94 PRACTICAL STRUCTURAL DESIGN 



port, then check to see that the area of the vertical legs is sufficient 

 in tensile strength to carry the load. This last item is generally 

 taken care of when the other conditions are satisfied. 



5. Design a strap hanger, or stirrup, for the 8-in. x 14-in. beam 

 in the last example. 



Answer. The total load = 10,700 Ibs. which gives a reaction 

 = 5350 Ibs. The allowable compression across the grain = 250 Ibs. 



5350 

 per square inch, so the bearing area in the stirrup = =21.4 



sq. ins. The width of the beam is 8 ins., therefore the width of the 



21 4 

 strap under the end of the beam = - - = 2.66 ins. Make the strap 



o 



2.75 ins. wide, a stock width. Allowing a value of 10,000 Ibs. per 



Fig. 62 Various Styles of Stirrups 



square inch tension for wrought iron the required area of the two 



5350 

 legs = IQQQQ = - 535 SQ- frs. or 0.2675 sq. ins. for each leg. The 



n 

 thickness of metal required = ' , = 0.097 in. (practically No. 



. i o 



10 gauge). Allowing a fiber stress of 14,000 Ibs. per square inch 



5350 

 for steel, the required area in the two legs = ^ = 0.382 sq. 



J.4,LMJvJ 



in., or 0.191 sq. in. for each leg. The thickness of metal required 



= ' - = 0.0695 in. (practically No. 13 gauge). Each leg must 

 z.< o 



rest on top of the girder with a length of not less than 4 ins. 



This is thin metal and will surely straighten under the load, 

 besides which it does not offer enough body to resist corrosion. 

 Use a minimum thickness of f in. The stirrup shown in Fig. 62 

 is double and the weight of the beam on either side tends to bal- 

 ance the weight of the beam on the opposite side of the girder. 

 A stirrup 2f ins. wide of f-in. metal will therefore be all right and 

 may be wrought iron or steel. A couple of holes drilled through 



