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Performance of Adjacent Prestressed Concrete Box Beam Bridge with Doweled Ultra‐High Performance Concrete (UHPC)
Longitudinal Joints
Professor Eric Steinberg, Ph.D., P.E.
October 27, 2015
ACKNOWLEDGEMENTSSteve Luebbe ‐ Fayette County EngineerTim Keller ‐ ODOT State Bridge EngineerBen Graybeal ‐ Turner‐Fairbank Research Center FHWALuke Dlugosz and Kyle Nachuk ‐ LaFarge North America Vic Perry ‐ V.iConsult, Inc. (formerly LaFarge North America) Robert Ballard and Rob Cunningham – URSPersonnel ‐ Stress‐Con in Kalamazoo, MIThe Righter Company, Inc. from Columbus, OH Ken Walsh, Issam Khoury, Josh Jordan – OUOU Students – Ali Semendary, Travis Ellison, Paul Leduc, Nate Hicks, and Husam Hussein
WK1
Slide 2
WK1 Walsh, Kenneth, 11/11/2014
INTRODUCTION
• About 2/3 of the State DOTs use box‐beam bridges
(Russell, H. G., 2011)
INTRODUCTION• 7,272 Box Beam Bridges in Ohio • Only IL (8,843) and CA (7,675) have more• Second largest type of bridge in Ohio (Stringer/Multi‐Beam or
Girder – 10,858 and Slab – 3,790)• Advantage: Economical for short and medium span bridges• Disadvantage: Longitudinal joint cracking
(NBI, FHWA 2013)
INTRODUCTION
• UHPC superior properties due to several components – Compressive strength greater than 22 ksi– Tensile strength in range 1.0 ksi
• Steel fibers allow ductile behaviorPercentage
Material lb/yd3 kg/m3 by WeightPortland Cement 1,200 712 28.5Fine Sand 1,720 1,020 40.8Silica Fume 390 231 9.3Ground Quartz 355 211 8.4HRWR (Water Reducer) 51.8 30.7 1.2Accelerator 50.5 30.0 1.2Steel Fibers 263 156 6.2Water 184 109 4.4
(Russell & Graybeal, 2013)
UHPC
INTRODUCTIONUHPC
• US Bridge Usage:– IA 2006, 3 ‐ 45” Bulb Tee Beams– VA 2008, 5 – 45” Bulb Tee Girders– IA 2008, 3 – 33” Pi‐Shaped Girders– NY 2009, Joints between Deck Bulb Tees– IA 2011, 14 – 8” Waffle Deck Panels– NY 2011‐2013 Multiple joints between deck panels and beams
• Disadvantages:– Unfamiliar material– Higher material costs– Lack of design code provisions– Special production issues (mixing, placement, forming)
Sollars Road Bridge
ODOT Standard Box
Sollars Road Shear Key
Beam Fabrication• Beams Fabricated May 2014 in Kalamazoo, MI• Wood used to Form Modified Shear Key
• 15 Vibrating Wire Strain Gages (VW4200) Installed in 3 Beams. 5/Beam – 2 Quarter Span and 3 Mid‐span
• 6 Dowel Bars (2/Beam ) Instrumented with Vibrating Wire Strain Gages (VW4150) at Quarter and Mid‐span
• 4 Thermocouple Wires Installed in Beam 3 to Record Temperature Gradients
Beam Fabrication
Beam Fabrication
Beam Fabrication
• Beams Delivered Saturday July 12, 2014. • 6 Dowel Bars Instrument with VW4150 and Installed on Beams
2, 3, and 4.
Beam Placement
Beam Setting
Bridge Instrumentation• Bridge Instrumented July 16, 2014• 3 Shear Keys Instrumented with 6 Vibrating Wire Strain Gages (VE4202) in Transverse Direction (2 Gages/Key ‐1 Quarter Span, 1 Mid‐span)
• Shear Keys 1 and 3 Instrumented with 4 Vibrating Wire Strain Gage (VW4200) in Longitudinal Direction (2 Gages/Key ‐ 1 Quarter Span, 1 Mid‐span)
Bridge Instrumentation
Bridge Instrumentation
UHPC Shear Key Casting
UHPC Shear Key CastingJuly 17, 2014, UHPC Joints Cast
Timeline• July 22, 2014 ‐ Shear Key Plywood Removed.
• July 24, 2014 ‐Waterproofing
• August 5, 2014 ‐ Asphalt
• August 6, 2014 ‐ Instrument Frames Erected Beneath Bridge
• August 7, 2014 ‐ 7 Strain Gages (WFLM‐60‐11‐2 LT) and 9 K‐100 Strain Gages in Brackets Mounted to Beam Bottom in Longitudinal Direction. 7 LVDT’ s and 3 Thermocouples also Installed
• August 8, 2014 – Truck Load Testing
• August 13, 2014 – Bridge Opened
Joints Exposed
Water Proofing
Instrument Frames
Instrumentation
Static Load Test4 static load configurations used in tests, and trucks positioned to obtain maximum moment at mid‐span. Configurations included:‐ A 56.1 kip truck load placed in left lane.‐ A 53.4 kip truck load placed in right lane.‐ 2 trucks placed side‐by‐side for a 109.6 kip total load‐ 2 trucks placed back to back in the left lane for a 109.6 kip
total load.
Truck Testing
Dynamic Load TestDynamic loading conducted by driving the 56.1 kip truck at speeds of 5, 10, 15, 25, and 30 mph, as data was collected.
