Adjustments Needed in the ACI 318-19 Design and Detailing Requirements for Special Reinforced Concrete Shear Walls

by S. K. Ghosh, Ph.D.

February 15, 2023 February 23, 2023; 11:00 AM - 1:30 PM Pacific Time

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ICC Preferred Provider Course Number: 34243

Seminar Description

It is common knowledge by now that very major changes in the design and detailing requirements for special shear walls was made in ACI 318-19, which goes into effect in California on January 1, 2023. Among the most important of the changes from ACI 318-14 are the following:

1. Shear amplification - design shear (required shear strength) Vu of ACI 318-14 is required to be amplified by a factor of up to 3 (similar to New Zealand, Canada).
2. Improved wall boundary and wall web detailing – required are overlapping hoops if the boundary zone dimensions exceed 2:1, crossties with 135-135 degree hooks on both ends, and 135-135 degree crossties on web vertical bars.
3. Check on mean top-of-wall drift capacity at 20% loss of lateral strength - a low probability of lateral strength loss at MCE-level hazard is required, and
4. Minimum wall boundary longitudinal reinforcement – this is required to limit the potential of brittle tension failures for walls that are lightly reinforced.
5. Severe restrictions on lap splice locations.

In a presentation before the Los Angeles Tall Buildings Structural Design Council, Wallace et al. concluded: ACI 318-19 increased the shear demand by a large factor to consider capacity-based design; however, it did not provide any increase on the capacity side … . Use of shear walls for mid-rise buildings will not be feasible. Moment frames will be the only alternative.” A near-consensus has now emerged that adjustments to some of the ACI 318-19 changes are badly needed. The proposed presentation will discuss a number of these needed adjustments.

Speaker Bio

Dr. S. K. Ghosh is known internationally for his work in earthquake engineering. He has influenced seismic design provisions in the United States for many years by serving on or chairing numerous committees and advisory panels. He specializes in the analysis and design, including wind and earthquake resistant design, of reinforced and prestressed concrete structures. Dr. Ghosh is active on many national technical committees and is a fellow of ASCE, SEI, ACI, and PCI. He is a member of ACI Committee 318, Standard Building Code, and the ASCE 7 Standard Committee (Minimum Design Loads for Buildings and Other Structures). He is a former member of the Boards of Direction of the Building Seismic Safety Council (BSSC), the American Concrete Institute (ACI), and the Earthquake Engineering Research Institute (EERI). In addition to authoring many publications in the area of structural design, he has investigated and reported on structural performance in recent earthquakes.

Registration Information

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Early Registration Discounted Fee*	$260	$460	$585	$640	$725	$130 per connection
Regular Fee	$275	$490	$630	$700	$800	$145 per connection
* Registration on or before February 13, 2023

Please note a single registration allows you to have one connection. However, a number of people can view and listen to the seminar using one connection by using an LCD projector (or a large computer monitor) and good computer speakers or a speaker phone.

All attendees, irrespective of the number of registered connections, can earn 0.2 Continuing Education Units (CEUs) or 2.0 professional development hours (PDHs). CEU/PDH certificates are provided free of charge.

FAQ

• A connection is defined as a single web connection plus a single telephone connection (if necessary). If you want to sign up for more than one connection for this seminar, you will have the opportunity to do so after placing the seminar in your cart.
• A $15 fee will apply if the seminar registrant wishes to revise the web seminar registration (e.g. switch from one web seminar to another).
• Refunds are limited to 80 percent of fee and must be applied for in writing WITHIN THIRTY DAYS after the scheduled seminar.
• We are a registered provider for continuing education in the State of Florida (Provider # 4732), the State of New York (Provider # 99), the State of New Jersey (Provider # 24GP00014200), the State of Maryland, and for the Structural Engineers Certification Board (SECB) of the National Council of Structural Engineers Associations (NCSEA).