Week 5 Challenge
Aim : To model and analyse the given bridge in Staad pro for Wind loads as per IS 875 Part III.
Introduction :
The bridge is assumed to be located in chennai and is of RCC I girder type with length of bridge as 15m. The distance between piers along the bridge deck width is 10m.
Height of pier given is 7m and pier dimension is 1.5x1.5m.
The given bridge has 5 RCC I girders having flange of 0.4x0.1m and web of 0.2x0.8m. The centre to centre distance between girders is 2.5m.
The bridge will be analysed for IS 875 Wind Loads.
Procedure:
Step 1 - Modelling of the bridge in STaad pro with given details.
Open Staad pro and click on geometry tab in left, insert node details in the dialog box that pops up. X,Y,Z indicates Longitudinal,Vertical and Transverse axis respectively. Create 1st node at 0,0,0 and 2nd node at 0,7,0 since pier height is 7m.
Now click on support tab in the left menu bar and create fixed support then assign it to the bottom node of pier.
Click on property tab in the left and create rectangle property of concrete with dimensions 1.5x1.5m and assign it to the pier.
Select the given pier and copy paste it to the distance of 10m in Z direction.
Click on geometry tab and select add beam from point to point and connect top nodes of pier.
Create the property of rectangle 1mx2m and assign it to the top beam. This is the pier cap.
Select the pier cap, right click and select insert nodes at 7 equal locations. Now we have points for 8 RCC I girders.
Now copy the entire frame and paste it at a distance of 15m as span length is 15m.
Connect the nodes of the top beam and assign property of I girder to them.
Model is ready.
Step 2 : Calculation of Wind Load.
WInd Load is calculated as per IS 875 Part 3.
As per the code,
Design Wind Speed Vz = Vb x k1 x k2 x k3 x k4
Vb = basic wind speed
For chennai Vb=50m/s as per Annex A
k1 = Risk Coefficient = 1.08 from table 1
Obstructions are of height less than 10m therefore terrain category 2 and height of bridge is 9m(pier+piercap+girder hts=7+1+1)
k2 = 1
Since there is no inclination k3 = 1
k4 = 1
Vz = 50x1.08x1x1x1 = 54 m/s
Wind pressure Pz = 0.6 x Vz x Vz = 1749.6 N/m2 = 1.75 kN/m2
Design wind pressure Pd = Kd x Ka x Kc x Pz
Kd = 1
Ka = 1
Kc = 0.9
Pd = 1.75x1x1x0.9 = 1.575 kN/m2
Wind in X Direction
On pier
Wx1 = Pd x width of pier = 1.575 x 1.5 = 2.36 kN/m2
On pier cap
Wx2 = pd x depth of pier cap = 1.575 x 1 = 1.575 kN/m2
Wind in Z Direction
On pier
Wz1 = Pd x width of pier = 1.575 x 1.5 = 2.36 kN/m2
On pier cap
Wz2 = pd x depth of girder = 1.575 x 1 = 1.575 kN/m2
Wind in Y direction
On girder
Wy1 = Pd x width of girder = 1.575 x 0.4 = 0.63 kN/m2
Applying all the loads in staad in positive and negative directions and proceeding for analysis
Results:
Deflections in X,-X,Z,-Z,Y and -Y directions respectively
Shear for wind in X,-X,Z,-Z,Y and -Y directions respectively
Bending moment for wind in X,-X,Z,-Z,Y and -Y directions respectively
Report:
1. STAAD SPACE
INPUT FILE: Challenge 5.STD
2. START JOB INFORMATION
3. ENGINEER DATE 12-JUL-22
4. END JOB INFORMATION
5. INPUT WIDTH 79
6. UNIT METER KN
7. JOINT COORDINATES
8. 1 0 0 0; 13 15 0 0; 17 0 7 2.5; 19 0 7 5; 21 0 7 7.5; 25 0 0 10; 26 15 0 10
9. 33 0 7 10; 34 0 7 0; 35 15 7 10; 36 15 7 0; 37 15 7 2.5; 38 15 7 5
10. 39 15 7 7.5
11. MEMBER INCIDENCES
12. 1 1 34; 3 34 17; 13 34 36; 24 13 36; 26 36 37; 27 17 19; 28 37 38; 29 17 37
13. 30 19 21; 31 38 39; 32 19 38; 33 21 33; 34 39 35; 35 21 39; 38 33 35; 39 25 33
