The Vilnius Cathedral Square: reinforcement of pavement by steel meshes

Abstract

The historical Cathedral Square of Vilnius, located in the heart of Lithuania, contains a large variety of archeological and structural remains representing over 700 years of development under its surface. The square is located at the bottom of a hill in the valley created by dried up rivers and their swampy banks and then overlaid, in archaeological terms, by a ‘thick cultural layer ’. For the reconstruction of the square’s pavement, the Lithuanian Department of Cultural Heritage issued a requirement forbidding the use of any structural element more than 70cm under the pavement surface. In order to meet this requirement while simultaneously providing for stability of the reconstructed pavement as well as for allowing for a smooth aesthetic appearance of the pavement surface, the authors proposed reinforcement with steel meshes laid under a crushed stone base. We present a design model for calculating the reinforcement strength and pavement surface deflection. To obtain the approximate supports needed for analysis highly accurate topographical survey of the ground surface was carried out. We present the results of the measurements, analysis and the construction procedure used. Based on our experience and the current appearance of the pavement eleven years after the reconstruction, we can now safely recommend the use of this type of reinforcement as good practice.