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Expansion joints for bridges

Expansion joints for bridges

General information

Expansion joints GUMBA BJ and BJR are suitable for longitudinal translations of 50 to 165 mm in bridges, roads and other constructions. Due to the simple design, both assembly and maintenance are simple of these expansion joints.

These expansion joints are installed between the running surface of the bridge and the road and they are designed to absorb the movements that arise from temperature differences, deformation and contraction of the structure and the traffic load. In special cases, they must absorb the transverse displacements and rotation around the three spatial axes and possibly longitudinal gradients must be considered. Expansion joints manufactured by the German company GUMBA meet all this. These expansion joints have waterproofing properties for drainage and vapor barrier.

Expansion joints type BJ and BJR are manufactured to the standard length of 1100 mm (despite the edges). It is also possible to produce smaller heads or curves. Installation of all types is done with fasteners such as Fischer fixing chemicals.

There are two types of expansion joints with four available versions. The drive joints are generally composed of an elastomeric body that meets all the requirements for expansion, hardness, stability and ozone resistance.

Properties and dimensions of materials for these

Rubber type CR60o 48ISO
Hardness shore A ± 5o 37ISO
Tensile Strength Limit ≥ 16 N/mm2 37ISO
Elongation at break ≥ 425 % 34-1ISO
Resistance to tearing ≥ 10 N/mm2 815ISO
Compression set ≤ 15 % 1431-1DIN
Ozone resistance Nivel „0”, fără crăpături EN 10025
Reinforcing with steel AlMgSi 0,5 F254 EN AW 6063
Temperature resistance – 300 – +100 oC T66/EN 573


Instructions for installing bridge expansion joints

Expansion joints manufactured by the German GUMBA type expansion joint BJ and BJR expansion joint

These expansion joints manufactured by GUMBA are easy to install.

The installation procedure includes preparing a mortar bed, drilling holes for fixings in pre-set positions, using chemical fixings, positioning and fixing BJ and BJR parts, including the sealing bar, and finally installing the installation holes back pouring the transition.

Required equipment:

  • Expansion joints type BJ or BJR (standard length 1100 mm).
  • Accessories (available separately from GUMBA)
  • Chemical fixing agents including anchors, washers and nuts
  • Washers BJ (R)
  • Sealing barrier
  • Epoxy repair mortar
  • General epoxy resin
  • Elastomeric sealant

The following tools are required:

    • Torque wrench
    • Air compressor for cleaning holes for fixing (eg Hilti Hit)
    • Concrete / floor cutter
    • Electric wire brush
    • Perforating hammer
    • Concrete crusher
    • Mixing palette

Other tools and equipment generally used on site.

  • (only required for renovation)

Expansion Joint Mounting Instructions – This Material Is Informative – Our Company reserves the right not to publish its entire system used for installing these expansion joints.

The center of the expansion joint must be detected. The tread surface should be cut on both sides of the longitudinal joint of the joint over its entire length, with equal distance from the joint on both sides. The installed installation width must be greater than the full width of the expansion joint element BJ (R) used. Surface material between cuts must be broken to see the concrete below. The exposed concrete surface should be polished to remove bitumen residues and level the surface. Then all material scraps have to be cleaned with brush or compressed air to have a clean and dry surface.

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  • The epoxy resin will be applied to the concrete surface as a bonding agent between concrete and mortar and also as a leveling layer. Then the mortar layer must be prepared. The finished road levels and the BJ (R) height and the sealing membrane must be considered when applying the mortar coat. The best way to do this is to use wooden sleepers during installation as guide rails in combination with a floorboard used as a floor.

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  • Once the mortar has hardened, the chemical fixtures must be made. The expansion joint element BJ (R) can be used as a template for fixing the holes. Remove expansion joint element BJ (R) before drilling.

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  • The holes must be clean, dry and free of dust. In these are placed the glass capsules of the chemical fixtures and the thread anchors hammer with the hammer and thus the quick-drying mortar is activated. Once the chemical fixation has dried the threaded anchors have to be shortened to the specified length in order not to protrude out of the expansion joint element BJ (R). Caution: shortening after installation is very difficult.

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  • the vapor barrier for sealing, which is wider than the BJ (R) expansion joint element, must be placed on the mortar bed. The edges of the membrane must be in line with the edges of the BJ (R) by creating a hole in the center of the joint. Small slots must be cut in the area of the threaded anchors.

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  • The expansion joint element BJ (R) is placed in the designated position so that the threaded anchors are accessible in the bolts of the expansion joint BJ (R). Expansion joints type BJ (R) is fixed with a special washer, a normal washer and a nut. The torque wrench is used to thread it. The first groove element must be installed at the bottom of the joint. The next expansion joint element BJ (R) is pressed over the fastener to close the longitudinal connection of the blade and the dowel before it is also fastened.
  • Generally, at least two BJ (R) expansion joint elements must be cut because the joint length is rarely multiple to the length of a single element. This can be done with the same tools that have been used to cut the surface, just keep in mind that the elastomer of the BJ (R) elements does not become hot. The elastomeric sealing compound will be applied to the cut edges of the expansion joint element. Then the BJ (R) elements are positioned in such a way that one end enters the bluff and the blade of the BJ (R) element installed and the cut ends of the BJ (R) elements are joined by moving them downwards until they are well and can be fixed.

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  • After the drying period of at least 4 hours, check the fixings and, if necessary, tighten them again with a torque wrench. Then, the holes of the expansion joints BJ (R) must be cleaned and filled with the epoxy filling compound. The gap between the road and the BJ (R) edges must be sealed with an elastomeric sealant and leveled.

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Expansion joints type BJ30

BJ30 expansion joints are designed to cover joints at bridges, walkways, walkways, longitudinal ramps from 20 to 40 mm.

The expansion joint body is made of high-strength steel reinforced neoprene and is designed to absorb movements that occur due to temperature differences, deformation and contraction of the structure. They are designed to ensure the waterproofing and waterproofing of the expansion joint, as well as the continuity of the tread.

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The installation of expansion joints devices BJ30 involves the execution of the following technological steps:

  • Cutting and preparing the mounting box of the expansion joist
  • Preparation of expansion joints for expansion joints
  • Drawing and making holes for mounting expansion joints
  • Mounting of expansion joints devices (threaded rod system + nut + flat washer + saiba grover)
  • Sealing the bolt holes and applying the transition for expansion joints devices

All the materials used for mounting expansion joints are approved and have certificates of conformity.

The warranty provided for both BJ30 expansion joints and mounting works is 10 years, as per the Technical Agreement.

This type of joint has an aluminum profile with wear-resistant ribs that protects the elastomeric body from traffic abrasion. The steel profiles that are vulcanized in the elastomeric body guarantee the stability of the expansion joint over 10 years.

In contrast to BJ type, BJR joints have an elastomeric surface with holes. Below this surface are steel reinforcement plates vulcanised in the elastomeric bin. The design and load capacities are the same as for GUMBA BJ expansion joints.