Vltava Tunnel
HEIGHT: 6.48m
WIDTH: 6.48m
TOTAL IMMERSED LENGTH: 336m (Two elements placed side by side 168m + 168m)
DEPTH AT BOTTOM OF STRUCTURE: Water depth above tunnel is 6-7m
ENVIRONMENTAL CONDITIONS:
The width of the river is 180m at the crossing point
FABRICATION METHOD:
On-line casting within cofferdam on line of tunnel
WIDTH: 6.48m
TOTAL IMMERSED LENGTH: 336m (Two elements placed side by side 168m + 168m)
DEPTH AT BOTTOM OF STRUCTURE: Water depth above tunnel is 6-7m
ENVIRONMENTAL CONDITIONS:
The width of the river is 180m at the crossing point
FABRICATION METHOD:
On-line casting within cofferdam on line of tunnel
Prague,
Czech Republic
DopravnĂ podnik hl. m. Prahy a. s.
Metrostav a.s. with Zakladani a.s., TGB Metrostav.a.s., PERI & VSL
Metroprojekt a.s
2 elements @ 168m Formed by 14 no 12m long segments connected by working joints. Reinforcement is going through the joints.
336m
6-7m
Project construction
2002-04-30
2, placed side by side
Single track in each element, for twin track metro line
6.48m
6.48m
Elements were cast on line and slid into position on a horizontal curve within narrow cofferdams
On-line casting within cofferdam on line of tunnel
Outfitting within cofferdam
The width of the river is 180m at the crossing point
The tunnel elements were negatively buoyant. A pontoon was used to support front of the
elements. Hydraulic telescopic sliding shoes were used at the secondary end. Elements were
pulled though cofferdam with winches. Sliding shoes were guided by rails.
elements. Hydraulic telescopic sliding shoes were used at the secondary end. Elements were
pulled though cofferdam with winches. Sliding shoes were guided by rails.
Along 168 m no expansion
joints. At the ends expansion
joints used stainless steel
elements and rubber sealing
joints. At the ends expansion
joints used stainless steel
elements and rubber sealing
Watertight concrete with no external membrane. Full section casting in a single pour avoided
cracks.
cracks.
Grout bags
0.5 to 3m cover with sand, gravel and
stone
stone
C30/37 ENV 206-1
Heating used at the working joints
Reinforcement using mild steel only
Heating used at the working joints
Reinforcement using mild steel only
Temporary overweight during sliding: Element 1 70t Element 2 57t Permanent loading by cover and bottom slab is anchored into the subbase using micropiles.