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HomeMy WebLinkAboutREPORT Windload 2051 Big Thompson Ave 1995-03 I:\EDrive\12GraphicsDesign\800Misc\windload PRAIRIE KRAFT SPECIALTIES 1500 51 Street South, Great Falls, MT 59405 ph (406) 727-3192 fax (406) 727-3239 sales@pkscabins.com www.pkscabins.com Wind Load Report KOA Kamping Kabins™ March 1995 I:\EDrive\12GraphicsDesign\800Misc\windload The following information has been gathered in response to concerns regarding wind load capacity of the KOA Kamping Kabins. The enclosed information and accompanying photographs will verify that your one- room or two-room KOA Kamping Kabins will more than adequately resist maxi- mum wind load in your area. If we supply any further information or clarification, please call Prairie Kraft Specialties. Wind Load Report – KOA Kamping KabinTM ~2~ March 1995 I:\EDrive\12GraphicsDesign\800Misc\windload Can your KOA Kamping Kabins resist a wind load of 120 mph? As we would say here in Montana – you bet! This report was developed to confirm that your one-room or two-room KOA Kamping Kabins will more than adequately resist maximum wind load in your area. In this report, we have detailed the following items: 1. The importance of the entire assembly of your cabin when exploring wind load ca- pacity; 2. Cabins put to the test in Hurricane Hugo and Hurricane Andrew; 3. Proof of wind load capacity in excess of 120 lbs/ft2 using actual photographs; and 4. Facts relating to tie-down anchors. 1. Assembly is the Key to Wind Load Capacity: In most areas of the building industry, the assembly of a structure is much more important than its individual components. This is also true of your KOA Kamping Kabin. There is nothing better than an actual test to indicate how much a particular assembly or structure is capable of supporting. A classic example is the wooden trusses which are commonly used in resi- dential and light commercial construction. The majority of the values concerning the holding power of the pressed-in metal truss plates have been derived from actual test data. This test data was accu- mulated by loading a truss assembly and measuring the deflections at each of the connections and, in particular, the truss plates. Over the past few years, we have performed a number of engineering calculations on both the one- room and two-room KOA Kamping Kabins. These calculations show that the cabins will resist winds measuring up by 120 mph. However, the calculations are based on a number of assumptions, and typically concentrate on an individual component of the cabin rather than the cabin as a whole. 2. Put to the Test: It isn’t easy to analyze a complete structure and how it reacts as an assembly without literally put- ting the structure to the test at hand. In this case, it would be Wind Load Report – KOA Kamping KabinTM ~3~ March 1995 I:\EDrive\12GraphicsDesign\800Misc\windload difficult to accurately test a complete cabin short of placing one in a wind tunnel. This test has, in fact, been executed with the help of Mother Nature and two past hurricanes – Hurricane Hugo and Hurricane Andrew. A. In the case of Hurricane Hugo, a KOA Kamping Kabins endured the eye of the hurricane and came out unscathed; and B. Two cabins located near Homestead Air Force Base experienced the most severe winds creat- ed by Hurricane Andrew (winds in excess of 150 mph were measured in this area). These cab- ins also suffered no damages with the exception of broken windows caused by flying debris. 3. Pictures Worth a Thousand Words: The old saying that a picture is worth a thousand words will prove true in this report. We have enclosed photographs from both Hurricane Andrew and Hurricane Hugo for your interest. The letter (marked Exhibit 1) and Photos A and B are before and after shots of the cabin which survived Hurricane Hugo in Manning, South Carolina. As you can see from the photos, the cabin suffered no damages. It is also worth noting that there was a couple that spent the night in this cabin during the passage of Hurricane Hugo. In the case of this cabin, not even the windows were broken (it is our opinion that this was extremely lucky considering the amount of flying debris normally generated by hurricane winds). Photos C and D show the two cabins that survived Hurricane Andrew at the Miami South KOA. These photos show some of the destruction that surrounded the two cabins, while Photos E and F sow the cabins themselves. These two cabins (not occupied at the time) were undamaged with the exception of broken glass in the rear windows, undoubtedly caused by flying debris. The front windows were not even damaged. 4. Should Tie-Down Anchors be installed? Another matter of concern to many building officials is whether the cabins need to be anchored to the ground with tie-down anchors. The cabins shown in these photos were not tied down with hurricane anchors. It should be noted that the cabins did not move during the hurricanes. Calculations based on wind loading will show that the cabins will not overturn with hurricane winds measuring up to 120 mph. These calculations will show, Wind Load Report – KOA Kamping KabinTM ~4~ March 1995 I:\EDrive\12GraphicsDesign\800Misc\windload however, that the cabin might slide if placed on an asphalt or concrete slab with sand between the concrete and the pressure treated skids. The reality of nearly every cabin installation is that the skids are placed on the ground or bedded in crushed gravel, sand, shells, etc. This was precisely the case of the cabins that went through Hurricanes Hugo and Andrew. The friction between these ma- terials and the cabin skids was such that the cabins did not slide. However, if local building codes do require that the cabin be anchored, it can be a fairly easy pro- cess. We recommend using a 30” screw-in earth anchor, which is capable of holding 1,400 lbs in normal soil. The eye of the earth anchor is attached to the pressure treated skid using a ½“ x 5” long lag bolt with a ½“ washer on its head. Exhibit 2 illustrates these anchors. We hope the information included in this report sufficiently confirms any doubts you may have had con- cerning wind load capacity of your KOA Kamping KabinTM. Again, if we can supply any further infor- mation or clarification, please do not hesitate to contact us. Loren Smith Professional Engineer Wind Load Report – KOA Kamping KabinTM ~5~ March 1995 I:\EDrive\12GraphicsDesign\800Misc\windload Wind Load Report – KOA Kamping KabinTM ~6~ March 1995 I:\EDrive\12GraphicsDesign\800Misc\windload Photo A Wind Load Report – KOA Kamping KabinTM ~7~ March 1995 Photo B I:\EDrive\12GraphicsDesign\800Misc\windload Photo D Wind Load Report – KOA Kamping KabinTM ~8~ March 1995 I:\EDrive\12GraphicsDesign\800Misc\windload Photo F Photo E Wind Load Report – KOA Kamping KabinTM ~9~ March 1995 I:\EDrive\12GraphicsDesign\800Misc\windload