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Pages 59-126

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From page 59...
... 59   A P P E N D I X C Experimental Program C.1 Introduction Experimental testing was performed to verify the findings of the analytical program and to determine the practical variables that cannot be addressed analytically. The experimental testing consisted of two phases: 1.
From page 60...
... 60 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-1. Shear Keys used in the full-scale tests.
From page 61...
... Experimental Program 61 Figure C-2. Typical test girder section with Type IV shear key on one face and Type V shear key on other face.
From page 62...
... 62 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-4. Strand location and stirrup detail for a typical test girder.
From page 63...
... Experimental Program 63 Figure C-5. Test girders.
From page 64...
... 64 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems To test the Type IV shear key configuration, the edge girders (Girder 1 and Girder 3) were placed with Type IV shear key face on the inside.
From page 65...
... Experimental Program 65 Figure C-8. Stages during girder fabrication: (a)
From page 66...
... 66 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-9. Stages during girder fabrication: (a)
From page 67...
... Experimental Program 67 Figure C-10. Girder instrumentation layout.
From page 68...
... 68 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems The specification for the girders called for the contractor to provide an exposed aggregate finish. The sides of the form were coated with a set retarding admixture and the surface cement was to be removed after the girder concrete had set.
From page 69...
... Experimental Program 69 Figure C-12. Finished girder surface alongside CSP-3 and CSP-4 chip.
From page 70...
... 70 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-13. Field monitoring of the girder.
From page 71...
... Experimental Program 71 Figure C-14. Temperature variation at various depths at midspan of the girder during field monitoring: (a)
From page 72...
... 72 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-15. Temperature variation at various depths at end of the girder during field monitoring: (a)
From page 73...
... Experimental Program 73 2. As expected, the gradients are more severe on the face shadowed from sunlight compared to the face exposed to sunlight because the shaded sides have only the top surface exposed to sunlight while the other sides are more uniformly heated.
From page 74...
... 74 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-17. Temperature profile across girder section at end of the girder during various times of the day compared to AASHTO gradient: (a)
From page 75...
... Experimental Program 75 C.2.5 Type IV Shear Key Testing This test assessed the effects of temperature and fatigue loading on a Type IV shear key cast with a nonshrink grout and a high bond grout. A system of three girders with two Type IV shear key joints was tested.
From page 76...
... 76 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-19. Insulated box over the girders to apply thermal loads.
From page 77...
... Experimental Program 77 To monitor the performance of the shear key at various stages during the test, several instruments were installed. As previously detailed, thermistor and VW gages were installed inside the girder during fabrication.
From page 78...
... 78 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems gages across the joints. Figure C-25 shows the location and labels of the VW gages embedded into the joints.
From page 79...
... Experimental Program 79 Figure C-23. Locations and labels for load cells at supports, LVDTs across joints, and wire potentiometers under girders for Type IV shear key test.
From page 80...
... 80 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems C.2.5.2 Thermal Loading Before Grouting Concrete does not have set thermal properties as the properties vary with the mix. Therefore, an initial establishment of thermal properties of the girders was required.
From page 81...
... Experimental Program 81 Figure C-26. Thermal gradient at a depth of 4 inches from the surface of the girder for various locations during a typical heat cycle of Type IV shear key.
From page 82...
... 82 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-28. Temperature gradient at various locations compared with AASHTO gradient band for a typical heat cycle of Type IV shear key.
From page 83...
... Experimental Program 83 C.2.5.3 Grouting of the Joints The Type IV shear keys were cast with two different grouts. Jute was used to seal the small gaps between the bottoms of the girders.
From page 84...
... 84 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Table C-2. Strength of the grouts used for Type IV shear key.
From page 85...
... Experimental Program 85 Figure C-30. Girder camber during thermal loading of Type IV shear keys after grouting: (a)
From page 86...
... 86 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-31. Differential joint movement during thermal loading of Type IV shear keys after grouting: (a)
From page 87...
... Experimental Program 87 Figure C-32. Strain across the top of the joint during a typical thermal loading of Type IV shear keys after grouting: (a)
From page 88...
... 88 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-33. Strains in VW gages embedded 1 inch into the joint.
From page 89...
... Experimental Program 89 Figure C-34. Flooding Type IV shear keys with dyed water to investigate leakage.
From page 90...
... 90 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-36. Leakage in the tie rod on the side face of Girder 1: (a)
From page 91...
... Experimental Program 91 Figure C-37. Live load setup.
From page 92...
... 92 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-39. Support reactions during static tests of Type IV shear key: (a)
From page 93...
... Experimental Program 93 Figure C-40. Girder camber during static tests of Type IV shear key: (a)
From page 94...
