Kurtuluş Soyluk

A stochastic analysis of long span structures subjected to spatially varying ground motions including the site-response effect

In this paper, a comprehensive investigation of the stochastic response of a cable-stayed bridge subjected to spatially varying ground motions is performed based on a recently proposed model. The spatial variability of ground motions is considered with incoherence, wave-passage and site-response effects. The importance of the site-response effect, which arises from the difference in the local soil conditions at different support points of the structure, is investigated particularly. Mean of maximum and variance response values obtained from the spatially varying ground motions are compared with those of the specialised cases of the ground motion model. It is pointed out that each component of the spatially varying ground motion model has important effects on the dynamic behaviour of the structure. Therefore, to be more realistic in calculating the bridge responses, the variability of the ground motions should be incorporated in the analysis of long span structures.

Comparison of asynchronous and stochastic dynamic responses of a cable-stayed bridge

In this paper, asynchronous and stochastic dynamic analyses of a cable-stayed bridge are carried out using the finite element method. The Jindo Bridge, constructed in South Korea, is chosen as a numerical example. In the asynchronous dynamic analysis, various wave velocities are used for the travelling ground motion. Displacements and internal effects are obtained using both methods, and compared with each other. It is observed that the velocity of the ground motion greatly influences the response of the Bridge.

Nonlinear Response of Earthfill Dams to Spatially Varying Ground Motion Including Site Response Effect

This paper presents the nonlinear response of an earthfill dam subjected to spatially varying ground motion, which includes the wave-passage, incoherence and site response effects. An equivalent linear method is considered in the nonlinear response formulation. The importance of the site response effect, which arises from the difference in the local soil conditions at different support points of the structure, is investigated particularly. The mean of maximum and variance response values obtained from a spatially varying ground motion case are compared with those of specialized ground motion models. It is observed that the variation in local soil conditions has important effects on the nonlinear response of earthfill dams.

Numerical investigation of stochastic response of an elevated water tank to random underground blast loading

This paper presents a stochastic finite element seismic response study of a water tank subjected to random underground blast-induced ground motion. Such tanks contain water and hazardous chemical substances, which implies significant risk to human life, serious environmental pollution, and considerable economic loss. The random blast-induced ground motion is represented by power spectral density function and applied to each support point of the three dimensional finite element model of the elevated water tank–fluid interaction system. A parametric study is conducted to estimate the effects of the blast-induced ground motion on the stochastic response of the elevated water tank system. Therefore, the analyses are carried out for different values of the charge weight and the distance from the charge centre. Additionally, in order to investigate the effect of the fluid on the stochastic response of the elevated water tank, three cases with different water levels are considered in the analyses. Finally, it is observed that underground blast loading considerably changes the stochastic behavior of the elevated water tank system.

Stochastic dynamic analysis of a historical masonry bridge under surface blast-induced multi-point ground motion

In this study, a parametric study is conducted to determine the stochastic dynamic response of a historical masonry bridge under blast-induced ground motions. With this purpose, an existing historical masonry bridge located in Turkey, called Kurt Bridge is considered and analyzed under blast-induced multi-point random ground motion. This sample bridge model reflects almost all of the structural characteristics of similar type historical masonry arch bridges whereby the results of this study can be generalized to similar structural systems. Blast-induced ground motion which is random in nature is described by power spectrum of a white noise process and is applied to support points of three-dimensional finite element model of the considered bridge system. To underline the importance of the blast-induced multi-point ground motion, three support regions are defined for the application of the random ground motion. Different charge weights and distances from the charge center are considered while determining the power spectral density functions. Depending on the considered charge weights and charge center distances power spectral density functions and shaded image counters of one standard deviation of the responses of the masonry bridge are determined. The results of the analyses show that blast-induced multi-point ground motion causes smaller structural responses if compared with those of the responses obtained from the blast-induced uniform ground motion.

Comparison of Stochastic Responses of Asphaltic Concrete Core and Asphaltic Lining Dams with Clay Core Dams to Stationary and Nonstationary Excitation

This paper presents the advantages of using asphalt in lining dams and in asphaltic concrete core dams when comparing with clay core dams. For this purpose, the linear and nonlinear stochastic responses of a clay core dam, an asphaltic lining dam and an asphaltic concrete core dam subjected to stationary and non-stationary excitation including spatially varying ground motion (SVEGM) effects are determined by finite element method. The nonlinear response is based on equivalent linear method, which considers the nonlinear variation of soil shear moduli and damping as a function of shear strain. The results are compared with those of the responses computed using linear response for uniform ground motion and SVEGM. The spatial variability of ground motion is taken into account with incoherence and wave passage effects. Stationary as well as non-stationary stochastic response analyses are performed for three types of dam. A time dependent frequency response function is used throughout the study for non-stationary responses. It is observed from the results that it can be possible to use of asphaltic lining dams and an asphaltic concrete core dams instead of clay core dams.