Seismic Study of Application of Lead Rubber Bearings in Kutai Kartanegara Steel Arch Bridge

Abstract

The basic concept of the application of base isolation is by extending the natural period of the structure in order to provide lower seismic acceleration. The paper focuses on the investigation of the application of lead-rubber bearings (LRBs) instead of pot bearings in a new Kutai Kartanegara steel arch bridge located in East Kalimantan province. Even though the bridge is known located in Seismic Zone 1 (the zone with the least seismic risk as per SNI 2833-2013), the study was extended for other higher risk seismic zones, namely Seismic Zones 2, 3, and 4. With the aid of Midas software, the analyses of the bridge structures were carried out and it can be concluded that the higher the seismic risk, the more effective the use of LRBs in dissipating the earthquake energy before transmitting to the bridge superstructure. The reductions of seismic base shears obtained from the analyses were between 23.10 and 44.67 percent and 17.07 and 31.47 percent in the longitudinal and transverse directions, respectively. However, the application of LRBs has a consequence of increasing the horizontal displacements of the bridge, which can be solved by introducing either larger expansion joints or passive dampers. In order to validate the seismic responses, the bridge was analyzed using Time History Analysis (THA) by imposing seven earthquake ground motions, which were scaled to a spectral design of Padang as a requirement by the Indonesian code.

Structural Systems Comparison of Simply Supported PSC Box Girder Bridge Equipped with Elastomeric Rubber Bearing and Lead Rubber Bearing

“…A numerical study by Edalathi and Tahghighi [8] showed that the application of LRB instead of ERB increased the structural flexibility, significantly reduced the base shear, bending moment, deck acceleration, pier displacement, and earthquake input energy of a continuous box girder bridge. Another study also showed that LRB significantly reduced the base shear of the suspension bridge [9] and the pier displacement of the continuous box girder bridge [10].…”

Hysteresis Loops of Base Isolation System - An Overview

“…Lately, this technology is used not only for structures of high importance but also for residential and low-rise buildings. The efficiency of base isolator depends on the amount of energy dissipated by the isolator, the flexibility of superstructure, efficiency of base isolator [6], and the ratio of base isolation mass to superstructure mass. The effect on the efficiency of base isolation and dissipation of hysteretic energy has an indirect relation with the post to pre-yield stiffness of base isolator [7].…”

“…Vasant et al [35] had studied the difference between a bi-linear model and an equivalent linear elastic-viscous damping model of the base isolation. The parameters of hysteresis loops in the bilinear model of base isolation have a significant influence on the response of base-isolated structure which did not portray the equivalent linear model of base isolation [35]. Azawi et al [36] had modeled the base isolation as a two spring and a deep beam where the energy dissipation of their model been assumed as equivalent viscous damping.…”