Restoration of the Old Bridge of Horcajo de la Sierra-Aoslos

The so-called Old Bridge is located within the municipality of Horcajo de la Sierra, to the northwest of it, outside its urban area and was built on a date prior to the XNUMXth century on protected undeveloped land. The bridge rises over the Madarquillos River, on the old Camino Real, forming part of the Cañada Real Segoviana.

It is a stone bridge, with a single arch, formed by a semicircular vault, with granite and gneiss stone voussoirs. The intrados of the vault and the thread are made with large masonry pieces, while both the tympanum and the abutments are built with rough stone masonry.

The restoration project falls within the scope of the Action Plan on Historic Bridges in the Community of Madrid, whose monitoring and management corresponds to the Conservation and Restoration Area of ​​the General Directorate of Cultural Heritage. The intervention has aimed to restore the original construction elements, recovering the volume in its entirety and considering its ethnological and landscape value.

The previous archaeological studies carried out on the bridge served to detect the existence of a contemporary water channeling that runs along the entire length of the element. In addition, the elevation and composition of the original soil to be recovered was determined.

The bridge deck was covered with earth and vegetation, raised approximately half a meter from its original height. This filling, apart from distorting the visual perception of the bridge and undermining the safety conditions, increased the weight on the vault and blinded the gargoyles and the drainage system, causing humidity and damage to it.

After the needs analysis, the interventions focused mainly on:

•  Board Restoration: cleaning of the entire stonework, eliminating all elements of biological colonization, with recovery of the original pavement and replacement with flooring similar to the existing one in the sections where the original pavement had been lost, thus protecting the vault from humidity and other damage. The original grade and drainage system of the deck have been recovered.
• Filling of voids and restoration of fissures of the intrados of the vault by sewing fiberglass rods, with resin injections. Exterior grouting with lime mortar. In the case of large joints, they have been previously sealed with resins at the bottom of the joint to prevent moisture.
• Recovery of the two types of parapets and zonal recovery of the fascia. Cleaning and replacement of gargoyles. To finish, a water-repellent treatment has been applied to all the stone walls.
• The accesses They have been leveled with gravel and earth, carrying out the necessary earthworks along the way, to recover the slopes of the deck, creating a route that is as smooth as possible to guarantee access without causing bumps. It has been discovered that the corner guards of the parapet on the left bank form an intrinsic part of it, so they have been maintained and restored. The rest, who were in the surroundings, have been relocated.