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From page 5... ... 5 2.1 Introduction Accelerated bridge construction (ABC) , an approach that utilizes new technologies, novel detailing, and enhanced planning, is expected to address key objectives of Federal Highway Administration (FHWA) Read the entire page →
From page 6... ... 6 Proposed AASHTO Seismic Specifications for ABC Column Connections A state-of-the-art literature review of the first three of these types of connections is presented in this chapter. Two of the excluded connections, connections with advanced materials and rocking connections, are emphasized in NCHRP Research Report 864 (Saiidi et al. Read the entire page →
From page 7... ... State-of-the-Art Literature Review 7 (a) Shear screw coupler (ancon.co.uk) Read the entire page →
From page 8... ... 8 Proposed AASHTO Seismic Specifications for ABC Column Connections mechanical bar splices available in the U.S. market, identifies their limitations, and provides information regarding bar end preparation and coupler configurations, but does not provide specifications or acceptance criteria. Read the entire page →
From page 9... ... State-of-the-Art Literature Review 9 screws to link the coupler to each bar. Read the entire page →
From page 10... ... 10 Proposed AASHTO Seismic Specifications for ABC Column Connections elongation was reduced to 3% in comparison to 10% for the control bars. At high strain rate, bars either ruptured inside the coupler or pulled out from the coupler (Figure 2-4c) Read the entire page →
From page 11... ... State-of-the-Art Literature Review 11 showed that the full ultimate strength of both deformed and smooth bars can be achieved. The bars fractured outside the splice in all specimens. Read the entire page →
From page 12... ... 12 Proposed AASHTO Seismic Specifications for ABC Column Connections of the bars because of the stress concentration under the screws. This limitation is critical for seismic applications, especially in the plastic hinge region, where large deformations are expected. Read the entire page →
From page 13... ... State-of-the-Art Literature Review 13 (a) Original column after testing (b) Read the entire page →
From page 14... ... 14 Proposed AASHTO Seismic Specifications for ABC Column Connections column with longer SSC couplers showed higher drift capacity and higher strength as compared with the reference test model. The limited drift capacity of the columns with short SSCs was attributed to the insufficient strain capacity of the short SSCs. Read the entire page →
From page 15... ... State-of-the-Art Literature Review 15 relationships of the repaired and original columns. The repaired column exhibited a displacement ductility capacity of 4.9, which was 4% higher than that of the original column. Read the entire page →
From page 16... ... 16 Proposed AASHTO Seismic Specifications for ABC Column Connections 2.2.4 Headed Bar Couplers 2.2.4.1 Performance of Headed Bar Couplers To splice bars with headed bar couplers (HCs) , each bar is heated and the bar end is flattened to form a head. Read the entire page →
From page 17... ... State-of-the-Art Literature Review 17 under cyclic loading protocols. The mode of failure was bar fracture outside the couplers in all specimens (Figure 2-15) Read the entire page →
From page 18... ... 18 Proposed AASHTO Seismic Specifications for ABC Column Connections hysteretic relationships for the original and the repaired columns are shown in Figure 2-16b. It can be seen that the lateral strength in the repaired column was higher and the displacement capacity was improved as compared with the original column. Read the entire page →
From page 19... ... State-of-the-Art Literature Review 19 (c) HCNP plastic hinge region (d) Read the entire page →
From page 20... ... 20 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) Shape memory alloy steel bar cage (b) Read the entire page →
From page 21... ... State-of-the-Art Literature Review 21 built with 1.0 Dc long SMA bars (Dc is the column side dimension) and another column (called SR99-SSE) Read the entire page →
From page 22... ... 22 Proposed AASHTO Seismic Specifications for ABC Column Connections tensile loading to fracture. The average ultimate load for GCs was comparable to that of the control bars. Read the entire page →
From page 23... ... State-of-the-Art Literature Review 23 strain rates, the average yield and the ultimate loads for GCs matched those of the control bars (Figure 2-22c) Read the entire page →
From page 24... ... 24 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) Slow strain rate tests (b) Read the entire page →
From page 25... ... State-of-the-Art Literature Review 25 dynamic testing. The loading rate had negligible effects on the coupler performance, and the ultimate capacities of the bars were developed. Read the entire page →
From page 26... ... 26 Proposed AASHTO Seismic Specifications for ABC Column Connections Study Bar Size Bar Type Mode of Failure Remarks Noureddine (1996) Read the entire page →
