INFLUENCE FUNCTION APPROACH TO ANALYSIS OF JOINTED PORTLAND CEMENT CONCRETE PAVEMENT

A technique for analyzing the interactions between typical highway loads and jointed rigid pavements by using influence functions is presented. Influence functions are generated by using a modified version of the ILLI-SLAB finite-element model. These influence functions can be used to estimate the minimum and maximum responses caused by moving wheel loads for any point of interest on the slab. A parametric study of the model is presented showing the effects of various key input parameters on the influence functions and stress distributions in the slab. A field model validation case study is presented for M-14, a 229-mm pavement built in Michigan in 1965. Traffic distributions were broken down into equivalent single axle loads per hour. Temperature and moisture gradient effects were estimated for a typical day. These factors were then reduced to obtain the daily fatigue loss. The results of the study indicate that the upward curled or nighttime temperature condition is prevalent and most severe. This results in the peak tensile stresses being located in the top of the slab. Results from the study compare well with field distress surveys for the test pavement.