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From page 345... ... 343 8.1 introduction A jointless bridge has a continuous deck with no expansion joints over the superstructure, abutments, and piers. Jointless bridges are commonly referred to as integral bridges. Read the entire page →
From page 346... ... 344 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Use of integral bridges continues to increase both in the United States and abroad. Several countries adopting the practice are Japan (1996) Read the entire page →
From page 347... ... 345 Chapter 8. JOiNTLESS BRiDGES Figure 8.1. Read the entire page →
From page 348... ... 346 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE used to reduce the level of longitudinal forces that can be developed, while making the gap between the end of the transition zone and the start of pavement manageable (to less than about 0.25 in.) Read the entire page →
From page 349... ... 347 Chapter 8. JOiNTLESS BRiDGES • Easier and faster construction; • Easier inspection; • Simplified bridge details; • Elimination of bearings (except for semi-integral bridges) Read the entire page →
From page 350... ... 348 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE The important differences between an integral abutment and a traditional abutment with a jointed deck include a lack of expansion joint, no bearings, reduced number of required piles, reduced number of concrete pours, and inclusion of a sleeper slab. Taking these differences into consideration, the cost savings are readily apparent. Read the entire page →
From page 351... ... 349 Chapter 8. JOiNTLESS BRiDGES 0 20 40 60 80 100 Relative Total Cost Life of Bridge (yr.) Read the entire page →
From page 352... ... 350 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE If a curved bridge does not have either of these conditions, the response of the curved bridge can be estimated by the response of a straight bridge of the same length (Doust 2011) Read the entire page →
From page 353... ... 351 Chapter 8. JOiNTLESS BRiDGES 8.4.5 other Considerations Other factors that can affect the performance of jointless bridges are primarily associated with foundation conditions. Read the entire page →
From page 354... ... 352 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Another possible solution for use in conditions in which rock is close to surface is to drill large-diameter holes in the rock and use piles, which would consequently allow the use of typical integral abutment construction. It must be noted that the concepts of integral abutments supported on spread footings or supported on piles placed in holes drilled into rock are not common practice. Read the entire page →
From page 355... ... 353 Chapter 8. JOiNTLESS BRiDGES Where pile locations interfere with the reinforcement, specific methods for field installation must be developed. Read the entire page →
From page 356... ... 354 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Figure 8.5b illustrates use of pile encased in a pressure-relieving sleeve that isolates the pile movements from the surrounding soil. Hassiotis (2007) Read the entire page →
From page 357... ... 355 Chapter 8. Read the entire page →
From page 358... ... 356 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE tA B LE 8 .2 . Read the entire page →
From page 359... ... 357 Chapter 8. Read the entire page →
From page 360... ... 358 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.6 deSign ProviSionS For jointLeSS bridgeS Design procedures for integral abutment bridges can range from a simplified method of analysis to a more detailed approach. This section includes provisions for both. Read the entire page →
From page 361... ... 359 Chapter 8. JOiNTLESS BRiDGES 8.6.2 Detailed method of Analysis If the requirements for the simplified method of analysis are not met, the bridge must be analyzed using the detailed analysis approach. Read the entire page →
From page 362... ... 360 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.6.2.1.3 Soil Load on Abutment The magnitude of soil pressure behind the abutment wall and the nonlinear distribution of this pressure depend on wall displacement, soil type, depth, pile stiffness, and also the direction of the displacement (Faraji et al. Read the entire page →
From page 363... ... 361 Chapter 8. JOiNTLESS BRiDGES Figure 8.6. Read the entire page →
From page 364... ... 362 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Source: Clough and Duncan (1991) Read the entire page →
From page 365... ... 363 Chapter 8. Read the entire page →
From page 366... ... 364 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE The values for T1 and T2 are given in Table 8.6 and vary by solar radiation zone as determined from the map shown in Figure 8.13. The values in Table 8.6 are positive temperature values. Read the entire page →
From page 367... ... 365 Chapter 8. JOiNTLESS BRiDGES Source: LRFD Specifications Figure 3.12.2.2-4. Read the entire page →
From page 368... ... 366 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE When considering the temperature gradient in the section profile, the analysis should consider axial extension, flexural deformation, and internal stresses (LRFD specifications Article 4.6.6) Read the entire page →
From page 369... ... 367 Chapter 8. JOiNTLESS BRiDGES The consequence of a temperature gradient is flexural deformation, the development of curvature (f) Read the entire page →
From page 370... ... 368 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE t = maturity of concrete (day) , defined as age of concrete between time of loading for creep calculations, or end of curing for shrinkage calculations, and time being considered for analysis of creep or shrinkage effects; ti = age of concrete at time of load application (day) Read the entire page →
From page 371... ... 369 Chapter 8. JOiNTLESS BRiDGES This article states that if the concrete is exposed to drying before 5 days of curing have elapsed, the shrinkage as determined in Equation 8.11 should be increased by 20%. Read the entire page →
