a Comment Click here to cancel reply.
Unique to cold-formed steel, an additional yield stress increase must be considered due to the cold work of forming and inelastic reserve capacity: This chapter, Analysisprescribes that the structural analysis should be done in accordance with z110 applicable building code and AISI S If an opening exists, details must be provided for load transfer around the opening. This system is formed by cold-formed channel beams and HSS columns with bolted moment connections, as detailed in Figure 3.
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. This first edition of AISI S represents a merging of the following previously published standards: 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 1s10.
Dr. S’s Cold-Formed Steel Library Page
The expected strength of this SFRS equals 1. For this SFRS, the expected strength equals 1. Type I shear walls Figure 2 a are fully sheathed and require hold-downs and anchorage at each end of the shear wall. 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 are avoided.
Type II shear walls Figure 2b permit openings in the wall without specific design for force zisi around the openings. A design guide for the seismic design of cold-formed steel framing will be published in