Apoyos POT – INTERBUNA

POT BEARINGS: GUIDED, FIXED AND MULTIDIRECTIONAL OR FREE

DEFINITION

POT (encapsulated) bearings are structural supports for bridges that support loads much higher than those supported by conventional elastomeric reinforced supports. They respond to new infrastructure design trends that require more spans and fewer joints to resist seismic movements, and also to the construction of, increasingly, curved bridges.

Combined with sliding elements, POT supports can rotate horizontally in one or more directions. One of its main characteristics, which is also its great advantage, is that the POT supports are completely removable, making them easier to repair in cases where an element of the structural support has to be replaced.

Interbuna's POT bearings, used in superstructure, marine and civil applications, are designed and manufactured taking into account the needs of each client (others can be added to the most basic design elements upon request), and the materials used are always of the highest quality.

TYPES OF POT BEARINGS

There are three main types of POT bearings:

Free or multidirectional POT bearings, type POT-PL

This type of structural bearings function as if they were a joint, while allowing rotations around the horizontal axes and displacements in any direction in the horizontal plane.

Guided POT bearings: PGX (X-guided) and PGY (Y-guided)

These structural bearings function as a joint, supporting rotations and allowing movement in the direction of the guide, but restricting it in the other direction.

Fixed POT bearings, type POT-PF

They are structural bearings for large loads, greater than 20 MN and up to 100 MN that act as a joint allowing rotations around the horizontal axes. They do not allow displacements in the plane.

COMPONENTS AND MATERIALS OF POT BEARINGS

Interbuna's POT bearings are made of high quality elastomer and steel. The difference with conventional elastomeric bearings is that, in POT systems, an elastomer “heart” is located inside a steel capsule capable of withstanding high pressures. The rubber behaves there as a viscous element that hardly offers any resistance to rotation.
The design is specially designed so that the structural bearings is capable of absorbing the rotations of the superstructure in the horizontal axis.
About 10 years ago, POT bearings with sliding elements based on UHMWPE began to be developed and are currently displacing the traditional ones made with PTFE, the same thing happens with spherical bearings.

QUALITY AND CERTIFICATES

Quality of our POT bearings and certificates that accredit it

The most prestigious international certifications for structural supports guarantee the quality of our POT bearings for bridges. Specifically, Interbuna's POT bearings comply with the regulations of the European standard EN 1337-5. This certificate is the one required by the European Union for POT supports of all existing types.
In the POT bearings, as in the rest of the infrastructure bearings that we manufacture, we carry out the actual control over the piece, as required by the European standard EN-1337-5.
We can also manufacture POT bearings in accordance with all international and customer-specific standards in force in the market: Europe and Africa (BS 5400, DIN 4141, Norway, Belgian and Dutch); America (AASHTO [ASTM], MCV 05, Mexican, Colombian and Peruvian); ASIA: (NH STD, NIS [INDIA]).

SPECS

Versatility and adaptation to the needs of our clients are one of our main values. At Interbuna, in addition to more than 50 years of experience that has allowed us to face highly complex technical challenges, we pride ourselves on our flexibility to
undertake the design and manufacture of POT supports tailored to the project presented to us by the main companies in the infrastructure sector. We make our consulting department available to our clients so that they can find the most appropriate structural bearing for the infrastructure in which they are immersed.

INSTALLATION AND MAINTENANCE

On-site installation of POT bearings

Preparation of waiting spaces to house the POT support bolts, using plastic tubes closed at the bottom with cellulose plugs. These tubes are left slightly protruding so that concrete does not enter them.
Ensure that the leveling is accurate so that the structural bearing is in a horizontal plane. The positioning of the POT bearings in their final location must be carried out with precise topographic measurements. It is important to reserve a space between the plastic tube and the base of the POT bearings so that the self-leveling mortar can fill the tubes completely.
The filling of high-resistance self-leveling mortar must be carried out on a formwork that is previously made. The high-resistance self-leveling mortar will be poured and if necessary vibrated in order to ensure that the leveling plateau has been made correctly.
The board formwork is mounted flush with the upper face of the tray, leaving the upper bolts embedded once the structure is concreted. The corresponding bearing reinforcement would be positioned on the board.
After the concrete of the deck has set, the bearing must be released, removing the lateral mooring accessories and temporary blockages.

On-site maintenance of POT bearings

During use, the POT bearing requires inspection and maintenance
regularly.

The points to inspect would be the following:

Check whether the anchor bolt has been cut and whether the rubber gasket is cracked and aged.
Check whether the relative displacement is uniform and record one by one.
Clean the “debris” (annular copper gasket) and the dust around the support, clean the stainless steel surface with cotton.
Loosen the anchor nuts, clean, grease to prevent rust and then tighten them.
Check the change in the height of the bearing to verify the state of wear of the PTFE or sliding material. When the height decreases above 3mm the rubber gasket must be removed to inspect the condition of the PTFE or sliding material.
Paint steel plates regularly to eliminate corrosion (except stainless steel).

PROJECTS

OUR FLEXIBILITY GOES FAR:
LEARN ABOUT THE PROJECTS WE HAVE ALREADY CARRIED OUT
IN MORE THAN 30 COUNTRIES.

CONTACT

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If you want to know how we can help you or have any questions about our products or services, write to us. We will study your case to design the solution that best suits your project.