Cyclic behavior of precast segmental concrete bridge columns with high performance or conventional steel reinforcing bars as energy dissipation bars

Abstract

The cyclic behavior of precast segmental concrete bridge columns with high performance (HP) steel reinforcing bars and that with conventional steel reinforcing bars as energy dissipation (ED) bars were investigated. The HP steel reinforcing bars are characterized by higher strength, greater ductility, and superior corrosion resistance compared with the conventional steel reinforcing bars. Three large-scale columns were tested. One was designed with the HP ED bars and two with the conventional ED bars. The HP ED bars were fully bonded to the concrete. The conventional ED bars were fully bonded to the concrete for one column, whereas unbonded for a length to delay fracture of the bars and to increase energy dissipation for the other column. Test results showed that the column with the HP ED bars had greater drift capacity, higher lateral strength, and larger energy dissipation than that with fully bonded conventional ED bars. The column with unbonded conventional ED bars achieved the same drift capacity and similar energy dissipation capacity as that with the HP ED bars. All the three columns showed good self-centering capability with residual drifts not greater than 0.4% drift. An analytical model referred to as joint bar-slip rotation method for pushover analysis of segmental columns with ED bars is proposed. The model calculates joint rotation from the slip of the ED bars from two sides of the joint. Good agreement was found between analytical predictions and the envelope responses of the three columns.CYCLIC BEHAVIOR OF SEGMENTAL COLUMNS WITH HP 1189 second, and third terms of Equation (8) represent displacements resulting from joint bar-slip rotations, shear deformations, and elastic flexural rotations, respectively.

Simplified Analytical Pushover Method for Precast Segmental Concrete Bridge Columns

“…The mild steel deformed bars through segment joints are called energy dissipation (ED) bars to distinguish them from the mild steel reinforcement staying within segments. Relevant studies on the reinforced concrete system can be found in Hieber et al (2005) and Matsumoto et al (2002), studies on the bonded posttensioning system can be found in Arai et al (2006), Shim et al (2008) and Wang et al (2008b), studies on the unbonded posttensioning system can be found in Hewes and Priestley (2002), Billington and Yoon (2004), and Chou and Chen (2006), and studies on the hybrid system can be found in Palermo et al (2007) and Ou et al (2010a).…”

Experimental test and seismic performance of partial precast concrete segmental bridge column with cast-in-place base

“…Several techniques have been developed to improve their seismic performance by increasing their energy dissipation capacity. The most popular approach to increase the energy dissipation capacity of the columns is the use of metallic yielding components at the base of the columns, such as mild steel bars [6,7], high-performance steel bars [8], exterior yielding braces [3,9], and shape memory alloy bars [10,11]. Steel or FRP jackets [12,13], ductile fiber-reinforced concrete [14], and ultra-high performance steel fiber concrete (UFC) segments [15] have also been adopted at the base of the columns, as well as non-metallic devices such as rubber pads [3], elastomeric bearing pads [13,16], and steel shear resistant connecting across segment joints including the base of the column [17].…”

Axial compression ratio limit for self‐centering precast segmental hollow piers

“…Mild steel reinforcements are usually disconnected across the joints and transverse reinforcements in segments are expected to control shrinkage and creep. However, precast segmental piers are limited in moderate and high seismicity due to incomprehension on their seismic performance …”

“…A hybrid connection incorporating unbonded PT and mild reinforcing steel across segmental joints was conceptually recommended to connect between precast piers and CIP foundation, which was proved to increase self‐centering capacity and ED capacity by cyclic loading tests . Those bars across segmental joints were referred to as ED bars, which were suggested to have a unbonded length and adopt high performance steel reinforcing bars to avoid premature fracture . More ED solutions were proposed for precast segmental piers, such as external mild steel ED device, friction ED caused by sliding of segment joints, external viscous damping device, and so on .…”