But what caused the bridge to
fail? The Miami Herald has published
an extensive investigative report,
starting with these questions:
“Did it crack when it was lifted
into place? Was it a snapping steel
support that did it in? Or was it a fa-
tally flawed design from the start?
And what was the doomed construc-
tion crew member doing when the
bridge buckled under him?”
Each of these questions could
have different answers, and the
newspaper reported about specula-
tions and varying interpretations
within engineering forums. But the
details of what really happened are
4 – SPRING 2018 — Florida Construction News
stored at the NTSB and it may take a
year or more for the investigators to
release their findings.

In the most recent news release
March 21, the federal agency said:
“The next update on the progress of
this investigation will likely be the
preliminary report. Preliminary re-
ports are generally completed within
a few weeks following completion of
field work. Preliminary reports do not
contain analysis and do not address
probable cause.”
In other words, NTSB will likely be
totally silent for several weeks, and
then will decline to answer (at least
for now) the questions about why
the tragedy occurred.

In its March public statement, the
NTSB said that significant develop-
ments in the investigation include:
• Investigators secured a contract
to have a company remove com-
ponents from the bridge that it be-
lieves warrant additional
examination and testing. These
components include sections of
the floor, the canopy, a vertical
member and a diagonal member;
all from the north end of the struc-
ture. These components were in
the area of where the failure oc-
curred. “In addition to these com-
ponents, we obtained additional
core samples from this area to
supplement the core samples we
obtained earlier,” the NTSB state-
ment said.

• Shipping the core samples along
with some recovered rebar and
tensioning rods to the Turner Fair-
bank Highway Research Center, in
McLean, VA, for testing and evalu-
ation. • The investigative team has ob-
tained an exemplar tensioning rod
and hydraulic unit used by the
construction crew to make ten-
sion adjustments to the tension-
ing rods. These items are also
being shipped to the Virginia re-
search center for evaluation and
testing. • The larger bridge components the
investigative team is removing are
being stored at a secured Florida
Department of Transportation fa-
cility, under the control of the