The Structural Performance of Stone-Masonry Bridges

Abstract

The structural performance of old stone-masonry bridges is examined by studying such structures located at the North-West of Greece, declared cultural heritage structures. A discussion of their structural system is included, which is linked with specific construction details. The dynamic characteristics of four stone bridges, obtained by temporary in situ instrumentation, are presented together with the mechanical properties of their masonry constituents. The basic assumptions of relatively simple three-dimensional (3-D) numerical simulations of the dynamic response of such old stone bridges are discussed based on all selected information. The results of these numerical simulations are presented and compared with the measured response obtained from the in situ experimental campaigns. The seismic response of one such bridge is studied subsequently in some detail as predicted from the linear numerical simulations under combined dead load and seismic action. The performance of the same bridge is also examined applying 3-D non-linear numerical simulations with the results used to discuss the structural performance of stone-masonry bridges that either collapsed or may be vulnerable to future structural failure. Issues that influence the structural integrity of such bridges are discussed combined with the results of the numerical and in situ investigation. Finally, a brief discussion of maintenance issues is also presented.

On the Assessment of the Plaka Bridge Collapse Using Non-Linear Analysis Preventable or Doomed?

“…The recent collapse of the historic, renowned stone arch bridge of Plaka from extreme flooding and debris [1], [2] prompting questions of either (a) negligence in failing to address structural degradation or (b) urgent need to consider "beyond design basis events" for these structures (at least beyond what had been historically observed up to the time of construction) heightened awareness. It is not only the scientific challenges that the study of these non-linearly behaving structures present but also the need to identify the structural deficiencies and apply the most appropriate restoration.…”

In-Situ Measurements Related to the Performance of Stone Masonry Bridges in Greece

“…All the obtained data were subsequently studied in the frequency domain through available FFT software [1], [4], [5]. This wind orientation relative to the geometry of each bridge structure coupled with the bridge stiffness properties could excite mainly the 1st symmetric out-ofplane eigen-modes.…”

“…The second type of excitation that was employed, namely vertical in-plane excitation, was produced from a sudden drop of a weight on the deck (figure 6) of the stone masonry bridge [1], [6], [7]. This weight was of the order of approximately 2.0KN that was dropped from a relatively small height of 100mm, so as to avoid even the slightest damage to the stone surface of the deck of each bridge.…”

“…In what follows selective results are presented from an extensive study, which focused on old stone masonry bridges that are located mainly in the prefectures of Western Macedonia and Ipiros in Greece ( [1], [2] , [3] and [27]). These bridges are examples of outstanding stonemasonry construction that was dominant for a long period in these parts of Greece.…”

“…On the contrary, their size spans from 8m to 40m when a single arch is employed (Konitsa) or over 70m for multi-arch structures. More information on the geometry, construction characteristics and mechanical properties of the employed materials are given by Manos et al (2016) [1]. Today, these structures have retain but only a small part of this primary function, as new roads and bridges have been built to facilitate the contemporary transportation needs.…”