Are seismic risk assessments needed on new construction?

[Yikes]

My client has a lender asking for a seismic risk assessment for a brand new apartment building currently in plan check under the 2022 California Building Code. Is this a common request for new buildings?

I assume this is a generic request / check-the-box kinda thing. I can understand asking for an existing structure - - but for new structures is there some default assumption that can be extrapolated based on its compliance with current code for new construction?

 

[classicT]

Are they perhaps referring to the geotechnical reporting requirements? SDC C+ require the geotechnical report to include seismic hazard evaluation.

2022 CA Building Code - 1803.5.11 Seismic Design Categories C Through F​

For structures assigned to Seismic Design Category C, D, E or F, a geotechnical investigation shall be conducted, and shall include an evaluation of all of the following potential geologic and seismic hazards:

1. Slope instability.
2. Liquefaction.
3. Total and differential settlement.
4. Surface displacement due to faulting or seismically induced lateral spreading or lateral flow.

 

[Yikes]

Thanks, classicT, but I think they are referring to studies that predict Probable Maximum Loss (PML).
I was just wondering if the seismic codes were developed based on some basked-in assumption: "Let's develop[ standards that will statistically result in a PML of less than 10% of buildings of an ordinary importance factor", or something like that.

 

[classicT]

Thanks, classicT, but I think they are referring to studies that predict Probable Maximum Loss (PML).
I was just wondering if the seismic codes were developed based on some basked-in assumption: "Let's develop[ standards that will statistically result in a PML of less than 10% of buildings of an ordinary importance factor", or something like that.

Perhaps via local amendment or a municipal code requirement.

 

[Mark K]

Thanks, classicT, but I think they are referring to studies that predict Probable Maximum Loss (PML).
I was just wondering if the seismic codes were developed based on some basked-in assumption: "Let's develop[ standards that will statistically result in a PML of less than 10% of buildings of an ordinary importance factor", or something like that.

No

The seismic provisions have focused on life safety not PML.

Ask the lender where this request is coming from. Find a new lender

 

[Yankee Chronicler]

California still has the strictest seismic requirements in the U.S. I've been NCARB-certified since 1975 or 1976, which is supposed to get me automatic reciprocal licensure in every state. When I decided to get a California license some years ago, I had to travel from the east coast to California and take a special exam on seismic. I passed, but only because I hired a structural engineering professor from a nearby university to tutor me before I went for the exam.

The notion that a new building would need anything beyond design in accordance with the code is ridiculous.

 

[Mark K]

California still has the strictest seismic requirements in the U.S. I've been NCARB-certified since 1975 or 1976, which is supposed to get me automatic reciprocal licensure in every state. When I decided to get a California license some years ago, I had to travel from the east coast to California and take a special exam on seismic. I passed, but only because I hired a structural engineering professor from a nearby university to tutor me before I went for the exam.

The notion that a new building would need anything beyond design in accordance with the code is ridiculous.

While there are some California specific seismic provisions I believe the major differences have to do with the fact that there are major earthquake Faults in California and the fact that the seismic provisions are enforced. In addition for certain types of buildings the engineer must be licensed as a "Structural Engineer".

While local jurisdictions can only enforce the adopted provisions it is not uncommon for California engineers to go beyond the code when there is a desire to reduce potential damage due to earthquakes. Note the emphasis on reducing potential damage since the seismic provisions focus on life safety which means the occupants can exit the building after an earthquake. A building could satisfy the code seismic requirements but be so damaged that it needs to be demolished.

 

[Paul Sweet]

It sounds like a lender requirement to make sure the collateral for the loan won't be too badly damaged by an earthquake.

 

[Joe.B]

Codes Display Text

Also see CEBC 317 for existing state-owned buildings, public school buildings, and community college buildings.