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Wednesday 23 May 2018

Trial Assembly of Steel Box Girder and Cross Beams





Trial Assembly

General

The trial assembly will be carried out for all bridges at Workshop to ensure that erection
tolerances will be achieved after the fabricated components are erected and assembled at
site. The trial assembly shall be performed according to the trail assembly plan.
The trial assembly shall verify that the individual elements have the shape to fit exactly
into adjoining elements. Also, the trial assembly shall verify that the camber aimed at, or
prescribed, actually exists, and that the geometry is correct.

Procedure

In the method of actually combining members it will be conducted with a support so
that each member is as being in the state of non-stress as shown in Figure-12.1. Temporary
bolts and drift pins must be used and solidly tightened up in the portion of on-site
connection of the primary part out of respective combined members. Additionally, when a
mismatch between the base material and connection plate arises, the necessary repair must
be performed.



Each part shall be carefully marked for the erection. Such marking shall be durable
but shall not injure the material. The marking of components shall be in accordance with
that shown in the fabrication drawings. Each trial assembly shall be completed and
measured.

All bearing position is checked to set templet of bearing form in soleplate








Hole Diameter Check


All matching holes shall register with each other so that a gauge or drift 2mm less in
diameter than the hole shall pass freely through the assembled contact faces at right angles
to them. Burrs, fins and other defects will be removed by automatic burr removing machine
or grinder.