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Tie the Buddha Down

Tie the Buddha Down

Tie the Buddha Down

(OP)
I'm working on the base support for a fairly large statue. It's 33m tall so roughly the equivalent of an elven story building.



The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

(OP)
Crap. Pushed submit before I was done somehow...

The statue superstructure will be designed by the statue supplier and will bear some resemblance to a transmission tower. The base that the statue will sit upon will be four concrete columns built integrally with a concrete shaft, somewhat like an elevator shaft. The columns and shaft will be constructed within an one story concrete bunker of sorts. Folks can go in there to perform various religious activities.

My questions are:

1) Is there anything special that we should consider in the design of the connection between the superstructure and the base? Fatigue? Should the anchor bolts be prestressed? Conceptually, this doesn't seem fundamentally different from a braced frame in any mid-rise building.

2) Our original contract excluded the design of the connection between the superstructure frame and the base. That was to be done by the statue supplier. I liked that arrangement because it put the responsibility for the connection with the party that I felt was best suited to design the connection. Recent events have led me to believe that I might be better suited to designing the connection. Any thoughts? Should I insist on doing the connection? Should I stand back from a liability perspective?

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

Neat... To be built in China? The markings look Chinese, but I thought this sort of icon was a no-no for the communist state.

By Chinese a company for somewhere else?

RE: Tie the Buddha Down

(OP)
To be erected in Canada by a predominantly Vietnamese Buddhist congregation. Design and fabrication of the statue will be done jointly in Japan and China (good call on that). Copper and structural steel for the most part.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

(OP)
200 metric tones all in.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

I see no interstitial horizontal diaphragms or cabled X-bracing as with the vertical planes. I doubt that the decorative skin can resist torsion...

Mike McCann, PE, SE (WA)


RE: Tie the Buddha Down

Copper, huh?

Sounds like a prime target for copper thieves!

Mike McCann, PE, SE (WA)


RE: Tie the Buddha Down

Are the panel points in the picture purposefully avoided by the bracing rods? This can't be a seismic solution for a structure that is definitely NOT meant to deform under action/in service.

I echo Mike's concerns, and add the following:

- Who is responsible to separate/isolate/break dissimilar metal contact?
- Who is responsible for setting the wind and seismic loads?
- Who is responsible to allow for / design against the different coefficients of thermal expansion? I have a mental image of the skin just crumpling on a hot day...

More concerns are likely to follow. This is an interesting one Kootk! :jealous:

RE: Tie the Buddha Down

(OP)
I'm content to let the statue designers sort out the details of their scope for now. Early days. I'm curious though Mike: why do you feel that horizontal bracing/diaphragms are necessary? I view the skeleton as just a big braced tube capable of resisting torsion sans diaphragm(s). There are some transmission towers near my house that are built this way (diaphragmless).

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

The budda is not a tube as soon as any of the material folds back upon itself... Which from the picture, it does. A lot.

Better to think about this as a stressed skin, like an aircraft. I do agree that the responsibility isn't your's on that point, but I stand by my questions. I hope your scope is *very* well spelled out.

RE: Tie the Buddha Down

(OP)
The skin is not a competent structural tube but the structural steel tube within is. Or at least it's intended to be. Are you guys worried about horizontal bracing between the skin and structural steel tube? My expectation is that, when all is said and done, the outriggers with either be braced horizontally or made beefy enough that the don't require it.

All concerns regarding the design of the superstructure will be the responsibility of... the designer of the superstructure. Now how about some answers to my specific questions regarding the base connections?

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

KootK:

It looks to me like the skin could be of pounded copper, attached by unknown spirit forces to the materialistic steel frame. shocked

I personally do not think of copper as a structural material, especially for the skin of an 11 story building. Personally, I feel that there will have to be something more here structurally... idea

I guess a good model to investigate would be the Statue of Liberty...

