suspended transformer

[Ingenieur]

All kidding aside
when I do things like this
never factor in hardware sf ultimate/working
mult load x 1.4 (or more depending on type, stationary, mobile, etc)
design for a sf of >4
use a greater number of smaller inserts (vs larger sized ones) to ensure if one fails/installed improperly, that no one bolt carries >rating or >50% of the load

in 30 years ain't bonked no one on the noggin' yet
my carreer
40% contracting, design build
50% consulting
10% regulatory

 

[jumper]

All kidding aside
when I do things like this
never factor in hardware sf ultimate/working
mult load x 1.4 (or more depending on type, stationary, mobile, etc)
design for a sf of >4
use a greater number of smaller inserts (vs larger sized ones) to ensure if one fails/installed improperly, that no one bolt carries >rating or >50% of the load

in 30 years ain't bonked no one on the noggin' yet
my carreer
40% contracting, design build
50% consulting
10% regulatory

Sounds good; you design, stamp and sign it off and I will build it.

 

[Ingenieur]

Yep.

Sorry Iggy but the specs, all of them, fall on the EE if requested.

not according to my lawyer and e&o insurer
my lawyer
West Point
viet nam
Corps of engineers
MS and PE
Went to law school after 15 years of engineering practice
I tend to trust him

as soon as I tell you how to do something I get a CO lol

means and methods of construction

A term used in construction to describe the day-to-day activities a contractor employs to complete construction. In some cases, these activities may require incidental design or engineering elements; the rigging of scaffolding for a particular purpose or minor modifications of plans to solve on-the-spot construction difficulties (e.g., moving a door a few inches to avoid interference with another door) are just a couple of examples of such "means and methods." Means and methods of construction are ordinarily understood to be covered under general liability policies, rather than professional liability policies.

1. The Contractor shall be solely responsible for and have control over construction means, methods, techniques, sequences and procedures and for coordinating all portions of the Work under the Contract, unless the Contract Documents give other specific instructions concerning these matters.

 

[iwire]

All kidding aside
when I do things like this
never factor in hardware sf ultimate/working
mult load x 1.4 (or more depending on type, stationary, mobile, etc)
design for a sf of >4
use a greater number of smaller inserts (vs larger sized ones) to ensure if one fails/installed improperly, that no one bolt carries >rating or >50% of the load

in 30 years ain't bonked no one on the noggin' yet
my carreer
40% contracting, design build
50% consulting
10% regulatory

Well as impressive as your years of experience are, I don't think they will substitute for sesimic protection in areas that require it.

 

[iwire]

not according to my lawyer and e&o insurer
my lawyer
West Point
viet nam
Corps of engineers
MS and PE
Went to law school after 15 years of engineering practice
I tend to trust him

as soon as I tell you how to do something I get a CO lol

means and methods of construction

A term used in construction to describe the day-to-day activities a contractor employs to complete construction. In some cases, these activities may require incidental design or engineering elements; the rigging of scaffolding for a particular purpose or minor modifications of plans to solve on-the-spot construction difficulties (e.g., moving a door a few inches to avoid interference with another door) are just a couple of examples of such "means and methods." Means and methods of construction are ordinarily understood to be covered under general liability policies, rather than professional liability policies.

:lol:

 

[Ingenieur]

Well as impressive as your years of experience are, I don't think they will substitute for sesimic protection in areas that require it.

60:1 covers it :happyyes:

 

[Ingenieur]

:happyyes:

[h=4]Abstract[/h]Design engineers traditionally have been responsible for the design of a project. They also have provided performance specifications for the protection of adjacent property owners, existing facilities, and so forth. Design engineers may also provide construction oversight and inspection. The role of the contractor has been to develop the means and methods and to construct the project in accordance with the performance requirements given in the contract documents. These traditional roles have changed over the past two decades. On complex projects, design engineers often provide "suggested methods of construction." However, design engineers are not constructors.

