Bridge Deck Slab Design Procedure 5u3i3n

This code covers the structural and design

aspects with reference to the use of prestressed concrete (post tensioned) for constructing road bridges.

The scope of this code covers the following areas:  Material properties of cement, aggregates and steel, including there permissible stresses  Minimum dimensions and section properties of various superstructure sections.  Various losses in prestress.  Shear and torsion.  Minimum reinforcements, end and anchorage blocks, splay of cables, etc.

LOAD AND BENDING MOMENT CALCULATIONS  Selecting material grades  Assume depth of slab, 50 mm per meter span

 Calculation of dead load and dead load bending

moments; weight of slab weight of wearing coat

….contd  Calculation of live load bending moments

• Consider IRC load class • Calculate impact factor according to loading class and

span • Calculate average intensity of loading and maximum bending moment due to live loads • Calculate design shear at

LOAD POSITION FOR MAXIMUM BENDING MOMENT AND MAXIMUM SHEAR

EFFECTIVE WIDTH OF DISPERSION FOR IRC CLASS AA LOAD

CHECKS TO APPLIED  Check for minimum section modulus  Minimum prestressing force  Check for stresses;

1. at transfer 2. at service  Check for ultimate strength 1. failure by yielding of steel 2. failure by crushing of concrete  Check for ultimate shear strength

 Supplementry reinforcement:

0.15 % of gross sectional area should be provided.  Design of end block: bursting tension should be computed and according to that area of steel should be calculated.

Section of Deck Slab at Centre of Span & Longitudinal Section of Deck Slab