Old Traditions for Masonry Arch Stone Bridges
Bridge constructors in old times used tested & traditional methods to build strong and durable facilitiest. Stone bridges are really durable and withstand the test of time. To this day, they remain part of the cultural and historical heritage of our country.
In the past, the stone was the most common building material, used to build roads, facilities, castles, houses and bridges. Mined natural stones were used in raw form or after being shaped with hammers. Both large boulders and smaller granite, marble and gneiss rocks were used.
Hewn stones are most commonly used for building bridges; for aesthetic reasons and to complete the appearance of the bridge decorative stones are placed at the most prominent parts. Since antiquity, masonry arch bridges have been constructed through a vault structure, with orifices left for a few culverts or only one, depending on the length. Usually binding solution for masonry is used in the construction of the bridges, but there is an option for building solely through set masonry.
Building a Dry Stone Bridge
Bridges, built with set masonry, are such that cannot support a lot of load and the distance they need to cover should not be large. These types of bridges are suitable for parks, paths and gardens, where the focus is on beauty from the presence of natural stones in outdoor spaces and on decorative elements.
The first step is to construct a special vaulted shuttering from a timber formwork, which would convey the shape of the curve of the future bridge. Around it, large flat stones of masonry are to be arranged in a fan-like way.
Stones should be arranged by their short side, in a way that they overlap but are also slightly not in line; this happens naturally, as unshaped stones for masonry are being used.
While the stones are being arranged, the base of the trail to the bridge needs to be constructed in a way to reach the required slope.
Steps with bigger flat stones or polygonal gneiss for floorings can be placed to prevent large displacements.
The bridge should be built fully, with the stones placed in a horizontal direction above the curve and above the side approaches of the path at the same time, until a common flat upper surface is reached.
The next step is to remove the shuttering template using levers for careful creeping and releasing.
Finally, the finishing works are carried out on the upper surface of the bridge: equal and flat stones such as gneiss stones from Ivaylovgrad are placed as flooring. Gneiss from Ivaylovgrad is very useful for building bridges due to its great endurance.
At the end, you have created a beautiful and strong facility, both practical and useful, that adds unique architectural accent in the garden and will remain for future generations.