From page 27... ... State-of-the-Art Literature Review 27 (a) GCNP or GCPP drawing (b) Read the entire page →
From page 28... ... 28 Proposed AASHTO Seismic Specifications for ABC Column Connections this detailing would be difficult for bridge columns, owing to size of the ducts and large number of reinforcing bars that are needed in bridge columns. A summary of the findings from experimental studies of columns with GCs is presented in Table 2-7. Read the entire page →
From page 29... ... Source: Noureddine (1996) Read the entire page →
From page 30... ... 30 Proposed AASHTO Seismic Specifications for ABC Column Connections The average yield and the ultimate loads for both coupler types were comparable to those of the reference bars at the slow strain rate. For tapered TCs, the average maximum strain was 11% as compared with 10% measured for the control bars. Read the entire page →
From page 31... ... State-of-the-Art Literature Review 31 (a) Shape memory alloy steel cage (b) Read the entire page →
From page 32... ... 32 Proposed AASHTO Seismic Specifications for ABC Column Connections in the column plastic hinge was removed after testing to locate the bar fracture. It was found that both SMA bars fractured away from the TCs as shown in Figure 2-31b. Read the entire page →
From page 33... ... State-of-the-Art Literature Review 33 and that column performance with tapered TCs is yet to be studied. Furthermore, the SMA bars were machined in a dog-bone shape in these studies to shift the yielding outside the coupler region. Read the entire page →
From page 34... ... 34 Proposed AASHTO Seismic Specifications for ABC Column Connections displacement ductility capacity of 2.4, which was 59% lower than that of the original column. The low displacement ductility of the repaired column was because of early termination of the test owing to rupture of the FRP jacket under torsional loading. Read the entire page →
From page 35... ... State-of-the-Art Literature Review 35 Reference Column Geometry Coupler Length Remarks Yang et al. Read the entire page →
From page 36... ... 36 Proposed AASHTO Seismic Specifications for ABC Column Connections precast columns incorporating GCs (Utah DOT 2010; Florida DOT 2019) Read the entire page →
From page 37... ... State-of-the-Art Literature Review 37 provided by the duct. Subsequently, Matsumoto et al. Read the entire page →
From page 38... ... 38 Proposed AASHTO Seismic Specifications for ABC Column Connections Source: Matsumoto et al. Read the entire page →
From page 39... ... State-of-the-Art Literature Review 39 The authors proposed a design equation for the embedment length (ld) of the bar in the groutfilled duct connection, as follows: max 8 ,12 in., 180 , 45 (2-2) Read the entire page →
From page 40... ... 40 Proposed AASHTO Seismic Specifications for ABC Column Connections is in contrast to the radial bond cracks observed in pullout test of bars in concrete with no ducts. The lack of longitudinal and radial cracks showed that the duct provided sufficient confinement around the bar to prevent splitting of the grout. Read the entire page →
From page 41... ... State-of-the-Art Literature Review 41 db = bar diameter (in.) , f g′ = grout compressive strength (psi) Read the entire page →
From page 42... ... 42 Proposed AASHTO Seismic Specifications for ABC Column Connections at low drift levels but did not delay the bar fracture as intended. It also had a minor effect on the overall hysteretic performance of the column. Read the entire page →
From page 43... ... State-of-the-Art Literature Review 43 stiffness of Specimen AD8-D2 was lower than that of the other two due to the flexibility added to the connection because of the debonding of the bars. The yield plateau and the strain hardening region of Specimen AD8-FB were shorter than those measured in the other two specimens because the bar was fully bonded in the ducts (Figure 2-43a) Read the entire page →
From page 44... ... 44 Proposed AASHTO Seismic Specifications for ABC Column Connections the column, footing starter bars are anchored in the ducts, and the ducts are grouted after the column installation. Even though seismic behavior similar to that of the reference specimens was reported in the study, the application of this detail would be impractical for bridge columns, owing to the size of the ducts and the large number of reinforcing bars that are typically used in bridge columns. Read the entire page →
From page 45... ... State-of-the-Art Literature Review 45 fs = bar stress (psi) (1.5fy or fu, whichever is greater, using expected properties, where fy = yield strength of anchoring bar and fu = ultimate strength of anchoring bar) Read the entire page →
From page 46... ... 46 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) Connection detail (b) Read the entire page →
From page 47... ... State-of-the-Art Literature Review 47 be considered as an alternative to CIP connections in high-seismic regions for connecting precast columns to shallow cap beams and footings. However, when the footing or cap beam depth is sufficient, high-strength grouts may be used in lieu of UHPC. Read the entire page →
