Weak Story Irregularity per ASCE 7-16

How does ideCAD control the weak story irregularity, according to ASCE 7-16, for two earthquake directions?

• Weak Story Irregularities are checked in the Irregularity Report, and necessary conditions are applied.

SYMBOLS
S_tri = Lateral strength defined at the i'th story

Discontinuity in lateral strength–weak story irregularity, is calculated as follows,

The Strength Irregularity Coefficient = ( S_tr )_i / ( S_tr )_i+1 < 0.80

Discontinuity in lateral strength–extreme weak story irregularity, is calculated as follows,

The Extreme Strength Irregularity Coefficient = ( S_tr )_i / ( S_tr )_i+1 < 0.65

According to article 12.3.3.2, structures assigned to Seismic Design Category E or F with horizontal irregularity Type 1b of Table 12.3-1 or vertical irregularities Type 1b, 5a, or 5b of Table 12.3-2 shall not be permitted.

According to article 12.3.3.2, structures with a vertical irregularity Type 5b, as defined in Table 12.3-2, shall not be more than two stories or 30 ft (9 m) in structural height, h_n.

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ASCE 7-16 Strength-Based Design

Related Topics

• Stiffness–Soft Story Irregularity and Extreme Soft Story Irregularity per ASCE 7-16

• Weight (Mass) Irregularity per ASCE 7-16

• Vertical Geometric Irregularity per ASCE 7-16

• In-Plane Discontinuity in Vertical Lateral Force-Resisting Element Irregularity per ASCE 7-16

• Discontinuity in Lateral Strength–Weak Story Irregularity per ASCE 7-16