Lightweight Concrete for High Strength - Expanded Shale & Clay

Table 5.5 –Transfer Length Results (inches)
G1A G1B G1C G2A G2B G2C
East West East West East West East West East West East West
19.5 18.75 25.00 18.75 28.00 21.50 17.50 13.25 13.00 13.00 19.00 18.00
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5.7 Girder Tests and Results
Each girder was loaded monotonically until failure at a load of approximately 400 kips.
Loading proceeded in increments of approximately 30 kips or in deflection increments of about
0.25 inches. After each load or deflection increment, concrete surface strain (CSS) readings,
deflection readings, crack spacings, and VWSG readings were recorded. Readings were also
taken at special occurrences such as first flexural or shear crack observation or initial strand slip.
Table 5.6 provides an overview of experimental results listing failure types, ultimate strain
values and moments at cracking and ultimate conditions. The failure types were classified using
the definitions below:
FL - The girder failed by “BOTH” crushing of the deck and yielding of the strands.
SH - The girder failed purely in shear. It did not meet the criteria for a flexural failure.
SH/FL - The girder failed predominantly in shear, but still yielded the strands and crushed the
deck. The two failure states occurred almost simultaneously.
SH-SL - The girder underwent a shear failure initiated by the strands slipping.
FL/SH-SL or SH-SL/FL - The girder underwent both failure modes with one occurring more
predominantly than the other. Both failures would result in yielding of the strands and crushing
of the deck.
Although there are five failure types listed in Table 5.6, the failures fell into two major
categories; flexural failures and shear failures.
5.7.1 Flexural Failures
Figure 5.12 shows a photo of girder test G1-B West, a typical flexural failure. The
vertical lines indicate the location of shear reinforcement. Flexural failures were ductile in
nature. A typical flexural failure showed flexural cracks extending from the bottom of the girder
up into the deck and evenly spaced shear cracks less than 0.02 inches in width between the
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