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Page 1 571 . 0 ; 429 . 0 = = CD CB DF DF b) Calculate fixed end moments due to applied loading. 2 2 12 3 3 9.0 kN.m 6 F AB M ×× == ; 9.0 kN.m F BA M =- 0kN.m F BC M = ; 0kN.m F CB M = 0kN.m F CD M = ; 0kN.m F DC M = c) Prevent sidesway by providing artificial support at C. Carry out moment- distribution ( Case . .e i A in Fig. 21.5b). The moment-distribution for this case is shown in Fig. 21.5c. Page 2 571 . 0 ; 429 . 0 = = CD CB DF DF b) Calculate fixed end moments due to applied loading. 2 2 12 3 3 9.0 kN.m 6 F AB M ×× == ; 9.0 kN.m F BA M =- 0kN.m F BC M = ; 0kN.m F CB M = 0kN.m F CD M = ; 0kN.m F DC M = c) Prevent sidesway by providing artificial support at C. Carry out moment- distribution ( Case . .e i A in Fig. 21.5b). The moment-distribution for this case is shown in Fig. 21.5c. Now calculate horizontal reaction at A and from equations of statics. D () 1 11.694 3.614 6 7.347 kN 6 A H - =+= ? () 1 1.154 0.578 0.577 kN 3 D H -- ==- ? ( ) 12 (7.347 0.577) 5.23 kN R=- - =- ? d) Moment-distribution for arbitrary sidesway ' ? (case B, Fig. 21.5c) Calculate fixed end moments for the arbitrary sidesway of EI 150 ' = ? . 6 (2 ) 12 150 ( ) 50 kN.m ; 50 kN.m ; 66 F F AB BA EI EI MM L EI ? =- = × - =+ =+ Page 3 571 . 0 ; 429 . 0 = = CD CB DF DF b) Calculate fixed end moments due to applied loading. 2 2 12 3 3 9.0 kN.m 6 F AB M ×× == ; 9.0 kN.m F BA M =- 0kN.m F BC M = ; 0kN.m F CB M = 0kN.m F CD M = ; 0kN.m F DC M = c) Prevent sidesway by providing artificial support at C. Carry out moment- distribution ( Case . .e i A in Fig. 21.5b). The moment-distribution for this case is shown in Fig. 21.5c. Now calculate horizontal reaction at A and from equations of statics. D () 1 11.694 3.614 6 7.347 kN 6 A H - =+= ? () 1 1.154 0.578 0.577 kN 3 D H -- ==- ? ( ) 12 (7.347 0.577) 5.23 kN R=- - =- ? d) Moment-distribution for arbitrary sidesway ' ? (case B, Fig. 21.5c) Calculate fixed end moments for the arbitrary sidesway of EI 150 ' = ? . 6 (2 ) 12 150 ( ) 50 kN.m ; 50 kN.m ; 66 F F AB BA EI EI MM L EI ? =- = × - =+ =+ 6( ) 6 150 ( ) 100 kN.m ; 100 kN.m ; 33 F F CD DC EI EI MM L EI ? =- =- × - =+ =+ The moment-distribution for this case is shown in Fig. 21.5d. Using equations of static equilibrium, calculate reactions and . 2 A H 2 D H ) ( 395 . 12 6 457 . 41 911 . 32 2 ? = + = kN H A ) ( 952 . 39 3 285 . 73 57 . 46 2 ? = + = kN H D ) ( 347 . 52 ) 952 . 39 395 . 12 ( ? - = + - = kN F e) Final results Now, the shear condition for the frame is (vide Fig. 21.5b) Page 4 571 . 0 ; 429 . 0 = = CD CB DF DF b) Calculate fixed end moments due to applied loading. 2 2 12 3 3 9.0 kN.m 6 F AB M ×× == ; 9.0 kN.m F BA M =- 0kN.m F BC M = ; 0kN.m F CB M = 0kN.m F CD M = ; 0kN.m F DC M = c) Prevent sidesway by providing artificial support at C. Carry out moment- distribution ( Case . .e i A in Fig. 21.5b). The moment-distribution for this case is shown in Fig. 21.5c. Now calculate horizontal reaction at A and from equations of statics. D () 1 11.694 3.614 6 7.347 kN 6 A H - =+= ? () 1 1.154 0.578 0.577 kN 3 D H -- ==- ? ( ) 12 (7.347 0.577) 5.23 kN R=- - =- ? d) Moment-distribution for arbitrary sidesway ' ? (case B, Fig. 21.5c) Calculate fixed end moments for the arbitrary sidesway of EI 150 ' = ? . 6 (2 ) 12 150 ( ) 50 kN.m ; 50 kN.m ; 66 F F AB BA EI EI MM L EI ? =- = × - =+ =+ 6( ) 6 150 ( ) 100 kN.m ; 100 kN.m ; 33 F F CD DC EI EI MM L EI ? =- =- × - =+ =+ The moment-distribution for this case is shown in Fig. 21.5d. Using equations of static equilibrium, calculate reactions and . 2 A H 2 D H ) ( 395 . 12 6 457 . 41 911 . 32 2 ? = + = kN H A ) ( 952 . 39 3 285 . 73 57 . 46 2 ? = + = kN H D ) ( 347 . 52 ) 952 . 39 395 . 12 ( ? - = + - = kN F e) Final results Now, the shear condition for the frame is (vide Fig. 21.5b) 129 . 0 12 ) 952 . 39 395 . 12 ( ) 577 . 0 344 . 