Structural joints:
1. Inter modular joints: SFT is a structure that is made up of prefabricated modules assembled in situ though it would be a complicated but it can have to do if the segment is not possible for the single one. So therefore, the joints between the modules. This part is sensitive because of waterproofing and safety of people inside the tunnel.
Nowadays, the inter modular joints are used for immersed tunnels (IT) in the form of flexible joint that performs many tasks such as: to ensure the waterproofing, to limit the relative displacement to avoid excessive stress increments due to differential settlements & to assure the equilibrium of the structure.
In the previous application, monolithic joints were used which proved to be …show more content…
IT is commonly supported by seabed but SFT is not. Therefore, flexible inter modular joint does not seem as a suitable solution for SFT for which the most rational solution is to have rigid inter modular joint & terminal joints allowing axial displacements.
As a matter of rigid joints, the inter-modular joints for the SFT (Archimedes Bridge Prototype in Qiandao Lake, China) are bolted connections when the modules are already submerged. The joint consists in two steel ring end plates (figure). Flanges are mutually connected by means of high strength steel bolts and flanges are placed at the internal concrete & steel layers. The tensile forces are transmitted by the bolts in tension whereas the compressive forces are transmitted by the contact between the adjacent steel end plates. The design shear forces are transmitted by friction whereas the ultimate shear force is assured to be transmitted by shear in the …show more content…
A part of tunnel is implemented between the SFT & BT and needs to joints at ends (figure p51) so that it can absorb the movement induced by thermal variation, earthquake, settlements and so on (FEHRL, 1996). Clearly, shore connection design is obviously related to hydro-geologic & geotechnical considerations of submarine and shore areas.
A detailed study of the configuration was made for ‘Messina Strait Crossing’ (Italy) by the ENI Construction (Nicolussi and Casola, 1994) and they show the different behaviours.
a. Joint B between the bored tunnel and landfall tunnel releases all 6 DOF and the responses are decoupled.
b. Joint A between BT & SFT releases all rotational DOF & axial moments. Therefore, it decouples the axial & bending behaviour reducing the stresses.
Both two joints have a gasket system resisting water leakage. Natural rubber gasket is squeezed between the surfaces of joints and Teflon sheets are stuck on the steel surfaces to reduce the friction forces (Nicolussi & Casola,
1. Inter modular joints: SFT is a structure that is made up of prefabricated modules assembled in situ though it would be a complicated but it can have to do if the segment is not possible for the single one. So therefore, the joints between the modules. This part is sensitive because of waterproofing and safety of people inside the tunnel.
Nowadays, the inter modular joints are used for immersed tunnels (IT) in the form of flexible joint that performs many tasks such as: to ensure the waterproofing, to limit the relative displacement to avoid excessive stress increments due to differential settlements & to assure the equilibrium of the structure.
In the previous application, monolithic joints were used which proved to be …show more content…
IT is commonly supported by seabed but SFT is not. Therefore, flexible inter modular joint does not seem as a suitable solution for SFT for which the most rational solution is to have rigid inter modular joint & terminal joints allowing axial displacements.
As a matter of rigid joints, the inter-modular joints for the SFT (Archimedes Bridge Prototype in Qiandao Lake, China) are bolted connections when the modules are already submerged. The joint consists in two steel ring end plates (figure). Flanges are mutually connected by means of high strength steel bolts and flanges are placed at the internal concrete & steel layers. The tensile forces are transmitted by the bolts in tension whereas the compressive forces are transmitted by the contact between the adjacent steel end plates. The design shear forces are transmitted by friction whereas the ultimate shear force is assured to be transmitted by shear in the …show more content…
A part of tunnel is implemented between the SFT & BT and needs to joints at ends (figure p51) so that it can absorb the movement induced by thermal variation, earthquake, settlements and so on (FEHRL, 1996). Clearly, shore connection design is obviously related to hydro-geologic & geotechnical considerations of submarine and shore areas.
A detailed study of the configuration was made for ‘Messina Strait Crossing’ (Italy) by the ENI Construction (Nicolussi and Casola, 1994) and they show the different behaviours.
a. Joint B between the bored tunnel and landfall tunnel releases all 6 DOF and the responses are decoupled.
b. Joint A between BT & SFT releases all rotational DOF & axial moments. Therefore, it decouples the axial & bending behaviour reducing the stresses.
Both two joints have a gasket system resisting water leakage. Natural rubber gasket is squeezed between the surfaces of joints and Teflon sheets are stuck on the steel surfaces to reduce the friction forces (Nicolussi & Casola,