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From page 391... ... 392 Chapter 12 Longitudinal Joint Details for Accelerated Bridge Construction: Fatigue Evaluation 12.0 Introduction Chapter 9 presented results of a preliminary study that assessed potential longitudinal and transverse joint connection details for CIP joints between DBTs or full-depth precast panel to panel connections. The investigation was conducted in two phases. Read the entire page →
From page 392... ... 393 behavior, cracking, deflection and steel strain. Based on these test results, the U-bar detail was deemed to be a viable connection system for the longitudinal joint. Read the entire page →
From page 393... ... 394 in. cover at the bottom. Read the entire page →
From page 394... ... 395 L1 L5 L8 R1 R4 R7 a (a) Bars instrumented with strain gages (marked with red) Read the entire page →
From page 395... ... 396 the length direction, were slotted at a spacing of 6 in. to fix the U-bars in place. Read the entire page →
From page 396... ... 397 removal of the deteriorated concrete, proper preparation should provide a dry, clean and sound surface offering a sufficient profile to achieve adequate adhesion. There were many methods of surface preparation considered such as chemical cleaning, mechanical cleaning and blast cleaning. Read the entire page →
From page 397... ... 398 A total of eight slab specimens were made. Each slab specimen consisted of two concrete panels connected with an overlapping U-bar detail and one of the selected closure pour (CP) Read the entire page →
From page 398... ... 399 used to measure the vertical deflection along the joint. LMT's 4, 6 and 7 were placed along the centerline of the joint while LMT 5 was placed at the panel edge off the interface of the joint. Read the entire page →
From page 399... ... 400 AA A - A P P 1 2 3 9 10 4 7 5 6 8 LMT 1, 2 and 3LMT 8, 9 and 10 10 in. Read the entire page →
From page 400... ... 401 Figure 12.1.8: Simple support boundary condition at edge of longitudinal joint specimen AA A - A 36 36 DEMEC 1-1 DEMEC 2-2 DEMEC 1-1 DEMEC 2-2 (a) DEMEC points for SF, SS, FS tests Read the entire page →
From page 401... ... 402 AA A - A 36 36 2P DEMEC 1-1 DEMEC 2-2 DEMEC 1'-1' DEMEC 2'-2' DEMEC 1'-1' DEMEC 2'-2' BB B- B DEMEC 1-1 DEMEC 2-2 (b) DEMEC points for FF Tests Figure 12.1.9: DEMEC points Read the entire page →
From page 402... ... 403 The static flexural (SF) test specimens were loaded with two equal loads spaced at 12 in. Read the entire page →
From page 403... ... 404 at the other end above and below the slab. The two loads spaced at 12 in. Read the entire page →
From page 404... ... 405 Table 12.1.2: Compressive strength of concrete panel and grouted joint Panel (psi) Joint (psi) Read the entire page →
From page 405... ... 406 (a) Static shear test (FE Model) Read the entire page →
From page 406... ... 407 For the FF specimen, static loading was applied with the two patch loads on either side of the joint in several increments up to 44.6 kips (22.3 kips on each pad) in order to produce the maximum positive moment of 7.92 kip-ft per unit length (Section 10.1.5.8) Read the entire page →
From page 407... ... 408 Figure 12.1.12: First two cycles of fatigue shear (FS) loading applied 12.1.8. Read the entire page →
From page 408... ... 409 (a) FF-O Specimen (b) Read the entire page →
From page 409... ... 410 (c) FS-O Specimen under P1 (d) Read the entire page →
From page 410... ... 411 (e) FS-7 Specimen under P1 (f) Read the entire page →
From page 411... ... 412 The test results for the moment capacity are compared with the calculated values in Table 12.1.3. The strengths shown in the table for the fatigue tests, FS and FF, were the cylinder strengths measured at the end of the tests, and Table 12.1.2 presents detailed information about the compressive strengths. Read the entire page →
From page 412... ... 413 Figure 12.1.14-b compares the moment-curvature curves obtained for the specimens tested in flexureshear under static loading (SS) with those tested in flexure-shear following 2.0 million cycles of fatigue loading (SF) Read the entire page →
From page 413... ... 414 (a) Flexure tests (b) Read the entire page →
From page 414... ... 415 12.1.9. Deflection Development Figure 12.1.15-a and b show a comparison of the load-deflection curves of the fatigue specimens after 2 million cycles and the specimens subjected to static loading without fatigue cycles, for the flexure and flexure-shear tests, respectively. Read the entire page →
From page 415... ... 416 b. Flexure-Shear tests Figure 12.1.15: Load-deflection curves of flexure and flexure-shear specimens The calculated response in the plots represents the expected load-deflection curve before cracking, after cracking to reinforcement yield, and the stage of plastic hinge development at midspan after reinforcement yielding. Read the entire page →
From page 416... ... 417 interface and joint center versus fatigue-cycle (N) curves for FS under specific loading levels during interim static load tests. Read the entire page →
From page 417... ... 418 (b) FS-O Specimen under P2 c. Read the entire page →
From page 418... ... 419 12.1.10. Crack Width Development During the tests, the cracks at the interface between the grouted joint and the concrete panel were measured. Read the entire page →
From page 419... ... 420 Figure 12.1.18 shows the moment-crack width relationship for the SF and SS specimens. The service live load shown in Figure 12.1.18-a was the maximum positive calculated moment of 4.55 kip-ft/ft, after cracking, reported in Section 10.1.5.9. Read the entire page →
From page 420... ... 421 (a) SF Specimens 0 5 10 15 20 25 30 35 0.00 0.04 0.08 0.12 0.16 Crack Width (in) Read the entire page →
From page 421... ... 422 (b) SS Specimens Figure 12.1.18: Moment-crack width curves for static flexure and static flexure-shear specimens Figure 12.1.19 shows the crack width-fatigue cycle curves (CW-N) Read the entire page →
From page 422... ... 423 crack measured under service live load, 0.012 in. compared with 0.008 in. Read the entire page →
From page 424... ... 425 Figure 12.1.20: Transverse crack in FF-7 test (circled in red) Read the entire page →
From page 426... ... 427 (a) Flexure tests (b) Read the entire page →
From page 427... ... 428 12.1.12. Failure of Specimen As shown in Figure 12.1.23, the failure modes exhibited by the SF-O and FF-O specimens were typical flexural failures. Read the entire page →
From page 431... ... 432 static load tests. For the specimens with 7-day cure material in the joint, fatigue loading had negligible effect on the results for the flexure-shear tests. Read the entire page →

From page 391...

... 392 Chapter 12 Longitudinal Joint Details for Accelerated Bridge Construction: Fatigue Evaluation 12.0 Introduction Chapter 9 presented results of a preliminary study that assessed potential longitudinal and transverse joint connection details for CIP joints between DBTs or full-depth precast panel to panel connections. The investigation was conducted in two phases.