From page 48... ... 48 Proposed AASHTO Seismic Specifications for ABC Column Connections development length for the bars ranged from 6 in. Read the entire page →
From page 49... ... State-of-the-Art Literature Review 49 column longitudinal bars fractured at high-amplitude earthquake motions, which indicated that the GD connections were able to anchor the bars fully. The peak drift ratio capacity of the bridge exceeded 10%, and the residual drifts were insignificant because of prestressing of the columns. Read the entire page →
From page 50... ... 50 Proposed AASHTO Seismic Specifications for ABC Column Connections Reference Test Variables Design Equation Remarks Matsumoto et al. Read the entire page →
From page 51... ... State-of-the-Art Literature Review 51 Reference Column Geometry Duct and Filler Remarks Matsumoto et al. Read the entire page →
From page 52... ... 52 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) Lake Belton Bridge, Texas (b) Read the entire page →
From page 53... ... State-of-the-Art Literature Review 53 Bar pullout and concrete breakout failure were observed in pocket specimens for straight and headed bars, respectively. The following design embedment length (Lemd) Read the entire page →
From page 54... ... 54 Proposed AASHTO Seismic Specifications for ABC Column Connections A safety factor of 1.7 was included in this equation to account for the bar overstrength capacity and the concrete strength reduction factor. A column connected to a precast cap beam by a double-line pocket system was tested by Matsumoto et al. Read the entire page →
From page 55... ... State-of-the-Art Literature Review 55 13%, as compared with 6.7% in CIP. The post-tensioning did not improve the column peak drift capacity, but led to smaller residual displacements. Read the entire page →
From page 56... ... 56 Proposed AASHTO Seismic Specifications for ABC Column Connections (c) Damage to Column CPFD plastic hinge (d) Read the entire page →
From page 57... ... State-of-the-Art Literature Review 57 of 8, which exceeded the ductility of the CIP column. The test results illustrated close correlation between the CIP column and CPLD in terms of stiffness, strength, and ductility. Read the entire page →
From page 58... ... 58 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) Bent detail (b) Read the entire page →
From page 59... ... State-of-the-Art Literature Review 59 and the pockets were cast at the same time around the embedded portion of the column. The damage of the column–shaft connections is shown in Figure 2-58, a and b. Read the entire page →
From page 60... ... 60 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) DS-1 pile shaft–column damage (b) Read the entire page →
From page 61... ... State-of-the-Art Literature Review 61 loading tests, SF-1 and SF-2 were loaded axially to failure. In both columns, the concrete in the plastic hinge failed in compression with no damage to the pocket connection. Read the entire page →
From page 62... ... 62 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) Bent detail Source: Kavianipour and Saiidi (2013) Read the entire page →
From page 63... ... State-of-the-Art Literature Review 63 to displacement ductility values of 9.36 and 8.36 without failure. The tests had to be terminated at this point to avoid overloading the shake table system. Read the entire page →
From page 64... ... 64 Proposed AASHTO Seismic Specifications for ABC Column Connections the damage to Pile C was more concentrated to the connection between the pile and the cap. Damage to the cap beam was limited to some minor spalling of concrete in the cap beam about the perimeter of the exterior connections. Read the entire page →
From page 65... ... State-of-the-Art Literature Review 65 Source: Larosche et al. Read the entire page →
From page 66... ... 66 Proposed AASHTO Seismic Specifications for ABC Column Connections column bases they had developed. The bent detail is shown in Figure 2-63a. Read the entire page →
From page 67... ... State-of-the-Art Literature Review 67 the pockets to a depth of 1.2Dc. The space between the column and the pocket was filled with high-strength, nonshrinkage grout. Read the entire page →
From page 68... ... 68 Proposed AASHTO Seismic Specifications for ABC Column Connections columns was 20 in. Read the entire page →
From page 69... ... State-of-the-Art Literature Review 69 multirun uniaxial shake table tests. The apparent damage to the plastic hinge was minimal (Figure 2-67c) Read the entire page →
From page 70... ... 70 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) BPSA bent detail (b) Read the entire page →
From page 71... ... State-of-the-Art Literature Review 71 (continued on next page) Reference Connection Column Geometry Embedded Length Remarks Matsumoto et al. Read the entire page →
From page 72... ... 72 Proposed AASHTO Seismic Specifications for ABC Column Connections Reference Connection Column Geometry Embedded Length Remarks Haraldsson et al. Read the entire page →
