| This thesis examines lateral load paths in historic truss bridges. The objective of the thesis is to ascertain if the deck of a representative historic truss bridge could be rationally accounted for in structural analysis under wind load.; The historical background of truss bridge development was reviewed, as was the historical development of design wind loads for bridges. Preservation issues were reviewed and examples of adaptive reuse of historic truss bridges were studied. Analytical studies were undertaken to investigate the influence of a deck under wind loading, and field tests were completed to verify the analyses.; It was found that prevailing codes mandate higher wind pressures that those used in the original design of historic truss bridges, which hampers efforts at historic truss bridge rehabilitation. The traditional basis for lateral structural analysis was found to be based on the presumption that the bridge structure acts as a skeleton framework. This thesis explores the stiffening effect of the deck system, which has the effect of reducing forces in the bottom chords when compared to analyses based on a skeleton. An analytical model was developed that demonstrated the stiffening effect of the deck. The analytical model was verified by two field tests, one on a truss bridge with timber stringers and a timber deck, and the other on a truss bridge that had no stringers or deck, making it a true skeleton structure. |
