490 likes | 508 Views
Disraeli Bridges Rehabilitation. Project Description City of Winnipeg Public Works Department. Introduction. Overview - Project Limits - Description of Bridges - Current Condition Assessment - Conceptual Design - Structural Evaluation - Traffic Management During Construction
E N D
Disraeli Bridges Rehabilitation Project Description City of Winnipeg Public Works Department
Introduction Overview - Project Limits - Description of Bridges - Current Condition Assessment - Conceptual Design - Structural Evaluation - Traffic Management During Construction - Public Consultation to Date - Construction Schedule
Project Background & Limits • Opened in 1960 • Roughly 2 km of Road & Bridge • Red River Bridge – 320 m (1050 feet) • CPR Overpass – 390 m (1280 feet)
Disraeli Bridges Rehabilitation Condition Assessment
Maintenance History • Early 1970’s – Open Grid Deck Infilled with Concrete & Asphalt Wearing Surface Installed. Girders were Painted. • 1979 – Concrete Median Barrier Installed • 1984 – Asphalt Wearing Surface Replaced with other Repairs to Structure • 2004 – Concrete Pier Repairs • 2004 – 2008 Structural Steel Deck Repairs
Condition Assessment Components • Bridge / Overpass Structures • Roadways • Geometry • Structural Evaluation • Road & Structure Safety • Pedestrian Safety & Accessibility
Geometry • Insufficient Radii on Roadway North of the Bridge and South of the Overpass • Existing On/Off Ramps Do Not Meet Current Geometric Requirements
Pedestrian Safety & Accessibility • Steep, Narrow Sidewalks with Potential Risk of Tripping Hazards • Limited Bicycle Facilities • Lack of Separation from Traffic
Summary of Deficiencies • Piers/Abutments and Bridge Deck are Severely Deteriorated • Limited Girder Corrosion • Bridge and Roadway Geometry • Universal Design and Overall Accessibility
Disraeli Bridges Rehabilitation Conceptual Design
Design Criteria • Structural Design • CSA-S6 • CL625 Loading & 62.5 T where possible • Geometric Design • TAC Geometric Design Guide • City of Winnipeg Standard Practice • Universal Design • City of Winnipeg Accessible Design Standards
Maintenance Considerations • Zinc-Metallize Girders • Chloride Extraction of Piers & Abutments • Possible Replacement of Select Piers & Abutments • Automated Anti-Icing System
Structural Evaluation • Original Design Based on 1950’s Codes and Standard Practice • Previous Load Ratings and Load Testing in Late 1970’s and Early 1980’s • Update to Current Design Codes and Truck Loading Where Possible.
Steel Coupons Taken From Damaged Girder and Three Other Locations. Verify the Steel Properties: Meets all requirements of ASTM A373-58T Does not meet current notch toughness requirements for new construction. Modern notch tough steel did not exist until the 1970’s. Physical Testing
Girder Rehabilitation Considerations • 36.5 T posting governed by stress in River Bridge plate girder spans. • Girders have infinite fatigue life at 36.5 T. • Very low ADTT at about 1% of ADT • Structures not fracture critical. • Brittle fracture affected by: • Triaxial state of stress (bad detailing) • Low temperature • Rapid rate of loading
Preliminary Design Findings • Wide flange girder spans can be rehabilitated & strengthened to CL-625 • Not feasible to strengthen river span plate girders to CL-625 or 62.5 T. Options are: • Rehabilitate plate girders and post bridge between 36.5 T and 62.5 T. • Replace plate girder spans. Allows for profile and cross section enhancements.
Disraeli Bridges Rehabilitation Traffic Management During Construction
Impacts on Traffic During Construction • Vehicular Traffic Capacity • Pedestrian & Cyclist Accessibility • Transit & Emergency Services • Trucking Industry • Local Business • Rail and Marine Traffic
Traffic Management Options • Partially Open • Full Closure
Risks Associated With Partially Open Option • Staged Construction • Longer Construction Schedule • Schedule Delays • Vibration-Induced Cracking Due to Traffic
Traffic Management Conclusions • Partially Open option is not practical. • Full Closure option is recommended for traffic management during rehabilitation of the Disraeli Facility. • Further work on a full closure traffic management plan is being undertaken to deal with community access, traffic management, and transit.
Disraeli Bridges Rehabilitation Public Consultation
Public Consultation Process • Key Stakeholder Advisory Committee (SAC) • News Letters • Phone and Mail-in Surveys • Public Open Houses • Report on Findings
Construction Schedule • Construction period estimated at 16 to 24 months. • Limit total bridge closure to 12 to 16 months.