Anchors away?

Code changes may limit your choices and increase your cost of installing mechanical anchors.

Recent code changes may increase the cost of post-installed anchors by as much 300 percent. Highly controversial, changes to the 2003 International Building Code (IBC 2003) are very specific about mechanical anchor use.

The upshot of the code change is that any anchor must remain in place in case the concrete cracks through the anchor placement from natural forces or seismic events, says Brett Turley, national manager of technical services at Simpson Strong-Tie Anchor Systems.

“It is hard to say which applications will be affected but, generally speaking, wherever an anchor is installed into a concrete member that encounters tensile forces, the new type of cracked concrete anchor must be used. We expect many engineers will specify this anchor to avoid confusion between suitable and unsuitable applications,” Turley says.

The IBC 2003 and NFPA 5000 codes include strict provisions that address concerns of post-installed anchor failure in cracked concrete. Both are based on ACI 318-02, which has its roots in European standards. Some in the industry allege it was ramrodded through the review process by an international concrete fastener interest.

Only a handful of mechanical anchors meet the standard and are often as much as four times as expensive as conventional drop-in or wedge anchors. Concrete fastener specialists report the new anchors can be more time-consuming to install, driving up installation costs.

Code controversy
Those against the standard say it eliminates most post-installed mechanical fasteners in use because they haven’t been tested under the ACI 318-02 Appendix D, and can’t be due to testing methods controversy.

Many industry experts believe the code change was unnecessary because it’s not based on any documented problems with post-installed anchors failing due to cracking.

“ITW Ramset Redhead believes in standards and helps make them. The standard must play a role to enhance safety and performance, but the cracked concrete standard and testing method creates a standard where there is no evidence that anchors have failed due to cracking,” says Mike Lynch, vice president of government affairs for ITW Ramset Redhead. “This test presupposes that today’s anchors in cracked concrete will fail. We haven’t found this. As a $10 million company, if such an instance would have happened, we would have heard about it.”

Turley concurs. “The main question is how often or likely will an anchor be involved in a crack and be the only one fastening the attachment to the concrete. We are stepping into a whole new landscape in anchoring products. We will continue to develop products to meet code requirements, but does it make sense to have code requirements for a problem that hasn’t existed?”

“Two types of anchors presently meet the standard: A specially designed heavy-duty sleeve-type anchor and an undercut-style of anchor,” says Chris Lavine, ITW Ramset Redhead product engineer.

“The sleeve-type anchors create expansion and friction forces that continue to hold if a crack as wide as .3 mm would travel through the fastener’s hole. These are highly engineered anchors. They use different types of coatings and materials to provide follow-up expansion in the unlikely event a crack occurs,” he says.

Undercut anchors provide installation challenges, Lavine says. “With an undercut anchor, the bottom of the hole must be larger than the top. They are costly anchors and require much more labor to install.”

Simpson Strong-Tie is presently the only U.S.-based traditional distribution manufacturer that has an anchor that meets this standard.

“The Strong-Bolt post-installed mechanical anchor recently met the testing criteria of the new standard. “When you compare the cost of the new Strong-Bolt style with a conventional wedge bolt, you are looking at a cost that will be at least twice as much. Further, other non-U.S. produced anchors that meet the standard are metric, which can create problems for trades set up to do all of their work in English or fractional measurements,” Turley says.

The Strong-Bolt features a tri-segmented clip that can adjust independently for follow-up expansion if the hole size increases due to cracking. Dual embossments on each clip segment allows the clip to undercut the concrete to increase follow-up expansion and a stainless steel clip that has corrosion resistance and a “memory” that causes the clip to expand if hole size increases due to a crack. The Strong-Bolt is easy to identify when installed because of the =/ or “no equal sign” stamped into the head.

Can you see it coming?
The experts agree that because the standard is now ingrained in the IBC 2003 and NFPA 5000 standard, it’s a matter of time before inspectors and engineers begin to enforce it.

“Historically, it takes one to two years for local building departments to begin implementing the new code, so in 2005, we should see more cracked concrete anchors specified. Many building officials are aware of the changes and are prepared to shift to the new anchor type,” says Turley.

“To date, 44 states, the Department of Defense and Washington D.C. reference the IBC standard, but do not yet specifically reference IBC 2003. However, I am aware that New Mexico, Maine, Utah and Rhode Island and the City of Las Vegas have adopted the IBC 2003 standard. I think mechanical, electrical and plumbing contractors will be affected by it. When the building inspection departments begin to enforce it, contractors have no choice but to comply,” Turley says.

Lavine takes a more pragmatic approach. “It will be a long time before this comes into play everywhere. I see this standard only coming into play in heavy duty or life safety situations. You will start to see it in some building codes, and it may bring to light the use of more cast-in-place anchors,” he says.

Published in the March 2005 issue of Contractor Tools and Supplies magazine.

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