Experimental testing of hybrid sliding‐rocking bridge columns under torsional and biaxial lateral loading

Abstract

Hybrid sliding-rocking (HSR) bridge columns are precast concrete segmental columns with unbonded posttensioning, end rocking joints, and intermediate sliding joints. Having been developed for construction in seismic regions, HSR columns offer self-centering, energy dissipation, and low damageability. Recent advances in the computational modeling of HSR columns have resulted in the proposal of a number of refinements to their original design, leading to the introduction of Second-Generation HSR columns. Compared to First-Generation HSR columns, Second-Generation HSR columns use a reduced number of sliding joints made of high-performance polytetrafluoroethylene (PTFE) materials to provide desirable levels of sliding and frictional energy dissipation. The seismic performance of Second-Generation HSR columns was recently investigated through an extensive experimental study. The present paper discusses the major results of the tests performed on two half-scale HSR column specimens under combined lateral-torsional loading and biaxial lateral loading to demonstrate their performance under such loading scenarios. A variety of loading protocols were used to test each column specimen, including both cyclic and arbitrary paths. Both columns sustained minimal damage under displacement demands representing 975-and 2475-year seismic hazards, meeting their design objectives.Because of the torsional sliding at sliding joints, the column subjected to lateraltorsional loading did not exhibit any distinct torsional damage. The biaxial lateral loading was, however, found more damaging to HSR columns than torsional and uniaxial lateral loading.

State-of-the-art review of the seismic performance of precast segmental columns

“…Overall, it was found that the sliding between the segments significantly contributed to the energy dissipation of the column. Further study was carried out to investigate the seismic performance of the sliding-rocking columns under torsional and biaxial loading (Salehi et al 2021b).…”

“…In 2009, Yamashita and Sanders (2009) conducted shake table tests on a 1/4 Fig. 8 Concept of sliding-rocking PSC (Salehi et al 2021b) scale PSC model on the shake table. The column had the geometry dimensions of 1016 mm × 457 mm × 2082 mm (length×width×height).…”

Seismic response of benchmark high-speed rail (HSR) round-ended rectangular-shaped cross-section solid (RERSCSS) concrete pier based on the shaking table tests

“…Then, the set-up allows large-scale models to be tested on the shake table system. The large-scale samples can then be studied without compromising the safety of the shake table system 18 .…”

“…Recently, more and more earthquake researchers have realized that the results, i. e., buildings' collapse resistance, are still quite skeptical after adopting the maximum considered earthquake (MCE) seismic design. Salehi et al 18 investigated the seismic performance of Second-Generation Hybrid sliding-rocking bridge columns through an extensive experimental study. The column specimen tested under combined lateral-torsional loading sustained minimal damage (i.e., sparse hairline cracks) under the peak drift ratios up to 2% (representing a 2475-year seismic hazard).…”

Self-centering seismic-resistant structures: Historical overview and state-of-the-art

“…Results of shake table tests on a large-scale bridge specimen validated the use of this hybrid sliding–rocking concept to enhance the seismic performance of bridges (Sideris et al, 2014a, 2015). Design objectives and equations were also elaborated for this concept based on quasi-static lateral cyclic tests at large drift ratios (Salehi et al, 2021; Sideris et al, 2014b) and numerical studies (Salehi et al, 2017).…”