CANTILEVER AND SIMPLE BEAMS 33 



287. A wrought-iron simple beam 6 feet in length, with cross-section 

 3 inches square, has concentrated loads of 1000 pounds 2 feet from 

 each end. Neglecting the weight of the beam, tind the factor of safety. 



288. Solve Problem 287, considering the weight of the beam. 



289. Solve Problem 287, if the diagonal is vertical. 



290. Determine the factor of safety for a wrought-iron beam 8 feet 

 in length, supported at its ends, with a total uniform load of 1000 

 pounds per linear foot and a concentrated load of 1000 pounds at the 

 middle. Its section is like Fig. 19, with & x = & 2 = 4, t 1 = 2 = t = 1, 

 and d 6 inches. 



291. A wrought-iron, circular simple beam 6 feet in length has 

 concentrated loads of 4000 and 1000 pounds at 1 and 2 feet respec- 

 tively from the left end. Is it safe if the diameter is 3 inches ? 



292. Find the factor of safety for the beam of Problem 291, if its 

 section is 3 inches square and a side vertical. 



293. A wrought-iron beam 8 feet span and supported at its ends 

 has an I-section, with 5 X = 2 = 4, t 1 = t 2 = t = 1, and d = 6 inches. 

 What concentrated load can it carry at its middle point with a factor 

 of safety of 6 ? Neglect weight of beam. 



294. A simple wooden beam 12 feet span, 9 inches deep and 8 inches 

 wide, carries two equal loads, each 3 feet from the middle, but on 

 opposite sides. Find these loads for a factor of safety of 10, neglecting 

 the weight of the beam. 



295. Solve Problem 294, considering the weight of the beam. 



296. Determine the total uniform load for a cast-iron beam 12 feet 

 span and supported at its ends for a factor of safety of 6, if the sec- 

 tion is like Fig. 18, with I = 5, d = 12, t = 1, and ^ = 2 inches. 



297. A cast-iron simple beam 10 feet span has a section like Fig. 18, 

 with 5 = 3, d=8, t = 1, and t l = 2 inches. What concentrated load 

 can it carry at the middle with a factor of safety of 8 ? Neglect weight 

 of beam. 



298. A 12-inch steel I-beam, weighing 35 pounds per linear foot, 

 of 10 feet span and supported at the ends sustains a total uniform 

 load of 20 tons. Find the factor of safety. 



299. Determine the total uniform load for a 10-inch steel I-beam, 

 30 pounds per foot, 12 feet span and supported at the ends, for a 

 factor of safety of 6. 



