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Roof Trib Area = 24’-0” x 9’-0” = 216 sqft DL = (90 psf)(216 sqft)/1000 = 19.44k

Roof Trib Area = 24’-0” x 9’-0” = 216 sqft DL = (90 psf)(216 sqft)/1000 = 19.44k LL = (20 psf) (216 sqft)/1000 = 4.32k CW = (15 psf)(24ft)(15ft)/1000 = 5.4k. 2 nd Floor Trib Area = 24’-0” x 9’-0” = 216 sqft DL = (100 psf)(216 sqft)/1000 = 21.6k LL = (100 psf) (216 sqft)/1000 = 21.6k

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Roof Trib Area = 24’-0” x 9’-0” = 216 sqft DL = (90 psf)(216 sqft)/1000 = 19.44k

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  1. Roof Trib Area = 24’-0” x 9’-0” = 216 sqft DL = (90 psf)(216 sqft)/1000 = 19.44k LL = (20 psf) (216 sqft)/1000 = 4.32k CW = (15 psf)(24ft)(15ft)/1000 = 5.4k

  2. 2nd Floor Trib Area = 24’-0” x 9’-0” = 216 sqft DL = (100 psf)(216 sqft)/1000 = 21.6k LL = (100 psf) (216 sqft)/1000 = 21.6k CW = (15 psf)(24ft)(15ft)/1000 = 5.4k

  3. DL 19.44k LL 4.32k CW 5.4k V P M Column C4 - 0 + - 0 + - 0 + -29.16k -77.76k DL 21.6k LL 21.6k CW 5.4k -77.76k - 0 + - 0 + - 0 +

  4. WIND LOADS SEISMIC LOADS LATERAL LOAD FLOW FRAMES and SHEAR WALLS

  5. WIND LOAD

  6. Wind Loading W2 = 30 PSF W1 = 20 PSF

  7. Wind Load spans to each level 1/2 LOAD W2 = 30 PSF SPAN 10 ft 1/2 + 1/2 LOAD SPAN 10 ft W1 = 20 PSF 1/2 LOAD

  8. Total Wind Load to roof level wroof= (30 PSF)(5 FT) = 150 PLF

  9. Total Wind Load to second floor level wsecond= (30 PSF)(5 FT) + (20 PSF)(5 FT) = 250 PLF

  10. wroof= 150 PLF wsecond= 250 PLF

  11. SEISMIC LOAD

  12. Determine Spectral Response Parameters at design location At 37.80 N , -122.37 W : Ss = 1.50 S1 = 0.60

  13. Determine Site Coefficients Site Class : D Ss > 1.25 Fa = 1.0 S1 > 0.5 Fv = 1.5 Determine Design Spectral Acceleration Parameters SMS = (1.0)(1.5) = 1.5 SDS = (2/3)(1.5) = 1.0

  14. Cs = SDS /(R/I) =1.0/(R/I) Class II : I = 1.0 Ordinary Moment Resisting Frame : R = 3.5 V = 1.0/3.5 W 0.3 W

  15. Seismic Load is generated by the inertia of the mass of the structure : VBASE Redistributed (based on relative height and weight) to each level as a ‘Point Load’ at the center of mass of the structure or element in question : FX VBASE Wx hx S(w h) VBASE = (Cs)(W) ( VBASE ) Fx =

  16. Total Seismic Loading : VBASE = 0.3 W W = Wroof + Wsecond

  17. Wroof

  18. Wsecond flr

  19. W = Wroof + Wsecond flr

  20. VBASE

  21. Redistribute Total Seismic Load to each level based on relative height and weight Froof Fsecond flr VBASE (wx)(hx) S (w h) Fx =

  22. VBASE (wx)(hx) S (w h) Fx = In order to solve the equivalent lateral force distribution equation, we suggest you break it up into a spreadsheet layout Floor w h (w)(h) (w)(h)/S(w)(h) Vbase Fx Roof 166.67k 30ft 5000k-ft 0.625 110k 68.75k 2nd 200k 15ft 3000k-ft 0.375 110k 41.25k S (366.67k) S(8000k-ft) S (110k) Vbase = 0.3W = 0.3(166.67k+200k) = 0.3(366.67k) = 110k

  23. Load Flow to Lateral Resisting System : Distribution based on Relative Rigidity Assume Relative Rigidity : Single Bay MF : Rel Rigidity = 1 2 - Bay MF : Rel Rigidity = 2 3 - Bay MF : Rel Rigidity = 3

  24. Distribution based on Relative Rigidity : SR = 1+1+1+1 = 4 Px = ( Rx / SR ) (Ptotal) PMF1 = 1/4 Ptotal

  25. Lateral Load Flow diaphragm > collectors/drags > frames

  26. STRUCTURAL DIAPHRAGM A structural diaphragm is a horizontal structural system used to transfer lateral loads to shear walls or frames primarily through in-plane shear stress Basically, combined with vertical shear walls or frames IT ACTS LIKE A LARGE I-BEAM

  27. STRUCTURAL DIAPHRAGM Flexible or Semi-flexible Type: Plywood Metal Decking

  28. STRUCTURAL DIAPHRAGM Rigid Diaphragm Type: Reinforced Concrete Slab Concrete-filled Metal Deck composite Slab Braced/horizontal truss

  29. STRUCTURAL DIAPHRAGM Rigid Diaphragm: Almost no deflection Can transmit loads through torsion Flexible Diaphragm: Deflects horizontally Cannot transmit loads through torsion

  30. COLLECTORS and DRAGS

  31. COLLECTORS and DRAG STRUTS A beam element or line of reinforcement that carries or “collects” loads from a diaphragm and carries them axially to shear walls or frames. A drag strut or collector behaves like a column.

  32. COLLECTOR FRAME DIAPHRAGM COLLECTOR FRAME Lateral Load Flow diaphragm > collectors/drags > frames

  33. COLLECTOR FRAME LATERAL LOAD (WIND) DIAPHRAGM COLLECTOR FRAME Lateral Load Flow diaphragm > collectors/drags > frames

  34. COLLECTOR FRAME LATERAL LOAD DIAPHRAGM COLLECTOR FRAME Lateral Load Flow diaphragm > collectors/drags > frames

  35. LATERAL LOAD COLLECTOR FRAME FRAME COLLECTOR DIAPHRAGM COLLECTOR COLLECTOR FRAME

  36. LATERAL FORCE RESISTING SYSTEMS: MOMENT Resisting frames Diagonally BRACED frames SHEAR walls

  37. INSTABILITY OF THE FRAME Pinned connectionscannot resist rotation.This is not a structurebut rather a mechanism.

  38. STABILIZE THE FRAME FIX ONE OR MORE OF THE BASES

  39. STABILIZE THE FRAME FIX ONE OR MORE OF THE CORNERS

  40. STABILIZE THE FRAME ADD A DIAGONAL BRACE

  41. RELATIVE STIFFNESS OF FRAMES AND WALLS LOW DEFLECTION HIGH STIFFNESS ATTRACTS MORE LOAD HIGH DEFLECTION LOW STIFFNESS ATTRACTS LESS LOAD

  42. BRACED FRAMES

  43. BRACED FRAMES

  44. SHEAR WALLS

  45. SHEAR WALLS

  46. SHEAR WALLS

  47. SHEAR WALLS

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