CORRUGATKD BAR COMPANY, INC. 



Moment at point Xi, M = Mi-jrViXi — 



WiXi^ 



= (18,516) (10.29) 



(1.800) (10.29)^ 



+ 95,243 ft. lb. 



This is the maximum positive moment in span h for this condition of loading. 

 Moment at point Xi, 



M = M2-\-V2X2 



w^X'i 



= (-99,604) + (13,870) (7.71) - -^^^^^^^^^^ = -46,166 ft. lb. 



This is the minimum negative moment in span U and indicates that no positive mo- 

 ment exists in the span for this condition of loading, a point that is worthy of 

 notice, as quite commonly this span is designed for positive moment only. Moment 

 at point Xz, 



2 



M = Mz-^ViXi 



= (-50,899) +(20,545) (11 .41) - (I'^QQ) (ll-^^)' = +66,350 ft. lb. 



If the beam is subjected to partial loading larger moments, shears and reactions may 

 be obtained than in Case 1. The maximum values for this problem are given in the 

 following cases when the live load is placed as shown. 



Case 2 



} 



— ^3 "H 



Max. if2= -103,506 ft. lb. 

 Max. F'2=- 26.6401b. 

 Max. F2=+ 16,9921b. 

 Max. «2 =+ 43,6321b. 



Max. 3/3=- 58,521ft. lb. 



Max. F'3=- 9,4651b. 



Max. F3 = + 20,926 lb. 



Max. R3=+ 30,391 lb. 



Case 4. 



iiimi I Ill iiiiiiiiiii 



-h- 



Max. positive moment in span Zi=+ 97,300 ft. lb. 

 Max. positive moment in span 4 = + 67,300 ft. lb. 



X— -?2 



■ 



^ h 



^— , Max. ri=+ 18,6141b. 

 ™™[ Max. F4=- 15,6061b. 



Max. /?i =+ 18,6141b. 



Max. /?4 = + 15,606 lb. 



Case 4 also gives the position of live load for maximum negative moment at the center 

 of span I2. 



42 



