**3. Bridges**

Seven basic types of bridges represent a majority of the highway, railroad, and pedestrian bridges in North America, and around the world. These include truss, tiedarch, suspension, arch beam, cable-stayed, and cantilever. Each type of bridge fulfills a specific requirement for a specific location. The distribution of stresses, both horizontal and vertical, determines the type of bridge structure required. It is interesting to note many bridge designs have been in practice for a number of centuries without major changes. For example the arch bridge was perfected by the Romans over 2000 years ago.

#### **3.1 Arch bridge**

Arch bridges are the oldest bridges in existence, with the Arkadiko bridge in existence today with many still in use. The basic design of the arch bridge allows the arch span to transmit lateral pressure to supporting abutments on a solid Greece, from the thirteenth century BC, still in service. Over 900 roman arch are in foundation. The simple design of the arch bridge with stone under compression allows for an extremely stable bridge, which explains why older arch bridges are still in existence and in use today, **Figures 1** and **2**.

An example of older arch bridges still in service is provided in a paper by D. Trajber et al. [3], in which they examine the condition of the bridges and assess the degree and rate of deterioration from anthropogenic and environmental factors, with the goal of providing accurate condition assessments and establishing necessary maintenance. In their paper they state "Historical masonry arch bridges still form an important part of Croatian transportation network. There are approximately 680

**Figure 1.**

*Roman Alcantura Arch Bridge in Spain Built 103–106 AD. CC BY-SA 3.0.*

**Figure 2.**

*Stari Most Arch Bridge Built 1557 Mostar, Bosnia Hersogevina. CC BY-SA 3.0.*

masonry arch bridges and culverts currently being used for railways and roadways. Many of these bridges are relatively old (more than hundred years in most cases) but still in usage. Increasing vehicle load and speeds as well as deterioration due to anthropogenic and environmental influence have highlighted the need for reliable assessment of their service condition and regular maintenance. The aim of this study is to provide a review of existing masonry arch bridges in Croatia. Firstly, a historical review of bridges is given showing the time period in which they were built, indicating the materials and design principles used for their construction. Next, bridge typologies are presented as well as their detailed analysis of geometric characteristics for brickwork bridges. Finally, a short review of damages and their impact on serviceability of bridges is given. This review presents masonry arch bridges in Croatia and the need for reliable method of assessing their service condition in order to provide proper maintenance, repairing and retrofitting." [3].
