Update of anchoring procedures for the ALS floor

09/19/2007

Why now?

• Retrofit of beamlines often replace equipment leaving behind abandoned shells/anchors/studs

• Review of HILTI Technical Guide and phone calls to HILTI highlighted some issues

• Drawings for HDI anchor details often used in BOM were incorrect

Non “Greenfield” installation

• Removed old 4.0.2 switchyard assembly

• Found ~40 cutoff studs or shells – – Eng. Note didn’t discuss this situation– 4” no-go zone for new shells was default

• Concrete patch (which sounded hollow) filling in old wire trench under shield wall

• Steel plate for shield door

Hilti Information• Table for derating of HDI anchors

– Copies for all– Will be added to new version of Engineering Note

M7696

• Multiple derating factors are multiplicative• Abandoned shells / studs need minimum of 3

diameters (of loaded shell) clearance for loaded shell to be fully rated – Conversation with HILTI and testing done at HILTI – “Effect of Abandoned Holes on Capacity of Wedge

Bolts”

For ½” HDI shells, need 7” between loaded shells and 6” from edge to be fully rated. Between 4” and 7” (or 6”) there is a derating factor; below 4” isn’t allowed. Derating factors are per shell / edge and are multiplicative.

Engineering Documentation• Engineering Note M7696 “Concrete Floor

Anchor Applications” controls our work for installing equipment at the ALS.– Version A is most current but needs revisions based

on the information presented here– Does not reference anchor detail drawings– Basic method for calculating seismic loads – uniform

loading, symmetric, no derating• In Work Manager:

– 26D412 : Anchor detail for HILTI ½” HDI– 26D409 : Anchor detail for HILTI HIS (epoxy)– Often are called out in BOM for installation drawings

along with the Engineering Note M7696– Current versions are incorrect; new versions are

being made

Seismic Calculations

• Dave Plate has a spreadsheet for basic calculations – best place to start

• For more complex situations (e.g. derated bolts) need to check all scenarios– Examples from MERLIN– Can have OSD calculate CG but need to have

correct density for parts.

2.13”

4”6”

What is rating of new ½” anchor for tension and shear during a seismic event?

From Eng. Note: ½” HDI has a load of 2380 lbs in tension and 1780 lbs in shear.

(takes into account 33% increase in load for short-term loading)

New anchor

(cutaway of floor)

Trench edge

1.88”

4”

4”6”

Note: Abandoned shell has no effect as 3x diameter away (1/2” HDI has .625” diameter)

Load = 2380 lbs x .5 (for 4” a-a) x .83 (for 6” a-a) x .8 (for 4” a – e) = 790 lbs in tension

= 1780 lbs x .5 (for 4” a-a) x .83 (for 6” a-a) x .65 (for 4” a – e) = 480 lbs in shear

Takeaways• Use revised anchor detail drawings in

BOM / drawing notes (let me know if you are using a different anchor detail).

• If a new shell/anchor is placed too close to existing anchor (e.g. a utility pole or a stand for another beamline), must derate both anchors and recalculate seismic.

• Careful of edges – concrete patches, trenches, steel plates in floor, etc.

Takeaways cont.

• Keep loaded ½” HDI anchors > 4” away from each other and edges at absolute minimum; 7” is necessary to be fully rated.

• Stay > 2” away from abandoned shells- – Possible to core out abandoned shell / stud and grout –

then need 1.5 diameters for fully rated.

• Visit and revisit location to make sure everything is captured in your model – will save rework later – For installations in non-Greenfield areas, consider

adding extra anchor holes in base.