Project

DETAIL DESIGN FOR THE NEW FOOTBRIDGE IN ARAVACA OVER THE A6

CLIENT DGC: DIRECCIÓN GENERAL DE CARRETERAS
SERVICE Basic design, detail design
DATE 2022
LOCATION Madrid, Spain

Aravaca, in the district of Moncloa-Aravaca to the west of the capital, is divided by the Autovía del Noroeste (A6) or La Coruña highway. This hinders pedestrian traffic between the Valdemarín area and the center of Aravaca, an area of commercial and leisure activity, with schools, hospitals, Aravaca station, etc.

Currently the pedestrian flow between Valdemarín and Aravaca is done by means of two pedestrian walkways, an overpass and an underpass of complicated accessibility since it has only one sidewalk of 0.70 m wide, which makes it almost unusable. The project of this footbridge aims to solve the problem of accessibility at this point by generating a cyclable crosswalk over the A6 and disembarking in both neighborhoods connecting with the urban fabric and integrated into the environment.

The footbridge will have to cross the Northeast Highway (A6), with three lanes in each direction and a two-lane bus/VAO lane. The average intensity is 5500 Veh/h, so the proposed solution must include a construction process that interacts minimally with the existing traffic, in addition to complying with the rest of the conditioning factors of gender, accessibility, gauges, etc.

The solution proposed is a 3-D truss structure with helical diagonals. The layout is curved in plan with radius 155 in the first section of 115.00m and straight in its final part of 60.00m, assuming the start of the footbridge on the Valdemarín side and its end on the Aravaca side. On the Valdemarín side there is a 65.00m concrete ramp section supported by a concrete structure that helps to gain height at this end. On the Aravaca side, the metal footbridge ends in a 16.00 m long concrete abutment.

The spans of the metal structure are 25.00+40.00+50.00+40.00+40.00+20.00, with a total length of 175.00m, making the total length of the footbridge 256.00m.

The cross section is closed section, semicircular with a radius of 1.65 m. In this case the truss presents a set of 7 helical diagonals by means of a circular section tube and circular diaphragms every 5.00 m.

This spatial structure allows to face torsional and bending stresses in an efficient way (closed section with large depth). The geometry of the closed section allows for a 2.75 m wide protected transit area inside and a clearance of more than 2.20 at all points.