**2. Geometric characteristics of the stone-masonry bridges located at North-West Greece**

In what follows, a brief review is given of the basic geometric and construction characteristics of the stone-masonry bridges located at the far North-Western part of Greece called Ipiros. Bridges of similar geometric and construction characteristics are also located in other parts of Greece. The present study has selected the stone-masonry bridges that are located in Ipiros as they are numerous and are located in a relatively confined area that facilitates their temporary *in situ* instrumentation. The objective of this instrumentation, as explained in Section 4, is to measure their dynamic characteristics that represent a significant part of this study. All these bridges, located in Ipiros as well as in other parts of Greece, have been documented, with relevant information included in [2]. Psimarni et al. [3] developed a geographic information system for the traditional bridges of Central Zagori, not yet accessible to the authors. Thus, all the geometric data utilized in this study were obtained through *in situ* measurements conducted by the authors.

In the same figure, the location of the remains of an ancient Roman bridge (blue arrow) is also indicated. These remains correspond today to only one main arch with a span of 15 m and a height of 7.5 m (**Figure 4b**). This surviving part of a Roman stone-masonry bridge is dated between 50 A.D. and 150 A.D. and, as can be seen in the map of **Figure 4a**, is located at a close distance (25 km) from the Macedonian palaces of Vergina and Pella as well as for the important cities of Thessaloniki and Dion (30–40 km). An inventory of Roman stone-masonry bridges is given by O'Connor [1]. These structures survive today, located in many European countries, having been in many cases preserved in good condition (**Figure 5a** and **b**) or partially collapsed

**Figure 5.** (a) Roman stone-masonry bridge Pont-Saint-Martin in Northern Italy. (b) The Pont Julien, a Roman stone arch bridge in the southeast of France, dating from 3 B.C. (c) The Pont Ambroix, first century B.C., Roman bridge in the south of France damaged by severe floods. (d) Ponte Rotto/Emilio, Rome (Broken/Emilio bridge). The remains of stone-

**2. Geometric characteristics of the stone-masonry bridges located at North-**

In what follows, a brief review is given of the basic geometric and construction characteristics of the stone-masonry bridges located at the far North-Western part of Greece called Ipiros. Bridges of similar geometric and construction characteristics are also located in other parts of Greece. The present study has selected the stone-masonry bridges that are located in Ipiros as they are numerous and are located in a relatively confined area that facilitates their temporary *in situ* instrumentation. The objective of this instrumentation, as explained in Section 4, is to measure their dynamic characteristics that represent a significant part of this study. All these

in other cases (**Figure 5c** and **d**).

78 Structural Bridge Engineering

masonry bridge damaged by flooding.

**West Greece**

**Figure 6.** (a) Kapetan Arkouda Bridge, Kipoi Village, East Zagori, Ipiros and (b) Agiou Mina Bridge, Kipoi Village, East Zagori, Ipiros.

**Figure 7.** (a) and (b) Konitsa Bridge, Ipiros, Greece (width 2.85 m); (c) and (d) Plaka Bridge, Ipiros, Greece (width 3.10 m).

A considerable number of relatively small stone-masonry bridges can be found in this region with a span smaller than 10 m as the ones depicted in **Figure 6a** and **b**. However, stone-masonry bridges with a much larger total span have also been constructed. Relatively long-span stone bridges with a single central span are relatively few in number. The longest stone bridges with one main central arch are the ones in Konitsa (**Figure 7a** and **b**) and the one in Plaka (**Figure 7c** and **d**). These stone-masonry bridges are very similar in the dimensions of the central arch, although the Arachthos river crossing by the Plaka Bridge is longer (75-m total span) due to adjacent additional arches at both ends (**Figure 7c**), whereas the main arch of the Konitsa Bridge is supported directly at the nearby slopes of the rocky Aoos river gorge. As will be presented briefly in Chapter 9 (see also figures 10g and 11 as well as section 7.3), the Plaka Bridge collapsed almost a year ago (31 January 2015). As can be seen in **Figure 7b** and **d**, the main central arch of both the Konitsa and the Plaka stone bridges has a clear span of nearly 40 m and a rise of 20 m.

Apart from the Plaka and Konitsa stone bridges, three more bridges will be examined in the present study. These stone bridges are depicted in **Figure 8a**–**f** and are namely the Kokorou Bridge, the Tsipianis Bridge and the Kontodimou Bridge. As can be seen in **Figure 8b** and **d**, the main central arch of the Kokorou Bridge has a clear span of 24.69 m and a rise of 12.71 m, whereas the Tsipianis Bridge has a clear span of 26.00 m and the rise 13.65 m. As can be seen, the central main arch of these two bridges has similar dimensions. Finally, the clear span of the Kontodimou Bridge is 14.50 m and the rise 7.40 m.

**Figure 8.** (a) and (b) Kokorou stone bridge, Kipoi Village, East Zagori, Ipiros (width 2.85 m); (c) and (d) Tsipianis stone bridge, Milotades Village, East Zagori, Ipiros (width 2.80 m); (e) and (f) Kontodimou stone bridge, Kipoi Village, East Zagori, Ipiros (width 2.77 m).

Thus, the present study covers stone bridges that are all dominated by a central main arch with a span/rise varying from 40.00/20.00 to 14.50/7.40 m. As can be seen in all cases, the clear span over rise ratio is close to 2.0 and the width is close to 3.0 m. In the cases of the longest span, the width of the structure increases as the arch approaches the foundation (Konitsa and Plaka Bridges). A distinct difference between the examined bridges is the fact that in the case of Konitsa, Kokorou and Kontodimou Bridges, the main arch is founded on abutments that are very close to the rocky slopes of the river gorge whereas for the Plaka and Tsipianis Bridges there is a mid-pier that is founded on the river bed together with adjacent smaller arches (**Figures 7d** and **8d**).
