OSHA Inspection: KIEWIT CONSTRUCTION CO.

Issued

Apr 30, 2001

Abate by

May 4, 2001

Penalty

Initial $7,000 · Current $7,000

General-duty citation text

Serious Citation 1, item 1
Title 40.1-51.1(a), Code of Virginia: The employer did not furnish
employment and a place of
employment which were free from recognized hazards that were causing or
likely to cause death
or serious physical harm to employees in that employees were exposed to a
tunnel cave-in hazard
while constructing a pedestrian walkback tunnel (south end) at Dulles
Airport.  On November 1,
2000, an employee of Kiewit Construction Company was killed when a section
of the tunnel
collapsed.
The employer knew that a catch basin was located above the tunnel between
excavation
rounds 104SE and 105SE, but failed to field verify the invert elevation of
the basin before
tunneling through this location, in accordance with the contract
specifications.  The
crown of the tunnel was approximately 16 feet below the surface.  The
catch basin, which
was part of the water collection system, was approximately 8 feet deep.
The employer
failed to verify not only the depth of the basin, but also failed to
consider that the original
excavation for the catch basin was likely deeper than 8 feet, and that
during its
installation and continued use as a water collection system, the soil
underneath could
have been compromised considerably in relation to surrounding soil
conditions.  The
October 31st falloff of 5 cubic yards (cy) of soil, and the tunnel
collapse November 1st,
occurred in close proximity to where the catch basin was located above the
crown of the
tunnel.
One feasible and acceptable abatement method among others to correct this
hazard is to
comply with the contract specifications, Section 03301, Paragraph 1.03.B.

