structural engineering - calculating moment & shear forces for a custom floor mounted hangman's style heavy bag stand?

Question

I own a martial arts facility and I have a few hangman's style (single arm) heavy bag stands that a fabricator friend made for me. These will be used to hang 6' heavybags (100lbs each) attached to a 7" spring and hung with just enough chain that the bag rests on the floor. The spring:
https://www.amazon.com/Ringside-HBS-Heavy-Bag-Spring/dp/B000112FOW

This is the style of bag rack (but not the exact one): https://www.grapplingstore.com/p/Fuji-Hangman-Rack/FCD-HangmanRackFM

• MATERIAL: 2" square carbon steel, .120 wall

• BASE PLATE: 8"x8" carbon steel, .25

• HEIGHT: 7'2" overall

• ARM LENGTH: 28" overall

• WELD MATERIAL: ER70S. .035

• COVERAGE GAS: 75%-25% Argon/CO2

• WELD TYPES: Right angle fillet, AWS-D 1.1

• BAG WEIGHT: 100 lbs.

• bottom of bag rests on the ground

My landlord is asking for "stamped engineering plans" to install the bag stands, but I've never had to do this at any of the gyms I've coached at. I don't know exactly what I'm supposed to ask for in the way of "plans" from an engineer and I don't know what information they'll need supplied to them to create said plans.

Is what I've supplied enough to provide what my landlord is asking for? How do I go about getting said plans created/stamped?

Thank you!

• Jon

Answer 1

Stamped engineering plans usually mean plans (and a report) signed by a licensed engineer.

For your case, you'll most likely need to hire a local engineer or engineering firm, supply them with the specs of the stand (what you have is most likely enough) and the original plans for the building (you need things like slab thickness, rebar, whatever).

They should produce plans with connection details and permissible locations for the bag stands and a report certifying the structure can handle them.

In my opinion, your landlord is being excessive, specially seeing that the thing weighs less than a person, but he's within his rights to ask.