Wind uplift tables...for a wall?

[AcousticRy]

The company which I work for has a SIPS style panel that uses 20 gauge steel framework that is imbedded in a set of grooves in a styrofoam cored, cement board skinned (on both sides) panel. As we have travelled to different tradeshows, one of the things that we have been asked for is a wind uplift table for our panel. Talking to any amount of engineering firms or testing laboratories, we've yet to truly figure out how to examine this particular aspect of our board, and if there is a certified test for doing it (Potentially the ASTM E2127-01a?) nor have we actually seen a "wind uplift table" that applies to anything but a roofing system. Is this simply a tensile strength rating? Or does such a table exist for wall systems? IT is rather confusing as we know how to calculate wind uplift on a roof..and the force that it applies to each truss, but we are still not getting an answer as to what the wind uplift resistance of a wall, nor what a table that is representative of this resistance even looks like. If someone could provide some information and an example to this type of table, or the testing that is used for finding out such information, I would be immensely grateful. Thank you.

Ryan

 

[jheidt2543]

I think I would suggest contacting Underwriters Laboratories. The perform wind uplift tests on lots of different material configurations and could provide suggestions and may even do the testing for you (for a fee). They are in the Chicago, IL area.

 

[FSS]

Not exactly sure how you are marketing your products or their end-use. However, look at Simpson Strong-Tie's web site for their engineered shearwall segments. I think some other manufacturers offer similar products. This may give you some insight into what kind of info engineers are looking for.

 

[AcousticRy]

Well, the SIPS system is one that is marketed for all levels of housing, from low-cost housing projects to upper end housing, because it has quite a bit of flexibility built into it. The marketing in question is in large coming from Texas, Florida, and Alaska, asking about wind uplift, and the most baffling thing is that we've never seen a wind uplift table for a wall system, so we're not even sure what they look like.

 

[RMalaska]

Speaking with experience in Alaska, there is no wind uplift table for walls, directly. I'm assuming the question is that when the roof trusses are attached to this wall panel, how can engineers be assured that the load has the ability to transfer to the sill plate. In high wind regions, roof overhangs have very amplified uplift loads, and each truss must be anchored to the wall below. If this connection is being attached to your cement board or the 20 ga studs, i would be very worried about pullout of the fasteners or block shear rupture of the panel. The suggestion to talk with UL is excellent....they could lead you in the right direction. Also, you may check some of your competition. We commonly use either Premier or Insulspan.

 

[JAE]

The word "uplift" may be exactly what RMalaska is talking about - the ability of your wall panel to resist the upward pull of wind loads from a bearing roof...assuming that your wall panels indeed support the roof structurally.

If you wall panels are non-load bearing and simply work as veneer attached to the main structure, then the word "uplift" may be simply mis-spoken - where they really mean wind suction - outward pressure on the exterior skin due to wind forces. In this case, there could be tables developed that show, for different wind speeds (90 mph, etc) what maximum span the wall panel can achieve under the component wind pressures required by the building codes.

 

[AcousticRy]

Well, using a fork truck we did some tensile load tests with a Simpson Strong-Tie. This was nailed through the concrete skin and into both the steel of the strong tie and the steel of the C-channel that lays as a top track. Lifting on this, it took nearly 3900 lbs to pull either the track, or the nails out of the track on a single truss. Now, obviously there's some things we could use such as Go-bolts or otherwise, but we are curious as to how far we have to go. Is this particular marking, especially in Alaska or other high-wind areas of any real quality, or must we add some things to our system to provide enough uplift resistance in order to maintain a proper safety level in these areas?

 

[AcousticRy]

These are structural panels, by the way..as the definition of SIPS is Structural Insulated Panel System. I apologize for not having made that clear previously..so tensile strength is an issue, but we've yet to truly have a great deal of problems with strength at all, passing and surpassing many tests and standards, so we are curious about this one.

 

[dpa]

AcousticRY,
It seems to me the easiest thing would be to ask the people who have this question what exactly they need to know about uplift. I think what they are looking for is a blanket answer to what is probably the job of the design engineer. That is, number and size of connectors. Overturning forces on a building due to wind or seismic forces is unique to each each design depending on wall height, wind exposure, or seismic zone etc.