Omega seals
17Pages

Omega seals

2 Design of an Omega Seal 3 3.3 Aqueducts, canals, sluices and other applications 6 5 Design application data 10 7 Policy quality, environment, safety and health 11 App. A Standard range of Omega seal types App. B Typical clamping system for Omega seals App. C Diagram of allowable deflection and water pressure Cover picture: Installation of an omega seal between a bored tunnel and a station.

1 Introduction Since the 60’s Trelleborg Ridderkerk B.V. has manufactured a large number of Omega seal joints. Originally the Omega Seal was designed as a secondary seal for immersed tunnels in combination with the Gina gasket/seal as the primary seal. Applications for the Omega Seal have now expanded to bored tunnels, aqueducts and ship lifts. Using the same construction techniques and materials as utilized in the original Omega shaped seal; the range has been expanded to flat seals. Trelleborg has manufactured a flat Omega seal 1.4 meter in width for an aqueduct in Germany! The Omega Seal...

Trelleborg Ridderkerk is able to calculate from the force-compression curves and elongation limits at various water pressures; that the selected Omega seal satisfies the following conditions within agreed safety limits: 1. the Omega seal construction will withstand the water pressure, including the accommodation of the expected gap movements in three directions; 2. the steel clamping construction is capable to keep the Omega flange in position and sealing against the water pressure whilst at the same time allowing for all gap movements, 3. the clamping and sealing function of the clamping...

3.2 Bored tunnels The Omega seal allows joint movement in combination with water pressure. Applications encompass the connection between a bored tunnel and the entrance to a structure such as a rail station, see. The bored tunnel is not under piled as opposed to the normal construction of a station, which results in differential settlement between the structures. For bored tunnels the Omega is often supplied as a closed ring. Pictures 2 & 3: Application of an omega seal in a bored tunnel. Omega 09/06 Trelleborg Ridderkerk B.V. Phone: +31 180 49 55 55 Telefax: +31 180 43 30 80 5

3.3 Aqueducts, canals, sluices and other applications A third application of the seal, mainly the flat type, is where the seal is bent to a U shape and used in the joints of aqueducts. Due to temperature effects, the joints in an aqueduct construction will be subjected to considerable axial movements. In general the sealing system consists of an inner and an outer Omega, so that a double safety system is built in, see appendix 3. The Omega’s are supplied in a U-shaped frame with sharp two 90 degree corners or four 135 degree corners. Picture 4: Omega seals between the structures of the...

Picture 5& 6: Applications of omega seals in sluices - Germany Omega 09/06 Trelleborg Ridderkerk B.V. Phone: +31 180 49 55 55 Telefax: +31 180 43 30 80 7

Another special application is to install the flanges of the omega seal under 90 degrees. This is used for instance as a watertight solution between a bridge deck or U-shaped canal and an abutment, see figures below. Figure 4: Omega seals with flanges perpendicular. Figure 5: U-frame of Omega seals with flanges perpendicular. Omega 09/06 Trelleborg Ridderkerk B.V. Phone: +31 180 49 55 55 Telefax: +31 180 43 30 80 8

4 Product range Omega For economic solutions Trelleborg Ridderkerk BV has selected a standard range of 4 types of Omega seals, which accommodate most required performance specifications. As many corner moulds for the standard types are available, no additional tooling costs have to be taken in account. When required other corners may be manufactured. Selecting one of the standard range provides for shorter delivery times. In table 1 the complete range of all presently available Omega joints, standard and non-standard are shown. The complete range of flat omega seals is shown in Table 2. The...

5 Design application data In Appendix C the design application data for the standard range of Omega seals is shown. The graphs show the allowable movements of the Omega seal for various water depths/pressures. The maximum water pressure is inclusive of a safety factor of 2.5 on the breaking strength of the Omega wall construction. The regressive line shows that when the gap under the Omega arc increases, less water pressure is allowed. The values are based on Omega seals with 2 nylon plies. For larger water depths with the same movement capacity the seal type OS 360-100 and OS 400-100 can...

clamping force is subjected to relaxation over time. The relaxation of the flange is 5 to 6% per decade, which results in a considerable loss of force over time and this should be considered in the design of the required initial clamping force The exact dimensions and sizes of the required clamping system and fixing bolts have to be calculated on a project basis and can be done by Trelleborg Ridderkerk upon request. Trelleborg Ridderkerk will forward storage instructions in accordance with the international standard ISO 2230. The installation of the Omega seal requires special techniques....

Appendix A: Standard range of Omega seal types OMEGA OS 240-40 OMEGA OS 300-70 Omega 09/06 Trelleborg Ridderkerk B.V. Phone: +31 180 49 55 55 Telefax: +31 180 43 30 80 12

Appendix B: Typical clamping system for Omega seals Typical clamping system of OMEGA OS 240-40 Typical clamping system of OMEGA OS 300-70 Omega 09/06 Trelleborg Ridderkerk B.V. Phone: +31 180 49 55 55 Telefax: +31 180 43 30 80 14

Typical clamping system of OMEGA OS 360-100 Typical clamping system of OMEGA OS 400-100 Omega 09/06 Trelleborg Ridderkerk B.V. Phone: +31 180 49 55 55 Telefax: +31 180 43 30 80 15