Lecture Content
Stress in Rigid Pavements
Stress due to wheel load
Westergaard Slab analysis
Stress due to wheel load
Wheel load is moving load , Change slab position , Induced stress in the slab
To Investigate critical positions in the slab
At the critical location max tensile stress will occur.
Westergaard determine the significance of the slab stress at different locations.
Westergaard analyze the stress at different location, which so called critical fail about to fail
Assumptions:
The concrete slab is homogenous, Isotropic, elastic, Static Position (Equilibrium or balance), Slab thickness is uniform.
Subgrade reaction are acted in vertical directions & directly proportional to deflections of the slab in vertical direction.
Slab thickness is uniform, where K= Stress/deflections =lb/m3
Single Wheel load considered to be uniformly distributed over Circular contact area in the interior of the slab.
The weight of the single wheel load for edge of the slab is considered to be distributed uniformly, over the semi-circular contact area.
Critical locations….
When wheel load is at interior location of the slab, the tensile stress will develop at the bottom of the slab
When wheel load is at the coroner position, the tensile stress will induce at the top of the slab
When wheel load is at the edge locations, tensile stress will occur at the bottom of the slab.
00:00 Stress in Rigid Pavements
00:45 Stress due to wheel load
01:36 Westergaard Slab Theory
05:24 Westergaard Slab analysis
10:45 One layer bedding Modulus
15:24 Bending tensile stress at Center, Mid and at edge
