scholarly journals Nonlinear Dynamic Analysis of a Masonry Arch Bridge Accounting for Damage Evolution

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 343
Author(s):  
Daniela Addessi ◽  
Cristina Gatta ◽  
Mariacarla Nocera ◽  
Domenico Liberatore
Keyword(s):  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
Damage Index ◽  
Nonlinear Dynamic Analysis ◽  
Time History ◽  
Damage Variable ◽  
Constitutive Law ◽  
Masonry Arch ◽  
Nonlinear Dynamic Response ◽  
History Of

This study investigates the nonlinear dynamic response of the masonry bridge ‘Ponte delle Torri’ in Spoleto, aiming at assessing the seismic performance of the structure and evaluating the occurring damaging mechanisms. A 3D Finite Element (FE) macromechanical procedure implemented in the FE program FEAP is adopted to model the bridge. To reproduce the typical nonlinear microcracking process evolving in masonry material when subjected to external loads, an isotropic damage model is used. This is based on a scalar damage variable introduced in the stress-strain constitutive law and equally degrading all the components of the elastic constitutive operator. A nonlocal integral definition of the damage associated variable, that is the equivalent strain measure governing its evolution, is adopted to overcome the mesh dependency problems of the FE solution typically occurring in the presence of strain softening behavior. Based on the results of a recent study by some of the authors, a single equivalent pier is analyzed, whose geometry and boundary conditions are selected so that its response can provide useful information on the out-of-plane dynamic behavior of the overall bridge. To perform the seismic assessment, a set of recorded accelerograms is properly selected to simulate the seismic history of the Spoleto site. The nonlinear dynamic response of the structure is evaluated and monitored in terms of top displacement time history, evolution of the global damage index, and distribution of the damage variable. First, a set of analyses is performed by imposing the selected ground motions one by one on the initial undamaged configuration for the structure with the aim of emphasizing the damaging effects on its dynamic response. Then, the accelerograms are arranged in sequence to reproduce the seismic history of the site and analyze the influence of accumulated damage on the dynamic amplification of the response. A critical comparison of the bridge response to the sequence of accelerograms and the single records is made, and the interaction between the damaged structure dynamic response and the signal characteristic is highlighted, as well.

scholarly journals Effects of Near Fault and Far Fault Ground Motions on Nonlinear Dynamic Response and Seismic Improvement of Bridges

2018 ◽  
Vol 4 (6) ◽  
pp. 1456 ◽  
Author(s):  
Mohammad Hajali ◽  
Abdolrahim Jalali ◽  
Ahmad Maleki
Keyword(s):  
Dynamic Response ◽  
Ground Motion ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Time History ◽  
Relative Displacement ◽  
Near Fault ◽  
Acceleration Rate ◽  
Near Fault Earthquakes ◽  
Far Fault

In this study, the dynamic response of bridges to earthquakes near and far from the fault has been investigated. With respect to available data and showing the effects of key factors and variables, we have examined the bridge’s performance. Modeling a two-span concrete bridge in CSI Bridge software and ability of this bridge under strong ground motion to near and far from fault has been investigated. Nonlinear dynamic analysis of time history includes seven records of past earthquakes on models and it was observed that the amount of displacement in the near faults is much greater than the distances far from faults. Bridges designed by seismic separators provide an acceptable response to a far from fault. This means that in bridges using seismic separators, compared to bridges without seismic separators, Acceleration rate on deck, base shearing  and the relative displacement of the deck are decrease. This issue is not seen in the response of the bridges to the near faults. By investigating earthquakes near faults, it was observed that near-fault earthquakes exhibit more displacements than faults that are far from faults. These conditions can make seismic separators critical, so to prevent this conditions FDGM should be used to correct the response of these bridges. Based on these results, it can be said that the displacement near faults with forward directivity ground motion is greater than far from faults. So that by reducing the distance from the faults, the maximum value of the shearing and displacement of the deck will be greater.

