Structural Systems in the Same Direction per ASCE 7-16 with ideCAD
How ideCAD defines structural systems in the same direction according to ASCE 7-16?
The most stringent applicable structural system limitations contained in Table 12.2-1 are applied by users.
The values for R, Ω0, and Cd at structural systems in Table 12.2-1 are chosen for structural steel and reinforced concrete systems by the user.
SYMBOLS
Cd = Deflection amplification factor
Ωo = Overstrength factor
R = Response modification coefficient
12.2.3 Combinations of Framing Systems in the Same Direction
If different seismic force-resisting systems are used in combination in the same direction, the most stringent applicable structural system limitations contained in Table 12.2-1 are applied.
The intent of the provision requiring the use of the most stringent seismic design parameters (R, Ω0, and Cd) is to prevent mixed seismic force-resisting systems that could concentrate inelastic behavior in the lower stories.
12.2.3.3 R, Cd, and Ω0 Values for Horizontal Combinations
The value of the response modification coefficient, R, used for design in the direction under consideration is not greater than the least value of R for any of the systems used in that direction. The deflection amplification factor, Cd, and the overstrength factor, Ω0, is consistent with the R required in that direction.
Structural System Type | Response Modification Coefficient, R | Overstrengh Factor, Ωo | Deflection Amplification Factor, Cd | Structural System Limitations Including Structural Height, hn (ft) Limits | ||||
|---|---|---|---|---|---|---|---|---|
Seismic Design Category | ||||||||
B | C | D | E | F | ||||
A. Bearing Wall Systems | ||||||||
A1 - Special reinforced concrete shear walls | 5 | 21/2 | 5 | NL | NL | 160 | 160 | 100 |
A2 - Ordinary reinforced concrete shear walls | 4 | 21/2 | 4 | NL | NL | NP | NP | NP |
A3 - Detailed plain concrete shear walls | 2 | 21/2 | 2 | NL | NP | NP | NP | NP |
A4 - Ordinary plain concrete shear walls | 11/2 | 21/2 | 11/2 | NL | NP | NP | NP | NP |
B. Building Frame Systems | ||||||||
B1 - Steel eccentrically braced frames | 8 | 2 | 4 | NL | NL | 160 | 160 | 100 |
B2 - Steel special concentrically braced frames | 6 | 2 | 5 | NL | NL | 160 | 160 | 100 |
B3 - Steel ordinary concentrically braced frames | 31/4 | 2 | 31/4 | NL | NL | 35 | 35 | NP |
B4 - Special reinforced concrete shear walls | 6 | 21/2 | 5 | NL | NL | 160 | 160 | 100 |
B5 - Ordinary reinforced concrete shear walls | 5 | 21/2 | 41/2 | NL | NL | NP | NP | NP |
B6 - Detailed plain concrete shear walls | 2 | 21/2 | 2 | NL | NP | NP | NP | NP |
B7 - Ordinary plain concrete shear walls | 11/2 | 21/2 | 11/2 | NL | NP | NP | NP | NP |
C. Moment-Resisting Frame Systems | ||||||||
C1 - Steel special moment frames | 8 | 3 | 51/2 | NL | NL | NL | NL | NL |
C2 - Steel special truss moment frames | 7 | 3 | 51/2 | NL | NL | 160 | 100 | NP |
C3 - Steel intermediate moment frames | 41/2 | 3 | 4 | NL | NL | 35 | NP | NP |
C4 - Steel ordinary moment frames | 31/2 | 3 | 3 | NL | NL | NP | NP | NP |
C5 - Special reinforced concrete moment frames | 8 | 3 | 51/2 | NL | NL | NL | NL | NL |
C6 - Intermediate reinforced concrete moment frames | 5 | 3 | 41/2 | NL | NL | NP | NP | NP |
C7 - Ordinary reinforced concrete moment frames | 3 | 3 | 21/2 | NL | NP | NP | NP | NP |
D. Dual Systems with Special Moment Frames Capable of Resisting at Least 25% of Prescribed Seismic Foces | ||||||||
D1 - Steel eccentrically braced frames | 8 | 21/2 | 4 | NL | NL | NL | NL | NL |
D2 - Steel special concentrically braced frames | 7 | 21/2 | 51/2 | NL | NL | NL | NL | NL |
D3 - Special reinforced concrete shear walls | 7 | 21/2 | 51/2 | NL | NL | NL | NL | NL |
D4 - Ordinary reinforced concrete shear walls | 6 | 21/2 | 5 | NL | NL | NP | NP | NP |
E. Dual Systems with Intermediate Moment Frames Capable of Resisting at Least 25% of Prescribed Seismic Foces | ||||||||
E1 - Steel special concentrically braced frames | 6 | 21/2 | 5 | NL | NL | 35 | NP | NP |
E2 - Special reinforced concrete shear walls | 61/2 | 21/2 | 5 | NL | NL | 160 | 100 | 100 |
E8 - Ordinary reinforced concrete shear walls | 51/2 | 21/2 | 41/2 | NL | NL | NP | NP | NP |
F. Shear Wall-Frame Interactive System with Ordinary Reinforced Concrete Moment Frames And Ordinary Reinforced Concrete Shear Walls | ||||||||
F1 - Shear wall-frame interactive system | 41/2 | 21/2 | 4 | NL | NP | NP | NP | NP |
G. Cantilevered Column Systems Detailed to Conform to the Requirement for | ||||||||
G1 - Steel special cantilever column systems | 21/2 | 11/4 | 21/2 | 35 | 35 | 35 | 35 | 35 |
G2 - Steel ordinary cantilever column systems | 11/4 | 11/4 | 11/4 | 35 | 35 | NP | NP | NP |
G3 - Special reinforced concrete moment frames | 21/2 | 11/4 | 21/2 | 35 | 35 | 35 | 35 | 35 |
G4 - Intermediate reinforced concrete moment frames | 11/2 | 11/4 | 11/2 | 35 | 35 | NP | NP | NP |
G5 - Ordinary reinforced concrete moment frames | 1 | 11/4 | 1 | 35 | NP | NP | NP | NP |
H. Steel Systems not Specifically Detailed for Seismic Resistance, Excluding Cantilever Column Systems | ||||||||
H - Steel Systems not Specifically Detailed for Seismic Resistance | 3 | 3 | 3 | NL | NL | NP | NP | NP |
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