Week 10 Challenge

AIM :- To calculate the snow load on bridge superstructure and then after that apply that load in stadd pro to analyse and results.

LIVE LOAD CALCULATION:-

Given:

Span of the bridge = 10 m

Density of snow = 300 KN/m3 (As snow is settled snow)

Depth of snow = 1.25 m

Flat deck, angle beta = 0 degree

Snow load, So = 3 x 1.25 x 10

= 37.5 KN/m

• Shape coefficient from IS 875 Part 4

• For angle beta < 30 degree, u = 0.8

Design snow load, S

• S = u x So

= 0.8 x 37.5

= 30 KN/m

• PROCEDURE:-

1. Firstly a node is created. The height of pier is taken as 10 m.

Figure Pier is created using node

2. After that with the help of translational repeat the frame of bridge is created.

Figure Bridge frame is created with the help of node using translational repeat option

3. The bridge deck is created by using the mesh size of 0.5*0.5 m. The thickness of deck slab is 0.9 m

4. A circular pier of diameter 2 m is created.

5. A fixed support is created at the base of the pier.

6. Rectangular girder and cross beam of size 0.6 m * 1.2 m is created using define option.

7. Cross beam of size 0.6 m * 1.2 m is created.

Figure 3D view of bridge

• LOADING

Firstly self weight i.e gravity load of -1 is applied on the whole structure

Loading-----load case details-----ADD-----SNOW LOAD------ADD------MEMBER LOAD ------NODE

Figure Defined loading condition

Figure Loading diagram of Snow Load

1. Firstly the snow load is applied at cross beam.

2. Then minimum snow load of 9 kn/m2 is applied on the superstructure as per IRC

• RESULT ANALYSIS:-

1. STATIC CHECK:- Static check is ok as the difference between load and reaction is zero.

Figure Static check

2. DEFLECTION:- Maximum deflection of the structure is 1.845 mm in Z direction at node 2.

3. REACTION:-

Horizontal	Vertical	Horizontal
Fx (KN)	Fy (KN)	Fz (KN)
36.114	1851.453	210.257

Moment	Moment	Moment
Mx (KN-m)	My (KN-m)	Mz (KN-m)
17	0.077	2.995

Figure Maximum reaction coming out of all the load cases

4. BEAM RESULTS:- GIRDER

Mz (KN-m)	My (KN-m)	Shear y (KN)	Shear Z (KN)
22.245	0.187	824.893	8.615

• CROSS BEAM

Mz (KN-m)	My (KN-m)	Shear y (KN)	Shear Z (KN)
5.431	0.244	326	21.447

Figure Bending moment diagram of girder

Figure Shear force diagram of girder

5. PLATE STRESSES

Deck slab

Mx (KN-m/m)	My (KN-m/m)	Mxy (KN-m/m)	Shear y (N/mm2)	Shear Z (N/mm2)
68.807	239.356	228.292	1350.536	1176

PARAPET WALL

Mx (KN-m/m)	My (KN-m/m)	Mxy (KN-m/m)	Shear y (N/mm2)	Shear Z (N/mm2)
23.548	6.666	10.968	66	79.173

Figure plate stresses in parapet wall

Figure plate stresses in deck slab (maximum moment in x direction)

6. PIER RESULT

Mz (KN-m)	My (KN-m)	Shear y (KN)	Shear Z (KN)
6.178	36.403	36.114	210.257

Figure Pier bending moment

Figure Pier shear force