Acknowledgm ents Effectiveness of Adjacent Funding Agencies: ODOT - - PDF document

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Effectiveness of Adjacent Precast Concrete Box-Beam Connections

OTEC 2015

Mohamed Habouh and Ali Almonbhi - Graduate Students Anil Patnaik - Professor Department of Civil Engineering

Acknowledgm ents

Funding Agencies: ODOT and Ohio’s Research Initiative for Locals (ORIL) ODOT SMEs: Dr. Waseem Khalifa, Mr. Perry Ricciardi, and Mr. Jim Welter ORIL TAC: Mr. Steve Luebbe, Mr. Warren Schlatter,

• Mr. Jim Wiechart, and Dr. Eric Steinberg

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The contents in this presentation do not necessarily reflect the official views or policies of ODOT, ORIL, or FHWA.

Outline

 Introduction: Box‐Beam Bridges  Current Practices and Research Significance  Objectives of the Study  Factors Affecting Shear Strength of Key Ways  Joint Tests to Study Shear Strength of Key Ways  Beam Assembly Tests Using Selected Grouts and Symmetric Loading  Waterproofing Membrane Studies  Potential Implementation  Summary and Preliminary Findings

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Consequences of Water Leakage at Joints

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Severe deterioration of underside of box beams at the longitudinal joints due to corrosion and spalling

Typical ODOT Standard Cross-Sections

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To develop insight into the performance of longitudinal joints with a particular reference to cracking and differential deflection that is believed to cause the waterproofing membrane to fail. The specific objectives of the study are to:

• Identify the sources, causes and effects of inadequate

waterproofing at the joints

• Develop preventive measures through careful evaluation of

alternatives

Objectives

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Tie Rods ‐ Key Way Geometries

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The State of the Art of Precast/Prestressed Adjacent Box Beam Bridges (PCI 2009) Maria, Jubum, and Zi, PennDOT Report (May 2010) Russell (PCI 2011)

Failure of specimens without tie‐rod

• ccurred by de‐bonding of grout

Failure of specimens with tie‐rod Lateral cracks at the tie rod location for specimens with high tie force

Joint Tests with Tie Rods

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1.Key way geometry

• 2. Grout types
• 3. Effects of bond characteristics

Bonding agent Cement slurry Sand blasting Shrinkage cracks

• 4. Improvement of Grout Performance

Joint Tests without Tie Rods

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Key Way Geometries Joint Test Setup

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Summary of Test Results

5,700 (100%) 4,767 (84%) 5,033 (88%) 14,833 (260%) 15,950 (280%) 5,200 (91%) 6,167 (108%) 37,000 (649%) 8,800 (154%) 5,800 (102%) 4,850 (85%) 17,167 (301%) 12,500 (219%) 14,550 (255%) 6,400 (112%) 8,333 (146%) 29,666 (526%) 16,500 (289%) 17,200 (302%) 17,439 (306%) 23,703 (416%) 34,700 (609%) 5,300 (93%) 24,067 (422%) 8,100 (142%)

5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000

ODOT Approved Grout Magnesium Phosphate (1) Magnesium Phosphate (2) Polymer Grout ODOT Approved Grout Magnesium Phosphate (1) Magnesium Phosphate (2) Polymer Grout ODOT Approved Grout Magnesium Phosphate (1) Magnesium Phosphate (2) Polymer Grout Concrete (5,400 psi) ODOT Approved Grout Magnesium Phosphate (1) Magnesium Phosphate (2) Polymer Grout Concrete (5,400 psi) HSC (9786 psi) HSC (4282 psi) with Bonding Agent HSC (4282 psi) with Bonding Agent and Sand Blasted surface HSC (9786 psi) with Sand Blasted Surface UHPG ‐ Sand Blast UHPG ‐ Cement Slurry UHPG ‐ Sand Blast + Cement Slurry UHPG ‐ No Sand Blast ‐ No Cement Slurry Partial / Narrow keyway Full / Narrow keyway Partial / Wide keyway Full / Wide keyway

Average first crack load (lb) Grout material / Key way geometry (Average first crack load) Vs. (key way geometry and grout material)

29,367 (515%)

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Effects of Key Way Geometry

5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 ODOT Approved Grout Magnesium Phosphate (1) Magnesium Phosphate (2) Polymer Grout