Mike McCann, PE, SE (WA)


RE: Tie the Buddha Down

(OP)
How about this: you guys agree to focus all future comments on the portion of the structure below the sandals; in return, when the shop drawing show up, I'll post them here for the group to devour mercilessly.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

Lol... I like it Kootk, and I am very impressed with your patience.

DIWYDAG anchor rods. Treat this as if it were be base of a large bridge, and anchor the living hell out of the thing.

I would be looking for long rods to something very solid, either competent bedrock or large mass pour concrete foundation. For the connections themselves I'd be keen to see a good old thick plate (like a multi-ply, multiple inch), or a casting assembly. Don't laugh; Custom cast assemblies have come way down in price, and are very effective. I'd use traditional framing right down to the base, and then "capture" the bottom with the casting or custom steel base assembly.

Either way, you need to have the connection to the base be capable of taking all overstrengths. I'd effectively design this like the base of almost any building, if you're willing to have lots of structure to foundation connections, and like a couple of large bridge piers, if you're keen to reduce the number of connections to the fewest possible.

RE: Tie the Buddha Down

Well... it is sketch... from China.

Mike McCann, PE, SE (WA)


RE: Tie the Buddha Down

Let's all sing it together now... A 1 and a 2 and a 3 and a...

Tie me Budda man down sport, tie me Budda man down....

Mike McCann, PE, SE (WA)


RE: Tie the Buddha Down

(OP)
Nice Mike...

Alright, Dywidags if I have say. Prestressed?

@IR: statue frame sits on shaft made from 300 walls and four 800 x 800 columns in corners. Shaft sits on monster pad footing. Ignore the base in the sketch.

So far, the only difference between this and a 6' statue is scale. As structural engineers, it's our prerogative not to be intimidated by scale.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

Yes, prestressed... WITH the debonded length. Often contractors and inexperienced teams think that you can bond the full length, but the failure mechanism them involved isn't what you want.

RE: Tie the Buddha Down

Thinking of the very base, at the connection between basic rock, concrete foundation, steel tower baseplates, and the copper statue suspended structure - kind of like the Statue of Liberty? with the copper skin outside of a structural tower?

For corrosion prevention (different electro potentials) and movement and thermal expansion and the very real probability of all the various parts of the sculpture moving at different rates at different times. Would you want to put a thin impermeable rubber or poly layers or sheets so that potential is stopped? Electro potential isolation would also require insulating shields for the bolts and fastener hardware.

Now, a gasket or sheet even 1/16 thick (1 -2 mm) would structurally require a "moment connection through the baseplate bolts" but would not the extra complexity of the structural loads be worth the avoidance of other problems?

RE: Tie the Buddha Down

KootK....while the structure looks a bit like a transmission tower, the skin is transmitting loads to the structure that a transmission tower never sees because of the openness of the structure. Torsion is an issue.

As well, there needs to be clear access to the turnbuckles as they will need to be tweaked as the load is placed on the structure.

I agree with the Dywidag anchors. Make them long enough that you don't have to worry about development. Cheap insurance.

Also keep in mind that your "11-story" structure does not have the dead loads of an 11-story building, so even if you are in the predominately lower wind zones of Canada, overturning might be an issue. You're catching a lot of wind area with seemingly little to resist at the base.

RE: Tie the Buddha Down

Well, I don't see any structure to support the ears of the statue. I can't believe their structural engineers would not recognize such an oversight. In my experience, that is the first issue I would address. Have you contacted your client rep on this?

My recommendation would be to install a moment frame sideways to the main structure with a direct connection to the lobes of the ears. Simpson, et al, make pre-engineered moment frames that could tie the ears to the main structure. A moment frame would permit any required movement of the ears in extreme wind events yet retain them under major seismic forces. I see there is no public access to the ears of the statue which should shield your client from the inevitable litigation when swaying ear lobes throw someone to the floor.

Foundation? That's why most Buddha statues are sitting or lying down and have a big belly - it keeps them from falling over and thus they need no foundation, other than clearing people out of the way so the thing can be built.

Interesting project.

