Lightweight Concrete for High Strength - Expanded Shale & Clay

objective of this test was to examine the shear strength of concrete. The shear crack running
from bottom to top occurred very suddenly and violently and was indicative of a pure shear
failure. Girders undergoing shear failures precipitated by strand slip showed different failure
modes.
Figure 5.14 Girder Test G2A-Center Showing Pure Shear Failure
5.8 Cracking Results
Table 5.7 provides an overview of the predicted and experimental cracking moment for
each girder test. The experimental cracking moment was determined by examining the
experimental load vs. deflection plot identifying the point at which a slope change occurred. In
every case, the cracking load indicated on the load vs. deflection plot matched the load recorded
where visible flexural cracking first occurred.
Based on the use of equation 5.1, the predicted cracking moment for the G2 series girders
was 10.8 percent greater than for G1 girders.
f
cr − Pr ed
= 7.5λ
f
'
c
(5.1)
where λ is the correction factor of unit weight of concrete, taken as 0.85.
5-18