 

[jumper]

not according to my lawyer and e&o insurer
my lawyer
West Point
viet nam
Corps of engineers
MS and PE
Went to law school after 15 years of engineering practice
I tend to trust him

as soon as I tell you how to do something I get a CO lol

means and methods of construction

A term used in construction to describe the day-to-day activities a contractor employs to complete construction. In some cases, these activities may require incidental design or engineering elements; the rigging of scaffolding for a particular purpose or minor modifications of plans to solve on-the-spot construction difficulties (e.g., moving a door a few inches to avoid interference with another door) are just a couple of examples of such "means and methods." Means and methods of construction are ordinarily understood to be covered under general liability policies, rather than professional liability policies.

1. The Contractor shall be solely responsible for and have control over construction means, methods, techniques, sequences and procedures and for coordinating all portions of the Work under the Contract, unless the Contract Documents give other specific instructions concerning these matters.

If I RFI for hanging this tranny, do you really think think such a clause would cover you for not responding?

This a case specific query that should invoke an answer beyond general construction IMO.

 

[Ingenieur]

If I RFI for hanging this tranny, do you really think think such a clause would cover you for not responding?

This a case specific query that should invoke an answer beyond general construction IMO.

I would respond
please submit your proposed means/methods for review
if required please retain a design professional
it would be a conflict of interest for me to provide such services to you

 

[__dan]

:happyyes:

Abstract

Design engineers traditionally have been responsible for the design of a project. They also have provided performance specifications for the protection of adjacent property owners, existing facilities, and so forth. Design engineers may also provide construction oversight and inspection. The role of the contractor has been to develop the means and methods and to construct the project in accordance with the performance requirements given in the contract documents. These traditional roles have changed over the past two decades. On complex projects, design engineers often provide "suggested methods of construction." However, design engineers are not constructors.

Depends on the State Statute and if it's being enforced or not.

Typical statute language ' no plans or drawings shall be accepted unless stamped sealed by the design professional' with a low threshold where this applies. (> 5,000 sf)

Above a higher threshold, 'licensed signature, stamp required as well as construction supervision and acceptance'. (>30,000 sf business use)

Trying to get it enforced for code violations and shoddy work, applies to sf increases but not electrical, but would not give me that opinion in writing (true story, could not get it enforced or applied to actual crime).

I'm sure as soon as I tried to offer drawings, calculations, consultations above the threshold in this state on my E1, the result would be fines and leg irons.

So it's a grey area in the statutes, b & w in the statutes but grey in the politics of enforcement. Next step was a request for interpretation from the Engineering Work Supervisory Board to get it either applied equally or get clearance to do the work myself.

 

[Ingenieur]

I've never had an rfi for
hanging a xfmr
building a panel rack/line up
hanging/routing conduit

I've had proposed methods submitted on ocassion for review/comment
and I will give non-binding comment if warranted
they usually opt to implement it
usually minor, contractors tend to know what they are doing, in fact good at it

 

[iwire]

60:1 covers it :happyyes:

In a trapeze situation hung with four rods I do not believe it does.

The transformer must be braced for horizontal movement.

 

[iwire]

What I am seeing in this area is a switch from simple threaded rod hangers to elaborate structures.

Here is a detail for a recent job

How much over kill is there in four, 2" x 2" x 5/15" angle iron?

Yet still it has to be tied into the wall for seismic bracing.

Below is a picture of another recent transformer installation and its hangers are well beyond what is needed to support the vertical weight yet still had to be braced horizontally.

To be clear, I liked doing things like hanging transformers, manly work but things in my area are changing and they are really cracking down on things that are hung.

 

[iwire]

I would respond
please submit your proposed means/methods for review
if required please retain a design professional
it would be a conflict of interest for me to provide such services to you

Yes, and then I would go to the GC and say this is going to cost you an extra, the designer is refusing to design. How do you want to handle it?

And you know what, I would get the needed response from the engineer for the job.

I don't know how it works for your section of the business but for us we work with the same customers, GCs, and engineering firms over and over again. If one of these groups is causing job delays or cost increases due to being a prima donna they are not going to get much more work. :happyno:

 

[Ingenieur]

In a trapeze situation hung with four rods I do not believe it does.

The transformer must be braced for horizontal movement.

