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Point load on basement slab

Mark K

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May 12, 2010
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2,133
My sense is that Florida is unique in the way they deal with approval of products. I would assume such approvals are only bestowed after they have gone through a process similar to the adoption of regulations.
 

Paul Sweet

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Oct 17, 2009
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1,931
Location
Bedford, VA
Allowable loads for engineered lumber, joist hangers, etc. are based on load tests as well as calculations and include a very conservative factor of safety. Professional Engineers are involved in generating the numbers in the tables. The manufacturers want to produce a safe product. If they didn't, people would find out and stop using them, and there would be plenty of attorneys anxious to start a class action lawsuit for everything the manufacturer is worth.
 

Mark K

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May 12, 2010
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There are several questions. Is the methodology used by the manufacturer appropriate? Do you trust the manufacturer? What do you feel is appropriate? What can be legally compelled?

Building departments are concerned with the question of what can be compelled. The other questions are the providence of the code writers, the applicant, and the design professional on the project.
 

redeyedfly

Registered User
Joined
Feb 22, 2021
Messages
373
Location
Minneapolis, MN
There are several questions. Is the methodology used by the manufacturer appropriate? Do you trust the manufacturer? What do you feel is appropriate? What can be legally compelled?

Building departments are concerned with the question of what can be compelled. The other questions are the providence of the code writers, the applicant, and the design professional on the project.
You've heard of ESRs? Nothing is specified on a commercial project without an ESR. That covers everything you're asking about.

https://icc-es.org/evaluation-report-program/
 

Mark K

Platinum Member
Joined
May 12, 2010
Messages
2,133
The ESR has no legal standing.

I have identified an ESR based on test procedure that was inconsistent with the code. The manufacture was not happy with me but I understand the ESR was changed. The point is that you cannot blindly trust them. That is one case where I had reason not to trust the manufacturer.
 

redeyedfly

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Feb 22, 2021
Messages
373
Location
Minneapolis, MN
You found one ESR out of thousands with an error?

Better throw out that baby when the bath is done!

The entire point of ESRs is to provide all the information to establish that a product complies with the code for a particular use. I think you just like to pick things apart that aren't broken. There are plenty of ambiguities and inconsistencies in the code, justification of joist hangers isn't one of them.
 

ADAguy

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Joined
Sep 11, 2013
Messages
6,231
Location
California
A " skeptic" remains among us? Much of what Mark has stated in the past remains true, however in many states picking and choosing your issues remains allowed.
 

Darren Emery

Sawhorse
Joined
Oct 20, 2009
Messages
480
Location
Manhattan, Ks
The 12" is the punch shear dim. Assume a 45 deg shear plane through the slab (footing) from the edge of the column. So a 4" square column would have a 12" square effective bearing area. That assumes no reinforcment. It gets much more engineery once you start adding reinforcement and your footing becomes a bending plate with spring supports.

I would be ok with a 1500# point load on a 4" slab by inspection.
I just want to weigh in with a thumbs up for use of the term "engineery". gonna have to borrow that one :)
 
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