Civil engineering design is generally guided by design codes. In some construction works, the conditions are not fully known in advance so that the design assumptions and consequently the design have to adjust to the new conditions that appear during the progress of works. An example is tunneling, where during construction differences between initial design assumptions concerning soil/rock properties, existence of underground water veins, and the real site conditions may occur so that design and construction have to be appropriately modified during construction works. In contrast, bridge design is subject to extensive regulations concerning loads, materials, required verifications, etc., provided by codes. How a bridge is to be built and how it is designed are strongly linked. The design then provides construction and erection methods and their sequences and includes the relevant verifications for situations during construction. Modifications of the design assumptions during construction should generally be avoided as they may result in increase in time and costs. This book makes reference to the Eurocodes [3.21] as design standards, which will be briefly presented and discussed in the following.