Issued

Apr 30, 2001

Abate by

May 4, 2001

Penalty

Initial $70,000 · Current $70,000

General-duty citation text

One feasible and acceptable abatement method among others to correct this
hazard is to
comply with the contract specifications, Section 02951-17, paragraph
3.08(11).
Title 40.1-51.1(a), Code of Virginia: The employer did not furnish
employment and a place of
employment which were free from recognized hazards that were causing or
likely to cause death
or serious physical harm to employees in that employees were exposed to a
tunnel cave-in hazard
while constructing a pedestrian walkback tunnel (south end) at Dulles
Airport.  On November 1,
2000, an employee of Kiewit Construction Company was killed when a section
of the tunnel
collapsed.
During the week prior to the accident the Employer experienced
deteriorating soil conditions and
three falloffs of more than 1.0 cubic yard (cy) of soil during tunneling
operations between
October 24th and October 31st.   The falloffs increased in severity from
1.0 cy on October 24th to
4.0 cy on October 25th to 5.0 cy on October 31st, the day before the
accident. No tunneling
occurred on October 29-30, 2000.  Based on tunneling records, it appears
that there were only a
total of ten falloffs equal to or exceeding 1.0 cy, including the three
already mentioned, that
occurred at the site in the six months preceding the accident.
The tunnel was being built using the soft ground tunneling method known as
the New
Austrian Tunneling Method (NATM).  Contract specifications required that
an NATM
engineer report for work at the site at least six weeks prior to
commencement of the
access ramp excavation and to remain at the site for a minimum of four
weeks after
completion of all mined tunnel concrete lining work.
The employers NATM engineer was apparently not on site during the entire
month of
October, 2000 and was on site for only a brief portion of September, 2000,
to perform the
following duties, among others, under the contract:
To supervise the excavation to ensure safety and quality of construction.
To devise and implement local support measures as required by the ground
conditions, coordinating remedial measures when ground loss at mined tunnel
heading or instability of mined tunnel occurs, or when they appear likely.
[NOTE: Local Measures are defined under the contract specifications as
grouted
pipe spiling, rebar spiling and metal sheeting installed in a systematic
or non-systematic manner installed individually or otherwise in addition
to pre-support
specified for the respective Excavation and Support Class, for local
stabilization
and safety during tunneling.]
To prepare a written daily interpretation of instrumentation measurement
readings
during excavation.
To hold daily discussions with the Metropolitan Washington Airport
Authoritys
Contracting Officers Technical Representative (COTR), Parsons Management
Consultants (PMC), at the tunnel face regarding ground conditions and
corresponding excavation and support requirements and other supports and
keeping written records thereof.
The NATM engineer was not present to address this escalating level of
falloffs, nor had
he even apparently been contacted on the falloffs.  Kiewits NATM
superintendents,
approved under the contract, made no changes in the tunneling method or
tunnelingsequence, nor applied  local measures as defined in the contract
to
support areas where
the falloff occurred, beyond filling the falloffs holes with shotcrete.
Contract drawing specifications define the tunnel excavation sequence and
support
mechanisms:
All support (flashcrete, shotcrete plus reinforcement) for each excavation
round must be
completed as shown prior to commencing next excavation round in sequence.
Support was to be applied immediately upon the completion of tunneling
each round:
apply 2 inches of flashcrete to all surfaces,
install the girders and spiling bolts (designed to reinforce the soil and
stabilize the
heading),
apply an additional 6 inches of shotcrete, before beginning tunneling on
the next
round,
contract drawings specified that the employer was supposed to stay 4 rounds
ahead on the southeast side of the tunnel, and alternate tunneling
operations
between one round on the southeast side and one round on the southwest
side of
the tunnel,
a total of  five rounds on the southeast side must be fully supported with
flashcrete, girders, spiling bolts and 8 inches of shotcrete before the
employer
could begin digging on the southwest side.
As allowed under the contract specifications, the above sequence could be
modified if
approved by PMC.  Apparently in response to stable ground conditions, the
employer
decided to only completely support one round on the southeast side with 2
inches of
flashcrete, girders and spiling bolts, and 6 inches more of shotcrete,
then dig 4 more
rounds ahead and apply the initial 2 inches of flashcrete coating.  The
employer would
then start tunneling the next round on the southwest side while workers on
the southeast
side were putting up the girders, spiling bolts, and additional 6 inches
of shotcrete on the
remaining 4 rounds on the southeast side.   This revised tunneling
sequence resulted in
both headings lacking full support and stabilization at the same time
during tunneling
operations.
When ground conditions deteriorated during the week before the collapse,
the NATM
engineer was not present to address the escalating level of falloffs.  He
was not available
to revise the tunneling sequence to conform to contract specifications.
Kiewits NATM
superintendents made no changes in the tunneling method or tunneling
sequence in
response to the deteriorating soil conditions, nor applied  local measures
as defined in
the contract to support areas where the falloff occurred, beyond filling
the falloff holes
with shotcrete.
One feasible and acceptable abatement method among others to correct this
hazard is to
comply with the contract specifications, Sheet T3.4, Note 5.
The employer, with the approval of PMC , reduced the number of spiling
bolts to be
installed on each girder from approximately 19 to 13 as part of the tunnel
support system,
by agreement dated August 22, 2000.  PMC approved this reduction on two
conditions:
1) that the tunneling was being conducted in stable ground conditions, and
2) is approved
on a case-by-case basis based on the employers NATM engineers observations
and
recommendations.  The NATM engineer was apparently not on site during the
entire
month of October, 2000 to observe the  escalating level of falloffs and
deteriorating soil
conditions in the week leading up to the tunnel collapse.  The NATM
engineer was not
available to approve or change from the continued use of 13 spiling bolts
instead of the
19 or more provided for in the contract, nor had he even apparently been
contacted on the
falloffs.
One feasible and acceptable abatement method among others to correct this
hazard
is to
comply with the contract specifications, Sheet T3.4, Cross Section A.
Contract specifications provide that  no excavation shall be permitted in
the absence of
sufficient amount of shotcrete available at the face.  For a significant
period of time, the
employer had been experiencing problems with shotcrete application to the
walls of the
tunnel.  The shotcrete machine became clogged on a frequent basis and less
frequently the
shotcrete failed to adhere to the walls.  On the day of the collapse, the
employer was
found running the tunneling machine while the shotcrete machine was
clogged.  Work
was ordered stopped by PMC until the shotcrete machine became available.
Immediately
before the accident, the shotcrete machine apparently clogged again.  At
the time of the
collapse, the employer began using the tunneling machine again, even
though the
shotcrete machine had not been put back in service.