Streetlamp Anchor Failure

I think you're seeing side-face blowout. Concrete breakout is likely next.

As for how long. Depends when the next big wind hits.

Notice the nut in the right side is nearer the bolt end. Do you think it just unscrewed slowly? or it's the original position of the nut?

Do you think it just unscrewed slowly? or it's the original position of the nut?

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Most likely it's the original position. The setting depth of anchor bolts and leveling the top of the foundation for those is typically not very precise, with leveling of the base plate relying on adjustment of the leveling nuts. They do tend to tighten them up well, otherwise the the pole wobbles badly.

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

Could be bad installation, insufficient edge distance, a gentle nudge from a vehicle or a combination of all of the above.

There’s no way to calculate how long it will last.

Any change the whole assembly got a solid nudge & deflected and they tried to re-plumb it using the bolts?

That could be a shear failure and not a tensile failure too.

The soil (rock ? Mud?) under concrete base is "failing" as well - the whole concrete assembly is tilted to the right in first photo.

The soil (rock ? Mud?) under concrete base is "failing" as well - the whole concrete assembly is tilted to the right in first photo.

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It looks to me that the foundation was out of plumb before. The base plate seems to have been adjusted relative to the foundation so it's level, even though the foundation is crooked.

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

Apparently the anchor bolt at right side mislocated and bended to the right to fit the hole of baseplate so the nut does not match with the base plate..

Another point , the pedestal is out of plumb as BridgeSmith (Structural) pointed out..

We just see two of the anchor bolts and it is hard to foresee the probable failure mode.

We have hundreds of such street lights and identical pedestal and baseplate design. I'll take a look at other poles to see their conditions.

Oopsy. One more issue requiring this pedestal, pedestal foundation, and light pole to be replaced.

We are looking at the near side (NS) of the pedestal, the Left Hand (original) anchor bolt is significantly further from its edge-of-concrete than the Right Hand (RH) Near Side anchor bolt. The RH-NS anchor bolt was also drilled in place, cast in place crooked and slanting significantly, so its bolt can only carry its load at the tip of one bolt corner, not all around the bolt hole as designed. This puts a point-load stress on the anchor plate.
BUT! The whole plate is twisted about its centerline!
The Far Side Right Hand anchor bolt is way too close to the RH concrete edge, violating all code requirements, The Far Side LH anchor bolt is pushed too close to the Far Side concrete edge as well.

A photo of the Far Side concrete should how even more concrete cracking and rebar exposure to rust.

I went back to the lamp pole but there was police car nearby patrolling and I don't want to get out of car and take a closer shot, because he might think I plan to destroy the pedestal. But looking at the other side from the car, It looked ok and I think it is just that particular bolt that has slightly pulled out of the broken concrete pedestal. It means 3 bolts still holding on.

I went to another part of street and this is another one pole. This looks good enough with the anchor bolts not at edge.

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I think that failure starts with one bolt...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

Maybe after the pier settled out of plumb, somebody bashed a shim under the right side of the base plate to help re-plumb the pole. Then that resulted in high local stresses and shear failure.

This sunday when there is no more police car nearby (they love to park near it). I'll take closer look at the baseplate. I have to learn how to look like just texting in cell phone when I will take picture.

I don't want them to review cctv and think I damage it when it falls down in the future.


Kootk, have you seen any pictures or have seen with your own eyes a pedestal baseplate that is retrofited with a side baseplate? Imagine side baseplates (shown in green label in picture below) welded to the top of the column, and anchor bolts inserted in the bottom of the side plate far enough which can't affect the tension breakout cone of the top anchors? I have a project with column where I need to put side baseplates to strength it against lateral movement when new 3 meter high 6" CHB wall be added. I can't add new epoxied anchors at top because of lack of space to drill the thick baseplate.

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By the way. This sideplate retrofit question is not to repair the lamp pole. Of course. It is built by the government and they have billions of dollars to replace that pole. I just want to know if anyone of you has ever seen in your life side baseplates to retrofit the top baseplates when there are not enough anchor bolts and difficult to insert new epoxied anchor bolt at top (for example can't drill a 20mm hole in existing baseplate). Please give some references or even ACI hints about this. Thanks.

I went back to the lamp pole and no one around so took some shots. This is closer picture of it:

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this is picture of the gap with something like shim inserted (background removed to protect location)?

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this is back of it:

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this is right of the crack side:

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So with complete pictures at all sides and angles. what do you think cause the crack? and possible failure mode? Usually how deep do you think they put anchor bars for lamp poles?

Is there any handheld radar or scanner that can map the anchor bars and reinforcement inside? Because I need it to scan a 20" x 20" column to see where to insert Hilti anchor bars (in between stirrups).

About 3'. Attached is a NYSDOT standard sheet for light pole foundations; the NYCDOT. They must work; I haven't seen or heard of any light poles falling down.

About 3'. Attached is a NYSDOT standard sheet for light pole foundations; the NYCDOT. They must work; I haven't seen or heard of any light poles falling down.lol

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3 feet of anchor is pretty deep. How could 3 feet anchors even suffer concrete cone breakout, pullout or side face blowout? In the plan you provided, where are the ties or stirrups locations?

What don't all just use 3 feet anchors for enough safety margin for tension and shear (even if calculated length needs only say 7 inches)? I see typical anchors that are short and hence the anchor failure modes become an issue.

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It could be spalling from water expansion or from corrosion or both.

1) Where was the inspection during installation?
2) Radiographic Test can be used to see anchor bolts, may be during the night with control of people near the column.
3) Nuts are not heavy nuts as per ASME B18.2.2
4) Distance between centerline of column and bolts are very low.
5) How lubrication and torque are controlled?
6) This column must be out of service and replace with a new one.

Regards