Learn what a structural engineer needs to know about the California Building Code 2022, from building regulations to key requirements. Get up to speed today!
As a structural engineer in California, staying updated on the latest building codes is vital to ensure the safety and integrity of the structures your design. The California Building Code 2022 is the most recent update to the state’s building regulations, and it includes several significant changes and additions that structural engineers need to know.
So whether you’re just beginning your career or are a seasoned pro, read on for some of the most important things you need to know about the newest version of California’s building code.
The California Building Code (CBC) is the set of regulations governing the design, construction, alteration, and maintenance of buildings and structures in the U.S. state of California. Part of Title 24 of the California Code of Regulations (CCR), the CBC falls under the jurisdiction of the California Building Standards Commission (CBSC).
The CBC includes multiple amendments by various state agencies, ranging from the State Fire Marshall to the Department of Health Care Access and Information (referred to as the Office of Statewide Health Planning and Development - OSHPD in the code). This article will principally focus on designs for light commercial and residential buildings.
In addition to the CBC, your local city or county may also file its local amendments to the CBC (known as Local Building Codes or Ordinances) with the CBSC. The amendments may be more or less restrictive in nature depending on the area’s climatic, geographical, or topographical conditions. You can find relevant ordinances for your local city or county on the CBSC website and contact them to get a copy of filed ordinances of the city or county of your interest.
Let’s say we’re designing a building in Pleasanton, California. Looking through the CBSC database, we’ll find that the city has filed Ordinance No. 2241 to their local amendments in conjunction with the adoption of the CBC 2022, where the Pleasanton Building Code Sections 20.08.080 completely replaces the CBC Section 1905.1.7 in Chapter 19 Concrete with fewer exceptions for allowable plain concrete in structures assigned to seismic design category C, D, E or F, among other things.
The California Building Code (CBC) is revised every three years. The most recent revision was published in 2022, and the next will likely be the 2025 version. The CBC 2022 is based on the 2021 International Building Code.
The 2022 edition was published on July 1, 2022, and went into effect across the state on January 1, 2023.
Some of the key provisions related to structural design in CBC 2022 include:
In the past, you might have been concerned about when a site-specific analysis is required for your projects, especially when dealing with structures on Site Class D, which is the default site class in most projects.
Given that site-specific ground motion procedures can be complicated and expensive, the adoption of Supplement 3 of ASCE 7-16 in the CBC 2022 clarifies the requirements to bypass the site-specific analysis. These can be avoided by:
Additional changes in the CBC 2022 are related to more complex seismic analysis, which you can refer to directly in Supplements 2 and 3 of ASCE 7-16, which are available for free online.
Where residential projects take place in frost-prone areas, the CBC 2022 now requires frost protection for all exits with outward-swinging doors to avoid any heaving to occur that might obstruct the opening of the exit doors.
Additionally, if you are designing deep foundations, the CBC 2022 includes requirements to design:
The American Wood Council's (AWC) Special Design Provisions for Wind and Seismic (SDPWS) has been updated to the latest 2021 edition with the CBC 2022, providing detailed governing criteria for engineered wood systems, members, and connections in lateral force-resisting systems such as wood shear walls and diaphragms.
Among other changes, the SDPWS 2021 has combined wind and seismic design values for diaphragms and shear walls into a single value, which is modified by safety factors appropriate for each condition (SDPWS 2021, 4.1.4 and Table 4.2 & 4.3). These changes have led to reductions in the shear strength for wood panel (LRFD) or gypsum board and plaster (ASD) by 11% and 30%, respectively.
In addition, there are now stricter rules for multi-story buildings with Seismic Design Category D, E, or F (SDPWS 2021, 4.1.8), as well as new provisions for construction with cross-laminated timber (CLT) in exterior walls (SDPWS 2021, 4.5 and 4.6).
The California Building Code 2022 (CBC 2022) has brought significant development to concrete design requirements. Instead of referring to the American Concrete Institute's ACI 318-14, it now uses the newly updated standard for structural concrete: ACI 318-19.
In particular, ACI 318-19 now allows more applications using high-strength reinforcements up to 100 ksi in your designs, opening up new possibilities for those working with this material.
Additionally, the shear strength calculation has been reworked, too, resulting in a much lower shear capacity for concrete structures that don’t have transverse reinforcement, such as stirrups.
Compared to the previous edition, the ACI 318-19 now introduces a size effect factor (λs) and considers reinforcement ratio (ρ) in its shear strength Vc calculation.
Let’s take a look at the differences in the shear strength formula:
Vc=8λs λ(ρw)1/3 √fc′ bwd
As an example, for a lightly-reinforced footing (ρw = 0.002 and size factor λs = 1.0 per Cl 188.8.131.52), we would obtain a factor of ~1.0 instead of 2.0 for the shear strength, resulting in a 50% reduction in shear capacity.
This formula modification may result in significantly thicker footings, structural slabs, and walls.
With the new set of equations for shear strength, ACI 318-19 introduces the factor λs, the "Size Effect" for sections with no minimum shear reinforcement.
This will affect beams, slabs, and walls with a depth of 10 inches or more. For instance, a 24-inch thick slab will have its shear capacity reduced by 25% with the size effect factor considered.
Isolated and combined footing designs are not affected by the size effect factor.
Managing the transition from the CBC 2019 to the CBC 2022 can be challenging. As a structural engineer, you’re always looking for ways to use technology to streamline your work.
Luckily, a few computer programs come in handy when following the latest California Building Code 2022.
Firstly, structural engineering software like ClearCalcs now enables you to define the California Building Code 2022 as the governing code of your project’s load combinations and design criteria in Project Defaults. This means the set of default/preset values for the code in question will carry through to every new calculation you create in ClearCalcs.
You can use wind load or seismic analysis calculators to meet the requirements of ASCE 7-16, which is referenced heavily in CBC 2022.
The ClearCalcs Wind Load Calculator to ASCE 7 is a tool that allows you to perform in-depth wind analysis, and the Seismic Analysis Calculator to ASCE 7 from ClearCalcs is a user-friendly tool for performing seismic analysis according to the ASCE 7 code.
Finally, the ClearCalcs Concrete Beam Calculator is now updated to the latest ACI 318-19 edition, and other calculations will be updated in the next few weeks.
There you go! We hope this guide has set you up to align with the California Building Code 2022.
To recap, the California Building Code 2022 incorporates some key changes to structural design requirements, including the complete adoption of ASCE 7 and Supplement 2 and 3 for seismic analysis requirements.
The most significant change to note is the update to the concrete design requirement with the ACI 318-19, which might affect the shear capacity of your concrete structures with the new reworked shear capacity formula.
So, whether designing a new building or retrofitting an old one, make sure you factor in these California Building Code 2022 requirements. If you are designing a residential home in California, check out ClearCalcs library of calculators to use from roof to foundation with presets for wood, steel, or concrete.
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