Carlos Perez Marin

This has been the element that has caused more discussions, due to its layout and conception, but perhaps it is also the one that best represents the complexity of the plot and the solutions that the architectural project offers. His analysis cannot be limited to a single aspect but to multiple ones; visual, spatial, economic, technical, functional, aspects that are related to each other and to other points and elements of the sector.

Let's start with the first decision:

Why do we propose to excavate the road?

In our visits to the works of the development of La Estación secteur with the project manager, we were able to observe the problems derived from granite and the increased cost that this has entailed. The option of adapting the road to the topography, excavating as little as possible, may be justified, as long as the terrain is not very irregular, as is the case in developments in the north of the city, despite the functional risks involved in having roads above the access levels to the plots if these are not properly studied. This option (minimal excavations) is possible in La Estación and in las Lavanderas, but the terrain forces it to be done on time to obtain a rational grade and in a general way for the underground infrastructures. At La Estación they told us that it was a great mistake to act in this way, because every time they were going to deploy a pipeline or cable, they had to open a new trench, on granite and with mechanical means, with the considerable increase in price and time.

To study the road with minimal excavations, we superimposed 10 sections of the current terrain with a section of the pavement (with the infrastructures). The first surprise was that in the transverse direction, we could have up to 5 meters of unevenness between the ends of the section, which forced us to excavate at least half of the road, even with the risk of leaving parcels at a lower level of about 4 meters.

The second surprise came when quantifying the cost of the excavation, because this solution would cost the same as excavating large quantities using different techniques, urbanization in the first case and civil works in the second.

At that time we remembered one of the visits we made to the plot in 2004 with one of the quarrying companies in the region; we had to think and act with the mentality of a mining engineer and not like an architect. From there, it was a question of seeing what advantages digging the entire road provided us, in addition to the fact that at the same price, we would have plenty of material for both the road fillings of zones 1 and 2 that would be executed on the current terrain, as for the construction of gravity walls, slopes, urban furniture, structural elements of reinforced concrete in buildings ...

accessibility of perpendicular roads

The two roads that connect the main one with the stream, would have a slope of 6 %, instead of 14 %. Although the Master Plan regulations allow up to 12 %, the truth is that what is recommended for good accessibility is 6 % which it is possible only if the elevation of the road is 7 meters below the current level.

acoustic protection

In previous projects (Desdoblamiento del Paseo de las Palmeras de Ceuta) we were lucky to work with one of the best acoustic engineers in the country Audioscan whose acoustic study allowed us to tackle and solve problems derived from road traffic, and most importantly, to have a sensitivity to noise. Despite the fact that the acoustic study requested for a Partial Development Plan is not as exhaustive as the one carried out for Ceuta, what was learned served to make a hypothesis of how noise would behave and how it would affect the dwellings and pedestrians if the excavation was not carried out.

In the case of excavating the road, the houses would not be affected by noise, neither would the two elevated walkways, thanks to the “natural” acoustic barrier of granite.

Regardless of the theoretical assumptions related to acoustics, it is always advisable to be able to verify the effects of elevated walks as acoustic barriers, something we were able to do, by chance, walking through Paris and more specifically along the banks of the Seine at the height of Bercy, with a succession of parallel spaces to the river; high-density road with 11 lanes, elevated promenade and a park.

The visual aspect of this "wall" from both sides can be debatable, but its function is not aesthetic but acoustic protection, so that the park is a pleasant place isolated from noise. In our case, we will not have a built wall but the granite of the site, the same one that gives Colmenar Viejo its identity and that we believe we should not be afraid of it being shown as it does in the existing quarries or in the sectors already urbanised.

visual aspect

Faced with the fear of driving through a space "boxed” in between two granite walls (which is not the same as two concrete walls), it would be convenient to clarify that it is fundamentally a road for cars, that although there are sidewalks, these will only be for those who park in it; those who want to walk will do so on the elevated part (protected from traffic). The maximum height that these walls will have will be 6.5 m and it will not be constant during the 400 m that separate the two footbridges, which we must not forget that they are the ones that “force” to have that height so that their clearance is sufficient. Well, a car traveling at 40 km/h will take 36 seconds to travel that space. Nor should we forget that this road will have large trees both in the car parks, as well as in the 2 m median, as well as climbing plants on the granite walls.

There is another detail in the section of the road, the luminaires will be hung from cables so that a homogenization of the light intensity can be achieved and as a consequence a decrease in it, without the need to use special poles, thanks to the two elevated walkways.

road functionality

The section of the road used throughout the city's bypass has an element that continues to be repeated in many cities, despite its dubious suitability, not because of its concept, but because of the scale: the boulevard.

These solutions make sense when it is not a simple gap between roads, but when it has the scale and dimensions to have its own entity, otherwise we go on a walk where it is pleasant to walk and stay, because it is visually and physically isolated from the cars thanks to the vegetation and possible constructions, to a sidewalk where it is best to pass as quickly as possible. If we add to this that we have to cross the sidewalk several times each time we come to a crossroads or a roundabout, the walk becomes a gymkhana, and also dangerous.  

In La Estación, there are 700 meters from the roundabout on the road to Hoyo de Manzanares to the Ciudad Deportiva. If you want to go by bicycle or walk through the median, you will have to cross the road 8 times, with the consequent danger that this entails.

In roundabouts, going from one median to another involves three crossings.

In Las Lavanderas, to go from the same roundabout on the Hoyo de Manzanares road to the Navallar median (north of our area), there is a kilometre away and whoever wants to walk or bike will have to cross once, in Navallar. We thought there would be no discussion between a solution with no crossings and another with eight, but we were wrong…

We insist on the fact that not only you don’t have to cross the road, but that the route will be completely independent from that of the cars. However, this was an initial premise, to continue allowing citizens to move from one end of the plot to the other through a natural space or at least through a real pedestrian road.

If we have achieved a completely independent network of pedestrian spaces, which in the case of the main road is double, does it make sense to maintain a third road that will not actually be used? Can it be considered that we have reduced the section of the structuring road by reducing the median from 10 to 2 meters, when now the road instead of being 36 meters, has 49? 

In the end, the criteria of the city council were imposed and they forced us to maintain the same section of the structuring road that was executed in the rest of the sectors, despite having functional problems.

The introduction of the 10 meter median forced us to suppress the elevated walkway in the section located to the east of the main road between the two pedestrian walkways, although they have been maintained at the ends to allow access to pedestrian paths through ramps. This modification left us with a single walk from north to south instead of the initial two, limiting the possible circuits that could be done and which meant an increase in the quality of public spaces for future users.

Although the final solution is not the best of all, it must not be denied that the final one entails significant benefits in terms of pedestrian routes and above all does not modify one of the fundamental aspects of the project, which is understood as a large green space of 113,000 m² (instead of the 60,000 m² required by the Master Plan) in which there are dwellings inside, which differs considerably from the idea of building dwellings with green areas distributed among their residual spaces.