Stone Soffit System Help

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Author Message Brian Payne, AIA Senior Member Username: brian_payne Post Number: 41 Registered: 01-2014 Posted on Tuesday, June 10, 2014 - 03:30 pm:    I am looking for any recommendations on a system to horizontally support 4 inch thick limestone to match the wall construction. Any suggestions? George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 751 Registered: 11-2004 Posted on Tuesday, June 10, 2014 - 03:39 pm:    What does the ILI Handbook say? I know at one time it had some recommendations for gravity loading in soffit and similar situations. Liz O'Sullivan Senior Member Username: liz_osullivan Post Number: 149 Registered: 10-2011 Posted on Tuesday, June 10, 2014 - 03:42 pm:    Kahn would say to "honor the materials that you use." But that doesn't help at all, does it? Wayne Yancey Senior Member Username: wayne_yancey Post Number: 655 Registered: 01-2008 Posted on Tuesday, June 10, 2014 - 03:50 pm:    Brian, Go to http://www.halfenusa.com/ for inspiration. Halfens soffit anchors may work for stone. Also check the Marble Institute of America manual. Wayne Wayne Robert E. Woodburn, AIA, CSI, CCS, CCCA Senior Member Username: bob_woodburn Post Number: 88 Registered: 11-2010 Posted on Tuesday, June 10, 2014 - 04:03 pm:    I asked the stone what it wanted to be, and it said, "I like bedrock..." (apologies to Kahn...) ken hercenberg Senior Member Username: khercenberg Post Number: 772 Registered: 12-2006 Posted on Tuesday, June 10, 2014 - 04:26 pm:    Halfen has a great system but it costs. A lot. There are a number of options available. See Cold Spring Granite, Hohmann & Barnard, and similar firms for their stone anchoring systems. MIA and ILI do have some useful details but they may not be all-inclusive of some options offered by manufacturers. spiper (Unregistered Guest) Unregistered guest Posted on Tuesday, June 10, 2014 - 05:57 pm:    Depending on the quantity of the soffit and the timeframe of the project you could consider reducing the weight of the soffits by going to a composite panel at these locations. Stone Panels, Inc. can do thin stone panels from the same material and the same quarry and they will be much easier to mount. They are not cheap and they have a long lead time but it may help you rest easier. ken hercenberg Senior Member Username: khercenberg Post Number: 773 Registered: 12-2006 Posted on Tuesday, June 10, 2014 - 07:55 pm:    Oh, and whatever system you use, don't use chemical anchors. Edward J Dueppen, RA, CSI, CCS, LEED AP Senior Member Username: edueppen Post Number: 8 Registered: 08-2013 Posted on Wednesday, June 11, 2014 - 08:43 am:    Ken, you roused my curiosity. Why not chemical anchors? ken hercenberg Senior Member Username: khercenberg Post Number: 774 Registered: 12-2006 Posted on Wednesday, June 11, 2014 - 10:33 am:    After the fiasco at the Big Dig where the chemical anchors in an overhead application failed horribly, there was backlash about putting chemical anchors in permanent stress/tension applications such as heavy soffits. It may be overkill, and maybe the anchor manufacturers have changed their stance again since then, but right after it happened I was instructed to avoid it by structural engineers and folks like Hilti. George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 752 Registered: 11-2004 Posted on Wednesday, June 11, 2014 - 11:52 am:    Hilti did the corrective work on the tunnel failure. I heard that the issue wasn't anything intrinsically wrong with chemical anchors, it was in the installation and quality control. If you aren't relatively precise in drilling the hole, and most important, if you don't clean the dust out first, you don't achieve the design structural capacity. Hilti's fix used an expansive anchor (perhaps with adhesive as well, I don't exactly remember) so they had a mechanical means to resist the gravity load. Like Ken, I don't know where they are now with their recommendations, but the point to take away - installation is perhaps more important than product in this application. I second the recommendation about Halfen - they can solve a myriad of tricky structural connections. True about the cost of their systems. On the other hand, a lawsuit resulting from falling limestone could be a bit expensive too, eh? Lynn Javoroski