METHOD
STATEMENT FOR
INSTALLATION
OF POT BEARING
Pot bearing, also known as pot rubber
bearing, with elastomeric bearing embedded
inside of the steel plate, can be divided into fixed pot bearing, guided pot
bearing and free sliding pot bearing. Pot bearings are special types of bridge
bearings for taking large loads, large horizontal displacements, and large
rotation requirements in confined areas. The loading capacity of elastomeric
bearings is limited, while pot bearings solved this problem, thus pot bearings
are often regarded as suitable for use when bridges need large bearing
reactions.
This method statement for installing bearing in roof steel structure
with mega truss
PURPOSE.
The purpose of this Method Statement is to highlight the
general measures and precaution required during the activity of installation of
Pot Bearing on site.
The objective of this Method Statement is to enable the
client, consultant, Contractor, Supervisors and work force to fully understand
our scope of works and associated risks and also to understand the safety
aspects of the project.
Procedure.
Pot bearing Installation
Procedure.
The bearing shall be fixed to
the concrete sub structure by lower anchor bars that will be fixed to the
bearings by anchor bolts, as you can see in the following figure. They will be
connected to the upper steel structure by means of a pin that will be inserted
in a counter plate welded to structure.
Here below the typical installation procedure for these pot bearings is described:
Level the plinth surface and prepare the recesses for the anchor bars by leaving piece of pipe during concrete casting.
Place the positioning tools(made of wood or mortar) that will temporarily support the bearing.
Install the Pot bearing on the positioning tool by using the suitable crane and Man lift.
Place the pre-assembled bearing(with lower anchor bars and masonry plate) onto the positioning tools. Centering the anchor bars and the recesses.
Prepare the lower formwork on the plinth for the bedding mortar.
Fill the lower recesses and the mold with approved epoxy mortar(fck ≥ 50 Mpa)
When bedding mortar has reach its design resistance, remove the lower formwork.
Place the upper counterplate. Centering the upper pin of the bearing.
Lower the mega truss on the counterplate, align the base plate and tag weld the counterplate with the base plate by mean of temporary additional steel plates. Bearing shall not be loaded.
When grout has reached at least 30% of curing, remove the red temporary fixing plate. From this moment the sliding plates of the moveable bearing can move.
Lift the mega truss frame for some MM, paying attention that the upper pin will be still inserted in the upper counterplate.
By using jacks, lower the counterplate upon the bearing. Remove the temporary welded plates and tag weld directly the counterplate to the base plate of the mega truss.
Lift again the mega truss frame for some MM, paying attention that the upper pin will be still inserted in the upper counterplate.
When the upper counterplate to the base plate by a continuous fillet. Check and record the temperature of the bearing plates. Not to damage mostly ptef and rubber. It should not overpass 60 c. in case this temperature is reaching the top limit, cool the plates by sprayed water.
By using the jacks, lower the counterplate upon the bearing. Remove the jacks. The bearing is installed and functioning.