Institute for Transportation

The objective of this study was to examine use of
stress wave nondestructive evaluation (NDE) techniques
to evaluate the in-place modulus of elasticity (MOE) of
the laminations in stress-laminated timber bridge decks.
Prior to bridge deck construction, longitudinal stress
wave and transverse vibration NDE techniques were
used to determine the MOE of 40 Southern Pine
lumber specimens. A strong correlative relationship
was found to exist between the MOE values obtained
by these two techniques. Then, several bridge decks
were constructed from these specimens, and several
types of instrumentation were used to measure the
MOE of individual specimens within the decks prior to
transverse stressing and at maximum transverse stress.
Excellent agreement was found between the MOE
values prior to bridge deck construction and those
observed after deck construction. More importantly,
average MOE values obtained from measurements of
the individual laminations showed strong agreement
with bridge deck MOE.