(HP-97) Linear Elastic Pavement

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An extract from I LEAP DEEP, PSAD - ett ADB-program för beräkning av spänningar och töjningar i en vägkonstruktion bestående av material med non-linjära E-moduler, av Håkan Jansson, Statensväg- och trafikinstitut (VTl), Nr 58 1977

Description of HP 97 Program "I LEAP DEEP"
I terative program
L inear
E lastic materials
A pplied procedure
D ual wheel loading
E quivalent thicknesses
E lastic 'theory
P avement structures

ACKNOWLEDGEMENTS
The table calculator program described herein was developed by the undersigned at the request of the National Road Laboratory of Denmark and the National Swedish Road and Traffic Research Institute.

THE "l LEAP DEEP" PROGRAM
The l LEAP DEEP program, as the title letters vaguely imply, is an iterative program which can be used to find the necessary layer thicknesses for pavement structure assuming linear elastic materials and where dual wheel loadings can be taken into account. Either 2, or layer systems are possible, and the uppermost layer must be asphalt bound.
Boussinesq's equations for an elastic half-space together with the approximate equations based on the well-known method of equivalent thicknesses are utilized. Basically, this involves finding an equivalent thickness (of linear-elastic material) above a point in the structure in which the E-modulus is the same as the assumed half-space below …

PROGRAM CARDS AND CALCULATION PROCEDURE
Three program cards are provided, a Raw Data Program and two stress and strain programs, one of which is related to vertical stresses in the structure and the other to the corresponding vertical strains. Both of the latter consider the horizontal tensile strain at the bottom of layer 1 (the asphalt-bound layer) …
To illustrate this procedure, some examples in the use of' the I LEAP DEEP program together with actual printed results from the paper tape of the HP 97 are presented in the following pages. In the appendices, step-by-step instructions as to the use of each specific program card are given together with pertinent tips on the use of the program.

complete & thorough: enjoy.

BEST!
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