University of California Transportation Center

A new dynamic finite-element computer program, DYNA-SLAB, for the analysis of jointed concrete pavements subjected to moving transient loads is presented. The dynamic solution is formulated in both the time and the frequency domains. The structural model for the slab system is the one used in the static computer program ILLI-SLAB. The foundation support is represented by either a damped Winkler model with uniformly distributed frequency-dependent springs and dashpots or a system of semi-infinite horizontal layers resting on a rigid base or a semi-infinite half-space. An important contribution from the study is a new analytical method for determining the stiffness and damping coefficients to be used in the Winkler foundation model. The accuracy of DYNA-SLAB has been verified by comparing the results produced by the program with those from theoretical closed-form solutions and from a powerful dynamic soil-structure interaction computer program called SASSI as well as with field data. The analytical results indicate that dynamic analysis is generally not needed for the design of rigid pavements and that it usually leads to decreased pavement response. Thus, it appears that a quasistatic analysis is sufficient and that the results from this type of analysis will generally be conservative, provided that the wheel loads used in the analysis have been adjusted for the effects of vehicle velocity, truck suspension characteristics, and pavement roughness.