TABLE 5 – Tower Capacities with Jacks and Extension Tubes as Indicated
Mar 31, 2017
For 2 and 3 frame high towers using 4′ and 6′ high frames completely interbraced with extension tubes and jacks therein at one end extended 12″ and with jacks extended 2″ or extension tubes extended 141/2″ in the other end replacing the jacks. (See maximum extension column.)
NOTE: One tier of 5′ high frames can also be used in a tower and still interbraced if used as the bottom frame. If towers are not completely interbraced, reduce all capacities by 25%. For towers only one frame high with extension tubes and jacks as indicated below reduce all load capacities by 15% (as one frame cannot be interbraced). For towers using only 4′ high frames. 2, 3, and 4 frames high completely inter- braced capacities can be increased by 15%.
| Length Extension Tubes Extended Max. complete with Jacks in Tubes Extended 12″ at One End Jacks Only or Extension Tubes Extended 14 1/2 ” at the other end | Max Extension | Safe Working Load for Each Leg Using 30″ Extension Tubes Plus Jacks Extended 12″ | |||
| A | Extension Tubes Extensions at One End Only | 8″+24″ of 2 – jacks = 14″+24″ of 2 – jacks = 20″+24″ of 2 – jacks = 26″+24″ of 2 – jacks = 32″+24″ of 2 – jacks = |
32″ 38″ 44″ 50″ 56″ |
10,500 lb (4760kg.) 9,500 lb. (4300kg.) 7,500 lb. (3400kg.) |
10,500 lb. (4760 kg) 9,700 lb. (4400 kg) 8,500 lb. (3860 kg) 8,000 lb. (3630 kg) 7,500 lb. (3400 kg) |
| ‘The following “B” Section is for towers with extension tubes and jacks at both ends of a tower or if no jacks are used at one end, the extension tubes can be extended ( 14″ more replacing the jacks, providing they are long enough. | |||||
| B | Extension Tubes Extensions at Both Ends | 8″+8″+24″ of 2 – jacks = 14″+14″+24″ of 2 – jacks = 20″+20″+24″ of 2 – jacks = 26″+26″+24″ of 2 -jacks = |
40″ 48″ 64″ 76″ |
9,500 lb. (4310kg.) 7,000 lb. (3175kg.) 5,000 lb.(2270kg.) |
10,000 lb. (4535 kg.) 7,500 lb. (3400 kg) 5,700 lb.(2585kg.) 4,500 lb. (2040kg.)* |
| *Not recommendable without auxiliary bracing | |||||
NOTE:
30″ Extension tubes must not be extended more than 20 1/2″
48″ Extension tubes must not be extended more than 32 1/2″
Safety Factor – 2.5 based on ultimate test results
