Loads and forces
Download as PPTX, PDF24 likes15,359 views
This document outlines various load types that must be considered in bridge design, including: 1. Dead loads from structural components like deck slabs, girders, and railings. 2. Live loads according to Indian Road Congress (IRC) standards, including Class A and 70R loadings. 3. Impact allowance as a percentage of live load to account for dynamic effects, ranging from 10-25% depending on span length and vehicle type. 4. Other loads such as wind loads, which are dependent on average height and wind velocity, and seismic forces. A table provides wind pressure and velocity values.
Loads and forces
- 1. IRC LOADINGS A DEERENDRA PRASAD
- 4. Loads, Forces and Stresses to be considered in the design 1. Dead Load 2. Live Load 3. Impact of Live load 4. Water currents 5. Longitudinal forces: a. Tractive or Braking force b. frictional resistance to bearings 6. Centrifugal forces 7. Buoyancy 8. Earth pressure incl. Live load surcharge 9. Temperature effects 10. Deformation effects 11. Secondary effects 12. Wind loads 13. Wave pressures 14. Impact due to floating bodies 15. Erection effects 16. Seismic forces
- 5. DEAD LOAD DEAD LOAD CONSISTS OF LOADS OF ALL COMPONENTS OF SUPER STRUCTURE: DECK SLAB AND GIRDERS FOOT PATHS WEARING COAT KERB HAND RAILING
- 6. LIVE LOAD ALL BRIDGES SHALL BE DESIGNED AS PER THE FOLLOWING INDIAN ROAD CONGRESS LOADINGS:
- 7. IRC CLASS A
- 8. IRC 70 R LOADING
- 9. IMPACT Impact allowance is a percentage of the applied live load and is for the dynamic action of live load as listed in table. Type of bridge Class A and Class B loading Class AA and 70 R loadin g For spans 3.0 to 45 m For Spans than less 9.0m For Spans or 9.0 m more Tracked vehicle Wheeled vehicle Tracked vehicle Wheeled vehicle RCC concrete bridges 4.5/ (6+span length) 25% upto 5m reducing linearly to 10% for 9m 25% 10% upto 40m and as per chart for above 40m 25% upto 12m and as per chart for above 12m Steel bridges 9/ (13.5+ span length) 10% for all spans 25% upto 23m and as per chart for above 23m
- 11. 11 WIND LOAD WIND PRESSURE & VELOCITY (Cl. 212.3 of IRC: 6-2000) H V P H P V H P V 0 80 40 15 128 107 60 168 183 2 91 52 20 136 119 70 173 193 4 100 63 25 142 130 80 177 202 6 107 73 30 147 141 90 180 210 8 113 82 40 155 157 100 183 217 10 118 91 50 162 171 110 186 224 Where H = Ave. height in m of the exposed surface above Ground level/ bed level/ water level V = horizontal velocity of wind at height H in Km/ hr P = horizontal wind pressure at height H in Kg/ m2
- 13. 13