Truck Testing
On December 15, 2014 and July 15, 2015• 3 LVDT’s used to monitor movement of Joints 4, 5 and 6. • 2 LVDT’S installed at each end of Beam 7 to monitor the
girder movement resulting from temperature changes. • A thermocouple installed on Beams 1 and 7 to monitor the
temperature on both exterior beams of the bridge. • A thermocouple was installed on the bottom of Beam 3 to
monitor the temperature at bottom of the beam.• All other instruments were connected to data acquisition.
Instrumentation
• Data was collected after UHPC placed in the Joints from July 17 to July 25, 2014 (asphalt overlay was not placed yet).
• Data was collected from August 8‐16, 2014 after the bridge had been open to traffic.
• The data was collected for different periods (December 15‐17, 2014, December 19‐25, 2014, December 30, 2014‐January 1, 2015, January 7‐10, 2015 and January 15‐19, 2015, July 9 ‐ July 14, 2015).
Monitoring
Mid span deflection‐ Deflection almost 0.5” for load configuration 3.‐ Higher deflections observed on right side compared to left side
Static Truck Test Results
Mid span strain• Measured strains only account for the truck loads• Tensile strains higher under loads and when total loads higher• Higher strains on right compared to left
Static Truck Test Results
Static Truck Test ResultsMoment Distribution Factor (DF)‐ Moment DF is portion of total moment that distributes to each
beam.‐ Was calculated by dividing the measured strain at the bottom
of each beam by the total recorded strains for each load configuration.
‐ AASHTO LRFD Bridge Design Specifications moment DF has 2 cases for adjacent box beam bridges‐ Beams act together as a unit (case 1). ‐ Beams connected only to prevent relative vertical
displacement at the interface (case 2).
Static Truck Test ResultsMoment distribution factors for 1 lane loaded
Static Truck Test ResultsMoment distribution factors for 2 lanes loaded
Moving Truck Test ResultsBottom strain at Mid‐span (5 MPH)
Moving Truck Test ResultsMid‐span Deflection (5 MPH)
Moving Truck Test ResultsBottom strain at Mid‐span (30 MPH)
Moving Truck Test ResultsMid‐span Deflection (30 MPH)
Dynamic Amplification FactorBased on Strain Data
Dynamic Amplification FactorBased on Deflection Data
Speed (MPH)
DAF
Beam 1 Beam 2 Beam 3 Beam 4 Beam 5 Beam 6 Beam 7
5 N/A 1.10 1.22 N/A 1.29 1.27 1.17
10 N/A 1.10 1.22 N/A 1.29 1.27 1.17
15 N/A 1.08 1.23 N/A 1.33 1.31 1.21
25 N/A 1.02 1.16 N/A 1.26 1.24 1.13
30 N/A 0.98 1.15 N/A 1.28 1.26 1.15
Thermal Test ResultsBeam 1 Longitudinal Interior Strains (July 17‐25, 2014)
Thermal Test ResultsBeam 1 Longitudinal Interior Strains (January 7‐10, 2015)
Thermal Test ResultsShear Key 3 Longitudinal Strain @ Mid Span (July 17‐25, 2014)
Thermal Test ResultsBeam 3 Transverse Interior Strain at Mid Span (July 17‐25, 2014)
Thermal Test ResultsTransverse Strain in Shear Key 1 at Mid‐span (First 24 hours)
Thermal Test ResultsTransverse Strain in Shear Key 1 at Quarter Span (First 24 hours)
• This same behavior was noted in all other instrumented shear keys after the first 24 hours.
• The behavior is the same as the transverse behavior of the beams in that the strains are a mirror image of the temperatures. When the temperatures increase, the strains become more compressive and when the temperatures drop the compressive strains are reduced.
• A difference in the transverse behavior of the shear keys is the continued increase in the compressive strains over time. This is likely due to the increasing compressive strength of the UHPC.
Thermal Test ResultsShear Keys 1 Transverse Strains after re‐zeroing the Gage upon 24 Hours of Curing
Shear Keys 1 Transverse Strains at Mid Span‐after re‐zeroing the gage upon 24 hours of curing
Thermal Test Results
Dowel Bar Strains for Part Embedded in Beams (July 17‐25, 2014 )
• Dowel bars embedded in Beams 1‐3 had same behavior as transverse beam behavior.
• The strain increased when the temperature decreased and the strain decreased when the temperature increased, all with a slight delay between peaks.
• Strains were relatively low (< 60 µε).• Similar behavior for other periods of data collection.
Thermal Test Results
• Behavior similar to transverse behavior measured in the UHPC of the shear key. Once the UHPC gained sufficient strength, the dowel bar began to show results as a mirror image to the temperature, increasing temperature resulted in decreasing strains. Also, the strains became larger compressive as the UHPC gained more strength toward the end of monitoring.
• Similar behavior for other periods of data collection.
Thermal Test ResultsDowel Bar Strains for Part Embedded in Shear Keys (July 17‐25, 2014 )
Costs
Total Project
Base Estimate % Increase
Engineer $416,275 $366,284 13.7
Contractor A $386,777 5.6
Contractor B $408,146 11.4
Contractor C $452,761 23.6
Contractor D $388,403 6.0
Contractor E $388,057 5.9
CONCLUSIONS• New shear key design with UHPC allowed elimination of
transverse ties and associated diaphragms.• No cracking was observed in the UHPC joints after plywood
removal and prior to waterproofing membrane placement. • AASHTO Distribution Factors are conservative for the bridge • Dynamic Amplification Factor (1.33) is valid for bridge• The bridge experienced less than 0.5 inches of deflection
when statically loaded in excess of 107 kips by trucks. • In terms of costs, contractors appeared to be more concerned
with using the UHPC than changing the geometry of the shear key joint. However, the majority of contractors had bids less than 6% above the base cost for the new design.
Any Questions?Thank you!