Erection of Cable-Stayed Bridges Having Composite Decks with Precast Concrete Slabs : Erection of Cable-Stayed Bridges Having Composite Decks with Precast Concrete Slabs Presented by: Adam Berg & David Jacobson CEE 949 03-26-03


Erection of Cable-Stayed Bridges: Erection of Cable-Stayed Bridges Overview of cable-stayed bridges Types of cable-stayed bridge decks Erection methods and analysis Conclusion


Cable-Stayed Bridges: Cable-Stayed Bridges The known use of cable “stays” dates back to ancient Egyptian times


Cable-Stayed Bridges: Cable-Stayed Bridges Modern use of cable-stayed bridges evolved in 1950’s (Germany)


Advantages of Cable-Stayed Bridges: Advantages of Cable-Stayed Bridges Economical choice for spans between 200 and 1000 meters Self-anchoring during construction React to live loads with only small deformations Easily constructed by cantilever method


Concrete Bridge Decks: Concrete Bridge Decks Used for spans up to 350 m Axial forces induced into the deck by cable stays serve as a cost-free prestress


Composite Bridge Decks: Composite Bridge Decks Advantageous for spans from about 350 m to 700 m Axial forces induced into the deck by cable stays serve as a cost-free prestress


Steel Girder w/ Orthotropic Decks: Steel Girder w/ Orthotropic Decks Advantageous for spans greater than 700 m


Erection of Cable-Stayed Bridges: Erection of Cable-Stayed Bridges Cantilever style construction Goal is to prevent locked in curvature and bending moments in bridge deck


Pure Concrete Deck Cable Tensioning: Pure Concrete Deck Cable Tensioning Proper one-step tensioning will yield this dead load configuration Dead Load Configuration: Full deck loads, w, and deck moments, M


Pure Concrete Deck Cable Tensioning: Pure Concrete Deck Cable Tensioning 3 2 4 1


Pure Concrete Deck Cable Tensioning: Pure Concrete Deck Cable Tensioning


Erection of Cable-Stayed Bridges..: Erection of Cable-Stayed Bridges.. Methods of erecting cable-stayed bridges having concrete or orthotropic decks are fairly well established. However, erection methods/analysis of composite decks with precast concrete slabs are not well published.


Composite Deck Cable Tensioning: Composite Deck Cable Tensioning One-step tensioning processes lock in initial deck curvature and moments


Construction Stages for Two-Step Composite Deck Cable Tensioning: Construction Stages for Two-Step Composite Deck Cable Tensioning Steel stage Erection of pre-fabricated steel grid


Construction Stages for Two-Step Composite Deck Cable Tensioning: Construction Stages for Two-Step Composite Deck Cable Tensioning Panel stage Placement of precast concrete slabs on steel grid Cables are tensioned as the first step of tensioning


Construction Stages for Two-Step Composite Deck Cable Tensioning: Construction Stages for Two-Step Composite Deck Cable Tensioning Freeze stage Survey is conducted to check precision of grid geometry and cable forces Joints between precast concrete slabs are cast; resulting deck acts continuously and compositely


Construction Stages for Two-Step Composite Deck Cable Tensioning: Construction Stages for Two-Step Composite Deck Cable Tensioning Final stage After sufficient deck strength is realized, cables are stressed to their final lengths (second step of tensioning)


Two-Step Composite Deck Cable Tensioning: Two-Step Composite Deck Cable Tensioning Deck shape with zero overall curvature


Two-Step Composite Deck Cable Tensioning: Two-Step Composite Deck Cable Tensioning


Two-Step Composite Deck Cable Tensioning: Two-Step Composite Deck Cable Tensioning


Further Considerations: Further Considerations


Further Considerations: Further Considerations


Further Considerations: Further Considerations


In Conclusion…: In Conclusion…