Slab Seal Expansion Joint: Download

SANDHYAFLEX Slab Seal Expansion Joint Unitary & The high efficiency, no maintenance, water proof, durable steel reinforced elastomeric slab-seal type expansion joints for bridges was introduced by SANDHYA ENTERPRISES under the brand name of ‘SANDHYAFLEX’ in early 2016’s. ‘SANDHYAFLEX brand Slab Seal Expansion Joints’ joints are available in different models with movement capacities ranging from 20 mm to 230 mm, which is catered by the shear deformation of elastomeric slab units and thereby provides a smooth riding surface and ensures no damage to the components.

The elastomeric slab units are made from imported chloroprene rubber and are not only abrasion resistant but also particularly suitable to all types of wheel profile. These units are not affected by fuel, oil, salt or grit, heat and direct sunlight, frost, ice and snow. The total length of joint is built up by smaller modules to facilitate very simple and quick fixing and replacement of any particular unit, if at all necessary.

1.       Steel structure are to be inserted as shown above in either sides, little lowered position.

2.       Top of the insert shall be at par with finished level of wearing coat to maintain the camber.

3.       Steel structure and main reinforcement bar shall be anchored with proper welding.

4.       If required spacer bar shall be used for proper alignment of bolt and leveling of steel insert

5.       Steel structure are to be packed with proper mixture of concrete as same as deck casting.

6.       With proper alignment, manufacturer’s recommended adhesive to be applied on the steel insertsand the elastomeric slab seal shall be placed over there.

7.       Elastomeric seal shall be tightened with S.S. nut & bold and shall be locked with washer.

8.       The cavity of the nut & bolt shall be filled with elastomeric plug, duly applying the adhesive recommended by the manufacturer.

9.       Wearing coat shall be done in the spot,with adequate care to ensure a waterproof joint with the existing wearing coat.

10.    Temperature to be checked before installing the elastomeric slab unit.


SLAB SEAL joint will consist of steel insert and elastomeric slab unit. This type of seal is recommended for simply supported or continuous spans, right or skew (less than 20 degree), moderately curved with maximum movement upto 50mm.

SLAB SEAL expansion joint has been used for many years with a good success rate. However, the larger size of the joint tends to create more noise under traffic.

SLAB SEAL expansion joint are normally supplied in unit length and fixed to the deck using bolt anchors. If required tensioned cast iron bolts should be used to anchor this joint. If site drilled installations are used, the holes should be under reamed prior to fixing the bolts. An adequate length of the bolt should be de-bonded so that any relaxation over the bolt length does not result in complete loss of tension in the bolt.

Properties of Elastomer

Physical Properties Unit Specified Test Method
1 Hardness IRHD 60 +5 IS:3400 (Part II)
2 Minimum Tensile Strength (Moulded Test Piece,                   Test Piece from Bearing          MPa                     17.0                 14.0                            IS:3400 (Part I)
3 Minimum Elongation at Break (Moulded Test Piece,                   Test Piece from Bearing           %                     400       350                            IS:3400 (Part I)
4 Maximum Compression Set (24h,100 +1oC) % 35 IS:3400 (Part X)
Accelerated aging (72h,100 +1oC) Maximum Change from un-aged Value
5 Maximum Change  in Hardness IRHD +5 IS:3400 (Part IV)
6 Maximum Change in Tensile Strength % -15 IS:3400 (Part IV)
7 Maximum Change in Elongation % -30 IS:3400 (Part IV)
8 Shear Modulus at Nominal Temperature G.MPa 0.9 (+0.18)
9 Ash Contant % 1.        Max IS:3400 (Part XII)
10 Plymers % 60.0min IS:3400 (Part XII)



Manufacturing Tolerances

Sr.No. Items Tolerances
1 Overall Linear Plan Dimensions -0mm,+6mm
2 Total Mean Bearing Thickness                                                                                                              (The mean thickness is the arithmetic average of  the thickness measured at five points on the major surface as indicated  for various shaped bearings                                                                                             Rectangular : Corners and Centre                                                                           Circular : Corners of Inscribed Square and Centre) -0,+5%
3 Parallism
a)     Of top surfaces of Bearing with respect to the Bottom surface as datum 1 in 200mm
B0 Of one side surface with respect to the other as datum 1 in 100mm
4 Thickness  of Individual Layer of Elastomer
a)     Inner layer of Elastomer + 10%
b)     Outer layer of Elastomer -0nn,+2mm
c)     Side Cover -0nn,+3mm
5 Dimension of Laminates
a)     Plan Dimension of laminates
b)     Thickness of laminates
c)     Parallelism of Laminate with respect to bearing bas as datum (with respect to diameter for plates circular in plan and shorter side for plates rectangular in plan)
6 Flatness (Flatness shall be assessed by placing a straightedge along the diagonal or diameter, The gap between the straightedge and the surface shall not exceed the tolerances specified below)
a)     Load bearing surface of the bearing ‘0.3% of diameter  or diagonal or 2% of mean beaing thickness whichever is higher
b)     Steel laminate 1% of diameter or diagonal (max. of 1.5mm)