... 94 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems C.2.5.6 Joint Cutting and Inspection After the load cycles were completed, the top deck of the girder system was cleared for joint cutting. The heat box, heating equipment, and instrumentations were all removed and stored for second series of tests.
From page 95...
... Experimental Program 95 Figure C-42. Signs of poor consolidation due to a cold joint in the region that leaked after first thermal cycle: (a)
From page 96...
... 96 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-44. Cracking at the west end of joint 1-2.
From page 97...
... Experimental Program 97 allowed the dye water to seep in and leave color patterns. Removing the grout and revealing the girder surface to examine these patterns would provide information about the time and the intensity of these defects.
From page 98...
... 98 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems C.2.6.1 Test Setup and Instrumentation Girder 2, the middle girder during Type IV shear key test, was removed from the laboratory floor. Girder 1 and Girder 3 were swapped such that Girder 1 was now at the south side and Girder 3 was on the north side.
From page 99...
... Experimental Program 99 However, because the girder assembly was changed to utilize the Type V shear key surface, a new scheme of instrumentation labels is used to be consistent with the changed girder labels and to avoid confusion with the previous scheme of instrumentation used in Type IV shear key. These are shown in Figure C-49, Figure C-50, and Figure C-51.
From page 100...
... 100 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-51. Locations and labels of VW gages embedded in the joints for Type V shear key test.
From page 101...
... Experimental Program 101 Figure C-53. Temperature profiles through girder depth at various locations during a typical heat cycle of Type V shear key.
From page 102...
... 102 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-55. Camber of the girders during a typical heating cycle before grouting for Type V shear key.
From page 103...
... Experimental Program 103 due to the need to work around the heat box. The concrete stopped flowing out from the bucket into the joint and an additional dose of high-range water reducer (HRWR)
From page 104...
... 104 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-56. Girder camber during thermal loading of Type V shear keys after grouting: (a)
From page 105...
... Experimental Program 105 Figure C-57. Differential joint movement during thermal loading of Type V shear keys after grouting: (a)
From page 106...
... 106 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-58. Flooding Type V shear keys with dyed water to investigate leakage.
From page 107...
... Experimental Program 107 Figure C-59. Support reactions during static tests of Type V shear key: (a)
From page 108...
... 108 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-60. Girder camber during static tests of Type V shear key: (a)
From page 109...
... Experimental Program 109 C.2.6.6 Joint Cutting and Inspection As with the Type IV shear keys, after the completion of cyclic loading, the joints were cut and inspected visually for any cracks or defects. Hammer sound technique was used to find any delamination.
From page 110...
... 110 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems However, it was found that outside of this area, the concrete bonded very well to the surface. It was difficult to remove with the chipping hammer.
From page 111...
... Experimental Program 111 4. The bonding characteristics of the grout are one of the most important parameters.
From page 112...
... 112 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems C.3.1 Pull-off Test Panel I: Steel Formed and Round Aggregate Finish An 8-foot-long by 4-foot-wide panel was constructed. It consisted of a 4-foot-by-4-foot section of steel formed surface and a 4-foot by 4-foot section of exposed aggregate surface (see Figure C-63)
From page 113...
... Experimental Program 113 Figure C-64. Prewetting a 2-foot-by-2-foot section before grouting.
From page 114...
... 114 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-65. Final specimen (panel I)
From page 115...
... Experimental Program 115 Table C-3. Pull-off test matrix for panel I
From page 116...
... 116 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems 2. The remaining materials seemed to perform about the same.
From page 117...
... Experimental Program 117 Table C-4. Pull-off test results for panel I
From page 118...
... 118 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Table C-5. Cube tests results for panel I
From page 119...
... Experimental Program 119 Figure C-67. Pull-off test panel II with exposed crushed aggregate surface.
From page 120...
... 120 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Table C-6. Pull-off test results for panel II.
From page 121...
... Experimental Program 121 C.3.3 Pull-off Test Panel III: Surface Sandblasted to CSP–4 The concrete surface profile in the girder keyways for system testing was not fabricated with an exposed aggregate. A member of the International Concrete Repair Institute (ICRI)
From page 122...
... 122 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems bond well with the substrate. In the full-scale test, the RT found the bond to be very good (see section on full-scale testing)
From page 123...
... Experimental Program 123 C.3.4 Pull-off Testing IV: Girder Sides The girders were to have an exposed aggregate surface. As detailed previously, the fabricator was unable to achieve this surface, so a roughly sandblasted surface was used.
From page 124...
... 124 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems Figure C-70.
From page 125...
... Experimental Program 125 Table C-10. Pull-off test results on the sides of girder.
From page 126...
... 126 Guidelines for Adjacent Precast Concrete Box Beam Bridge Systems 4. The surface roughness affected the bond performance.

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