7 ( 12 ) ( ) ( 2 2 1 1 = = + + - = + + + k k H H k H H D A D A Now the actual end moments in the frame are, AB AB AB M k M M ' ' ' + = 11.694 0.129( 41.457) 17.039 kN.m AB M=+ + =+ 3.614 0.129( 32.911) 0.629 kN.m BA M =- + + = 3.614 0.129( 32.911) 0.629 kN.m BC M=+ - =- 1.154 0.129( 46.457) 4.853 kN.m CB M =- + - =- 1.154 0.129( 46.457) 4.853 kN.m CD M =- + + =+ 0.578 0.129( 73.285) 8.876 kN.m DC M =- + + =+ The actual sway EI k 150 129 . 0 ' × = ? = ? EI 35 . 19 = The joint rotations can be calculated using slope-deflection equations. [ ] ? ? ? 3 2 ) 2 ( 2 - + + = - B A F AB AB L I E M M or [] ? ? ? ? ? ? ? ? ? ? ? ? - - = ? ? ? ? ? ? + - = + L EI M M EI L L EI M M EI L F AB AB F AB AB B A ? ? ? ? 12 4 12 4 2 [] ? ? ? ? ? ? ? ? ? ? ? ? - - = ? ? ? ? ? ? + - = + L EI M M EI L L EI M M EI L F BA BA F BA BA A B ? ? ? ? 12 4 12 4 2 17.039 kN.m AB M =+ Page 5 571 . 0 ; 429 . 0 = = CD CB DF DF b) Calculate fixed end moments due to applied loading. 2 2 12 3 3 9.0 kN.m 6 F AB M ×× == ; 9.0 kN.m F BA M =- 0kN.m F BC M = ; 0kN.m F CB M = 0kN.m F CD M = ; 0kN.m F DC M = c) Prevent sidesway by providing artificial support at C. Carry out moment- distribution ( Case . .e i A in Fig. 21.5b). The moment-distribution for this case is shown in Fig. 21.5c. Now calculate horizontal reaction at A and from equations of statics. D () 1 11.694 3.614 6 7.347 kN 6 A H - =+= ? () 1 1.154 0.578 0.577 kN 3 D H -- ==- ? ( ) 12 (7.347 0.577) 5.23 kN R=- - =- ? d) Moment-distribution for arbitrary sidesway ' ? (case B, Fig. 21.5c) Calculate fixed end moments for the arbitrary sidesway of EI 150 ' = ? . 6 (2 ) 12 150 ( ) 50 kN.m ; 50 kN.m ; 66 F F AB BA EI EI MM L EI ? =- = × - =+ =+ 6( ) 6 150 ( ) 100 kN.m ; 100 kN.m ; 33 F F CD DC EI EI MM L EI ? =- =- × - =+ =+ The moment-distribution for this case is shown in Fig. 21.5d. Using equations of static equilibrium, calculate reactions and . 2 A H 2 D H ) ( 395 . 12 6 457 . 41 911 . 32 2 ? = + = kN H A ) ( 952 . 39 3 285 . 73 57 . 46 2 ? = + = kN H D ) ( 347 . 52 ) 952 . 39 395 . 12 ( ? - = + - = kN F e) Final results Now, the shear condition for the frame is (vide Fig. 21.5b) 129 . 0 12 ) 952 . 39 395 . 12 ( ) 577 . 0 344 . 7 ( 12 ) ( ) ( 2 2 1 1 = = + + - = + + + k k H H k H H D A D A Now the actual end moments in the frame are, AB AB AB M k M M ' ' ' + = 11.694 0.129( 41.457) 17.039 kN.m AB M=+ + =+ 3.614 0.129( 32.911) 0.629 kN.m BA M =- + + = 3.614 0.129( 32.911) 0.629 kN.m BC M=+ - =- 1.154 0.129( 46.457) 4.853 kN.m CB M =- + - =- 1.154 0.129( 46.457) 4.853 kN.m CD M =- + + =+ 0.578 0.129( 73.285) 8.876 kN.m DC M =- + + =+ The actual sway EI k 150 129 . 0 ' × = ? = ? EI 35 . 19 = The joint rotations can be calculated using slope-deflection equations. [ ] ? ? ? 3 2 ) 2 ( 2 - + + = - B A F AB AB L I E M M or [] ? ? ? ? ? ? ? ? ? ? ? ? - - = ? ? ? ? ? ? + - = + L EI M M EI L L EI M M EI L F AB AB F AB AB B A ? ? ? ? 12 4 12 4 2 [] ? ? ? ? ? ? ? ? ? ? ? ? - - = ? ? ? ? ? ? + - = + L EI M M EI L L EI M M EI L F BA BA F BA BA A B ? ? ? ? 12 4 12 4 2 17.039 kN.m AB M =+ 0.629 kN.m BA M = () 9 0.129(50) 15.45 kN.m F AB M =+ = () 9 0.129(50) 2.55 kN.m F BA M =- + = - 1 change in near end + - change in far end 2 3 1 (17.039 15.45) (0.629 2.55) 2 0.0 3 6 A EI L EI ? ?? ?? ?? = ?? -+- + ?? ?? == 4.769 B EI ? = Example 21.3 Analyse the rigid frame shown in Fig. 21.6a. The moment of inertia of all the members are shown in the figure.Read More
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1. What is the Moment Distribution Method? |
2. How does the Moment Distribution Method handle frames with sidesway? |
3. What are the advantages of using the Moment Distribution Method for frames with sidesway? |
4. Are there any limitations to the Moment Distribution Method for frames with sidesway? |
5. What are some practical applications of the Moment Distribution Method for frames with sidesway? |
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