Breakaway CMU Walls in VE Flood Zones

[jar546]

How do you navigate supporting unbalanced backfill with the requirements for breakaway CMU walls?

CFR Title 44, 60.3 says:
For the purposes of this section, a breakway wall shall have a design safe loading resistance of not less than 10 and no more than 20 pounds per square foot. Use of breakway walls which exceed a design safe loading resistance of 20 pounds per square foot (either by design or when so required by local or State codes) may be permitted only if a registered professional engineer or architect certifies that the designs proposed meet the following conditions: (i) Breakaway wall collapse shall result from a water load less than that which would occur during the base flood; and, (ii) The elevated portion of the building and supporting foundation system shall not be subject to collapse, displacement, or other structural damage due to the effects of wind and water loads acting simultaneously on all building components (structural and non-structural). Water loading values used shall be those associated with the base flood. Wind loading values used shall be those required by applicable State or local building standards. Such enclosed space shall be useable solely for parking of vehicles, building access, or storage.

ASCE 24 says:
4.6.1 Breakaway Walls Breakaway walls and other similar nonload bearing elements, including open-wood lattice work and insect screening, shall be designed and constructed to fail under base flood or lesser conditions, without imparting additional flood loads to the foundation or superstructure and without producing debris damage to the structure or adjacent structures. Breakaway walls and their connections shall be designed in accordance with the requirements of Section 5.3.3 of ASCE 7 Minimum Design Loads for Buildings and Other Structures (ASCE/SEI 2010). Attendant utilities and equipment shall not be mounted on, pass through, or be located along breakaway walls.

I don't have ASCE info to post. Here is an example of a breakaway wall design. I am not convinced this is a breakaway wall.

 

[Paul Sweet]

It might break if a large ship was washed up against it in a hurricane.

 

[Msradell]

It certainly doesn't look like a breakaway wall.

 

[Mark K]

Since when does the building department enforce federal law (CFR)? Building codes are reserved for the states to adopt and enforce. I assume we are not talking about a federally funded project.

I agree that this does not appear to be a breakaway wall. The wall will likely resist more load than intended.

 

[jar546]

Since when does the building department enforce federal law (CFR)? Building codes are reserved for the states to adopt and enforce. I assume we are not talking about a federally funded project.

Mark,
I am going to assume that you don't work in any special flood hazard areas and are not familiar with the requirements of municipalities to participate in the National Flood Insurance Program. If you were, you would understand the legalities and nuances of how it works and who is responsible for enforcement. I encourage you to receive training and get your certification as a Certified Floodplain Manager (CFM) through FEMA's training and testing requirements which would then give you the basic knowledge to understand the system in place. Once a municipality agrees to participate in the NFIP, the residents can then purchase flood insurance through the NFIP. Without participation in the NFIP, property owners can only purchase private flood insurance which is typically much higher in premiums. Participation requires a local floodplain ordinance the meets minimum standards set by FEMA. The municipality then must designate a Floodplain Administrator who is responsible for the enforcement of the floodplain ordinance which specifically references the regulations required by FEMA.

I hope this clarifies your question.

I agree that this does not appear to be a breakaway wall. The wall will likely resist more load than intended.

The licensed structural engineer is hanging is hat on the following component of the design which is being questioned by our structural engineer who I've directed to review.

 

[tmurray]

Since when does the building department enforce federal law (CFR)? Building codes are reserved for the states to adopt and enforce. I assume we are not talking about a federally funded project.

There would be two situations where this would exist:

Where governmental hierarchies exist, higher governments can establish laws that bind a lower level to action. In the case of the US, it would be much more common to see this interaction between the state and local level governments than between the federal and state levels due to the US Constitution.

A lower level may voluntarily establish a standard of care to review requirements of a higher level. This choice can be formed based on strategic objective of the local government, or incentivization (as is the case here). Ultimately, enforcement of the higher-level law may be limited, but it certainly could be tied to administrative functions, such as permit issuance and issuance of a certificate of occupancy.

 

[Paul Sweet]

The details in the OP showing a reinforced block wall connected to the footing at the bottom and the beam conflict with the note to not connect the stemwall to the grade beam.

