Bridge Design

6Superstructure: Analysis and Design

6.1 Introduction

Analysis and design of bridge superstructures is made, after the concept design stage, and is made on the basis of simplified models. Concept design may need modifications as a consequence of detailed analysis, but, no matter what, the complexity of the structure concept, design should be made on the basis of simple structural models highlighting bridge structural behaviour. The complexity of the structural models should progress with design evolution from concept to final design stages.

Structural analysis and design integrates:

• Definition of structural models for the complete structure and evolution of static schemes under construction;
• Analysis of internal forces, stresses, deformations and displacements;
• Design verifications of prestressing steel reinforcement in concrete superstructures or steelwork in steel and composite bridges;
• Design verifications for detailing and bridge equipment, like bearings, dampers and expansion joints.

In this chapter, specific aspects of structural analysis of bridge decks are presented and discussed. The aim is not to cover general aspects of structural analysis and prestressed structures or steel structures, but main specific aspects of analysis and design of bridge superstructures. It is assumed the reader is familiar with the general aspects referred to above.

One specific aspect of bridge structural analysis is the need and possibility of performing transverse and longitudinal structural ...