A. Findings of Fact: It has been determined by the Board of Commissioners that, for the purpose of providing for safe living conditions in mobile homes within the jurisdiction of the City and for the protection of the persons and property adjoining such mobile homes, it has become necessary to adopt the following standards requiring mobile home tie-downs.
B. House Bill 1193 Adopted: The Board of Commissioners hereby adopts and incorporates herein House Bill 1193 concerning mobile home tie-down standards.
C. Application of Standards: The following standards for mobile home tie-downs have taken into account probabilities of providing protection to mobile homes from high winds. Mobile homes require two (2) types of anchorage. Over-the-top tie-downs are required to restrict overturning and frame ties are required to prevent the mobile home from being pushed off its piers. The standards apply to single mobile homes up to fourteen feet (14') in width. Double-wides do not require over-the-top ties but are subject to the same requirements insofar as the number of frame ties per side is concerned. The assumption is made that the ground on which the mobile home is situated will support two thousand five hundred (2,500) pounds per square foot. Anchoring specifications assume normal soil and that each anchor, when installed, will hold at least four thousand eight hundred (4,800) pounds without failure.
D. Piers and Footings:
1. All piers shall be placed on footings of solid concrete with minimum dimensions of sixteen inches by sixteen inches by four inches (16" x 16" x 4").
2. Piers shall be constructed of standard eight inch by eight inch by sixteen inch (8" x 8" x 16") celled concrete.
3. Piers shall be topped with a solid concrete cap eight inches by sixteen inches by four inches (8" x 16" x 4").
4. Treated shims shall be driven tight between the cap and the main frame to provide uniform bearing. These shims shall be impervious to salt air and to rot.
5. Other types of piers and foundations of equivalent permanence and weight bearing ability may be approved. The use of a heavy metal adjustable column, anchored to both frame and foundation may be used.
6. Piers shall be centered under each main frame (or chassis) member with a maximum spacing of ten feet (10') on centers. The end piers shall be no farther than five feet (5') from the ends of the mobile home.
E. Tie-Downs: Each mobile home shall be provided with over-the- top tie-downs and frame ties as follows:
TIE-DOWN ANCHORAGE REQUIREMENTS*
10 and 12 Ft. Wide Mobile Homes
| 12 and 14 Ft. Wide Mobile Homes
| |||||
30 - 50 Ft. Long
| 50 - 60 Ft. Long
| 60 - 70 Ft. Long
| ||||
Wind Velocity Miles per Hour
| No. of Frame Ties
| No. of Over-the-top Ties
| No. of Frame Ties
| No. of Over-the-top Ties
| No. of Frame Ties
| No. of Over-the-top Ties
|
10 and 12 Ft. Wide Mobile Homes
| 12 and 14 Ft. Wide Mobile Homes
| |||||
30 - 50 Ft. Long
| 50 - 60 Ft. Long
| 60 - 70 Ft. Long
| ||||
Wind Velocity Miles per Hour
| No. of Frame Ties
| No. of Over-the-top Ties
| No. of Frame Ties
| No. of Over-the-top Ties
| No. of Frame Ties
| No. of Over-the-top Ties
|
70 | 3 | 2 | 4 | 2 | 4 | 2 |
80 | 4 | 3 | 5 | 3 | 5 | 3 |
90 | 5 | 4 | 6 | 4 | 7 | 4 |
100 | 6 | 5 | 7 | 5 | 8 | 6 |
110 | 7 | 6 | 9 | 6 | 10 | 7 |
*Tie-down components utilized, including anchor systems, must be able to withstand at least 4,800 pounds without failure.
1. Over-the-top tie-downs shall be positioned at stud and rafter locations near each end of the mobile home. Others, if needed, may be positioned between them.
2. Wherever feasible, over-the-top tie-downs and frame ties directly beneath them may use the same anchors. Mobile homes with clerestory roofs are particularly vulnerable to high winds. Over- the-top tie-downs at each end of the clerestory section are required in addition to the anchorage presented in the above table.
3. All ties shall be fastened to ground anchors as described in subsection F of this Section and be drawn tight with galvanized turnbuckles or with a yoke-type fastening and tensioning devices. Turnbuckles shall have a capacity to withstand a four thousand eight hundred (4,800) pound tension without failure and shall be ended with jaws or forged or welded eyes. Turnbuckles with hook ends are not approved.
4. All cable ends shall be secured with at least two (2) U-bolt type cable clamps or other fastening device as approved by the enforcing officials.
5. Cable used for this shall be of either galvanized steel or stainless steel having a breaking strength greater than four thousand eight hundred (4,800) pounds. Cable shall be either seven thirty-seconds inch (7/32") diameter or greater, seven by seven (7 x 7) steel cable or one-fourth inch (1/4") diameter or greater, seven by nineteen (7 x 19) aircraft cable.
6. When flat steel strapping is used, it must be in accordance with Federal specification QQ-S-78I, i.e., one and one-fourth inch by thirty five one-thousandths inch (11/4" x 0.035"), Type I, Class B Grade I, with breaking strength at least four thousand seven hundred fifty (4,750) pounds.
7. Steel strapping used for ties must terminate with a D-ring, bolt or other fastening device which will not cause distortion of the band or reduce the breaking strength of the strapping.
8. Wherever feasible, care should be taken to evenly space the frame ties and over-the-top tie-downs. They should not be bunched together.
9. Sharp edges of the mobile home that would tend to cut the cable or strap over-the-top tie-downs must be protected by a suitable device which prevents such cutting when the mobile home is buffeted by the wind. Likewise, special adapters need to be installed to prevent the cable or strap from knifing through the mobile home.
10. Connection of cable frame tie to the I-beam (or other shape) main structural frame member should be by a five-eighths inch (5/8") drop forged closed eye, bolted through a hole drilled through the center of the I-beam. A washer, or equivalent, should be used so that the beam is sufficiently fish-plated around the hole. If steel strapping is used, care should be exercised to insure that minimum bending radius is adhered to so that the breaking strength of the strapping is not reduced.
11. Frame ties should be the connection between the anchor and the steel I-beam (or other shape) main structural frame member which runs lengthwise beneath the mobile home. Frame ties should never be connected to any of the steel outrigger beams which fasten to and intersect the main I-beams at right angles. The outriggers do not have adequate structural strength to resist the frame tie loadings.
F. Anchors:
1. Ground anchors should be aligned so that they are close to a pier. They should also be situated immediately below the outer wall to also accommodate over-the-top ties as well as frame ties.
2. Anchors shall be capable of withstanding four thousand eight hundred (4,800) pounds of pull in a vertical or diagonal direction without failure.
3. Augers shall have a minimum diameter of six inches (6") (arrowheads 8 inches) and be sunk to a depth of at least four feet (4'). Steel rods shall be at least five-eighths inch (5/8") in diameter with a forged or welded eye at top or with a yoke- type fastening and tensioning device.
4. Deadman anchors shall be sunk to a depth of five feet (5') and have a minimum length of two feet (2') and a diameter of at least six inches (6"). Celled concrete blocks are not approved. Solid steel rods shall be at least five-eighths inch (5/8") in diameter with the bottom hooked in the concrete deadman.
5. Anchors to reinforced concrete slabs must be of strength comparable to that presented above. (Ord. 604, 4-20-76)