Optimum characteristic properties of isolators with bilinear force-displacement hysteresis for seismic protection of bridges built on various site soils

2011-07-01
In this study, closed form equations as functions of the isolator, bridge and ground motion properties are formulated to calculate the optimum characteristic strength, Q(d) and post-elastic stiffness, k(d), of the isolator to minimize the maximum isolator displacement (MID) and force (MIF) for seismic isolated bridges (SIBS). For this purpose, first, sensitivity analyses are conducted to identify the bridge, isolator and ground motion parameters that affect the optimum values of Q(d) and k(d). Next, for the identified parameters, nonlinear time history analyses of typical SIBs are conducted to determine the optimum values of Q(d) and k(d) for a wide range of values of the parameters. Next, nonlinear regression analyses of the available data are conducted to obtain closed form equations for the optimum values of Q(d) and k(d), to minimize the MID and MIF. The equations are then simplified for various site soil conditions. It is observed that the optimum Q(d) and k(d) are highly dependent on the site soil condition. Furthermore, the optimum Q(d) is found to be a linear function of the peak ground acceleration.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING

Suggestions

Optimum Properties of Seismic Isolation Systems in Highway Bridges to Minimize Isolator Displacements or Substructure Forces
Dicleli, Murat (null; 2019-07-06)
In this study, closed form equations as functions of the isolator, bridge and ground motion properties are formulated to calculate the optimum characteristic strength, Qd and post-elastic stiffness, kd, of the isolator to minimize the maximum isolator displacement (MID) and force (MIF) for seismic isolated bridges (SIBs). For this purpose, first, sensitivity analyses are conducted to identify the bridge, isolator and ground motion parameters that affect the optimum values of Qd and kd. Next, for the identif...
Spatial sensitivity of seismic hazard results to different background seismic activity and temporal earthquake occurrence models
Yilmaz, Nazan; Yücemen, Mehmet Semih (Elsevier BV, 2011-07-01)
Spatial sensitivity of seismic hazard results to different models with respect to background seismic activity and earthquake occurrence in time is investigated. For the contribution of background seismic activity to seismic hazard, background area source with uniform seismicity and spatially smoothed seismicity models are taken into consideration. For the contribution of faults, through characteristic earthquakes, both the memoryless Poisson and the time dependent renewal models are utilized. A case study, ...
Optimum design of rigid and semi-rigid steel sway frames including soil-structure interaction
Doğan, Erkan; Saka, M. Polat; Department of Engineering Sciences (2010)
In this study, weight optimization of two dimensional steel frames is carried out in which the flexibility of beam-to-column connections and the soil-structure interaction are considered. In the analysis and design of steel frames, beam-tocolumn connections are assumed to be either fully rigid or perfectly pinned. However, the real behavior of beam-to-column connections is actually between these extremes. Namely, even the simple connections used in practice possess some stiffness falling between these two c...
Optimum design of seismic isolation systems using metaheuristic search methods
ÇERÇEVİK, ALİ ERDEM; Avsar, Ozgur; Hasançebi, Oğuzhan (Elsevier BV, 2020-04-01)
This study addresses the optimum design of seismic isolated structures via metaheuristic search methods. Three recently developed bio-inspired search methods, namely crow search (CSA), whale optimization (WOA) and grey wolf optimizer (GWO), were employed to develop efficient design optimization algorithms for parameter optimization of seismic isolated structures. The developed design optimization algorithms have been applied to optimize a shear frame model with a base isolation system, where the main object...
Live load distribution equations for integral bridge substructures
Erhan, Semih; Dicleli, Murat (Elsevier BV, 2009-05-01)
In this study, live load distribution equations (LLDEs) for integral bridge (IB) substructures are developed. For this purpose, numerous 3-D and corresponding 2-D structural models of typical IBs are built and analyzed under AASHTO live load. In the analyses, the effect of various superstructure and substructure properties such as span length, girder spacing, girder stiffness, abutment height, pile size, pile spacing and foundation soil stiffness are considered. The results from the 2-D and 3-D analyses are...
Citation Formats
M. Dicleli, “Optimum characteristic properties of isolators with bilinear force-displacement hysteresis for seismic protection of bridges built on various site soils,” SOIL DYNAMICS AND EARTHQUAKE ENGINEERING, pp. 982–995, 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/36634.