BS5400 Part 2 : Bridge loadings (Explained)

what load to consider and how to apply loads

1. BRIDGE LOADINGS TO BS 5400

2. Wind Load Primary Highway Load Temperature Load Exceptional Load Secondary Highway Load Erection Load Transient Load Type of Bridge Loadings Permanent Load Dead Load Differential Settlement Load Derive from Nature of structural material Superimposed Dead Load Load Due to Filling Material Primary Highway Load HA Load HA + HB Load Centrifugal Load Collision with support Longitudinal Braking Fatigue & Dynamic Load Skidding Collision With Parapet Secondary Highway Load

3. 5 Earth Pressure 4 Backfill 2 Slab Self weight 1 Dead load Beam Self weight 3 Diaphragm Self weight 6 Pier/Abutment Self weight Skidding Load 7 Creep 7 Shrinkage

4. Effect of creep  is the tendency of a solid material to undergo slow deformation while subject to persistent mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength of the material shrinkage is a changes of pore water content due to drying processes cause significant volume changes of concrete in load-free specimens (typically causing strains between 0.0002 and 0.0005, and in low strength concretes even 0.0012)

5. Super Imposed Dead Load 2 Premix 1 Parapet 3 Services Normally apply to model as Line load or UDL load PARAPET LOAD PREMIX LOAD

6. Differential Settlement Skidding Load Effect of settlement of any one of the foundation Normally taken as 12mm for SLS condition and 38mm for ULS condition but these value depend on project needs Calculated using computer aided analysis software by applying support movement to specific foundation in modelling of the structure DIFFERENTIAL SETTLEMENT

7. Wind Load Wind load is apply in substructure analysis Basic Hourly mean speed is normally decide and define in Design criteria according to available data or history of wind at that area. For general case, value of 32.5m/s is used. From the basic hourly mean speed, we can then derive maximum wind gust speed using formula and factors given in BS5400. The load is then apply to pier modelling in analysis software WIND LOAD

8. Temperature Load Temperature strain is taken as 0.00012 Force acting on deck due to differential temperature on top of deck toward bottom soffit of deck is calculated using TEMPERATURE LOAD

9. TRAFFIC LOADS

10. Traffic Lanes Notional Lanes Carriageway Marked lane for vehicle Width between raised kerb Notional parts of carriageway used solely for the purposes of applying loads

11. Shall not be less than 2.5m wide Where number of notional lanes exceed two, their individual width should not be more than 3.65m. Notional Lanes

12. HA Loads Consist of UDL load occupying notional lanes with intensity explain below and knife edge load apply in line crossing one notional lane with intensity of 120kN

13. HB Loads One unit of HB load taken as equal to 10kN per axle (2.5kN per wheel)

14. HA+HB Loads

15. Centrifugal Loads

16. Traction Loads

17. Skidding Loads

18. Collision Loads (BS5400)

19. Collision Loads (BD60/94)

20. Loads Combinations