Nonlinear Dynamic Response Analysis of the Braced Steel Frame with Wedge Devices

2011 ◽  
Vol 368-373 ◽  
pp. 685-689
Author(s):  
Jin Song Lei ◽  
Yin Sheng Zou ◽  
Ya Li Wang ◽  
Qing Ma
Keyword(s):  
Plastic Deformation ◽  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
Nonlinear Dynamic Analysis ◽  
Steel Frame ◽  
Structural Deformation ◽  
Response Analysis ◽  
Lateral Stiffness ◽  
Earthquake Intensity ◽  
Nonlinear Dynamic Response

In order to research the nonlinear dynamic respond analysis of a new braced steel frame with wedge devices under the action of earthquake, its damping mechanism is analyzed, and the computational model is obtained. Based on the mechanism of multiple resistant lateral system, the explicit nonlinear dynamic analysis and dynamic contact algorithm are adopted to separately analyze the steel frame with no brace, with centric and eccentric brace, and with the new braced wedge block. During the analysis, in order to take the material and geometrical bi-nonlinear into account, the material model is chosen as the bilinear equivalent strength, and the explicit centered difference algorithm is adopted. It can be obtained from structural deformation and energy and so on. The results show that the stiffness of structure decays after plastic deformation in the earthquake effect, and the hysteresis energy consumption and system dumping appear. The nonlinear dynamic response of steel frame is affected by resistant lateral stiffness, plastic deformation, and system damping. The braced steel frame with wedge block regulates the displacement and acceleration response with yield energy dissipation of brace, as it provides resistance lateral stiffness to control the deformation. This kind of structure has strong adaptability to earthquake intensity and good seismic performance.

Nonlinear Dynamic Response and Buckling of Damaged Composite Pipes Under Radial Impact

2006 ◽  
Author(s):  
Wenyong Tang ◽  
Tianlin Wang ◽  
Shengkun Zhang
Keyword(s):  
Dynamic Response ◽  
Shear Deformation ◽  
Nonlinear Dynamic ◽  
Shear Deformation Theory ◽  
Nonlinear Dynamic Response ◽  
Nonlinear Dynamic Equations ◽  
Geometric Deformation ◽  
Initial Geometric Imperfections ◽  
Set Up ◽  
Composite Pipes

In this paper, the nonlinear dynamic response and buckling of damaged composite pipes under radial impact is investigated. A model involving initial geometric deformation, delamination and sub-layer matrix damage is set up for theoretical analysis. Based on the first order shear deformation theory, the nonlinear dynamic equations of the composite pipe considering transverse shear deformation and initial geometric imperfections are obtained by Hamilton’s theory and solved by a semi-analytical finite difference method. The effects of damage on the dynamic response and buckling of composite pipes are discussed.

Nonlinear dynamic response and vibration of imperfect eccentrically stiffened sandwich third-order shear deformable FGM cylindrical panels in thermal environments

2017 ◽  
Vol 21 (8) ◽  
pp. 2816-2845 ◽  
Author(s):  
Nguyen D Duc ◽  
Ngo Duc Tuan ◽  
Phuong Tran ◽  
Tran Q Quan ◽  
Nguyen Van Thanh
Keyword(s):  
Dynamic Response ◽  
Nonlinear Dynamic ◽  
Geometrical Nonlinearity ◽  
Cylindrical Panel ◽  
Geometrical Parameters ◽  
Third Order ◽  
Nonlinear Dynamic Response ◽  
Elastic Foundations ◽  
Thermal Environments ◽  
Cylindrical Panels

This study follows an analytical approach to investigate the nonlinear dynamic response and vibration of eccentrically stiffened sandwich functionally graded material (FGM) cylindrical panels with metal–ceramic layers on elastic foundations in thermal environments. It is assumed that the FGM cylindrical panel is reinforced by the eccentrically longitudinal and transversal stiffeners and subjected to mechanical and thermal loads. The material properties are assumed to be temperature dependent and graded in the thickness direction according to a simple power law distribution. Based on the Reddy’s third-order shear deformation shell theory, the motion and compatibility equations are derived taking into account geometrical nonlinearity and Pasternak-type elastic foundations. The outstanding feature of this study is that both FGM cylindrical panel and stiffeners are assumed to be deformed in the presence of temperature. Explicit relation of deflection–time curves and frequencies of FGM cylindrical panel are determined by applying stress function, Galerkin method and fourth-order Runge-Kutta method. The influences of material and geometrical parameters, elastic foundations and stiffeners on the nonlinear dynamic and vibration of the sandwich FGM panels are discussed in detail. The obtained results are validated by comparing with other results in the literature.

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