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Engineering Projects: Col.lector General, Aigües Residuals



Sant Julià de Lòria (Principat d'Andorra)

Date: 2002-2005
Col.lector General, Aigües Residuals, Engineering (Principality of Andorra)

Col.lector General, Aigües Residuals

The project defines the layout of a collector of pipe of double wall with manholes in a section of 1569.96 meters

The design is developed within the Gran Valira riverbed. It connects to the general collector which ends just upstream of the bridge that accesses the Bordes del Jaile, and intercepts all drain wastewater that currently discharged into the river, communal and private, ending this phase of the project just downstream of the Fontaneda bridge.

The project also defines some measures of environmental restoration of the river. For the collector: PEAD's Pipe diameter 800/678 mm of ECOPAL surrounded by a reinforced concrete die as 1.30x1.30 m, with 34 manholes and five wells with overflow. For the restoration of the river:
The concrete die is lined with a vegetated riprap or concrete on the sections that is not buried.

This riprap allows the passage of maintenance technicians, who will enter to the collector with metal ladders or natural accesses.

Slope vegetation with nylon net fixed and hydro-seeding. Planting poplars, hazels, birches, willows and ash.

The collector is a pipe that in a buried section is filled to the mark with the river. It was carried out with concrete riprap. It demolished the Valireta irrigation canal entry, to do it again later.
We performed a parallel path to the collector, 3 m wide along the entire route, which is withdrawn once the work is completed. The excavations were in granular soil and rock.
All excavations must be expected depletion of water. The track has a variable slope between 1% and 4%. The wells are planned with prefabricated ring with an inner diameter of 120 cm and an upper cone with an inner diameter of 65 cm, surrounded by a solid mass concrete with an hydrodynamic shape and with a stone cladding.
It is made the formwork with concrete in situ in the lower part of the wells, in the entrance and exit of the pipe.