|
|
|
Prediction of mean asphalt layer temperature
and normalization of maximum deflection values to a standard temperature of 70° F are
accomplished using the Asphalt Institute methods. The program also have the capability to
normalize the backcalculated asphalt concrete layer moduli to any required temperature. When testing concrete pavements, the slabs
are tested across the joints with one slab loaded and a sensor bridging over to the
unloaded slab. From these deflections, the load transfer between slabs can be calculated.
This is important at the Design/Analysis stage to determine the extent of stress reduction
on the loaded slab due to load transfer. This module utilizes the deflections measured
at the corner of concrete slabs to determine the presence of voids under the slab. This module is extremely helpful to the
engineer in analyzing the pavement. It provides the opportunity of plotting, either to the
screen or to a printer, the maximum deflection versus distance profiles, thereby allowing
the engineer to formulate a preliminary idea on the structural condition of the pavement
tested. The deflection profiles are also used to divide the pavement into uniform
sections. This program utilizes a theoretical
representation of the pavement structure in conjunction with the collected FWD data to
backcalculate the moduli values of the pavement's layers. Up to five layers can be
analyzed. This module utilizes closed form solution
based on extensive and comprehensive evaluation of concrete slabs using a finite element
program. This program is capable of predicting the strength of the layers for a given slab
thickness, or the pavement thickness for a given slab stiffness. Given a slab thickness, strength, and the
anticipated load and tire pressure, this module will calculate the induced stresses and
deflections in the slab thereby allowing for determination of its structural capacity. This is a very powerful computer program
capable of utilizing any aircraft loading configuration in conjunction with backcalculated
pavement layer moduli values to calculate the overlay thickness required for a given
design period. One of its capabilities is to divide the year into different seasons. This
is important to account for the variation in the anticipated pavement support condition
and/or traffic intensity. The output includes both graphical and text format detailing the
fatigue analysis per pavement section over the design period. Similar to the program for airfield
pavements, this module can calculate the overlay thickness for highway pavements. However,
it accounts for traffic differently since the applied traffic is converted to Equivalent
Single Axle Loads.
|