Week 3 Challenge

Aim and Introduction:

To design an I girder railway bridge and to apply Indian Railway(IRS) load using staad pro and to perform a structural analysis of the bridge.

The railway loading based on Indian Railway standards are,

1. Metro Rail Loading:

Fig.1

• This diagram shows length of metro car, length a is 2150mm, length b is 2200mm, length c is 12400mm, overall car length is 19000mm. The maximum axle load for metro rail = 17tonne

2. Braud gauge rail loading:

Fig. 2

• The above broad gauge loading shows the 25t axle load and 9.3 train load on both sides of the locomotives(with reference from the bridge rule book).

3. Electric train loading:

• In the electric train loading, all wheels have equal axle loading of 75.5KN and the train load of 27.8KN/m(by reference from video lecture).

4. Guage A and Guage B loading:

Fig.3

• The above one shows the guage A loading as per IRC bridge rules, for the train load of 2.83tonnes, and axle load of 6.1t,7.1t,8.1t

Fig. 4

• The guage B loading - Axle load of 6.1t and train load of 2.83t

5. Footway loading:

• The live load can be taken as uniformly distributed load, for the design of footover bridges or footpaths on railway bridges the live load taken as 490kg/m^2.

Procedure:

Fig. 5

• Firstly we enter nodes as (0,0,0) and (0,10,0) for the pier height, connect the two nodes by using add beam command thus pier is formed.

Fig. 6

• After connecting nodes, add an another pier by using translational repeat command at distance of 15.25m, connect the two pier by using add beam command, this forms the width for carriageway.

Fig. 7

• The above image is a view of the bridge, which the given question shows the width of the carriageway.

Fig. 8

• This shows the width of the bridge deck along distance between the piers, by taking two nodes either side of pier at a distance of 3.25m and connecting them, it forms the entire width for deck slab which is 26m.

Fig. 9

• By selecting whole structure and using transitional repeat command at a spacing of 5m for another 5 no. of steps in X-direction, thus forms the bridge span of 25m.

Fig. 10

• Form the I girder in between the piers connecting with cross girder to form a deck slab, thus cross girder and main girder are added to the structure.

Fig. 11

Fig. 12

Fig. 13

Fig. 14

• Specifying the dimension for the bridge, assign a diameter of 2.3m for the pier and cross beam dimension as width and depth as 0.5m and 1m respectively.
• The I girder dimension are assigned as specified above, and the above image shows 3 dimensional image of the bridge with cross beam and I girder.
• By selecting four corner of the deck slab and provide plate property to the deck slab of thickness 0.35m
• Now loading is to be added.

Fig. 15

• The above entered loads are for broad guage train, hence the loads are defined as broad guage for the designed bridge.
• The initial position of the load is placed at the coordinates(0,10,3.05 ) at the increment range of one meter(X-increment= 1, Range=25) and click add to generate the load.

Fig. 16

• Fixed support is assigned to the piers.

Results:

Fig. 17

• The broad guage loading is generated on the designed beaam, the green arrow shows the loads are applied on the bridge.

Fig. 18

Fig. 19

• The above images shows load generation at the middle and ends respectively, it showcase the train enters the starting point of the bridge and travel towards the end of the bridge.

Fig. 20

• The maximum and minimum bending stress of the beams are taken from the report.
• And the bending stress due to the application of load is shown below.

Fig. 21

Fig. 22

• The above image shows the bending at Z(Mz) for the load case generation 2 from high to low.
• Hence the bridge is designed and IRS liveloads had applied and structural analysis is performed using staad pro.