1.11.1 Ordinary Bolts and Nuts
1.11.1.1 Ordinary bolts and nuts shall
comply with BS 3692, BS 4190 and BS 4933.
1.11.1.2 All ordinary
bolts shall be fitted with washers and nuts
complying with BS 4320. Nut
shall be of at least the
strength grade appropriate
to the
grade of the
bolt used. Tapered washers shall
be
used where necessary.
1.11.2 High Strength Friction Grip Bolts
1.11.2.1 The
use of
high
strength friction
grip bolts
and associated nuts and
washers
complying with BS 4395 shall be in accordance with BS 4604.
1.11.2.2 Other types of friction
grip fasteners may
also be used subject to the approval of the Engineer provided they have mechanical properties not inferior to bolts complying with BS 4395 and provided they
are
capable of being reliably tightened to the minimum shank tensions specified in BS 4604.
1.11.3 Surface Finish
1.11.3.1 Bolt assemblies in externally exposed locations are to be galvanised in accordance with BS EN ISO 1461.
1.11.3.2 In addition
to all
other testing requirements,
galvanised
grade
8.8 bolts and
galvanised HSFG bolts shall be tested for head soundness according to Appendix
D9 of BS 3692 and also
subjected to supplementary
tensile testing to confirm their mechanical properties. Each test is to be carried out on 1% of the total
number in each batch of
galvanised bolts.
1.11.4 Holes
1.11.4.1 All
holes shall be drilled or sub-punched
and reamed.
1.11.4.2 Holes for ordinary bolts shall not be more than 2mm greater in diameter than the bolt
for
bolts not exceeding 24mm diameter and not more than 3mm for bolts over 24mm
diameter, unless otherwise specifically required by the design.
1.11.4.3 Holes for friction grip bolts shall be in accordance with BS 4604.
1.11.4.4 Holes for bolts shall be
formed by drilling and all burrs shall be removed before
assembly.
1.11.4.5 Holes for
fitted bolts or pins shall have a diameter equal to or not more than 0.15mm of the nominal
diameter of the bolt
or pin.
1.11.5 Protection of Hollow Section
1.11.5.1 Where a sealed hollow member is holed by a fastener or pin, provision shall be
made
to prevent ingress of moisture to the interior of the member. If not shown on
the
Drawings, the Contractor
is
to propose the method on the Shop Drawings.
1.11.6 Limits to Length
1.10.6.1 The length of bolts is to be such that at least one clear thread shows above the nut after tightening, and at least one thread plus the
thread run out is clear between the
nut and the unthreaded shank of the bolt.
1.11.7 Foundation Bolts
1.11.7.1
Foundation bolts shall
be cast in to the dimensions shown in the Drawings. The Contractor shall ensure that
the projecting
ends of the bolts are free to move horizontally. The projecting ends of bolts shall
be well greased and wrapped in sacking that shall remain in position until the commencement
of
steelwork erection.
1.11.7.2 Prior to delivery of steelwork for erection, the Contractor shall check the concrete bases
or seatings for level, setting out, projection and full degree of adjustment of the holding-down bolts.
1.11.7.3 The Contractor shall remedy any discrepancies or inaccuracies to the satisfaction of
the Engineer. Modification
to the
steelwork, bending of the holding-down
bolts
or the use of excessive number of washers to accommodate errors in position and projection of bolts shall
not be carried out except with the written permission of the Engineer.
1.11.8 Grouting
1.11.8.1 Grout around
foundation bolts and under column base plates is to be supplied and placed by the Contractor and is to have a minimum compressive strength at 28 days
of
60 N/mm2.
1.11.8.2 The grout mix shall be polymer based, prepared, mixed and placed in accordance with the manufacturer’s specifications approved by SCI.
1.11.8.3 Grouting under the column bases shall
only be carried out after a sufficient portion of
the
steel structure has
been aligned, levelled, plumbed and adequately braced by other structural components which have been levelled and are securely held by their permanent connections. Immediately before grouting, the space under the column
base plates is to be clean and free of all extraneous matter.
1.11.9 Riveting
1.11.9.1 The use of rivets shall be
in accordance with BS 4620.
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