Holes f o r f r i c t i o n - g r i p fasteners shall be checked f o r clearance and, a f t e r the
parts have been assembled by means o f barrel d r i f t s , the holes shall be checked f o r
alignment. Errors i n alignment of a hole i n an inner component shall be corrected
by d r i l l i n g or reaming the hole. Lack of alignment of a hole i n an outer component
shall be corrected by d r i l l i n g or reaming the hole through the assembled components
t o a larger size, and using a b o l t of larger diameter.
The diameter of holes f o r f i t t e d bolts or pins shall, subject t o a tolerance of
nim, be equal to the nominal diameter of the b o l t or pin. -0 Where practicable,
parts t o be connected by f i t t e d bolts or pins s h a l l be t i g h t l y clamped or bolted
together and the holes d r i l l e d through a l l the thicknesses i n a single operation
and subsequently reamed t o size. Holes not so d r i l l e d shall be sub-drilled o r subpunched
t o a diameter at least 2 mm under size and reamed t o f u l l size after
assembly or, where t h i s i s not practicable, the parts shall be d r i l l e d and reamed
separately through hard bushed steel j i g s . Holes f o r f i t t e d bolts o r pins shall not
be f i n a l l y reamed u n t i l welding and other f a b r i c a t i o n procedures are complete.
The d e t a i l s of holes f o r holding-down bolts shall be as shown on the drawings.
Slotted holes shall be formed by
a) d r i l l i n g or, subject t o the provisions of 5.2.4.4 and 5.2.4.5, punching a p a i r
of holes and flame-cutting between the holes; o r
b) s l o t punching i n the case of material of thickness not exceeding 12 mm .
A l l burrs s h a l l be removed from holes before assembly except that, where holes are
d r i l l e d i n one operation through assembled parts that w i l l not be separated a f t e r
d r i l l i n g , burrs on only the outside surfaces of such assemblies shall be removed.
Where a sealed hollow member i s holed f o r a fastener or pin, provision shall be
made t o prevent ingress of moisture t o the i n t e r i o r of the member.
Joints i n Compression. The abutting surfaces of a j o i n t dependent on contact f o r
� F E m m i s s i o n of load shall so b u t t that the areas necessary to transmit the
load are i n contact. A bearing face t h a t i s to be grouted d i r e c t t o a foundation
need not be machined but such a face shall be true and p a r a l l e l t o the upper face
of the foundation.
-Str uctural Hollow Sections. Where so required i n the design, the ends of hollow
sections may b e - i T X m or otherwise formed, f o r welded, bolted or riveted connections
provided that the method employed does not damage or deface the material.
The change of shape of a section shall be gradual.
Unless special protection against corrosion i s provided by other means, the
i n t e r i o r of any hollow member, whether a structural hollow section or a fabricated
member, shall be so sealed as t o prevent the ingress of moisture.
ASSEMBLY
General. The component parts shall be so assembled that
V t K w h o l e and a l l parts of t h e f i n i s h e d s t r u c t u r e are within the tolerances spec
i f i e d i n Clause 6;
b) no member i s bent, twisted or otherwise damaged; and
c) specified cambers are obtained.
A l i nment of Holes. A l l matching holes f o r fasteners o r f o r pins s h a l l so register
E&e#ac h other t h a t the fasteners can be inserted f r e e l y through the assembled
members i n a d i r e c t i o n a t r i g h t angles t o the faces i n contact. D r i f t i n g to align
holes, other than holes f o r f r i c t i o n - g r i p fasteners (see 5.2.4.8), shall be so done
t h a t t h e metal i s not d i s t o r t e d and the holes are not enlarged. Holes that cannot
be a1 igned without enlargement shall be cause f o r r e j e c t i o n unless enlargement by
reaming i s s p e c i f i c a l l y approved.
Lvoidance of Excessive Stresses d u r - Construction. Structures, composite units,
a n d ' m K m Z ; i i i b l ies t h a t o @ r i S e component Fa743 shall not be subjected t o
excessive stresses during the assembly, f a b r i c a t i o n or erection process.
We1 ding. We1 di ng shall be c a r r i e d o u t i n accordance with the re1 evant recommendaE5ns
of SABS 044, SABS 0162 and AWS D 1 . l or BS 5135. P a r t i c u l a r attention shall
be paid t o the following:
a) Welding techniques shall be such as to prevent undue d i s t o r t i o n and minimize
shrinkage stresses.
b) A l l slag and spatter s h a l l be removed.
wo ther than Friction- ri e par s-U6'6TFiiGd3ia11- --eij -fi"rm ly drawn toqether. Grade 4.6 bolts and
Grade 8.8 bolts i n shear and bearing type connections shall be tensioned by hand t o
the l i m i t of the torque that can be applied by the use of a standard podger
spanner. High t e n s i l e b o l t s f o r major tension type or moment type connections and
where fatlgue i s a consideration, shall be tightened to a tension of 75 % of the
proof load stress of the b o l t .
Except i n the case of f i t t e d bolts and unless othet-wi se requi red i n terms of the
project specification or s p e c i f i c a l l y ordered, washers need not be used where surfaces
are f l a t and flanges untapered, and holes have normal clearances (see 5.2.4).
On tapered flanges, tapered washers shall be used to give b o l t heads and nuts a
satisfactory bearing. Where holes have greater than normal clearance, washers shall
be used under b o l t heads and nuts.
The length of each b o l t shall be such that a f t e r the b o l t has been tightened, a t
least one thread projects through the nut and a t least one f u l l thread (in addition
t o the thread runout) remains clear between the nut and the unthreaded shank.
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