Post on 03-Oct-2020
transcript
Load Rating of Post-Tensioned
Cast-in-place Concrete Segmental
Bridge
Ken Lee and Nyssa Beach
H-09-U: SH 82 over Maroon Creek, Aspen CO
Buttermilk Ski ResortH-09-U
Project Overview – CDOT Load Rating
• First of two task orders to rate Colorado structures
that are either missing load ratings or in need of
updated load ratings.
• 20 structures rated in the first task order
• Load ratings included:– Cast-in-place post tensioned segmental structure (Maroon Creek – Midas)
– 10-span curved welded plate steel girder (AASHTOWare BrR)
– Multi-cell cast-in-place post tensioned box girder (AASHTOWare BrR)
– 8-span spliced post-tensioned concrete U-girder (Bentley Consplice)
– 3-span welded plate girder steel slant leg (Midas)
– Concrete Arch Culvert (SAP2000)
Bridge Overview – Maroon Creek Bridge
Bridge Overview – Maroon Creek Bridge
Completed in 2005
3 Spans (170ft. – 270ft. – 170ft.)
Bridge width = 73’-0”
Typical Box Depth = 13’-6” along
Bridge Width = 73’-0”
Fully Integral at Piers
Bridge Overview – Maroon Creek Bridge
Bridge Overview – Maroon Creek Bridge
Bridge Overview – Maroon Creek Bridge
Bridge Overview – Maroon Creek Bridge
Challenging aspects of Bridge Design
• Transverse and Longitudinal Analyses
• Construction Stages
• Time-dependent Behavior
• Interaction of Transverse Bending and Longitudinal
Shear in Webs
• Geometry
• Prevention of Substructure Flexural Crack
• Load Ratings
Main Topics
• Longitudinal Analysis and Design
• Construction Stages
• Time-dependent Behaviors
• Load Ratings
Modeling of Maroon Creek Bridge
Connectivity and BCs
Modeling of Maroon Creek Bridge
Creep/Shrinkage: CEB-FIP (1978)
Time-dependent Material and Behavior
Creep Coefficient
Modeling of Maroon Creek Bridge
Tendon Profiles
Modeling of Maroon Creek Bridge
Tendon Properties (low relaxation)
Modeling of Maroon Creek Bridge
Jacking Force
Modeling of Maroon Creek Bridge
17- Load Cases
Load Combination
20 Load combinations
Temperature and Structural Behavior
TG [AASHTO 3.12.3]
Why Construction Stage Analysis is crucial?
M under Selfweight wo/ CS – 3 span continuous
M under Top PT w/ CS– Cantilevers and closure pour
Why Construction Stage Analysis is crucial?
M under Top PT wo/ CS – Secondary PT included!!
M under Top PT w/ CS – No Secondary PT Effect
Construction Stage Analysis- Total 11 CSs.
360days for Bridge Completion
Construction Stage Analysis
Assign Groups to Each Construction Stage
Construction Stage Analysis
Construction Stage Analysis
360 days at Bridge Completion and 10 years for CR/SH
Construction Stage Analysis
Summation of CS
Summation of CS
Reaction
DL+ER+Secondary PT+Secondary CR+Secondary SH
Deformation
DL+ER+Primary PT+Primary CR+Primary SH
Force
DL+ER+Primary PT+Secondary PT+Secondary CR+
. Secondary CR
Evaluation of Post-Analysis: Const. Stages
Evaluation of Post-Analysis: After Completion
Tendon Stress Limits
Evaluation of Post-Analysis: Tendon Loss
Midas Design Feature
Longitudinal Reinforcing
Midas Design Feature
Shear and Torsional reinforcing
Load Rating
Design Vehicles – HL93 / 9 Legal / CDOT Permit
Define Rating Cases
Load Rating
Summary of Ratings in Strength
Summary
• Load Rating = 1.3
• Construction Stage Analysis is crucial
• Verification of Behavior of Time-dependent material
• Evaluation of Post-Analysis
• Midas Design Features for Seg. PT Concrete Bridge
• Capability of Midas Load Rating for Seg. PT Concrete
Bridge
Acknowledgement