14. 40 26 35
15. DEFINE MATERIAL START
16. ISOTROPIC CONCRETE
17. E 2.17185E+007
18. POISSON 0.17
19. DENSITY 23.5616
20. ALPHA 1E-005
21. DAMP 0.05
22. ISOTROPIC STEEL
23. E 2.05E+008
24. POISSON 0.3
25. DENSITY 76.8195
26. ALPHA 1.2E-005
27. DAMP 0.03
28. END DEFINE MATERIAL
29. MEMBER PROPERTY AMERICAN
30. 13 29 32 35 38 TAPERED 1 0.2 1 0.4 0.1 0.4 0.1
31. 3 26 TO 28 30 31 33 34 PRIS YD 1 ZD 2
32. MEMBER PROPERTY AMERICAN
33. 1 24 39 40 PRIS YD 1 ZD 2
34. CONSTANTS
35. MATERIAL CONCRETE ALL
36. SUPPORTS
37. 1 13 25 26 FIXED
38. LOAD 1 LOADTYPE WIND TITLE WIND IN X DIRECTION
39. MEMBER LOAD
40. 1 39 UNI GX 2.36
STAAD SPACE -- PAGE NO. 2
41. 3 27 30 33 UNI GX 1.575
42. LOAD 2 LOADTYPE WIND TITLE WIND IN -X DIRECTION
43. MEMBER LOAD
44. 24 40 UNI GX -2.36
45. 26 28 31 34 UNI GX -1.575
46. LOAD 3 LOADTYPE WIND TITLE WIND IN Z DIRECTION
47. MEMBER LOAD
48. 1 24 UNI GZ 2.36
49. 13 UNI GZ 1.575
50. LOAD 4 LOADTYPE WIND TITLE WIND IN -Z DIRECTION
51. MEMBER LOAD
52. 39 40 UNI GZ -2.36
53. 38 UNI GZ -1.575
54. LOAD 5 LOADTYPE WIND TITLE WIND IN Y DIRECTION
55. MEMBER LOAD
56. 13 29 32 35 38 UNI GY 0.63
57. LOAD 6 LOADTYPE WIND TITLE WIND IN -Y DIRECTION
58. MEMBER LOAD
59. 13 29 32 35 38 UNI GY -0.63
60. PERFORM ANALYSIS PRINT STATICS CHECK
P R O B L E M S T A T I S T I C S
-----------------------------------
NUMBER OF JOINTS/MEMBER+ELEMENTS/SUPPORTS = 14/ 17/ 4
SOLVER USED IS THE IN-CORE ADVANCED SOLVER
TOTAL PRIMARY LOAD CASES = 6, TOTAL DEGREES OF FREEDOM = 60
STAAD SPACE -- PAGE NO. 3
STATIC LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 1
LOADTYPE WIND TITLE WIND IN X DIRECTION
CENTER OF FORCE BASED ON X FORCES ONLY (METE).
(FORCES IN NON-GLOBAL DIRECTIONS WILL INVALIDATE RESULTS)
X = 0.000000000E+00
Y = 0.462984214E+01
Z = 0.500000017E+01
***TOTAL APPLIED LOAD ( KN METE ) SUMMARY (LOADING 1 )
SUMMATION FORCE-X = 48.79
SUMMATION FORCE-Y = 0.00
SUMMATION FORCE-Z = 0.00
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= 0.00 MY= 243.95 MZ= -225.89
***TOTAL REACTION LOAD( KN METE ) SUMMARY (LOADING 1 )
SUMMATION FORCE-X = -48.79
SUMMATION FORCE-Y = 0.00
SUMMATION FORCE-Z = 0.00
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= 0.00 MY= -243.95 MZ= 225.89
MAXIMUM DISPLACEMENTS ( CM /RADIANS) (LOADING 1)
MAXIMUMS AT NODE
X = 1.60121E-02 19
Y = -2.52984E-04 38
Z = 3.50095E-06 33
RX= -5.79321E-07 39
RY= 2.19182E-06 36
RZ= -2.49919E-05 35
STATIC LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 2
LOADTYPE WIND TITLE WIND IN -X DIRECTION
CENTER OF FORCE BASED ON X FORCES ONLY (METE).
(FORCES IN NON-GLOBAL DIRECTIONS WILL INVALIDATE RESULTS)
X = 0.150000005E+02
Y = 0.462984214E+01
Z = 0.500000017E+01
STAAD SPACE -- PAGE NO. 4
***TOTAL APPLIED LOAD ( KN METE ) SUMMARY (LOADING 2 )
SUMMATION FORCE-X = -48.79
SUMMATION FORCE-Y = 0.00
SUMMATION FORCE-Z = 0.00
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= 0.00 MY= -243.95 MZ= 225.89
***TOTAL REACTION LOAD( KN METE ) SUMMARY (LOADING 2 )
SUMMATION FORCE-X = 48.79
SUMMATION FORCE-Y = 0.00
SUMMATION FORCE-Z = 0.00
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= 0.00 MY= 243.95 MZ= -225.89
MAXIMUM DISPLACEMENTS ( CM /RADIANS) (LOADING 2)
MAXIMUMS AT NODE
X = -1.60121E-02 38
Y = 2.52984E-04 38
Z = -3.50095E-06 33
RX= 5.79321E-07 39
RY= -2.19182E-06 34
RZ= 2.49919E-05 33
STATIC LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 3
LOADTYPE WIND TITLE WIND IN Z DIRECTION
CENTER OF FORCE BASED ON Z FORCES ONLY (METE).
