Week 7 Challenge

Aim :- To Create 90 Meter Long spam Bridge Model and Applying Water Current Load On Pier as per IRC:6 and performing analysis using STAAD.Pro software.

* Mannual Calculation of water current load acting on pier.

Given Data :-

1. The high flood level is 2 m above the foundation level.
2. The span of the bridge is 45m.
3. The mean velocity of the river is 3 m/s.

Assumption :-

1. We are assuming rectanguler pier so K factor as per IRC:6 is 1.50 .

To Find :-

1. Maximum Velocity (V).
2. Intensity Of pressure due to water current. in kg/`m^2` (P).

Solution :-

Calculation of maximum velocity, V

V = `sqrt 2`x Vmean

= `sqrt 2` x 3

= 4.24

Claculation of Water Current, P

P = 52 x K x `V^2`

= 52 x 1.50 X `4.24^2`

= 1402.25 KN/`m^2`

* Modeling and Analysis using STAAD.pro

Step (1) :- Opening of STAAD.Pro Software.

• Open a STAAD.pro software.
• Fill all detail about model in model information.
• Then click on the create to open the model.

Step (2) :- Creating Crossbeam grid.

• After opening STAAD.Pro software.
• Create the first node.
• Copy the node in global Z direction using translation repeat option.
• 
• No of step should be 3 and spacing should be 4 meter.
• Click on the link step to connect all the node.
• We are assuming 12 meter width of the bridge.
• 3 span of 4 metre width.

Step (3) :- Creating Main girder grid.

• For creating Main girder grid copy this grid in X direction using translation repeat option.
• 
• 90 Meter long span is given in question.
• So no of step in 2 and spacing is 45 m.
• click on the link step to connect the node and then click on the ok button to create the grid.

Step (4) :- Adding Pier to the Grid model.

• We have to create the pier in center of the span in Global Y direction.
• Fo that select the span centerd both end node and copy this node in global Y direction using translation repeat option.
• 
• No of step is 1 and spacing is 7.36 and click on link step to connect the 2 node and then click on OK to create the pier.
• In question high flood level is 2 m above the foundation level and Vertical clearence is given 5.36 M.
• So, 2+5.360 = 7.36 M.
• We have to provide the 7.36 metre height of pier in global Y direction.

Step (5) :- Creating abutment to both end of the bridge.

• Select the any one node of starting point of the bridge.
• Copy this node in Z direction using translation repeat option upto 0.5 meter spacing.
• And again select both the node and copy them in global Y direction using translation repeat option upto 0.5 meter spacing.
• After creating of node next step is to add plate on it.
• For that go to goementry in that select add plate opton and then connect all the node using add plate option.
• Hence one plate is created.
• Then select that plate using plate cursor option and copy that plate in global Z direction using translation repeat option.
• 
• No of Step we have to provide 23 and spacing is 0.5 in Z dirction.
• We assume 12 meter span of bridge so, 12/0.5 = 24 -1 = 23 no of step we have to provide.
• Then Click Ok to copy the plate in Z direction.
• Again select all the plate and copy them in Y direction using translation repeat option.
• 
• No of step we have to provide 11 and spacing is 0.5 in Y direction.
• We assume 6 meter height of the abutment so, 6/0.5 = 12-1 = 11 no of step we have to privide.
• Then Click on Ok to copy all the plate in Y direction.
• Hence abutment is created.
• After Creation of Abutment again repeat this process in end side of the span to create the secound abutment.

