A Personal Recollection

by

Roger A.Dorton

Expo ‘67 Bridge Design Competition, 1967

A. Murray MacKay Suspension Bridge , 1970

Lions’ Gate Bridge Renovation, 1976

Conestogo River Test Bridge , 1976

Ontario Highway Bridge Design Code, 1979

Twinning the Burlington Skyway, 1985

Confederation Bridge, N.B. to P.E.I., 1997

Twinning the Blue Water Bridge, 1997

Angus L. Macdonald

Bridge, 1956, by

P.L. Pratley.

Through Truss Design

Suspended Deck

Details, MacKay

Bridge

Cross Section of Deck, B-B

Full Aeroelastic Model, Tested by Alan Davenport

Suspended Span

Weights for Medium

Span Bridges

A. Murray MacKay Bridge the lightest suspension bridge with spans over 1,000 feet in 1970.

Modification to the North Cable Bent, 1976

Replacement of the Suspended Structure, 2002

Lions’ Gate Bridge

Renovation, 1976,

2002

North Cable Bent

Cable Slippage

Deformed Shape

from 125mm Cable

Slippage and

Footing Rotation

Sequence of

Operations

For rotation of the north cable bent footings

1979,1983,1991

1. Limit States Design Replaced Working Stress

2. Load Factors Calibrated to 3.5 Safety Index

3. Deck Slab Arching Action, Only 0.3% Steel

4. Allowed Increase in Legal Truck Loads

5. New Dynamic Load Allowance

6. Full Commentary for the Code

7. Paid Consultants

8. Not a Consensus Code

9. Full MTO Management Support

Load and Resistance Factors Calibrated to a Safety Index of 4.0