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HY 200 Edge Distance

Posted by Tomover 6 years ago
HY 200 Edge Distance

We are reviewing a proposed connection to a hollow-core precast, prestressed concrete wall panel that utilizes 1/2" diameter x 5 1/2" embed. threaded rod anchor fastened with the Hilti HIT HY 200 system. A generic cross-section through the wall panel is attached. In the proposed connection, the anchors are to coincide with the center of the 3" wide webs of the wall panel. While there is no edge distance issue at the face of the wall panel, would the width of the webs not limit the design as, in a perfect installation, the edge distance would be only 1 1/2"? This anchorage condition does not appear to comply with the limitations of ESR-3187. Any insight that you might provide would be much appreciated.

Edge distance,HIT-HY 200

1 Reply
Posted by Randyover 6 years ago
Hilti Verified

Thomas:

You are correct in your assessment that if an anchor was installed into the center of the rib (web) of the precast panel the edge distance would be 1.5” in both directions. You might consider HIT-HY 70 Hybrid for Masonry Construction with screen tubes and locate the anchor on the panel face in line with a foamcore cell. Although we don’t have published data for HIT-HY 70 in pre-stressed concrete foamcore panels our published values for hollow CMU should provide a starting point for determining load capacity. You may want to consider testing to verify anchor capacity based on specific requirements for the connection. The HIT-HY 70 screen tube system relies on the void or hollow sections to create a mechanical interlock. This is achieved when the anchor rod is inserted and the adhesive is forced through the screen tube and into the void. You will need to develop some means of removal insulation around the backside of the anchor hole. Care should be taken when drilling to avoid spalling the backside of the concrete panel at the foamcore cell. Many contractors often start the hole with the drill in hammer drill mode and then switch to rotary only to finish the hole. Another option would be to consider the Kwik HUS-EZ screw anchor and testing to verify anchor capacity. 

Link to the HIT-HY 70 section in our Anchor Fastening Technical Guide, 2017 digital edition: https://submittals.us.hilti.com/PTGVol2/#224 Reference Figure 5 and 6 on page 229 for a graphic representation of the screen tube system.

Link to the KH-EZ: https://submittals.us.hilti.com/PTGVol2/#330

Let me know if you have any questions.

Regards,

Randy

HIT-HY 70,Foamcore Precast