From page 372... ... 370 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.6.2.1.9 Wind Wind load needs to be considered in accordance with LRFD specifications Article 3.8. As with braking and centrifugal forces, longitudinal and transverse forces resulting from wind loads should also take into consideration the considerable stiffness of the integral abutments (see Section 8.6.2.1.2) Read the entire page →
From page 373... ... 371 Chapter 8. JOiNTLESS BRiDGES Because the effects of γTG are typically self-limiting and do not significantly affect strength or ductility at strength limit states for the types of bridge girders typically used in jointless bridges, γTG can commonly be taken as zero for the design of foundations in integral and semi-integral abutments. Read the entire page →
From page 374... ... 372 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.6.2.3.1 Displacement of Straight (Nonskew) Bridges Bridges expand and contract because of temperature changes and time-dependent volume changes associated with concrete creep and shrinkage. Read the entire page →
From page 375... ... 373 Chapter 8. JOiNTLESS BRiDGES The procedures presented in the following sections outline how to determine the maximum end movements of jointless bridges, including use of these Γ factors. Read the entire page →
From page 376... ... 374 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE where Dl = maximum end movement; eth = thermal strain; esh = shrinkage strain; ecr = creep strain; a = coefficient of thermal expansion; E = modulus of elasticity; A = cross-section area; l = length from the point of fixity to the end of the bridge. Note that for an unsymmetrical bridge two values of l are involved; and Γ = magnification factor to account for uncertainty listed in Table 8.10, where etotal = eth – esh – ecr for expansion, and etotal = –eth – esh – ecr for contraction. Read the entire page →
From page 377... ... 375 Chapter 8. JOiNTLESS BRiDGES For steel girder bridges, the same procedure as that used for prestressed concrete bridges should be used to calculate bridge end movements, except that the extreme effective bridge temperatures should be calculated using the recommendations of Section 8.6.2.1.5. Read the entire page →
From page 378... ... 376 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.6.2.4 Design of Pile Foundation The main steps in design of piles are as follows: • Based on subsurface explorations, develop a soil profile for the site. Details of strength profiles, compressibility characteristics, stress history, and geology of the subsurface materials should be included. Read the entire page →
From page 379... ... 377 Chapter 8. JOiNTLESS BRiDGES 8.6.2.4.1 Pile Orientation: Straight and Curved Bridges Abutment piles of straight bridges should be oriented so that the strong axis of the piles is perpendicular to the longitudinal direction of the bridge (Doust 2011) Read the entire page →
From page 380... ... 378 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE two HP piles (HP 10x57 and HP 12x84) and four soil conditions. Read the entire page →
From page 381... ... 379 Chapter 8. JOiNTLESS BRiDGES 8.6.2.4.2a Geotechnical Axial Resistance The axial nominal resistance of a pile is the sum of its tip and friction resistance minus the weight of the pile, as shown by Equation 8.18: Q Q Q Ws tnom = + − (8.18) Read the entire page →
From page 382... ... 380 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Tensile loading for a foundation design is well covered in the LRFD specifications, which provide guidance to design against uplift for both single piles and pile groups. The design of single piles, drilled shafts, and micropiles in groups is addressed in Articles 10.7.3, 10.8.3, and 10.9, respectively. Read the entire page →
From page 383... ... 381 Chapter 8. JOiNTLESS BRiDGES • The state of stress and strain throughout the affected soil zone; and • The rate sequence and history of load cycles. Read the entire page →
From page 384... ... 382 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.6.2.5.3 Micropiles Micropiles may be a viable option for jointless bridges. Note that micropiles, similar to regular piling, should only be used in a single row for integral abutments. Read the entire page →
From page 385... ... 383 Chapter 8. Read the entire page →
From page 386... ... 384 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE It follows then that the maximum stress on the concrete cap is the combined resultant of the bending and shear stresses (fcb1) , as shown in Equation 8.22: = +f f V a bcb cb p1 2 (8.22) Read the entire page →
From page 387... ... 385 Chapter 8. JOiNTLESS BRiDGES Figure 8.20. Read the entire page →
From page 388... ... 386 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.6.2.6.3 Seamless Details The design of the pile cap for a seamless bridge should follow the same procedure as for integral abutment bridges. 8.6.2.7 Design of End Diaphragm (Backwall) Read the entire page →
From page 389... ... 387 Chapter 8. JOiNTLESS BRiDGES Figure 8.23. Read the entire page →
From page 390... ... 388 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE for backfill settlement exists. Backfill settlement will occur and introduce voids regardless of the degree of compaction and must be considered in design (Schaefer and Koch 1992) Read the entire page →
From page 391... ... 389 Chapter 8. JOiNTLESS BRiDGES Figure 8.24. Read the entire page →
From page 392... ... 390 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.6.2.9 Design of Superstructure–Pier Connection By definition, bridge decks in jointless bridges are continuous, including the region over the piers. The connection between the piers and the bridge deck could be integral, pinned, or expansion types, or they could be connected with a link slab. Read the entire page →
