Steinway D Grand

[ImagineerTom]

and thus I refer back to my starting comment Timsabre - there's some over-complication going on here. If the "structural engineer" (and that's a hideously vague term that covers everything from someone who should know all about this to someone who's about as experienced as a dolphin to design this solution) is asking for complicated data (ie point loading) then he is over-complicating the data which suggests either he's not the right person for this job or that he's misunderstood or been mis-briefed on the problem; I'm also confused as to why he's asked a (nothing personal to the op) completely un-qualified person to get hold of key technical data that he could just as easily get hold of himself. As others have pointed out these pianos are regularly used and moved on steeldeck type stages, victorian stages, dancefloors without any major problems.

 

To the OP - it's worth speaking with this structural engineer and see where his thoughts are going on a solution as the questions he's asked /suggest/ he's seeing complexities that real-world experience suggest aren't a problem; that he has not perhaps yet visualised and considered the problem (and is thus asking generic "safe" questions for now) or that his initial design thoughts are for something complicated and mechanical when a more simple solution would suffice.

 

Based on the description given so far my first suggestion for this problem is to span the gap with steeldeck type staging (essentially replacing your current wooden rostra method with a metal version) possibly double-skinned, there may be an argument for developing some sort of drawbridge arrangement or attaching fixing brackets on either stage section so that the deck is held up by the existing structures (and such an arrangement would require some extra sums to cope with the total weight) but frankly anything more complicated than this would be just too complicated and would fall over in a cost/benefit/practicality analysis. I honestly can't see where detailed point-loading information (beyond a knowledge of other surfaces this type of piano is normally moved on) would be of any relevance or use?

 

I'm happy to be educated otherwise if I'm wrong.

 

 

[timd]

I assume that the engineer will be writing a formal spec along the lines of "freestanding bridge structure spanning Xm at height Ym to support a load not exceeding 1t, point loading not exceeding 500kg", not "Bridge for Steinway D in XYZ venue". As it turns out, defending the latter in front of insurers/in court is much harder than the former. Plenty of engineers would be able to design to the former, without knowing a Steinway from a saxophone, the latter spec obviously requires a lot of industry knowledge.

[Vraicbeard]

Thank you Blue room for your help in defining my question better - This morning Steinway replied with all the details I needed for our piano. I had written to info@steinway.co.uk.

 

"Thank you for your enquiry regarding the point loading of a Steinway model D.

 

According to my colleagues at the factory in Hamburg the weights are as follows.

 

Back leg – 198kg

 

Front left (bass) leg – 203kg

 

Front right leg (treble) – 220kg

 

These measurements are not guaranteed to be accurate but give an indication of what to expect.

 

The overall weight of the piano is 480kg."

 

The chap also let me know ,we are also due for our 100,000,000 note service too.

 

 

ImagineerTom - The guy I'm dealing with is extremely experienced and we have already talked through all of your concerns regarding realistic assessment of the problem (including weak wooden moulding on both permanent stages), portability and cost, when designing and building a scratch built solution. He was getting as much information as possible so as to understand the problem fully before attempting to fix it and I'm more than happy with his approach. As a new OP to Blue room, I added a very simplified back ground of the problem to explain why I was asking such a specific question on a technical forum. Brackets you say?....hmmmm Better than the piano trebuchet on youtubes.

 

 

 

 

Thanks again,

 

VB :)

 

I assume that the engineer will be writing a formal spec along the lines of "freestanding bridge structure spanning Xm at height Ym to support a load not exceeding 1t, point loading not exceeding 500kg", not "Bridge for Steinway D in XYZ venue". As it turns out, defending the latter in front of insurers/in court is much harder than the former. Plenty of engineers would be able to design to the former, without knowing a Steinway from a saxophone, the latter spec obviously requires a lot of industry knowledge.

 

Bang on Tim - that's it exactly

[jonathanhill]

The weights given add up to more than the weight of the piano

 

Interesting.

[djw1981]

are they weighing piano is a transport case type thing or just the maximum loading on each leg?

[Robin D]

I guess that they are allowing something for shifts in centre of gravity as piano is moved. Given the relatively high CoG in a piano. it wouldn't take much vertical displacement on any leg to substantially affect the apparent weight on the other two with corresponding impact on point force.

 

It would be a foolish person that designed something that didn't adequately exceed the manufacturers figures IMHO.

[Seano]

It would be a foolish person that designed something that didn't adequately exceed the manufacturers figures IMHO.

 

It would be a foolish person who designed a device for piano storage/transport on the assumption that it would only ever be used to store/move a) a piano or b) that specific piano. Especially something as generic as a 'bridge'.

[MarkPAman]

It would be a foolish person who designed a device for piano storage/transport on the assumption that it would only ever be used to store/move a) a piano or b) that specific piano. Especially something as generic as a 'bridge'.

 

c) that the piano is self propelled, rather than moved by 400 - 500kg of crew.

[timsabre]

It would be a foolish person who designed a device for piano storage/transport on the assumption that it would only ever be used to store/move a) a piano or b) that specific piano. Especially something as generic as a 'bridge'.

c) that the piano is self propelled, rather than moved by 400 - 500kg of crew.

 

The main problem with a piano from a structural point of view is not the overall weight, although that is significant, it is that the point loads are very high, 200kg in a contact area of a few mm2.

[MarkPAman]

The main problem with a piano from a structural point of view is not the overall weight, although that is significant, it is that the point loads are very high, 200kg in a contact area of a few mm2.

 

True.

 

These would help.