OSHA Inspection: PARSONS MANAGEMENT CONSULTANTS

Issued

Apr 30, 2001

Abate by

May 4, 2001

Penalty

Initial $7,000 · Current $7,000

General-duty citation text

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 Kiewit Construction Company, the
tunneling
contractor, 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.
a)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 NATM engineer, with the knowledge of Parsons Management Consultants
(the
Metropolitan Washington Airport Authoritys Contracting Officers Technical
Representative (COTR), 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 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 tunneling
sequence, nor applied  local measures as defined in the contract to
support areas where
the falloffs occurred, beyond filling the falloff 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 southwest side and one round on the northeast
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 this 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 tocomply with the contract specifications, Sheet T3.4, Note 5.