A new design method has been developed according to the dynamic theory of the equivalent plate on the subgrade, and its validity has been verified using 18 types of pavement structure. According to existing Czech method, design of flexible pavements is based on an ideal n-layer flexible system characterised by modulus of elasticity, Poisson's ratio for subgrade and individual layers, and interaction between layers in the range q = 0-1. Load due to vehicles is replaced by static equivalent load generated by a design axle which is uniformly spread on substitution surface. The program OPMEKO I for this method does not consider the dynamic load due to moving vehicles. The dynamic equivalent plate (EP) method has therefore been developed. This is based on the fact that shape of the dispersion curve of the phase velocities of surface waves of stress is to some extent identical with shape of the dispersion curve for bending waves in the equivalent plate. To analyse pavement behaviour, deflections w, bending moments M, transverse forces Q and subgrade reaction q must be determined. NS and EP methods were used for 18 structures of different types. It is difficult to decide which is better, since in-situ tests on existing roads have not yet been made.
Abstract