as approved by the Contracting Officer. Any redesign of the [anchored
structure] [ ] due to relocation of anchor holes [will be performed by the
Government] [shall be performed by the Contractor]. Unless otherwise
specified, theThe Contractor shall determine the drilling method to be
used. No holes shall be drilled within [15] [_____] meters [50] [_____]
feet of a grouted hole until the grout has set at least 24 hours.
[Pressure grouting and drilling shall not be simultaneously performed
within a distance of [15] [_____] meters [50] [_____] feet.] Care shall be
taken while drilling to avoid damage of any kind to the existing
structures. Damages of any nature will be evaluated by the Contracting
Officer and repairs or replacements shall be made at his discretion. Holes
shall be drilled a maximum of [1] [_____] meter[3] [_____] feet beyond the
required anchor bond length. A temporary plug shall be provided for all
holes drilled more than 10 days prior to installation of the anchor.
[Waste water from drilling operations shall be collected and recycled or
treated; it shall not be discharged directly into the [river] [water] or on
the ground. See also Section 01355A ENVIRONMENTAL PROTECTION].
3.2.2
Drilling Through Existing Structures
**************************************************************************
NOTE: Core drilling through existing structures
should only be required where close tolerances are
required or where vibrations from other drilling
methods might be objectionable.
**************************************************************************
Holes through existing structure shall be drilled by [core drilling
equipment to prevent][any method which does not cause] damage to the
surrounding structure. The Contractor is advised that foreign material,
including metals and other materials remaining from original construction
of the existing structure, may be encountered during drilling through
existing structures.
3.2.3
Drilling In Soil
**************************************************************************
NOTE: Where loss of surrounding material could
endanger nearby structures, the casing should be
advanced by methods which preclude removal of
material surrounding the casing, such as use of
duplex method with annular flow of drill water or
fluid between the inner drill string and the casing.
**************************************************************************
Holes in soil may be drilled by rotary drilling, rotary percussive, or
vibratory driven casing. Holes in soil shall be provided with steel casing
where required for support of the surrounding material. [Casing shall be
removed [prior to] [during] anchor grouting.] [Hollow-stem augers which
are used for installation of the tendon shall be removed during anchor
grouting.] Where soil is susceptible to caving, holes through soil shall
be drilled by the duplex method using an inner and outer casing with return
water flow between the casings.
3.2.4
Casing
**************************************************************************
NOTE: Casing may also be required to span voids
when drilling through existing structures.
SECTION 02490
Page 30
Previous Page
