Week 7 Challenge

AIM :- To calculate the water current forces which acts on the bridge and then after that apply that load in stadd pro to analyse and results.

LIVE LOAD CALCULATION:-

Given: High flood level = 2 m

span of bridge = 45 m

mean velocity of river = 3 m/s

k = 0.6 (for circular pier)

Maximum velocity, V = `UNDER ROOT`2 * Vmean

= Root 2 * 3

= 4.24 m/s

Water current, P = 52*K*V*V

= 52*0.6*4.24*4.24

= 560.90 KN/m2

• 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 250 mm

4. A circular pier of diameter 2.5 m is created. The centre to centre distance between the pier is 9 m.

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

6. Tappered I section girder is created using define option.

Figure Property of I Section

7. Cross beam of size 0.5 m * 1 m is created.

Figure 3D view of bridge

• LOADING

Loading-----load case details-----ADD-----WATER CURRENT FORCES------ADD------MEMBER LOAD------LINERLY VARYING-----

Figure Defined loading condition

Figure Loading diagram of water current forces in -Z direction

• 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 11.435 mm in Z direction at node 12

3. REACTION:-

Horizontal	Vertical	Horizontal
Fx (KN)	Fy (KN)	Fz (KN)
4.201	358.615	2809.725

Moment	Moment	Moment
Mx (KN-m)	My (KN-m)	Mz (KN-m)
17499.327	8.320	12.579

Figure Maximum reaction coming out of all the load cases

4. BEAM RESULTS:- GIRDER

Mz (KN-m) (At middle)	Mz (KN-m) (At support)	My (KN-m)	Shear y (KN)	Shear Z (KN)
38.511		7.691	21.039	4.193

• CROSS BEAM

Mz (KN-m)	My (KN-m)	Shear y (KN)	Shear Z (KN)
1029.566	0.360	291.468	0.568

Figure Bending moment diagram of girder

Figure Bending moment diagram of cross beam

5. PLATE STRESSES

Mx (KN-m/m)	My (KN-m/m)	Mxy (KN-m/m)	Shear y (N/mm2)	Shear Z (N/mm2)
7.9847	32.147	3.73	0.053	0.184

Figure plate stresses (maximum moment in x direction)

6. PIER RESULT

Mz (KN-m) (At middle)	My (KN-m)	Shear y (KN)	Shear Z (KN)
36.789	17499	4.201	2809.725

Figure Pier bending moment

Figure Pier shear force