post-tensioning developments in texas
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Post-Tensioning Developments in Texas
John E. Breen, P.E.The Nasser I. Al-Rashid Chair in Civil Engineering
Ferguson Structural Engineering LaboratoryThe University of Texas
IntroductionSegmental box girder bridgesPost-tensioned anchorage zonesStrut-and-tie modelingPrecast post-tensioned substructuresCable stay and post-tensioned tendon fatigue criteriaCable stay and post-tensioned tendon corrosion protection systems
Introduction
40 years of continuous applications oriented research and development studies in post-tensioned concreteBroad sponsorship– TxDOT – RCRC– FHWA – NSF– NCHRP – Industry– PTI
Introduction
Wide RecognitionASCE Croes Medal, 4 ASCE T.Y. Lin Medals, Freyssinet Medal, FIP Medal, ASBI Leadership Award, PCI Outstanding Structure Award, ACI Structural Engineering Medal
Pages upon pages in AASHTO Standard Specs, AASHTO LRFD Specs, AASHTO Segmental Box Girder Guide Spec, ACI Building CodeEducated dozens of highly qualified practitioners, researchers, and teachers
Segmental Box Girder Bridges
Corpus Christi JFK CausewayFirst precast segmental box girder bridge in USA
Model Construction Model Testing
Corpus Christi JFK CausewayFirst precast segmental box girder bridge in USA
Corpus Christi JFK CausewayFirst precast segmental box girder bridge in USA
Corpus Christi bridge under construction
Corpus Christi bridge completed
Segmental Box Girder BridgesEpoxy Joint Technology
Application Results
Segmental Box Girder BridgesExternal Tendon Deviators Design
Cage Post-test
Segmental Box Girder BridgesExternal Tendon Bridges
Span-by-span model Test results
Segmental Box Girder BridgesExternal Tendon Bridges
183 N - Austin Thermal gradient results
Post-Tensioned Anchorage Zones
JFK Causeway Tendon path cracking
Test specimen
Post-Tensioned Anchorage Zones
Local ZoneEnd Zone
Local Zone Acceptance Criteria
Post-Tensioned Anchorage Zone Design Criteria
FEA STM
Strut and Tie Modeling
3D STM Diaphragm 3D Diaphragm Test
Precast Post-tensioned Bridge Substructures
Precast Post-tensioned Bridge Substructures
Fatigue Criteria
Post-tensioning tendon
Specimen Test
Fatigue Criteria
External tendon
Test Post-test
Fatigue Criteria
Cable stay
Installation Post-test
Cable Stay Corrosion Protection Systems
Grouting of specimen Voids forming
Cable Stay Corrosion Protection Systems
First study that showed concrete grout was not an effective protective barrier
Grout cracked when sheath cut
Corrosion at grout crack
Post-tensioning Tendon Corrosion Protection Systems
Post-tensioning Tendon Corrosion Protection Systems
Post-tensioning Tendon Corrosion Protection Systems
Post-tensioning Tendon Corrosion Protection Systems
Improved grouts
Major contributor to ASBI & PTI improved grouting procedures
Voids
Special Thanks
Great studentsDedicated techniciansCooperative facultyPatient and visionary sponsors– Especially TxDOT who never
hesitated to try results in practice
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