RE: Tie the Buddha Down

(OP)
@racooke: dissimilar metals issues will be an issue for the designer of the superstructure. By the time that it gets to me, it's just a plain old carbon steel to concrete base plate connection.

@CEL: know of a good reference for the debonded/prestressed method? I've got a few paragraphs in a PIP document but that's it. Debond it all? Prestress to the max? Provide an anchor plate and use standard anchorage checks? Transfer shear via friction?

@Ron: torsion is an issue but it is primarily an issue for the superstructure designer. And rest assured that I plan to devise a base capable of resisting the applied loads. And "applied loads" will mean those supplied by the superstructure designer and verified by me. Keen observation with the turnbuckles. The supporting shaft will have an access hatch up the middle for just that reason.

@Buggar: I hear 'ya. The ear lobes will be liquid filled mass tuned sloshing vibration dampers. No public access.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

There is a decent US Army Corp of Engineer's guide, but I'll be darned if I can find it online... Diwydag is a good place to start:http://www.dsiamerica.com/products/geotechnic/dywi...

Also, I would suggest that you have 1/2 to 2/3 bonded, depending on your specific situation, and use only a minor prestress. You're just looking to keep it all tight and allow for shrinkage, etc.

Generally I've anchored like this to bedrock, but in the case of the Alexandra bridge we "made" our own rock by pouring the old piers full of concrete. The techniques for rock are generally applicable for concrete, and conservative when used that way...

RE: Tie the Buddha Down

This is a very interesting project. We have imported products from China (sunshades mainly), and the engineering can be a bit sketchy. When I asked about snow loads and drifts they seemed very puzzled. If they have an engineer registered in Canada, it could be fine, but it is the type of structure that some think falls outside the NBCC and that can lead to a headache if you are the only Canadian Eng involved (CSAS16/CWB Headaches/Steel worker unions...). Unless they have shown that they have a qualified engineer at this point, I too suspect you are amply more qualified to determine the anchorage forces and devise an appropriate base connection. While there is the liability issue from a contractual standpoint, I think this is a case where you might want to look into a few things to make sure. This is the type of project that makes the press and we all know what happens if there is ever a problem anyway.

I would research the Statue of Liberty to see what others have done with respect to dissimilar metals. Liberty had extensive repairs in 2012. I suspect you will be able to find a lot of useful discussions; however, if your role is limited to the foundation I doubt there is much for you to concern yourself with beyond the grout between the base and the Budda where it intersects your scope of works.

RE: Tie the Buddha Down

(OP)
@Brad: I can feel exactly those kind of headaches coming on I'm afraid. A bridge to be crossed when we come to it I suppose.

@Everybody: so we've got a concensus for prestressing. Why is that? If I told you this really was a braced frame for a mid-rise building and I was going with some good old F1554's, you wouldn't bat a collective eye. So what's so special here? And no, I was not able to maintain a straight face while typing that last bit.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

What's different is a whole lot of things. Off the top I'd say:

- Lack of weight (as mentioned by others above).
- Lack of inspection/ease of access and maintenance (yes, I am assuming here).
- Lack of redundancy... This is not going to have the same number of connections as a midrise would.
- Lack of reliability/known conditions.

- Lots of "how the hell is all of this going to behave".
- Lots of secondary stresses (and potential for releases!) due to mixing of systems and materials.
- Lots of dubious workmanship.
- Lots of shrinkage (and potentially creep) in a mass foundation.

RE: Tie the Buddha Down

Perhaps studying the construction of the Statue of Liberty may offer some clues.

RE: Tie the Buddha Down

(OP)
Thanks for the list CEL. I should point out that there is actually a significant amount of weight coming down on the support structure. The entire statue (~200 metric ton) is supported by the steel skeleton frame.