From page 393... ... 391 Chapter 8. JOiNTLESS BRiDGES Figure 8.27. Read the entire page →
From page 394... ... 392 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Figure 8.28. Read the entire page →
From page 395... ... 393 Chapter 8. JOiNTLESS BRiDGES 8.6.2.9.2 Fixed (Pinned) Read the entire page →
From page 396... ... 394 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE secondary positive moments at the piers. Most importantly, positive moment reinforcement should be designed and detailed such that any cracking, if it occurs, should be limited to the relatively less critical diaphragm region of this type of structural system." Further discussion of this problem and solutions to avoid it have been published by Oesterle et al. Read the entire page →
From page 397... ... 395 Chapter 8. JOiNTLESS BRiDGES were somewhat larger than the measured crack widths. Read the entire page →
From page 398... ... 396 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE fixed point to the pier to the distance from fixity to the end support. Second, assume that 30% of the expected lateral deflection is accommodated by the foundation rotation. Read the entire page →
From page 399... ... 397 Chapter 8. JOiNTLESS BRiDGES For integral and seamless bridges, additional considerations for wingwalls include the loading effect they have on the bridge structure. Read the entire page →
From page 400... ... 398 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Figure 8.32. General integral abutment concept. Read the entire page →
From page 401... ... 399 Chapter 8. JOiNTLESS BRiDGES Figure 8.33. Read the entire page →
From page 402... ... 400 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE Figure 8.34 is an adaptation from an Ohio DOT standard drawing showing a prestressed concrete beam. A standard detail for most prestressed girders includes providing holes through the beam for reinforcing. Read the entire page →
From page 403... ... 401 Chapter 8. JOiNTLESS BRiDGES a bent hook bar connecting the approach slab, but Figure 8.35 shows that continuity is maintained by a straight bar connecting the approach slab to the deck; and (2) Read the entire page →
From page 404... ... 402 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE may be cast level and the superstructure superelevation can be accommodated through the use of bearing pedestals. The second method is to step the pile cap. Read the entire page →
From page 405... ... 403 Chapter 8. JOiNTLESS BRiDGES polystyrene filler surrounding the bearings. Read the entire page →
From page 406... ... 404 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.7.3 Sleeper Slab A sleeper slab is appropriate for all integral or semi-integral bridges and is placed at the roadway end of the approach slab. The intent of this slab is to provide a relatively solid foundation for the far end of the approach slab and to provide a location for limited expansion and contraction (see Figure 8.39) Read the entire page →
From page 407... ... 405 Chapter 8. JOiNTLESS BRiDGES Figure 8.40. Read the entire page →
From page 408... ... 406 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.7.4 Details for Skewed and Curved Bridges Transverse movements of integral abutments associated with large skews or horizontal curves should be accommodated by the details for barrier walls, drainage structures, and the ends of the approach slabs. In addition, the foundation and pier structure stiffness will likely be significant for movement parallel to the pier cap. Read the entire page →
From page 409... ... 407 Chapter 8. JOiNTLESS BRiDGES Horizontal cracks and efflorescence have been found on the forward face of integral abutments at the construction joint on top of the pile cap. Read the entire page →
From page 410... ... 408 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.8.5 fill Compaction Construction can follow normal compaction procedures as specified by the owner agency except as noted in the section on construction sequencing. Fill compaction has been modified and adjusted using several variables, including the use of specialized material. Read the entire page →
From page 411... ... 409 Chapter 8. JOiNTLESS BRiDGES of the semi-integral bridge concept will be improved when bearing manu facturers and bridge design engineers combine their expertise to design and manufacture more functional structure movement systems for these applications. Read the entire page →
From page 412... ... 410 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE 8.9.2 Deck Replacement Figure 8.42 shows what can happen when the proper procedures and sequences for deck replacement and integral abutment backfilling are not followed. It should be anticipated that large compressive forces are acting on the whole structure as a result of soil pressure on the abutments and restrained expansion of the girders. Read the entire page →
From page 413... ... 411 Chapter 8. JOiNTLESS BRiDGES 8.10 retroFitS A large percentage of existing bridges are simple-span bridges that rely on expansion joints at piers and abutments to accommodate longitudinal movements. Read the entire page →
From page 414... ... 412 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE associated with such behavior is preferred over the long-term consequences associated with open movable deck joints or poorly executed joint seals. 8.10.2 Details over the Abutment For existing stub abutments with a single row of piles, the following procedure (shown in Figure 8.44) Read the entire page →
From page 415... ... 413 Chapter 8. JOiNTLESS BRiDGES Figure 8.44. Read the entire page →
From page 416... ... 414 DESiGN GUiDE FOR BRiDGES FOR SERviCE LiFE The state of New Mexico has presented several case studies (Maberry et al. Read the entire page →

From page 345...

... 343 8.1 introduction A jointless bridge has a continuous deck with no expansion joints over the superstructure, abutments, and piers. Jointless bridges are commonly referred to as integral bridges.