Displacement Based Design Procedures for RC Bridges - Formulation and Comparison of Two Approaches

This paper presents the formulation, evaluation and comparison of two newly developed displacement based design procedures for reinforced concrete bridges. The foundations of both methods are established within the framework of the performance based design philosophy, however they are different inasmuch as the first one is an iterative linear method based on the concepts of the substitute structure, proposed more than three decades ago, and the use of seismic demands given by damping reduced design spectra and the other is a direct non-iterative non-linear procedure based on the concepts of a non-linear SDOF reference system and seismic demands given by uniform hazard design spectra for an assumed rate of exceedence of the target performance. To understand the potential of application of both methods, the issue of bridge regularity is explicitly examined showing that, further to the concept that regularity of a bridge is closely related to the expected seismic performance under design actions, it is also linked to the used performance based evaluation/design method. It is shown that when a bridge structure is irregular, both proposed procedures may lead to incorrect evaluations/designs unless some additional considerations are introduced in the procedures. The results obtained from both methods are illustrated by applying them to five bridges.

AYALA Gustavo;  PAULOTTO Carlo;  TAUCER Fabio; 

2008-12-02

Università di Pisa

JRC42671

http://www2.ing.unipi.it/bandi/programma_ANIDIS_Pisa20070605.pdf,    https://publications.jrc.ec.europa.eu/repository/handle/JRC42671,