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 High-Strength 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.
  1. Ensure contact surfaces are clean and free from defects.
  1. 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.
  1. Install bolts in the remaining holes, one washer only required to be placed under the rotating component.
  1. 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.

TIGHTENING PROCEDURE

  1. 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.
  1. Bolts shall be finally tightened by rotating the nut by the amount give in the Minimum tightening torque Table Below. During the final tensioning.

Bolt Tension & Torque Information

  1. Minimum Tension Indicators:

Bolt Tension Information

Bolt Tension

Nominal

Bolt Minimum

Diameter

KN Kips ton f

M16 95 21.3 9.5

M20 145 32.6 14.55

M24 210 48.621.7

M30 335 77.1 34.4

M36 490 112.950.3

b) Bolt Tightening Torque:

Property
Class / Torque
Unit / Nominal Bolt Diameter with corresponding Torque.
A325M/8.8 / N.M / M16 / M20 / M24 / M30 / M36
200 / 390 / 675 / 1350 / 2350

Equipments:

Impact WrenchTorqueWrenchHammer Ring Spanner

Ratchet WrenchAdjustableWrenchRing 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) / Both Faces Normal
to Bolt Axis / One Face
Normal toBolt Axis and OtherSloped / Both Faces Sloped
Up to and Including 4 Diameters / 1/3 Turn / 1/2 Turn / 2/3 Turn
Over 4 Diameters but
not Exceeding 8
Diameters / 1/2 Turn / 2/3 Turn / 5/6 turn
Over 8 Diameters but
not Exceeding 12
Diameters / 2/3Turn / 5/6 Turn / 1 Turn

Notes:

  1. 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.
  1. 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.