Portland Armory
Description
This section is from the book "Building Construction And Superintendence", by F. E. Kidder. Also available from Amazon: Building Construction And Superintendence.
Portland Armory
92 feet span. Length, 153 feet. Five main trusses, 25 feet apart. Height to eaves, 24 feet. Height to ridge, 50 feet.
Fig. 223. - Elevation.
Fig. 224. - Plan.
Quantities. | Lbs. |
3 trusses, at 17,860 .............................. | 53,580 |
2 trusses, at 19,700 ................................. | 39,400 |
6 cast shoes................... | 2,100 |
4 cast shoes........................ | 1,400 |
3 tie rods........... | 2,457 |
2 tie rods..................... | 1,980 |
28 purlins.................... | 19,100 |
8 " | 9,600 |
18 " ........................................ | 22,400 |
8 " ........................................... | . 5,184 |
4 " ............. | 2 876 |
44 struts in bracing.............. | 4,488 |
36 struts in bracing.................. | . 3,300 |
72 rods ......................... | 3,540 |
Total.......................... | .171,400 |
Fig. 226. - Plan of Roof Framing.
This weight corresponds to 9.7 lbs. per square foot of sloping roof surface, or 11.7 lbs. per square foot of ground covered. -
The trusses in this case were built strong enough to carry a 13-foot gallery, on two sides and one end, to be added in future.
PHOENIX HALL, at Brockton, Mass., is 100 feet wide, and 144 long, outside. It has 5 main arches, 94 feet, c. to c. Distance between trusses is 24 feet. It is 33 feet high to eaves, and 67 feet to ridge. It has a gallery 17 feet wide. The only steel included for the gallery is the ten gallery brackets.
Quantities. | Lbs. |
42 purlins............. | 28,700 |
48 struts............. | 6,600 |
Rod bracing......... | 2,600 |
5 tie rods................ | 4,680 |
5 arches............... | 99,500 |
10 shoes.................. | 3,100 |
10 gallery brackets........... | 6,060 |
Total........................... | 151,240 |
This weight is equal to 8.6 lbs. per square foot of sloping roof surface, or 10.6 lbs. per square foot of ground covered.
NORTHAMPTON ARMORY is 100 feet square. It has 3 main trusses, and 11 lines of trussed purlins. It has no gallery.
Quantities are as follows: | Lbs. |
3 trusses, at 17,000.............. | 51,000 |
6 cast shoes, at 350............. | 2,100 |
3 tie rods, at 780................ | 2,340 |
44 purlins, at 670.................... | 29,500 |
Struts in bottom chord................ | 5,200 |
Ties in bottom chord.................. | 2,100 |
Total........................ | 92,240 |
The sloping roof area = 11,600 sq. ft. . . Weight per sq. ft. = 92,240 ÷ 11,600 = 7.95 lbs.
THE PALACE AMUSEMENT CO.'S RINK, at Hartford, Conn., is 104 feet wide and 124 feet long. It has 4 main ribs 54 feet high, c. to c, pins. It is 24 feet high to eaves. It has a gallery 16 feet above the floor. There are 7 lines of trussed purlins. The gallery in this case is framed of steel, the main brackets being included with the trusses.
Quantities. | Lbs. |
Trusses and rafters..................... | 132,400 |
Purlins..................... | 34,400 |
Rods........................... | 18,000 |
Total......................................... | 184,800 |
Gallery......................... | 67,600 |
Fig. 227. - Section, 13th Regiment Armory, Scranton, Pa.
The total exposed roof area is 15,600 square feet. Hence the weight per square foot is:
Roof.......................... | 184,800 | ÷ | 15,600 | = | 11.8 lbs. |
Gallery........................ | 67,000 | ÷ | 15,600 | = | 4.4 lbs. |
PROVIDENCE EXPOSITION HALL. - This is 118 feet wide, and 196 feet long. It has 7 main trusses, 20 feet high to eaves. Figure 103 illustrates the design.
Quantities. | Lbs. |
7 trusses at 25 000 .......... | 175,000 |
104 purlins, at 580............................... | 60,300 |
7 tie rods, at 1,100 | 7,700 |
Rod bracing on rafters.................. | 4,000 |
96 spacing struts, at 100......................... | 9,000 |
14 cast shoes, at 600..................... | 8,400 |
Total........................................... | 265,000 |
This weight corresponds with 9.5 lbs. per square foot sloping, or 11.5 lbs. per square foot horizontal.
The following illustrations and descriptions give a good idea of the manner in which some of the largest armories and coliseums have been roofed:
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