When designing buildings in Southern California, architects must take into consideration the unique climate as well as the possibility for earthquakes and high winds. Robert Andrews of Childs Mascari Warner Architects in San Diego explained the issues that need to be taken into consideration.
"When it comes to installation and application, I need to know how something is going to be installed and how well it's going to be maintained after it's installed. I also need to know its properties, such as with Devonian stone, the quartz component has made it stronger than many other stones. For example, if I want to put 26" square tiles on the fa?ade of a building, I'll need to know the properties of the material because the structural engineer is going to ask me how this is going to take bending, flexing, and whether or not I need to have gaps within the tile itself to make sure that if the element moves that holds the tile, how much mitigation we need to employ in order to make sure that the tile stays intact without cracking because of the movement of the element."
"I see it a lot here in Southern California when we put up a lot of facades or vertical siding, we need to know how the stone is going to respond to movement in case there is an earthquake. When it comes to the floors, we have to be cautious of the expansion and contraction, sealers and adhesives to make sure there are no air spaces underneath the tile, as well as recommended substrates. So specs and any kind of information I can pass on to the structural engineer is very important to me because I can only get something used if I can prove that it will satisfy certain criteria, as far as expansion, contraction and its durability."
"We don't just have to deal with earthquakes, we also have to calculate against 70 mph winds which is fairly substantial. Those are the Santa Ana's, and that's pretty strong. So that isn't going to cause any ground movement, but it can cause other damage, for instance a big canopy coming off your building or a big trellis, it will cause it to move. That is up there with the components, all the elements are put together and if that building moves, how will it respond to that. On one side the building will be expanding, on the other side the building will be contracting."
"In an application where I tried to install a porcelain tile, I had to consider the expansion and contraction of the tile and then I had to prove that it could withstand certain impact and movement. The structural engineer will be the one who will tell me whether or not something will meet design criteria for the state, based upon his calculations. I do have to satisfy some criteria and the more information I have on the product the more likely I'm able to do that."
According to the ATC/SEAOC Joint Venture, a partnership of the Applied Technology Council (ATC) and the Structural Engineers Association of California (SEAOC), Briefing Paper 6 deals with Seismic Code Requirements for Anchorage of Nonstructural Components and consists of two parts. This Part A provides a brief history of how earthquake-resisting provisions of the Uniform Building Code (UBC) have evolved and relates those changes to the expected seismic performance of nonstructural building components in older buildings. Part B describes current trends in the codes for anchorage of nonstructural components and provides design examples based on the 1997 UBC provisions. It states, "The seismic force factor for non-structural and structural components in the UBC (e.g. in the 1994 edition) governs the seismic strength of nonstructural building components. The purpose of the factor is to reduce the risk of nonstructural component failure (that is, the architectural, mechanical, and electrical components). Examples of components that are designed in accordance with this factor are chimneys, parapets, exterior cladding, partitions, ceilings, light fixtures, ornamentation, boilers, fans, elevators, and sprinkler systems." Copies of Briefing Papers can be downloaded from ATC's web site by going to: www.atcouncil.org
Andrews mentioned Devonian Sandstone and asked, "What I would like to see more is testing information on the stone, how it responds to movement, and how it responds to substrate failure. We've used porcelain tiles which are usually cut to 3/8" of an inch thick, it's not very thick at all, and I'd like to know if the stone at that thickness is just as feasible."
Test Specifications for Glacier Blue® Devonian Sandstone are as follows:
Flexural Strength ASTM C880 2563psi
Bulk Specific Gravity 2.58
Bulk Specific Gravity (SSD) 2.63
Apparent Specific Gravity 2.72
Absorption (%) 1.9
Compressive Strength over 19,000 psi
Los Angeles Abrasion Test1
Test Specification: ASTM C 131 Grading
Test Values: NYSDOT Maximum Allowable Loss - 45%
Test Results: 33.61% Loss
Also tested a 48" x 18" x 2" thick paver supported on four corners with a concentrated load applied at the center. The paver withstood over 3,000 lbs. before failure occurred.
1These tests were conducted according to ASTM C 127 Specifications by Atlantic Testing Laboratories, Ltd., Albany, New York and Soil & Material Testing, Inc., Binghamton, New York.
Andrews continues, "If you ever see a graphic of the fault lines in Southern California, this is the reason why we have to build things so sturdily. And because our company is in healthcare, they have even more stringent applications, there is basically a whole subset of code for healthcare facilities."
After receiving samples of Glacier Blue® Devonian Sandstone, Andrews stated, "I think the product is beautiful and it would be nice to see more of it around."
As far as lead time in getting the stone from our plant in New York to the site in California, Robert Bellospirito, President of Devonian Stone of New York cited an example: "For a 16 x 16" square tiles for a 500 square foot space, the turnaround time would be approximately two weeks. All stone is made to order. As far as shipping, it will take usually a week by truck, it would also take a week by rail. If you have to do a large job over 2,000 square feet, it's generally more economical to ship it by rail container because it's about half the price of trucking. You can get door to door service. When you ship it out, usually a common carrier is going to put it in a box truck, they're going to move it to the back of the truck with a power jack and then you're going to need a forklift to take it from the truck down to the ground. If it's a big job they usually have some way of loading and unloading trucks. For 500 square feet, if they're fairly thin tiles you can unload it by hand. We do a really good job of packaging and crating, and we've shipped tens of thousands of square feet out to California and we've had good reports back from customers."
A Los Angeles architect from one of our previous projects noted, "We were looking for a durable material that had a high density that would hold up to weather, both through the issues of heat on the west coast, and a lot of sun, and also the traffic and water and cleaning and those kinds of things. The consistency of the material is very good. Plus the machining that they promised us in terms of the thickness of the material, the gauging of it, it was a good product to work with. The other thing was that a lot of the other colors we were looking at were on the light side, and what happens in full sun is that it becomes very blinding, it's reflective. But the Devonian doesn't have that problem because of its hue. The timeline was very important as well, and they were able to produce the material and get the material to us in a certain amount of time."
Andrews asked, "I would like to know more about adhesives that will work with your stone against water moisture and water vapor. It's basically moisture vapor that re-condenses once it gets under the stone. And if it's going to destroy your adhesives we have to come up with something that will keep the stone intact. More than likely it's a bigger concern on a wall because it will come off the wall if there's water trapped in the wall. But if it's on the floor, it's not going to come up but over time it might move which will cause maintenance problems."
We will be addressing the issue of adhesives in an upcoming newsletter as our Educational Topic of the Month.