| Bridges are all about connecting things together. | | | | leaning considerably - from having any tendency |
| Sometimes a train will need to cross an obstacle, | | | | to buckle. |
| sometimes it is vehicles or sometimes it is just | | | | The steel rods which support the outer pedestrian |
| pedestrians. | | | | section of the bridge are also sloping. The angles |
| In the case of the Bach de Roda bridge in | | | | of the rods change as you get closer to each |
| Barcelona, there was a need to move both | | | | end, but for the most part, the rod angle is close |
| people and vehicular traffic across a large | | | | to that of the arch itself. |
| expanse of railway tracks. In this instance, the | | | | One of the novel aspects of this bridge, is that |
| trains were the problem, not the solution. | | | | there are two decidedly independent sets of |
| The design for this new bridge incorporated twin | | | | arches, each of which is capable of carrying its' |
| pairs of supporting steel arches. The inner pair are | | | | own section of the bridge. |
| mounted vertically and suspend their share of the | | | | There is a span in the center of the bridge which |
| load (mainly the roadway) via the typical steel rod. | | | | carries the vehicular traffic. This section is entirely |
| The outer pair of arches are quite different. | | | | independent and separated from the pedestrian |
| These arches lean in toward the center arches, | | | | section by the supporting rods from the vertical |
| and are in fact welded to the center arch on each | | | | arches. Unlike the old style of steel bridge, there is |
| side by a series of steel plates. The purpose of | | | | no structure above the roadway itself. Stability is |
| this part of the design is to preclude any | | | | gained from the sloping outside arches, which |
| possibility of the outer arch - which remember is | | | | have an extremely wide base at their ends. |