Design

1
Design Using Ultra High Performance Concrete

• Dean Bierwagen
• April 12th, 2006

2
Why UHPC?

• High compressive strength (gt18.0 ksi)
• High durability
• Low permeability
• Remove mild reinforcement
• More efficient sections

3
Replacement Bridge

• 110 ft single span
• 3 beam cross section
• Modified Iowa bulb-tee
• Integral abutments
• 8 inch cast-in-place deck

4
Replacement Bridge
5
Design Background

• French Guide Specification
• Design Guidelines for RPC Prestressed Concrete
  Beams, University of New South Wales
• Research work by Dr Ulm, MIT
• Discussion w/ Vic Perry of LaFarge, Chris Hill of
  Prestressed Services, Lextington, KT, Ben
  Graybeal of FHWA Turner Fairbanks Lab.
• Research by FHWA Turner-Fairbanks

6
Design Work

• Joint Design
• Wapello County
• Iowa State University
• Iowa Department of Transportation
• Design reviewed by Dr Ulm, MIT
• CADD sheets by ISU coop students
• Verified by flexure and shear test

7
Iowa Standard 45 in. Bulb-T
8
Preliminary Section
9
Final Modified Section

• Reduced section
• 1 inch top flange
• 2 inch web
• 2 inch bottom flange

10
Final Modified Section
11
UHPC Design Data

• Release compressive strength 14.5 ksi
• Release modulus of elasticity 5,800 ksi

12
UHPC Design Data

• Final Compressive Strength 24.0 ksi
• Expected 30.0 ksi
• Final modulus of elasticity 8,000 ksi

13
Allowable Service Stresses

• Allowable compressive release 8.7 ksi
• Allowable compressive flange 14.4 ksi
• Cracking tension 1.2 ksi
• Allowable tension 0.6 ksi

14
Loading

• AASHTO-LRFD HL93
• Distribution Factor Grillage Analysis (ISU)
• Simple beam supports

15
Shear Capacity

• Service
• Vu 189 kips
• Vtest 315 kips
• Ultimate
• Vu 300 kips
• Vtest 501 kips

16
Composite Connection

• Concern w/ proper placement of plastic
• Provide flat surface
• 3 options test beam
• ¼ inch roughness

17
Composite Connection
18
Anchorage

• Transfer of prestressing force
• Ohio University (lt 12 inches)
• MIT analysis pi section
• Debonded steps and draped strands
• Release of strands

19
Summary of Beam

• 49-0.6 inch diameter strands
• 72.6 of ultimate
• 5 draped
• 16 debonded

20
Summary of Beam
21
Comments

• Compressive strength
• Durability
• Quality
• Release 14.5 ksi to final 24.0 ksi
• Allowable tension
• Cost

22
Comments

• Develop experience
• Designers
• Materials Eng.
• Precasters
• Special testing
• Start small

23
Additional Applications

• PI section
• Precast paving notch repair
• Post-tensioned bridge