THE IMPACT OF THE EVOLUTION OF SIMPLIFIED METHODS OF ANALYSIS IN CANADIAN HIGHWAY BRIDGE DESIGN CODES ON THE EVALUATION OF TIMBER BRIDGES

Abstract

The design of bridge structures in Canada is currently undertaken according to the Canadian Standards Association (CSA) S6-14 Canadian Highway Bridge Design Code (CHBDC). Historically, previous versions of this code have been used to design bridge structures along with provincial codes such as the Ontario Highway Bridge Design Code (OHBDC). A key feature of these codes is the ability to employ a Simplified Method of Analysis (SMA) when designing and evaluating bridges. The evolving nature of design codes, including the SMA, has largely been governed by the analysis of larger structures such as prestressed concrete girder bridges and composite steel girder bridges as opposed to shorter timber stringer bridges. The scope of this research was to investigate how the SMA has evolved over the course of the past 40 years with a specific focus on timber stringer bridges. This work is being done with the support of Nova Scotia Transportation and Infrastructure Renewal (NSTIR) so as to better understand the behavior of timber stringer bridges and ultimately better inform maintenance decisions. Accomplishing this goal was done through the following steps: performing a parametric study of the existing Nova Scotia timber bridge inventory, thoroughly investigating how the SMA has changed since the early 1980s, testing a third-scale representative bridge structure and rigorously analyzing the representative bridge using computer modelling. By comparing the SMA described behavior of timber stringer bridges to testing and parametric computer modelling, the validity of evaluating these bridges using the SMA was assessed.