Step (6) :- Creating raft foundation plate

• First select buttom node of the pier using node cuirsor then copy that node in X direction using translation repeat option upto 0.5 m.
• Again select both the node and copy them in Z direction using translation repeat option.
• Then add plate in it, for that go to geometry in that select add plate option then connect all the node using add plate option hence plate is created.
• Select that plate using plate cursior option then copy that plate in Z direction using translation repeat option.
• We assume 12 meter deck width so, no of step should be ( 12/0.5 )= (24-1) = 23 nos and spacing should be 0.5 meter.
• Again select all the plate and copy them in X direction using translation repeat option.
• No of step we consider 3 nos and spacing is 0.5 M.
• Again select this first plate and copy them in inverse X direction.
• No of step we consider 4 nos and spacing in -0.5 M.
• Width of the raft foundation is 3.5 meter.
• Select the top plate and copy them in inverse Z direction no of step we consider 2 nos and spacing is 0.5 m.
• Do same for buttom plate of raft foundation also. Lenght of raft foundation is 14 meter.
• Repeat the same procedure below the both abutment wall to create the foundation plate.
• Now apply foundation property to it.
• For that go to specification in that select foundation option then this window will open.
• 
• Select foundation plate mat type and direction in Y assuming the sbc 12500 Kn/`m^2` then click on add.
• Select all foundation plate and assign this to foundation property to it.

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Step (7) :- Creating Deck plate on the top of bridge.

• Select first node above the foundation.
• Copy that node in X direction using translation repeat option upto 0.5 meter.
• Again select both the node and copy them in Z direction.
• Add the plate in that node for that go to geomety and select the add plate option then connect all the node using that.
• Hence one plate is created.
• Select that plate using plate coursor option and then copy it in the Z direction using translation repeat option.
• We consider 12 meter width of birdge so, No of step is 23 and spacing should be 0.5 meter.
• Again select all the pier and again copy them in X dirtection using translation repeat option.
• 90 meter span in given so , no of step is 197 and spacing should be 0.5 meter.
• Hence deck is created.

Step (8) :- Assigning property to Girder.

• For assigning property go to specification in that select prasmatic option then this window will open.
• 
• Select tapperd I section and select concrete as material and put value as mention in above window then click on add.
• Then select all the girder which is parellel to X direction.
• Assign this property to it.

Step (9) :- Assigning property to crossbeam.

• For assigning property go to specification in that select prasmatic option.
• In that window select the rectangular option and assume the size of crossbeam 0.75 X 1.6 meter click on add.
• Then assign this property to it.

Step (10) :- Assigning property to pier.

• Assuming Size of pier is 1.2 M X 1.2 M.
• For that go to specification in that select prasmatic opton.
• Select rectangular and put size of the pier in it.
• Select the pier and assign this propeerty to it.

Step (11) :- Adding plate thickness to Abutment .

• Go to specification in thet select plate thickness option then this window will open.
• 
• We are taking plate thickness as 1.065 m which is given in the question.
• Then click on add button.
• Select all abutment plate and assign this property to both end side of the bridge.

Step (12) :- Adding plate thickness to deckslab of the bridge.

• Repeat same procedure as mention in above step .
• Thikness we have to assume 0.350 m.
• Then Assign this property to deckslab of the bridge.

Step (13) :- Assigning plate thickness to raft foundation.

• Repeat same procedure as mention above.
• Thikness we have to provide 0.765 m which is given in question.
• Then Assign this property to both side of the abutment wall foundation plate.

( 3D Model )

Step (14) :- Applying Water current load on structure.

• After assigning all propery to the structure.
• Next step is to apply loading on the structure.
• For that go to loading option the this dialog box will shown in right side of the window.
• 
• In this dialog box click on the load cases detail then click on add option.
• And creater load case 1
• Select the load case 1 (Water current load) click on add button then window will open
• 
• In above window go to member load in that select Linear varing load and put value as mention in above window.
• We calculate water current load munnualy which is 1402.25 `m^2`.
• This value we have to put in above window as water current pressusre.
• After adding all value and selecting direction click on add option.
• Then Select the pier of structure and assign this water current load to it.

Step (15) :- Analysis of Model

• After Applying load to the structure go to analysis and design option and click on run analysis.
• Then analysis process will start.
• After analysis process is done then click on postprocessing mode to view the result

Note - Before starting analysis check for the plate connectivity, duplicate node or duplicat plate to verify where our structure which we have model is correct or not.

Results :-

A) Reaction Result

B) Deflection and Bending moment diagram of structure in Z direction.

C) Pier Result

D) Section forces result

E) Pate stress in MY local