Week 5 Challenge

Given Data:

1. Location of Bridge at Mumbai

2. Bridge is located at open terrain with well scattered obstruction of height less than 10m.

3. Height of Pier = 9m

4. Size of Pier = 1.5 x 1.5 m

5. Width of Deck Slab = 7.5m (Assumed)

6. Length of Bridge = 15m (Assumed)

Wind Load Calculation as per IS 875: Part-III

To calculate the design wind speed IS 875: Part-III given the formula in clause 6.3

Design wind speed Vz = Vb x k1 x k2 x k3 x k4

• As per given data the location of bridge is Mumbai so as per IS 875: Part-III Annex - A basic wind speed Vb is given 44m/s.
• k1 is risk coefficient as our structure is Bridge it comes into Important structure class and our basic wind speed Vb is 44m/s so k1 will be 1.07

• k2 is terrain and height factor, as our structure is located at open terrain with well scattered obstruction of height less than 10m so as per IS 875: Part-III it comes into category 2. So k2 will be 1.00

• k3 is the topography factor as our bridge upward wind slope is less than 3 degree and it doesn't comes into hilly areas so as per IS 875: Part-III clause 6.3.3.1 k3 will be 1.00.
• k4 is the importance factor for cyclonic region as our bridge located in mumbai which doesn't comes into cyclonic region so as per IS 875: Part-III clause 6.3.4 k4 will be 1.00.

So, Design wind speed Vz = Vb x k1 x k2 x k3 x k4

= 44 x 1.07 x 1 x 1 x 1

Vz = 47.08 m/s

Now, As per IS 875: Part-III clause 7.2 design wind pressure is

Pz = 0.6 x 47.08 x 47.08

= 1329.91 N/m2

Pz = 1.330 kN/m2

Wind Load Calculation in Staad Pro.

1. First I created Staad Model as per given data. In which height of pier is 9m and 1.5 x 1.5m size of pier, span of bridge 15m, creating threenumbers of longitudinal girders and two cross girder, bridge deck slab having depth of 300mm. Providing fixed support to the piers.

Step 2: After that I go to the loading where I defined the wind definition. Where I choose IS 875 Part-III 2015 Code and generate the load. Where I provided height of the structure, location of structure, wind parameters as per IS 875 Part-III code. And than software itself calulated the Vz & Pz value. Which is coming same as I calculated manually.

Step - 3: After that I go to the load case details where I defined 4 load cases Wind +X, Wind -X, Wind +Z, Wind -Z.

First I select Wind +X and go to the wind load where I select windward face in +X and provide 1 factor and defined the X,Y,Z Ranges as per node details of structure.

After that I select Wind -X and go to the wind load where I select windward face in -X and provide -1 factor and defined the X,Y,Z Ranges as per node details of structure.

After that I select Wind +Z and go to the wind load where I select windward face in +Z and provide 1 factor and defined the X,Y,Z Ranges as per node details of structure.

After that I select Wind -Z and go to the wind load where I select windward face in -Z and provide -1 factor and defined the X,Y,Z Ranges as per node details of structure.

Step- 4

After that I gave the analysis command and run the structure to the Postprocessing menu.

Where i firstely select the Beams and go to the reports, section forces and checked for the Maximum Bending Moment in MZ for load cases Wind +X, Wind -X, Wind +Z, Wind -Z. Where I got maximun bending moment in MZ -79.987kN-m.

After that i again select the Beams and go to the reports, section forces and checked for the Maximum Bending Moment in MY for load cases Wind +X, Wind -X, Wind +Z, Wind -Z. Where I got maximun bending moment in MY 253.699kN-m.

After that i again select the Beams and go to the reports, section forces and checked for the Maximum Shear Force in FY for load cases Wind +X, Wind -X, Wind +Z, Wind -Z. Where I got maximun Shear Force in FY 20.948kN.

After that i again select the Beams and go to the reports, section forces and checked for the Maximum Shear Force in FZ for load cases Wind +X, Wind -X, Wind +Z, Wind -Z. Where I got maximun Shear Force in FZ 40.399kN.