PRESTRESSED PAVEMENT THICKNESS DESIGN (DISCUSSION AND CLOSURE)

A computerized procedure for thickness design of zero-maintenance prestressed concrete pavements is presented. Factors considered in developing the design procedure include traffic loading, temperature and moisture variation in the concrete slab, loss of subbase support, properties of concrete, properties of subbase, properties of subgrade, and effective midslab prestress. The procedure is based on flexural stress analysis and prevention of bottom transverse cracking that may initiate from the longitudinal edge of the slab in the vicinity of midslab. Inputs for the computer program include number and magnitude of axle loadings, wheel placement, traffic volume distribution during a 24-h day, temperature data, load transfer effectiveness, and effective prestress at midslab. Program output is in terms of total fatigue consumption at the end of design life. If fatigue consumption is less than 100 percent, then the thickness meets design criteria. A design example is presented for a rural four-lane highway in Illinois. (Author)