I intend to go with a prestressed AB connection for all the of reasons supplied by contributors above. My scepticism regarding pretensioned anchor bolts is, in part, informed by the excerpt from PIP STE05121, shown below. In an application where construction quality is a concern, reliance on prestressing seems like it would exacerbate the reliability problem rather than alleviate it.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

(OP)
The attached sketches (4 pages) show the preliminary concept for the statue support. I'd love to get some feedback on them. Note that I haven't done much with the column connection as, for now, that's still in the statue supplier's scope.

In discussing the column base connections with the statue supplier, two issues have arisen:

1) When asked about the column connections, the statue supplier recommended "just welding them down". Would that be feasible? Would there be issues with weld quality, fatigue, plumbing of the structure etc?

2) The statue supplier is insisting that the column size is as follows: wide flange; section depth = 200 mm; flange width = 500 mm. And no, I didn't miss type any of that. The statue supplier writes it that way and sends me pictures that reflect those dimensions. I can't find the section in any catalogue and, to be frank, the proportions seem unlikely to me. Anybody heard of such a thing?

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

You might want to look at wind turbine foundations as a ref.
I saw one recently, 144 anchor rods, 150ksi steel, 1.5" diameter.
They were bolted into a ring that was set into about 8' of concrete, and then they projected enough to hold the base.

You might recall that when they rebuilt the Statue of Liberty all of the armature that contacted the Cu skin was replaced with 2205 duplex stainless steel.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube

RE: Tie the Buddha Down

I like your sketches, and the approach is a good one. I don't know if I am completely convinced as to the thicknesses, but I think we've confirmed that I tend to be more conservative than you...

I'd give serious thought to using an increased cover (2" or 2.5" as per bridge code) and a minimum of 35MPa concrete, as is required in parking garages these days.

As for the steel section, I have run accross these only second hand. I have a good buddy (childhood friend all the way through to University and beyond) who's an Engineer with ProSlide. They make what it sounds they make - Water slides. They often do business in China and he was telling me they have absolutely unbelievable sections that he couldn't see the purpose behind.

When dealing with chinese construction, you have to remember that they are a completely unique structural engineering tradition. They do not apply plastic analysis in steel, partly due to a long history of crap steel. Their steels are improving these days, but still aren't great. So it is likely that the section is compact in the extreme and made from 250MPa or so, low ductility, crap. That the welds theya are recommending are about as good an idea as our field welding was in the 1920s, with very poor notch toughness. Good luck with matching your electrodes... *sigh*

RE: Tie the Buddha Down

(OP)

Quote (CELInOttawa)

I like your sketches, and the approach is a good one. I don't know if I am completely convinced as to the thicknesses, but I think we've confirmed that I tend to be more conservative than you...

Thanks for taking the time to check out the sketches CEL. I think that we're just conservative about different things in different ways sometimes. Which thicknesses are you concerned about? The mega-shaft thing doesn't depend on any connection to the roof slabs that tie in. It's a pure cantilever from the foundation below. At least, that's the story that I'm telling. Does that help on the thickness front any?

Quote (CELInOttawa)

I'd give serious thought to using an increased cover (2" or 2.5" as per bridge code) and a minimum of 35MPa concrete, as is required in parking garages these days.

I think that you've touched on something that I'm also worried about. This is unheated space and there's really no building envelope to speak of. In that respect, it really does mimic a SE asia temple. I'll consider incorporating some parking standard durability requirements. That's clever.

Thanks for the Chinese steel info as well. I'll change my tack from assuming it's a communication error to assuming that it's a bizarre section (by NA standards at least). You called it right, the b/t on the flanges is freakishly high. The steel quality issue certainly doesn't make the "just weld it down" connection plan any more appealing.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

(OP)
@EdStainless: thanks for your reply. Can you point me to anything that would show me how a turbine foundation is constructed? It's a ways outside my realm of experience.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

(OP)
Tower by others for now IR.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Tie the Buddha Down

Quote:

The mega-shaft thing doesn't depend on any connection to the roof slabs that tie in. It's a pure cantilever from the foundation below. At least, that's the story that I'm telling. Does that help on the thickness front any?

Yes.

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