I mentioned a ship in my previous post because I remembered driving along the Mississippi coast several months after hurricane Camille hit. There were almost no houses within 1/2 mile of the shore, just some brick piers where the houses once were. The only building was a brick building on concrete piers - an elevated blockhouse. There were 2 ships, each a couple hundred feet long, washed up on the shore.

 

[SCBO1]

Cities adopt a model floodplain ordinance after it is reviewed by the SEMA (State Emergency Management Agency) or FEMA. Cities can adjust the above flood elevation if they choose too. We are 1-ft above flood stage but could increase that to 1.5 or more, it depends on the tributary issues each city has to deal with.

The city has to designate a Flood Plain Manager typically a BO or city engineer. If you want your community to have flood insurance you adopt an ordinance and the city provides an enforcer. There is training provided and certifications are encouraged.

The IBC has flood resistant construction and flood hazard areas in the code. Also appendix-G in the 2021 IBC can be adopted.

 

[Mark K]

Cities adopt a model floodplain ordinance after it is reviewed by the SEMA (State Emergency Management Agency) or FEMA. Cities can adjust the above flood elevation if they choose too. We are 1-ft above flood stage but could increase that to 1.5 or more, it depends on the tributary issues each city has to deal with.

The city has to designate a Flood Plain Manager typically a BO or city engineer. If you want your community to have flood insurance you adopt an ordinance and the city provides an enforcer. There is training provided and certifications are encouraged.

The IBC has flood resistant construction and flood hazard areas in the code. Also appendix-G in the 2021 IBC can be adopted.

What is described is not universal for all jurisdictions. In some cities do not have a SEMA and in some states the ability to impose local requirements can be limited.

 

[jar546]

What is described is not universal for all jurisdictions. In some cities do not have a SEMA and in some states the ability to impose local requirements can be limited.

Mark,
This is precisely how it works for any municipality participating in the NFIP. It is an absolute requirement. Otherwise, residents can't even get a mortgage without flood insurance, and private flood insurance is cost-prohibitive. As a matter of fact, communities that participate in the Community Rating System (CRS) are encouraged to adopt more restrictive requirements than FEMA, which then provides a discounted insurance rate to the residents. This is often done by requiring a freeboard higher than BFE, often 18 to 14 inches of freeboard, and providing cumulative time frames for owners who try to circumvent substantial improvement rules. In all actuality, FEMA encourages more restrictive ordinances. Again, I encourage you to receive training as a CFM, as it is obvious you are commenting on a subject in which you have little to no experience.

 

[Mark K]

Mark,
This is precisely how it works for any municipality participating in the NFIP. It is an absolute requirement. Otherwise, residents can't even get a mortgage without flood insurance, and private flood insurance is cost-prohibitive. As a matter of fact, communities that participate in the Community Rating System (CRS) are encouraged to adopt more restrictive requirements than FEMA, which then provides a discounted insurance rate to the residents. This is often done by requiring a freeboard higher than BFE, often 18 to 14 inches of freeboard, and providing cumulative time frames for owners who try to circumvent substantial improvement rules. In all actuality, FEMA encourages more restrictive ordinances. Again, I encourage you to receive training as a CFM, as it is obvious you are commenting on a subject in which you have little to no experience.

I refer you to the 10th amendment to the US Constitution:

"The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people."

The US Constitution does not delegate building codes to the Federal Government.

In some states the ability of local jurisdictions to modify the building code are limited

While states may provide for the consideration of flood loading, the provisions for breakaway walls would be considered building regulations It all depends on what the State has adopted.

 

[jar546]

I refer you to the 10th amendment to the US Constitution:

"The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people."

The US Constitution does not delegate building codes to the Federal Government.

In some states the ability of local jurisdictions to modify the building code are limited

While states may provide for the consideration of flood loading, the provisions for breakaway walls would be considered building regulations It all depends on what the State has adopted.

Now you are just being silly and arguing simply for the sake of arguing while grasping for straws in an arena you have absolutely no knowledge or experience in. This is a federal program that is a requirement and local jurisdictions must enforce. Here is the best part. In many municipalities, this responsibility is not even in the building department, but a separate department. Many CFMs are not Building Officials, Inspector, or even Plans Examiners. They act as the Floodplain Manager. Their sign off for development orders and building permits is just part of the process

If you want to practice constitutional law, I'm sure there's a forum for that somewhere. Just not here.