FCSI CCS LEEDŽ AP SCIP Affiliate Senior Member Username: lynn_javoroski Post Number: 1829 Registered: 07-2002 Posted on Wednesday, June 11, 2014 - 12:01 pm:    Read about a falling concrete panel here: http://www.nbc15.com/home/headlines/UPDATE_Milwaukee_Garage_to_Reopen_Year_after_Accident.html Yeah, a bit expensive. Lynn Wayne Yancey Senior Member Username: wayne_yancey Post Number: 656 Registered: 01-2008 Posted on Wednesday, June 11, 2014 - 12:24 pm:    Pay attention to George's last comment. You get what you pay for. We are to poor to buy cheap. ken hercenberg Senior Member Username: khercenberg Post Number: 776 Registered: 12-2006 Posted on Wednesday, June 11, 2014 - 12:50 pm:    To my understanding the failure in the epoxy was due to cold flow (creep) which occurs over time. See http://en.wikipedia.org/wiki/Big_Dig_ceiling_collapse for a wiki post about it. George A. Everding, AIA, CSI, CCS, CCCA Senior Member Username: geverding Post Number: 753 Registered: 11-2004 Posted on Wednesday, June 11, 2014 - 12:55 pm:    I wanted to clarify my previous comment which wasn't entirely clear - there isn't anything intrinsically wrong with chemical anchors, assuming you use the right anchors and install correctly with proper testing and quality control. There were issues with the epoxy used in the ceiling collapse as Ken stated. Read about it in the NTSB report: http://www.ntsb.gov/doclib/reports/2007/HAR0702.pdf Edward J Dueppen, RA, CSI, CCS, LEED AP Senior Member Username: edueppen Post Number: 9 Registered: 08-2013 Posted on Wednesday, June 11, 2014 - 01:15 pm:    George - thanks for sharing this document. I have a new understanding of the limitations of epoxy anchors. Mark Gilligan SE, Senior Member Username: mark_gilligan Post Number: 665 Registered: 10-2007 Posted on Wednesday, June 11, 2014 - 01:29 pm:    These suspended systems need to be designed by a registered engineer. While the detailed design may be delegated the engineer designing the building should make sure that the structure can accommodate a reasonable design strategy. There are special code provisions related to the installation of adhesive anchors that suggests that any specification for their use be reviewed if not written by somebody who is familiar with the code provisions. John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1577 Registered: 03-2002 Posted on Wednesday, June 11, 2014 - 06:24 pm:    In the case of the failure on the Big Dig (in my fair city), it was reported to be cold flow as Ken mentioned. (There were several structural engineers involved in the design and construction of these anchors.) There were some lawsuits about whether the formulation was appropriate, and whether the manufacturer's recommendations were followed or correct. My own take on that issue, after reading about it, was this was a bit of a red herring; but I don't know what the courts concluded. It also seemed to me that there was not much redundancy in the system, allowing for progressive collapse - one anchor no longer carrying any load led others nearby to be significantly overloaded. The fix was to use mechanical anchors as mentioned above. I believe there were some code changes made after this incident to address the issue. John Bunzick, CCS, CCCA, LEED AP Senior Member Username: bunzick Post Number: 1578 Registered: 03-2002 Posted on Wednesday, June 11, 2014 - 06:30 pm:    My post above was about the collapsing concrete ceiling panels. But the Big Dig also had a failure of lighting fixture attachment after that, which probably did not get much national publicity. In that case; there was corrosion between stainless steel attachment hardware and the aluminum of the fixture (or something quite similar.) In this case, it seemed like the choices made for alloys and materials should have worked, but in the damp (and I suppose polluted) environment of the tunnel - not so good. No one was hurt in this case. I'll skip the story about the excessive water infiltration. anon (Unregistered Guest) Unregistered guest Posted on Wednesday, June 11, 2014 - 05:59 pm:    you might consider using a thin stone of the type/variety you want over a lightweight core material - Thin Stone Systems makes a very nice version of this (there are a few others), and they provide engineering and details for fastening. http://www.thinstonesystems.com/