HIGHWAY ENGINEERING Highway engineering is an engineering discipline branching fromcivil engineering that involves the planning, design, construction, operation, and maintenance of roads, bridges, and tunnels to ensure safe and effective transportation of people and goods. PAVEMENT The pavement carries the wheel load and transfer the load stresses through a wider area on the soil sub grade below. Thus the stress transferred to the sub grade soil through the pavement layers are lower than contact pressure or compressive stresses under the wheel load on the pavement surface & reduction in the wheel load stress due to the pavement depend on thickness & characteristics of the pavement layers. TYPES OF PAVEMENT Differentiate by sketches :
DESIGN OF FLEXIBLE PAVEMENT Flexible pavement also design by : Group Index Method CBR Triaxial Method MC Load method Burmister Method DESIGN OF RIGID PAVEMENT Modulus of sub-grade reaction: Westergaard considered the rigid pavement slab as a thin elastic plate resting on soil sub-grade, which is assumed as a dense liquid. The upward reaction is assumed to be proportional to the deection. Base on this assumption, Westergaard de_ned a modulus of sub-grade reaction K in kg/cm3 given by K = p _ where _ is the displacement level taken as 0.125 cm and p is the pressure sustained by the rigid plate of 75 cm diameter at a deection of 0.125 cm.