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 ASCE 7-22,Table 12.2-1 SFRS confusion

  • ASCE Standards
  • ASCE7-22
Anonymous Member's profile image
Anonymous Member posted 02-22-2023 12:23 PM
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I am writing to request clarification on the differences between Special reinforced concrete shear walls and Reinforced concrete ductile coupled walls, as outlined in ASCE 7-22 Table 12.2-1. While I understand that Ductile coupled walls comprise ductile shear walls and ductile coupling beams, I would appreciate a more comprehensive understanding of how these differ from special reinforced concrete shear walls.

Additionally, I noticed that ASCE 7-22 Table 12.2-1 allows for Ordinary reinforced concrete shear walls for SDC-C or lower. If an ordinary shear wall is joined by an ordinary coupling beam, I am curious if the detailing requirements of ordinary moment frames should be followed.

Thank you for your time and consideration.

Ronald Hamburger's profile image
Ronald Hamburger

The new ductile coupled wall system introduced in ASCE 7-22 uses similar detailing to the Special RC Wall system but also is required to have coupling beams, meeting specific dimensioning and detailing requirements contained in ACI 318 and ASCE 7- Chapter 14.  The primary difference between the system is that inelastic (nonlinear) behavior in SRCSW structures is intended to consist of flexural yielding (plastic hinging) at the base of the wall.  Becasue almost all of the nonlinearity occur in the hinge region ,at the wall's base, the amount of energy dissipation that this system can develop is limited.  In the ductile coupled wall system, additional hinges will develop in the coupling beams, as well as the hinge at the base of the wall.  This provides greater ability to dissipate energy  and allows assignment of higher R values in Table 12.2-1.  The ACI 318 detailing requirements are intended to assure a sufficient number and size of coupling beams to develop the  required energy dissipation.

Coupling beams in Ordinary RC Shear Wall structures should be detailed as per Ordinary Moment Frames.  ACI 314 contains the specific requirements.