Mediterranean Highway A3 Salerno-Reggio Calabria
The modernization works of the highway Salerno-Reggio Calabria, between the exits Lauria North and Lauria South, include the realization of the Serra Rotonda and Costa del Monte tunnels. The one-directional double-tube tunnels are 3'800 m respectively 800 m long.
The first 600 m of the Serra Rotonda tunnel are excavated under difficult geomechanical conditions: Argillites and Calcilultites with poor mechanical properties.The remaining parts pass through formations of limestone and dolomite rock. The excavation method is drill-and-blast (conventional system) full-face advance with 130 to 160 m² excavation. The overburden reaches up to 450 m. The difficult geomechanical parts need pre-reinforcement of the tunnel face (pipe umbrella system and glass fiber anchoring system on excavation front).
The tunnels comply with CNR/80 standards type 1/a. With a radius of 6.6 m, the tunnel holds a 11.2 m wide highway with a traffic lane and a fast lane of 3.75 m each, as well as an emergency lane (3.0 m) and a marginal strip (0.7 m).
The Serra Rotonda tunnel is equipped with 11 bypass connections between the two tubes (7 pedestrians and 4 trafficable) and 6 service lay-bys. The Costa del Monte tunnel is provided with 2 pedestrian bypasses.
A transversal ventilation with jet fans is planned at the crown.
The main tasks of the mandate are the following:
Support and interpretation of the geological investigations;
GLF grandi Lavori Fincosit per ANAS SpA
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Civil designs; Electromechanical designs