First Cracking Load (lb) Grout Material

Effect of Interface Length (Narrow)

Partial / Narrow Full / Narrow

5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 ODOT Approved Grout Magnesium Phosphate (1) Magnesium Phosphate (2) Polymer Grout

First Cracking Load (lb) Grout Material

Effect of key way width (Partial depth)

Partial / Narrow Partial / Wide

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Sand‐ blasted surface As‐cast concrete surface

Grout material Cement slurry Sandblast

UHP Grout 28 day Compressive strength = 19,100 psi

X X √ X X √ √ √

UHP grout

Effects of Surface Preparation

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5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000

Concrete (5,400 psi) HSC (9786 psi) HSC (4282 psi) With Bonding Agent HSC (4282 psi) Bonding Agent and Sand Blasted Surface HSC (9786 psi) Sand Blasted Surface

First Cracking Load (lb) Normal and High Strength Concrete

Full / Wide

5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 No Sand Blast, No Cement Slurry Sand Blast Cement Slurry Sand Blast, Cement Slurry

First Cracking Load (lb) UHPG

Full / Wide

Surface Preparation Type: Sandblast / Cement Slurry / Bonding Agent

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Failure Modes

Failure through key way Observed in one specimen with polymer grout Failure through Concrete Units

• Observed for 11 specimens out of 12 in the

Polymer

• 6 specimens in the UHPG with sandblasting with

and without cement slurry

• And for 12 specimens in the HSC grout

Debonding Mode Observed in 48 test specimens

• Six sets of three beams each
• 1” tie rod at the ends of the beams through 2”

holes

• Torque of 250 ft‐lb (15 kips of clamping force)

which is the current practice

• Vertical deflection, lateral movements, and the

vertical movements were measured with LVDTs and dial gages

• Strains in the rebar and on the concrete surface at

the top at mid‐span were recorded Beam Assem bly Tests under Sym m etric Loading

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Summary of Beam Assembly Tests

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The first two beam assemblies were grouted with ODOT standard key way geometry and approved grout

Beam Assembly Tests (Sets # 1 and 2)

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Test Setup for Sets #4, 5 and 6

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Failure Loads of Beam Assemblies

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20,000 40,000 60,000 80,000 100,000 120,000 140,000 ODOT Approved Grout As‐Cast Concrete Surface ODOT Approved Grout As‐Cast Concrete Surface Polymer Grout As‐Cast Concrete Surface ODOT Approved Grout As‐Cast Concrete Surface High Strength Concrete As‐Cast Concrete Surface Polymer Grout As‐Cast Concrete Surface Set # 1 Set # 2 Set # 3 Set # 4 Set # 5 Set # 6

Cracking Load (lb)

Beam Assembly Test Results for Symmetric Loading Sets #1 and 2 Set #3 Set #4 Set #5 Set #6

ODOT Grout ODOT Key Way Failed Specimen Regrouted ODOT Grout Wide, Deep Key Way HSC Wide, Deep Key Way Polymer Narrow, Deep Key Way

Load at First Crack 37 kips 121 kips 73 kips 107 kips 131 kips

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Beam Assembly Tests (Set # 1 and 2)

Polymer Grout Condition After Typical Beam Failure

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• Bond between the new grouts

and the beam surfaces was excellent

• It took lots of effort to separate

the grout from the key ways

• Joint failures were all local
• Some of the beam units were

used for regrouting and retesting

Waterproofing Membrane Studies

• The main objective in this part of the project was to evaluate

sheet membranes based on their ability to adhere to concrete, accommodate strains, and resist punching at the same time provide waterproofing.

• Several Type II and Type III waterproofing membranes are

included in ODOT QPL (qualified product list).

• Five different commercially available membranes were

studied in this study.

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Waterproofing Membranes Studied

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Membrane # Type 1 Type III 2 SA, Not in ODOT QPL (Type II) 3 SA, Not in ODOT QPL (Type II) 4 Type III 5 Type II

SA refer to Self‐Adhesive (Type II) QPL refer to Qualified Product List

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Tests Conducted on Waterproofing Mem branes  Tensile tests at different temperatures  Adhesion tests  Differential deflection tests  Punching tests  Tests to detect initiation of leakage

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Tensile Tests

• Five different systems were tested at

different temperature 70°, 40°, 23°, 14° and –4° F

• Each sample was conditioned in an

environmental chamber at the desired temperature for at least one hour.

