Optimal design on dowel length for cement concrete pavement

In order to compute the optimal dowel length in cement concrete pavement, semi-infinite beam on elastic foundation was deduced and modified for the analysis of dowel bars. The dowel deflection, bending moment and shearing were analyzed for dowel bars under the traffic loading, dowel length based on the second inflexion distance was computed and a relationship between dowel length and dowel diameter was established. The theoretical analysis found that the dowel length in Chinese specification is conservative. A finite element model was also established to simulate the dowel load system. Based on the result of maximum value and variation tendency of mises stress for different dowel diameters and dowel lengths, it is feasible to shorten dowel length specified in JTG D40-2002 by 50%. However, considering the construction tolerances in the making and sawing of joints in new pavement construction, which might add 50-150 mm to the required overall dowel length, it's more appropriate to reduce the dowel length by 20% in practice.