Week 1 Challenge
Aim: To calculate the dead load of bridge and apply it in staad pro and perform structural analysis.
Given data:
Location of bridge= 60KM within radius from the Bay of Bengal
Type of bridge= RCC box girder bridge
Width of the bridge deck=10.2M
Span of bridge=12M
Pier diameter=2.5M
Seismic zone=IV
Wind speed=47KM/hr
Unit weight of soil=19KN/M3
Theory:
Dead load: A constant load in a structure (such as a bridge, building) that is due to the weight of the member, the supported structure, and permanent attachments.
Dead load of the bridge= self weight of super structure + self weight of substructure.
Self weight elements (KN/M) = unit weight X cross section area of the structural.
Self weight of structure (KN) = unit weight X volume of structure (cross section area of the structural X span length)
Unit weight of reinforced cement concrete=25KN/M3
Due to symmetric of box girder
Self weight of structure =2 X self weight of half portion.
Calculation:
Self weight of super structure
|
S.No |
Length in mm |
Width in mm |
Depth in mm |
Volume in M3 |
Self weight in KN |
|
1 |
12000 |
5100 |
225 |
12x5.1x0.225=15.39 |
15.39x25=384.75 |
|
2 |
12000 |
1504.5 |
125 |
12x1.504x0.125=2.256 |
2.256x25=56.4 |
|
3 |
12000 |
1334.5 |
125 |
12x1.334x0.125=2.004 |
2.004x25=50.1 |
|
4 |
12000 |
3655 |
250 |
12x3.655x0.25=10.968 |
10.968x25=274.2 |
|
5 |
12000 |
1821 |
200 |
12x1.821x0.2=4.370 |
4.37x25=109.25 |
Self weight of half portion= 384.75+56.4+50.1+274.2+109.25 = 874.7KN
Self weight of super structure = 874.7x2= 1749.4KN
Self weight of substructure
Assume height of pier 7M
Volume of pier= x2.5x2.5x0.25x7=34.361M3
Self weight of sub structure= 34.361x25= 859.029KN
Total dead load of bridge = 1749.4+859.029 = 2608.429KN
Draw 12M length beam
Assume width = 0.1m and depth = 0.1m
In nodes 1 and 2 except X and Y all fixed ( FZ,MX,MY,MZ)
Uniform Load are apply with whole 12M span = 217.35KN/M
Final run analysis and take final report
Maximum displacement = 322.446M at centre of span.
Maximum bending = -34626.77kip-in at centre of span
Maximum share force = 1304.1KN at both support