Assembly Recommendations

General information

Apart from co-operation with design agencies and contractors concerning selection and design of structural bearings, Betomax offers supervision, and, since 2010, also installation of structural bearings. We currently utilise two specialised teams of structural bearing installation specialists. Installation covers arrangement of the bearing on the support structure, levelling and adjusting the bearing with respect to axes, execution of formwork, grouting using low-contraction mortar and protecting the bearing after installation. Our teams are equipped with specialised tools required for correct bearing installation. they utilise the following measurement devices: high-precision levels, electronic levelling instruments, infra-red thermometers and power tools required at installation. The installation concludes with the issue of a bearing installation protocol transferred to the site contractor.
We co-operate with the largest construction companies operating in Poland, i. e. Skanska, Strabag, Polimex Mostostal, Budimex. We have participated in the construction of the first sections of Polish highway A1 and several sections of highway A2. For the installation of structural bearings, we adhere to the current standard PN-EN 1337-11, complying with the strictest EU requirements, as proven by the respect of our satisfied customers.

The installation of a bearing is preceded by creation of image documentation and its transfer to the construction site. After it is approved, preparatory works may commence. The first stage is the execution of lower plinths. The plinths are executed individually for every bearing, considering the hints included in assembly drawings transferred by Betomax. The plinth needs to be reinforced and covered by formwork up to an appropriate height. In case of anchored bearings equipped with studs, openings need to be left clear in the plinth. After appropriate concrete strength is reached, the installation of the bearing may commence. The part on which the grout shall be executed must be prepared accordingly. The bearings are arranged according to the axes indicated by the geodesic services. Then, the bearings are levelled, and their arrangement is checked and approved by a geodesic specialist. A further step is preparing the formwork, after which the grout may be executed. The grout is introduced in a manner ensuring removal of air from under the bearing, so as to avoid emergence of so-called air bubbles under the bearing. Depending on the grout type, after appropriate resistance strength is reached, the load bearing structure of the element may be executed. For transport and assembly, the bearings are protected by assembly securing screws, which must be removed when the structure starts transferring loads and working by itself.

 

Assembly work

1. Preparation of plinth surface by graining 2. Cleaning of lower plinth surface

3. Assignment of bearings 4. Layout and levelling of elastomer bearing

5. Grout execution 6. Securing the bearing

 

Structural bearing replacement

Extensive investments related to the construction of new road sections and engineering structures are currently carried out in Poland, along with repairs and upgrades of existing structures and roads. In case of existing structures, old, used-up bearings needs to be replaced with new products. Viaducts and bridges often rest on corroded roller bearings which do not work properly, with the entire structure at risk of failure. Betomax offers assistance in the selection of appropriate solutions and in the installation of new bearings. The first stage is designing appropriate bearings, which shall ensure the transfer of vertical loads, horizontal forces and thermal deformations of the existing structure. The above solutions must be accepted by the design office executing the site upgrade design. The replacement of the delivered bearings itself entails lifting the existing structure by hydraulic motors to an appropriate height, thus ensuring the space necessary for removal of the current bearings, in most cases by chiselling them away, and the installation of new bearings.
Professional evaluation of the condition of elastomer bearings requires to a great extent knowledge and experience, and must be conducted by qualified personnel. If divergences are found, consultations with the bearing manufacturer are recommended.
During the inspection of a bridge, structural bearings are also controlled. During an inspection, among others, the following factors are analysed:

  • elastomer bearing position
  • elastomer bearing contact area size with surrounding surfaces
  • quality of elastomer bearing surface (springing effects, cracks)
  • allowable horizontal shift
  • allowable rotation
  • slip surface quality
  • corrosion protection quality

Below may be found a few examples of upgrade works completed. Photographs provided by Other Montagen.

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