Bridge Design

4Conceptual Design and Execution Methods

4.1 Concept Design: Introduction

Concept bridge design is an iterative process requiring a comparative analysis of a variety of possible options satisfying a set of data (constraints), namely those related to topographic, geometrical (road or rail alignments), hydraulics, geotechnical, environmental or any other constraints as referred to in Chapter 2. This comparative analysis is usually done at the preliminary design phase. Concept design should take into consideration the objectives of Functionality, Safety and Durability, Economy, Aesthetics and Environmental Integration.

In this chapter, a synthesis of multiple aspects of bridge concept design is presented. Options for the longitudinal and transverse structural systems for the bridge structure are discussed, as well as the choice of structural materials and options for superstructure and substructure. Finally, execution methods and their influence on the concept design is discussed.

The aspect of bridge location, longitudinal and transverse alignments and the elements that should be integrated in the bridge deck were already discussed in Chapter 2. The next step in the design process should be the definition of the main concepts to be taken into consideration in the study of bridge options.

Concepts – This aspect is discussed based taking the bridge case of Figure 4.1. The bridge is located in a deep valley. Piers should be avoided in the central part of the valley due to increased ...