H1Composite ordinary braced frames (C-OBF)

H1.1 Scope

Composite ordinary braced frames (C-OBF), where at least one of the elements (columns, beams, or braces) is a composite or reinforced concrete member, shall be designed in conformance with this section. Columns shall be structural steel, encased composite, filled composite, or reinforced concrete members. Beams shall be either structural steel or composite beams. Braces shall be structural steel or filled composite members.

H1.2 Basis of Design

This section is applicable to braced frames that consist of concentrically connected members. Eccentricities less than the beam depth are permitted if they are accounted for in the member design by determination of eccentric moments.

C-OBF designed in accordance with these provisions are expected to provide limited inelastic deformations in their members and connections.

The requirements of Sections A1, A2, A3.1, A3.5, A4, B1, B2, B3, B4, D2.7, and Chapter C apply to C-OBF. All other requirements in Chapters A, B, D, I, J, and K do not apply to C-OBF.

User Note: Composite ordinary braced frames, comparable to other steel braced frames designed per the Specification using $R=3$, are only permitted in seismic design categories A, B, or C in ASCE/SEI 7. This is in contrast to steel ordinary braced frames, which are permitted in higher seismic design categories. The design requirements are commensurate with providing minimal ductility in the members and connections.

H1.3 Analysis

There are no analysis requirements specific to this system.

H1.4 System Requirements

There are no requirements specific to this system.

H1.5 Members

H1.6 Connections

Connections shall satisfy the requirements of Section D2.7.