(FORCES IN NON-GLOBAL DIRECTIONS WILL INVALIDATE RESULTS)
X = 0.750000026E+01
Y = 0.495923407E+01
Z = 0.000000000E+00
***TOTAL APPLIED LOAD ( KN METE ) SUMMARY (LOADING 3 )
SUMMATION FORCE-X = 0.00
SUMMATION FORCE-Y = 0.00
SUMMATION FORCE-Z = 56.67
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= 281.02 MY= -424.99 MZ= 0.00
***TOTAL REACTION LOAD( KN METE ) SUMMARY (LOADING 3 )
SUMMATION FORCE-X = 0.00
SUMMATION FORCE-Y = 0.00
SUMMATION FORCE-Z = -56.67
STAAD SPACE -- PAGE NO. 5
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= -281.02 MY= 424.99 MZ= 0.00
MAXIMUM DISPLACEMENTS ( CM /RADIANS) (LOADING 3)
MAXIMUMS AT NODE
X = -6.29305E-04 36
Y = 7.11468E-04 39
Z = 5.08398E-03 34
RX= 7.71915E-06 35
RY= 5.30831E-06 36
RZ= 1.04946E-06 36
STATIC LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 4
LOADTYPE WIND TITLE WIND IN -Z DIRECTION
CENTER OF FORCE BASED ON Z FORCES ONLY (METE).
(FORCES IN NON-GLOBAL DIRECTIONS WILL INVALIDATE RESULTS)
X = 0.750000026E+01
Y = 0.495923407E+01
Z = 0.100000003E+02
***TOTAL APPLIED LOAD ( KN METE ) SUMMARY (LOADING 4 )
SUMMATION FORCE-X = 0.00
SUMMATION FORCE-Y = 0.00
SUMMATION FORCE-Z = -56.67
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= -281.02 MY= 424.99 MZ= 0.00
***TOTAL REACTION LOAD( KN METE ) SUMMARY (LOADING 4 )
SUMMATION FORCE-X = 0.00
SUMMATION FORCE-Y = 0.00
SUMMATION FORCE-Z = 56.67
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= 281.02 MY= -424.99 MZ= 0.00
MAXIMUM DISPLACEMENTS ( CM /RADIANS) (LOADING 4)
MAXIMUMS AT NODE
X = -6.29305E-04 35
Y = 7.11468E-04 37
Z = -5.08398E-03 33
RX= -7.71915E-06 36
RY= -5.30831E-06 35
RZ= 1.04946E-06 35
STATIC LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 5
LOADTYPE WIND TITLE WIND IN Y DIRECTION
STAAD SPACE -- PAGE NO. 6
CENTER OF FORCE BASED ON Y FORCES ONLY (METE).
(FORCES IN NON-GLOBAL DIRECTIONS WILL INVALIDATE RESULTS)
X = 0.749999984E+01
Y = 0.699999978E+01
Z = 0.500000017E+01
***TOTAL APPLIED LOAD ( KN METE ) SUMMARY (LOADING 5 )
SUMMATION FORCE-X = 0.00
SUMMATION FORCE-Y = 47.25
SUMMATION FORCE-Z = 0.00
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= -236.25 MY= 0.00 MZ= 354.38
***TOTAL REACTION LOAD( KN METE ) SUMMARY (LOADING 5 )
SUMMATION FORCE-X = 0.00
SUMMATION FORCE-Y = -47.25
SUMMATION FORCE-Z = 0.00
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= 236.25 MY= 0.00 MZ= -354.38
MAXIMUM DISPLACEMENTS ( CM /RADIANS) (LOADING 5)
MAXIMUMS AT NODE
X = 4.95197E-04 36
Y = 2.18370E-03 19
Z = -3.07865E-05 34
RX= -5.04695E-06 17
RY= -1.07445E-06 36
RZ= -2.59386E-05 38
STATIC LOAD/REACTION/EQUILIBRIUM SUMMARY FOR CASE NO. 6
LOADTYPE WIND TITLE WIND IN -Y DIRECTION
CENTER OF FORCE BASED ON Y FORCES ONLY (METE).
(FORCES IN NON-GLOBAL DIRECTIONS WILL INVALIDATE RESULTS)
X = 0.749999984E+01
Y = 0.699999978E+01
Z = 0.500000017E+01
***TOTAL APPLIED LOAD ( KN METE ) SUMMARY (LOADING 6 )
SUMMATION FORCE-X = 0.00
SUMMATION FORCE-Y = -47.25
SUMMATION FORCE-Z = 0.00
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= 236.25 MY= 0.00 MZ= -354.38
STAAD SPACE -- PAGE NO. 7
***TOTAL REACTION LOAD( KN METE ) SUMMARY (LOADING 6 )
SUMMATION FORCE-X = 0.00
SUMMATION FORCE-Y = 47.25
SUMMATION FORCE-Z = 0.00
SUMMATION OF MOMENTS AROUND THE ORIGIN-
MX= -236.25 MY= 0.00 MZ= 354.38
MAXIMUM DISPLACEMENTS ( CM /RADIANS) (LOADING 6)
MAXIMUMS AT NODE
X = -4.95197E-04 36
Y = -2.18370E-03 19
Z = 3.07865E-05 34
RX= 5.04695E-06 17
RY= 1.07445E-06 36
RZ= 2.59386E-05 38
61. FINISH