ERECTION OF PRIMARY AND SECONDARY STRUCTURAL
GENERAL INFORMATION
Many methods and procedures are in for erection the structural portion of metal buildings. For example,
the techniques of raising frames vary all the way from erecting small clear spans and end wall frames in
units, to erecting the larger clear spans and modular frames in sections. The erection methods used
depend strictly on the type of buildings, the available equipment, the experience level of the crews, and
the individual job conditions.
The variation in these factors precludes the establishment of a firm or specific set of erection rules and
procedures. Consequently, the erection operation must be tailored, by the erection himself, to fit
individual conditions and requirements. However, there are certain erection practices, pertaining to
structural members, which are in general use and have proven sound over the years. Description of these
follow.
The erection should have all the lifting equipment, cranes, forklifts, bars slings, guy wires, come-along,
and hand tools necessary to erect the building.
A basic list of equipment is shown in the appendix
STUDY THE DEAWINGS!
ERECTING THE FRAMES
Instructions are directed to a single-span structure.
Review erection drawings. Determine which bay includes permanent bracing. Set columns for braced bay.
Do not include end wall columns in this initial phase. Set a minimum of four interior frame columns.
Tighten anchor bolts and nuts sufficiently to prevent columns from rocking.
Install all side wall grits between each pair of columns. Install permanent bracing as indicated in erection
drawings.
Assemble rafter section on wood blocking. Placing flange stays in position on rafter.
Install all bolts in rafter splice to the proper tension, using turn of nut method or torque wrench.
All buildings require temporary bracing which should be attached to the rafter before it is lifted into place,
then tied off to prevent buckling of the rafter.
Raise rafter into position at top of columns.
Hold in place with hoisting equipment while required bolts are installed through the column caps, tighten
to snug fit.
Tie off first frame with cables extending lengthwise of the building.
The quantity and location of this temporary will vary with the size of the Structure.
CAUTION: ALL BUILDING MUST BE BRACED DURING ERECTION .THE DEGREE OF BRACING BEING
DEPENDENT ON THE SIZE OF THE BUILDING AND LOCAL WEATHER CONDITIONS. DO NOT COMMENCE
ERECTION IF WEATHER CONDITIONS ARE UNSETILED OR STRONG WINDS IMMINENT
Using above procedure, assemble second rafter.
Place it on top pf second set of columns.
Bolt to columns to hold second rafter with rig until a minimum of a quarter of the purlins are installed.
Release rig .Between erected rafters, place remaining roof purlins at every purlin location.
Install permanent rod bracing between rafters, Bolt flange stays in position.
Note: Flange brace may occur on either side of the rafter.
Before proceeding further this first bay must be made plumb and square.
Use the temporary braces to pull the columns into plumb.
When all columns of the first bay are plumb, tighten all anchor bolts, eave strut bolts, girt bolts, and
column to rafter bolts.
Resume erection of columns, rafters, and purlins in same manner in successive Bays.
Use additional temporary bracing as work progresses.
As each frame is erected, plumb columns, tighten anchor bolts, eave strut bolts, purlin bolts and fix flange
braces.
After completing all main frames the endwalls can be erected. Follow details from standard erection
drawing, ensure that high strength bolts are used where indicated.
Complete installation of grits, sag rods and bracing.
Install door frames and extra window framing, if any.
Make a final check of structural frame for alignment and plumb. Check all connections to be sure that all
bolts have been installed, and that all high strength bolts are tensioned to correct requirements.
NOTE : PLEASE, BE CAREFUL TO FILL UP ALL RELEVANT PARTS OF
THE ERECTION CHECKLIST.
BOLT TIGHTENING PROCEDURE
Scope:
This Specification covers the tightening and inspection procedures to be adopted in tightening HighStrength steel bolts using in the Pre-engineered Steel Structures.
American Standard Standards shall be followed for both material selection and tightening procedure.
General
We will tighten the Nut-Bolts in manual spanners, torque wrenches and power driven impact
wrenches.
The system of part-turn tightening shall be adopted, and shall be carried out in accordance with the
following procedure.
ASSEMBLY PROCEDURE
1.
Ensure nuts be placed so that high strength nut is visible after tightening.
2.
Ensure contact surfaces are clean and free from defects.
Line up holes with enough drift pins to maintain dimensions and plumbness of the
structure. Pins should not be removed until bolts in balance of holes have received final
tightening.
3.
Install bolts in the remaining holes, one washer only required to be placed under
the rotating component.
4.
Snug-tightening and final tensioning of the bolts in a connection shall proceed
from the stiffest part of the connection towards the free edges. High strength Bull Pin or
structural bolts that are to be tensioned may be used temporarily during erection to facilitate
assembly, but if so used they shall not be finally tensioned until all bolts in the connection
have been snug tightened in the correct sequence.
5.
TIGHTENING PROCEDURE
On assembly, all bolts in the connection shall be first tightened to a snug-tight
condition to ensure that the load transmitting piles are brought into effective contact.
Snug-tight is the tightness attained by a few impacts of an impact wrench or by the full
effort of a person using a standard spanner.
1.
After completing snug-tightening, location marks shall be established to mark the
relative position of the bolt and the nut and to control the final nut rotation. Observation
of the final nut rotation may be achieved by using marked wrench sockets, but location
marks shall be permanent when required for inspection.
2.
Bolts shall be finally tightened by rotating the nut by the amount give in the
Minimum tightening torque Table Below. During the final tensioning.
3.
Bolt Tension & Torque Information
1.
Minimum Tension Indicators:
Bolt Tension Information
Bolt Tension
Nominal
Bolt
Minimum
Diameter
KN
M16
95
21.3 9.5
M20
145
32.6
M24
210
48.621.7
M30
335
77.1
M36
490
112.950.3
Kips
ton f
14.55
34.4
b) Bolt Tightening Torque:
Property
Torque
Class
Unit
A325M/8.8
N.M
Nominal Bolt Diameter with corresponding Torque.
M16
M20
M24
M30
M36
200
390
675
1350
2350
Equipments:
Impact WrenchTorque WrenchHammer Ring Spanner
Ratchet WrenchAdjustable WrenchRing Spanner
SocketsHigh Strength Bull Pin
NUT ROTATION FROM THE SNUG-TIGHT CONDITIONTABLE
Disposition of Outer Face of Bolted Parts
(Notes 1,2,3 &4)
BOLT LENGTH
(underside of head to
end of bolt)
Up to and Including 4
Diameters
Both Faces
Normal
One Face
to Bolt Axis
Normal toBolt Axis and
OtherSloped
Both Faces
Sloped
1/3 Turn
1/2 Turn
2/3 Turn
1/2 Turn
2/3 Turn
5/6 turn
5/6 Turn
1 Turn
Over 4 Diameters but
not Exceeding 8
Diameters
Over 8 Diameters but
not Exceeding 12
2/3Turn
Diameters
Notes:
Tolerance on rotation for 1/2 turn or less, 1/12 of a turn (30°) over and nil under
tolerance, for 2/3 turn or more, 1/8 of a turn (45°) over and nil under tolerance.
1.
The bolt tension achieved with the amount of nut rotation specified in Nut Rotation
from the Snug-Tight Condition Table will be at least equal to the minimum bolt tension
specified in the Minimum Bolt Tension Table.
2.
3.
Nut rotation is the rotation relative to the bolt, regardless of the component turned.
Nut rotations specified are only applicable to connections in which all material within the grip of the bolt
is steel.