From page 73... ... State-of-the-Art Literature Review 73 Reference Connection Column Geometry Embedded Length Remarks Thonstad et al. Read the entire page →
From page 74... ... (a) Column–cap beam, Texas (b) Read the entire page →
From page 75... ... State-of-the-Art Literature Review 75 (a) Top pipe pin to transfer shear and compressive axial loads (b) Read the entire page →
From page 76... ... 76 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) Details of pipe shear lug (b) Read the entire page →
From page 77... ... State-of-the-Art Literature Review 77 Source: Doyle and Saiidi (2008) Read the entire page →
From page 78... ... 78 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) Push loading b) Read the entire page →
From page 79... ... State-of-the-Art Literature Review 79 (c) Reinforced concrete column pipe-pin damage (d) Read the entire page →
From page 80... ... 80 Proposed AASHTO Seismic Specifications for ABC Column Connections Socket Connections" (Figure 2-60) Read the entire page →
From page 81... ... State-of-the-Art Literature Review 81 (38-mm) -diameter high-strength threaded rod anchored by square bearing plates at the ends in the column and the footing. Read the entire page →
From page 82... ... 82 Proposed AASHTO Seismic Specifications for ABC Column Connections except that the tensile force was resisted through two end plates installed on the pipe ends as well as welded studs on each pipe surface. The new pipe-pin detail showed excellent performance during the test. Read the entire page →
From page 83... ... State-of-the-Art Literature Review 83 2.5.3 Summary of Pipe-Pin Connection Tests A summary of the seismic performance of bridge columns incorporating either top or base pipe-pin connections is presented in Table 2-15. 2.5.4 Pipe-Pin Connection Field Application The top pipe pin connections have been used in practice in several bridge columns including approach ramps of the replacement of the San Francisco–Oakland Bay Bridge (Figure 2-78) Read the entire page →
From page 84... ... 84 Proposed AASHTO Seismic Specifications for ABC Column Connections (a) Column top (b) Read the entire page →
From page 85... ... State-of-the-Art Literature Review 85 (a) Column details (b) Read the entire page →
From page 86... ... 86 Proposed AASHTO Seismic Specifications for ABC Column Connections Source: Tazarv and Saiidi (2015a) Read the entire page →
From page 87... ... State-of-the-Art Literature Review 87 Overall, 560 analyses were carried out in the study. Figure 2-82 shows a sample result. Read the entire page →
From page 88... ... Source: Tazarv and Saiidi (2015a) Read the entire page →
From page 89... ... State-of-the-Art Literature Review 89 Pertold et al. Read the entire page →
From page 90... ... 90 Proposed AASHTO Seismic Specifications for ABC Column Connections European steel section HEB 300 (height of section = 300 mm) but with different embedment lengths. Read the entire page →
From page 91... ... State-of-the-Art Literature Review 91 Source: Mehrsoroush and Saiidi (2014) Read the entire page →
From page 92... ... 92 Proposed AASHTO Seismic Specifications for ABC Column Connections 2. Because the current AASHTO and Caltrans design documents ban couplers in plastic hinges of columns in moderate- and high-seismic zones (Table 2-1) Read the entire page →
From page 93... ... State-of-the-Art Literature Review 93 of the grout also failing if the grout is not sufficiently strong (Figure 2-87d) Read the entire page →
From page 94... ... 94 Proposed AASHTO Seismic Specifications for ABC Column Connections Columns with Grouted Duct Connections. Table 2-13 presents a summary of the seismic performance of column test models that incorporate grout-filled duct connections. Read the entire page →
From page 95... ... State-of-the-Art Literature Review 95 members. The minimum and maximum clear distances between the mechanical splices are recommended to be the same as those specified for reinforcing steel bars. Read the entire page →
From page 96... ... 96 Proposed AASHTO Seismic Specifications for ABC Column Connections Depending on the pocket and column detailing, the construction sequence may be slightly different. Providing sufficient tolerance for the installation of precast cap beams is particularly critical in multicolumn bents. Read the entire page →
From page 97... ... State-of-the-Art Literature Review 97 to footings and cap beams. The table also includes the critical parameters that need further investigation for the development of guidelines. Read the entire page →
From page 98... ... 98 Proposed AASHTO Seismic Specifications for ABC Column Connections Huaco, G Read the entire page →
From page 99... ... State-of-the-Art Literature Review 99 Pecce, M., and Rossi, F Read the entire page →
From page 100... ... 100 Proposed AASHTO Seismic Specifications for ABC Column Connections Zaghi, A E., and Saiidi, M Read the entire page →

From page 5...

... 5 2.1 Introduction Accelerated bridge construction (ABC) , an approach that utilizes new technologies, novel detailing, and enhanced planning, is expected to address key objectives of Federal Highway Administration (FHWA)