SHRP-A-379 traducir

Sy = log S(8) + log S(15) + ... log S (240)
S_y = log S(8)(log (8)) + log S(15) log (15) + ... log S(240) log (240)
S_= [log (8)] 2 log S(8) + [log (15)] 2 log S(15) + ... [log (240)] 2 log S(240)
1.8.2 Calculate the estimated stiffness at 8, 15, 30, 60, 120, and 240 seconds as:
logS(t) = A + B[log(t)] + C[log(t)] 2 (13)
1.8.3 Calculate the estimated m value at 8, 15, 30, 60, 120, and 240 s as the
absolute value of
[m] = B 2C[log(t)] (14)
1.8.4 Calculate the fraction of the variation in the stiffness explained by the quadratic
model as:
R z = 1.00 - [l°gS(8)-l°gS(8)]2 + ""[l°gS(240)-l°gS(240)]2]
[logS(8)-log(S)l 2 + ...[logS(240)-log(S)] 2 ]
(15)
as:
1.8.5 Calculate S the average of the stiffness values at 8, 15, 30, 60, 120, and 240 s
log -S = [logS(8) + ...logS(240)]/6 (16)
1.8.6 Use the estimated values of the stiffness and m at 60 s for specification
purposes. Measured and estimated stiffness values should agree to within 2 %. Otherwise, the
test is considered suspect.
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