ABSTRACT
Shallow foundations are obviously preferable to deep foundations where the situation allows because of ease of investigation and construction costs. As illustrated in Figure 7.1, in the case of foundations for bridges, foundations will be constructed on land where possible, perhaps using a temporary cofferdam to work in the dry. For some bridges large diameter caissons are constructed on land or in dry docks and then floated and towed to position where they are sunk onto prepared rock surfaces. Caissons are also used sometimes on soil surfaces, either sunk into the soil or placed onto the soil that has been prepared and perhaps reinforced by piling (as at the Rion-Antirion bridge).
