Asphalt anchors? 2

[struct_eeyore]

Hi all,

Do any of you have experience with using asphalt anchors? In particular I'm looking at BoltHold. The model I'm looking at is rated for 2000 lbs pullout, but I just feel sketchy using them, especially in hot weather (Florida here). Contractor is pushing on using these to hold down some bleachers - so nothing critical - till hurricane hits...

 

[XR250]

I'd like to see some legit testing of these anchors. The values seem high.
Have you checked the asphalt for the bleacher gravity loads?

 

[KootK]

Neat. The article linked on their website looks reasonably legit: Link

I'm sure that, if you email that Rodor Teich guy, he'll be all over trying to convince you that these things work. He is German.

I'd be curious about edge distances etc. Obviously, to resist 2000 lbs, you'd want to engage at least 2000 lbs of asphalt.

I'd also be curious about asphalt design properties. A playing field parking lot is surely not the same animal as an airport runway.

 

[XR250]

I would feel better about the test if they used a crane to pull instead of reacting the load to nearby surrounding areas with their test rig

 

[KootK]

It's often a similar setup for Hilti I think.

 

[human909]

The German company that actually makes these things is busy promoting these as anchors for structures.

https://www.toge.de/en/products/item/65-asphalt-screw-anchor.html#desc

 

[Ingenuity]

I would feel better about the test if they used a crane to pull instead of reacting the load to nearby surrounding areas with their test rig

That asphalt anchor pulltest setup is basically identical to how concrete and masonry anchors are tested, either UNconfined or confined pull test, according to ASTM E3121 Standard Test Methods for Field Testing of Anchors in Concrete or Masonry.

A crane would not be a good idea to apply load for a pull test of an anchor.

 

[JLNJ]

Just to hold down some bleachers?

I wouldn’t use the word “just”. A lot of people could be involved and they might be stressing those flimsy bleachers to the max with their impact loads.

I would not use an unproven anchor where lives are at stake.

 

[XR250]

A crane would not be a good idea to apply load for a pull test of an anchor.

Yes, I was kinda being facetious. I don't feel like those standard anchor tests make sense for Asphalt unless a lot of judgement is used by the designer. My limited experience with asphalt is that it breaks easily and it very soft when baking in the sun (I've found a few of my motorcycles on their side after the kickstands dug in on a hot day)

 

[phamENG]

Those are pretty interesting. Looks like you have to penetrate into the base layer (at least) and fill it with grout before inserting the anchor. So I would think it's relying on a mushrooming effect under the asphalt to engage the whole section. They also have lots of warnings on their website. I like the big banner on the homepage "Asphalt is 20 times weaker than concrete." At least they're honest. They also don't recommend using these for static loads. Only very brief cycles. They specifically call out the flow effect in hot weather that XR250 is alluding to.

I don't think I'd be brave enough to spec them on anything bigger than a temporary hold down strap, though.

 

[phamENG]

And here it is. I wouldn't use these on bleachers or anything else upon which a human life would depend - "just" as JLNJ stated.

 

[phamENG]

It's also worth noting that the installation instructions don't seem to say anything about the asphalt thickness - just that the various anchors have certain capacities. Seems like the thickness of the asphalt would be pretty important in this determination.

 

[MR_E30]

This product does not instill confidence. At all.

I've worked with asphalt. One of my properties has an asphalt parking area. I added a wooden fence next to the house to give the tenants a place to store things outside.

I figured I would need to give it my all to blast through the asphalt with a pick ax, but that was not the case. Just dropping it from waist height allowed penetration. Outside temperature wasn't above 60 degrees.

Would not recommend these for anyone on this site.

 

[Rabbit12]

I especially like my Teich's qualifications:

Rudor (Dori) Teich is president of Designated Parking Corp., which manufactures parking barriers and asphalt anchors. Teich holds a bachelor’s and a master’s degree in electrical engineering yet spends more of his design time on mechanical designs than electronic ones. His professional background includes management and design of hotel room management systems, garage door controls and burglar and fire alarms.

How does one go from hotel room management systems and garage door controls to an expert in asphalt anchors?

 

[BridgeSmith]

I agree with the other posters - sketchy test setup and sketchy qualifications of the manufacturer's 'technical staff'.

If the contractor wants to demonstrate the adequacy of the anchors with a legitimate test of their own (with a wider-spanning rig and testing on a hot day, with the actual asphalt thickness and compaction to be used), that's the only way I'd even think about allowing those anchors.

OTOH, there's not likely to be anyone using the bleachers during a major hurricane...

Rod Smith, P.E., The artist formerly known as HotRod10

 

[LittleInch]

I had zero idea what a "bleacher" was until I had to go look it up. Its a spectator stand for anyone else.

So assume you're talking about wind load mainly. That sounds like a constant load to me.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bridgebuster]

What does the bleacher manufacturer recommend? Could you install some screw/earth anchors and clamp the frame to them?

 

[EdStainless]

Even here in WI the bleachers don't sit on asphalt. There are poured concrete supports (beams? pads?) while the rest of the area is asphalt. Part of this is to prevent them from sinking into the ground, but it does give you a great place to anchor them down.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy

 

[Ron]

Structee....not likely you'll find 4 inches of asphalt anywhere in Florida except on major roads. I question their results as well....need to know temperature of the asphalt at time of test and pull rate among other parameters.

I agree with bridgebuster...use earth anchors.

 

[ldeem]

I think you have to consider the dead load of the bleachers and creep as asphalt deflects under the constant load. Which of course leads back to cutting out the asphalt and pouring concrete pads.