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.
|Published (Last):||4 December 2009|
|PDF File Size:||9.55 Mb|
|ePub File Size:||13.53 Mb|
|Price:||Free* [*Free Regsitration Required]|
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 Cold-formed steel special bolted moment frame. Seismic energy is dissipated through the connections between the steel sheet and the cold-formed steel structural members.
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.
Chapter A, Scope and Applicability 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 and detailed requirements are provided in Section E6 of the standard.
This chapter, General Member and Connection Design Requirementsreferences Chapters E and F for specific member and connection design and is reserved for future development.
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.
Type I shear walls Figure 2 a are fully sheathed and require hold-downs and anchorage at each end of the shear wall. Aspect ratio shear wall height, h, divided by length, w limits for the various assemblies are also provided. 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.
Yielding also occurs in the tension fields across the steel sheet. Acting to collect and distribute seismic forces to the SFRS, diaphragms must be designed to resist the forces specified by the applicable building code. Chapter Wisi also provides the provisions for determining the s10 expected strength for steel. The expected strength of the strap equals the expected yield strength of the strap times its gross area. 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 aisii or through other similar methods of installing the tension-only strap bracing. A design guide for the seismic design of cold-formed steel framing will be published in Your message Submit Comment.
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.
For this SFRS, the expected strength equals 1. This chapter discusses Quality Control and Quality Assurance. The expected strength of steel-sheet sheathed shear walls is specified as 1.
Free CFS Publications from the AISI/SMDI Construction Market Council
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 C This chapter, Analysisprescribes that the structural analysis should be done in accordance with the applicable building code and AISI S Safety and resistance factors: For instance, it is limited to single story structures no higher than 35 feet. 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.
This first edition of AISI S represents a merging of the following previously published standards: 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 shear wall strength is determined by the nominal strength of the strap as follows:. 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.
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.
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:. The modification coefficient for strength increase due to cold work of forming is determined as: 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.
If an opening exists, details must be provided for load transfer around the opening. Shear wall sheathed with wood structural panels. First Name Last Name. 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 system is formed by cold-formed channel beams and HSS columns with bolted moment connections, as detailed in Figure 3. Type II shear walls Figure 2b permit openings in the wall without specific design for force transfer around the openings. This standard currently provides the design provisions for cold-formed steel-framed diaphragms sheathed with wood structural panels.
STRUCTURE magazine | AISI S/S
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 s1110 and buckling of the chord studs are avoided. In addition, a new effective strip method has been introduced in this edition, which can be used to determine the nominal shear d110 of the shear wall analytically.
This chapter outlines requirements for Diaphragms. Seismic energy is dissipated through sliding and bearing deformations in the bolted connections between the beams and columns.