• More than 75 specimens were tested

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Dimensions in inches

Comparison of Tensile Strengths at Different Temperatures

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50 100 150 200 250 300 350 400 450 70 40 23 14 ‐4 Load, lbf Temperature, Degrees F 665 ClodFlex Polyguard Paveprep Paveprep SA

#2 – SA Type II #3 – SA Type II #1 – Type III #4 – Type III #5 – Type III

Comparison of Elongations

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0.0 5.0 10.0 15.0 20.0 25.0 70 40 23 14 ‐4 Elongation, % Temperature, Degrees F 665 ClodFlex Polyguard Paveprep Paveprep SA

#2 – SA Type II #3 – SA Type II #1 – Type III #4 – Type III #5 – Type III

Adhesion Tests

• Adhesion is measured by

peeling strips of membrane

• ff of hardened mortar at

180°.

• The test consists of adhering

membranes to carefully prepared mortar block surfaces, cutting the membrane into one inch wide strips, and applying a tensile load at a constant rate of extension until each strip peels off from the mortar blocks completely.

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Dimensions in inches

Adhesion Tests

In order to measure the potential improvement of the application of heat to membrane for Type II SA membrane, three samples of three strips were tested. Sealant is normally used for Type III at 380 degrees F. 1. Samples subjected to direct heat with the use of sealant as bonding agent. 2. Sample with no heat application and with the use of sealant as bonding agent. 3. Sample with the use of direct heat and the use of primer as the bonding agent, no sealant. The Sealant used was a “Hot‐Applied Modified Asphalt” Sealant. The primer was an “Asphalt Primer”.

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Adhesion Test Setup

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Comparison of Three Sets of Trend Lines

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5 10 15 20 25 1 2 3 4 5 6

Load, lbf Extension, inch

Power (Heat & sealant ) Power (NO heat & sealant ) Power (Heat & primer)

Ultimate Differential Deflection Tests

This test was designed to determine the maximum differential deflection that a membrane can accommodate

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Waterproofing Membrane Load Load

Differential Deflection Test Setup

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Punching Tests

• Acme Laboratory Penetrometer was

used and attached to an ohmmeter to detect when puncture occurs.

• It is equipped with an arm to apply

load manually and has a load cell to measure the applied load during the test.

• The ohmmeter terminal wires are

connected to the tip on one side and to a steel plate under the membrane test specimen on the other.

• The ohmmeter initiates an indication
• f punching by making a beep sound

and changing the digital reading when the circuit becomes closed, i.e., the tip penetrates the membrane and touches the steel plate below the membrane.

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Test Setup

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Tests to Detect the Initiation of Leakage

• The capacity of membranes to elongate is

large.

• The intent of leakage tests was mainly to

investigate if there is any leakage before the membrane reaches its deformation limits.

• A new water leakage test was performed after

several trials.

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Test Setup

Detection of Leakage Initiation Test

Detection of Leakage Initiation Test

Top view

Bottom view, some rupture in the external fabric, but no leakage

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Waterproofing Membrane Construction Issues

• Protection of

waterproofing membrane is needed

• Need to prevent

construction equipment

• n the top of installed

unprotected membrane

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24’‐0” 6‐ B42‐48 103’‐0”

Potential Implementation

Original Key Way Geometry Suggested Key Way Geometry Other Recommendations

• No loads to be applied until a minimum

compressive strength of 10 ksi is achieved in the grout material

• Use #8 maximum size aggregate and

vibrate the grout for consolidation

• Carefully prevent leakage of wet grout
• Carefully protect membrane before

asphalt overlay – strictly no traffic or construction equipment

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Sum m ary and Prelim inary Findings

 Typical waterproofing membranes tested in this study possess the capacity to stretch adequately both in terms

• f in‐plane elongations and out‐of‐plane shear

deformation by over one inch while retaining their water‐ tightness.  A membrane by itself may not be the sole source of water leakage problems in box beam bridges.  With suitable modifications to the key way geometries, judicious selection of grout material and precautions during construction, it is possible to increase the shear transfer strength of longitudinal joints in box beam assemblies.

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Questions