This book describes the underlying behaviour of steel and concrete bridge decks. It shows how complex structures can be analysed with physical reasoning and relatively simple computer models, and without complicated mathematics. In recent years the computer methods of grillage and space frame have become very popular and accessible as microcomputers and software have developed rapidly. In this second edition, the intrinsic safety of these methods when used in a systematic manner is explained. New chapters have been included on the analysis of distortion of box girder bridges, on the stiffnesses of supports and foundations, and on integral bridges. The chapter on beam decks and frames now includes demonstrations of the influence of foundation stiffnesses on the frame behaviour of a portal bridge and an arching structure. Coverage of beam-and-slab bridges has been enlarged to explain "torsionless design" which simplifies the design of some bridges. New examples illustrate the grillage analysis of a composite bridge using AASHTO type prestressed concrete girders, and of a composite steel deck.
Additional comparisons between grillage and finite strip analyses of cellular structures are included. The wide range of applications of simple space frame idealisations of three dimensional structures is now discussed and an additional example of a space frame analysis of a multispan curved bridge has beed added. The chapter on temperature and prestress has been enlarged to demonstrate the use of space frame models for calculation of the effects of temperature and prestress on multispan curved bridges. A new appendix explains the calculation of torsion stiffness.