Depends on the zone
but at an actual say 10:1 probably not
even a severe zone will impose a 1 g force laterally
the resultant still << 10:1

attachment to the wall is always preferred
I also use vibration isolators on the clg strut if not braced to wall, otherwise on xfmr base
I also prefer angle > threaded rod and limit length

weight factors in
200 lbs requires a different approach than 1000
F = ma
a is a resultant of g gravity (basically the weight) and external, usually siesmic
m is mass or weight, ie, proportion to the net force

 

[Ingenieur]

Yes, and then I would go to the GC and say this is going to cost you an extra, the designer is refusing to design. How do you want to handle it?

And you know what, I would get the needed response from the engineer for the job.

I don't know how it works for your section of the business but for us we work with the same customers, GCs, and engineering firms over and over again. If one of these groups is causing job delays or cost increases due to being a prima donna they are not going to get much more work. :happyno:

Good luck with that
my obligation is to my client, not covering your butt
I would say don't hang it, I'll get someone to do it and back-charge deductive CO
All in writing with notice from the solicitor
it would be hung one way or the other

 

[Ingenieur]

What I am seeing in this area is a switch from simple threaded rod hangers to elaborate structures.

Here is a detail for a recent job

How much over kill is there in four, 2" x 2" x 5/15" angle iron?

Yet still it has to be tied into the wall for seismic bracing.

Below is a picture of another recent transformer installation and its hangers are well beyond what is needed to support the vertical weight yet still had to be braced horizontally.

To be clear, I liked doing things like hanging transformers, manly work but things in my area are changing and they are really cracking down on things that are hung.

Nice install

he's got 4 each 1/2 bolt in the wall, 2 per side
6" long working load is well over 6000 lb in tension and 8000 in shear
that is more than bracing lol
I would use 3/8 x 3 each side in case one failed one bolt is not relied upon
that is carrying some load in shear
without seeing the clg attachment
There would be a tension adj on it
apply load to wall then take it up on the hangers

 

[wwhitney]

Depends on the zone
but at an actual say 10:1 probably not
even a severe zone will impose a 1 g force laterally
the resultant still << 10:1

The engineering is not that simple. Depending on the natural period of the hanging structure and the seismic zone, the design lateral acceleration could be up to 3 g. And even if the rod won't break, allowing the transformer to fall, the lateral displacement of the transformer could be big enough to cause other problems in the system.

Here's another way of thinking about the physics: say you install a rectangular array of four 3/8" threaded rods horizontally sticking out of a wall 6 feet, supporting a platform on the end, and a 400 pound person stands on the platform and starts jumping up and down. How long do you think those threaded rods are going to last without at least permanently deforming?

Cheers, Wayne

 

[Ingenieur]

The engineering is not that simple. Depending on the natural period of the hanging structure and the seismic zone, the design lateral acceleration could be up to 3 g. And even if the rod won't break, allowing the transformer to fall, the lateral displacement of the transformer could be big enough to cause other problems in the system.

Here's another way of thinking about the physics: say you install a rectangular array of four 3/8" threaded rods horizontally sticking out of a wall 6 feet, supporting a platform on the end, and a 400 pound person stands on the platform and starts jumping up and down. How long do you think those threaded rods are going to last without at least permanently deforming?

Cheers, Wayne

hard to image 3 g
I would not use rod, use angle

your example is not valid
the forces sum g plus seismic
not the case when hanging, the vector is resultant with forces negating
the mass tensioning the rod/angle would tend to resist the lateral bending moment

 

[wwhitney]

hard to image 3 g

Well, my address (in Berkeley, CA) has a S_MS of 2.617 g and an S_DS of 1.745 g. I'm sufficiently rusty on this stuff to forget the difference. This is per http://earthquake.usgs.gov/hazards/designmaps/

I would not use rod, use angle

Sounds like a good idea, I thought the earlier examples you gave used rod, but I wasn't reading closely.

the forces sum g plus seismic
not the case when hanging, the vector is resultant with forces negating
the mass tensioning the rod/angle would tend to resist the lateral bending moment

I agree that the mass tensioning the rod would increase lateral stiffness, but I don't think that's going to be nearly enough. Rod's going to perform well for a force parallel to its length, not so well for a resultant force at, say, a 45 degree or greater angle to its length.

My main point is that there's no safety factor for gravity load that ensures adequate lateral capacity. The two are separate issues.

Cheers, Wayne