Dynamic Analyses of a Skewed Short-Span, Box-Girder Overpass

1994 ◽  
Vol 10 (4) ◽  
pp. 729-755 ◽  
Author(s):  
David B. McCallen ◽  
Karl M. Romstad
Keyword(s):  
Dynamic Response ◽  
Seismic Response ◽  
Nonlinear Material ◽  
Earthquake Response ◽  
Detailed Model ◽  
Response Data ◽  
Modeling Approaches ◽  
Bridge Superstructure ◽  
Short Span ◽  
Stick Model

A number of recent research studies have provided insight into the seismic response characteristics of short-span overpass bridge systems. Application of system identification techniques to measured earthquake response data for this class of bridges has indicated that the bridge superstructure, abutments and approach embankment soil constitute a strongly coupled system. The dynamical behavior of the foundation and embankment soil have a first order influence on the dynamic response of the bridge superstructure. Analysis of measured strong motion response data has also indicated that localized nonlinear behavior of the embankment soil can result in significant nonlinear global behavior of the entire system, even when the bridge superstructure remains linear. The current paper presents the results of detailed numerical simulation studies of the dynamic response of a short-span overpass bridge system. Two distinctly different modeling approaches are investigated. The first approach utilizes simple reduced order “stick” model idealizations of the bridge, and the second approach utilizes a detailed, large scale, three dimensional finite element model. The detailed model includes a discretization of the soil embankments and a simple nonlinear material model is used to represent the hysteretic soil behavior. The sensitivity of bridge response to various parameters, such as deck skew, embankment soil stiffness and soil mass, stick model modal damping values, and soil nonlinearity has been investigated. Earthquake response predictions are performed with both model types and the response computations are compared to earthquake response data measurements. The ability of the models to accurately represent the bridge seismic response is discussed, and the two modeling approaches are compared and contrasted.

scholarly journals On Predicting the Seismic Response of Acceleration-Sensitive Non-Structural Components in Buildings

2018 ◽  
Author(s):  
Carmine Lima ◽  
Enzo Martinelli
Keyword(s):  
Dynamic Response ◽  
Seismic Response ◽  
Parametric Analysis ◽  
Short Review ◽  
Structural Components ◽  
Main Structure ◽  
Current State ◽  
Critical Issues ◽  
Key Features ◽  
Two Degree Of Freedom

This paper is intended at highlighting the main mechanical parameters controlling the behavior of the so-called "acceleration-sensitive" Non-Structural Components (NSCs). In the first part a short review of the current state of knowledge and the critical issues related to the prediction of the seismic response of NSCs is reported. Then, the paper presents the results of a numerical parametric analysis intended to capture the key features of the dynamic response of a two-degree-of-freedom (2DOF) system which is supposed to be representative of both the main structure and the "non-structural" component (NSC). Particularly, it allows to simulate the coupled behaviour of both main structure and NSC and evaluating their response. The main parameters controlling the dynamic response of NSCs emerge from this study, which could pave the way towards formulating more mechanically consistent relationships for evaluating the maximum accelerations induced by seismic shakings on NSCs.

Data-driven seismic response prediction of structural components

2021 ◽  
pp. 875529302110533
Author(s):  
Huan Luo ◽  
Stephanie German Paal
Keyword(s):  
Experimental Data ◽  
Seismic Response ◽  
Computational Cost ◽  
Data Driven ◽  
Computational Time ◽  
Lateral Stiffness ◽  
Hysteretic Model ◽  
Structural Components ◽  
Rc Columns ◽  
Detailed Model

Lateral stiffness of structural components, such as reinforced concrete (RC) columns, plays an important role in resisting the lateral earthquake loads. The lateral stiffness relates the lateral force to the lateral deformation, having a critical effect on the accuracy of the lateral seismic response predictions. The classical methods (e.g. fiber beam–column model) to estimate the lateral stiffness require calculations from section, element, and structural levels, which is time-consuming. Moreover, the shear deformation and bond-slip effect may also need to be included to more accurately calculate the lateral stiffness, which further increases the modeling difficulties and the computational cost. To reduce the computational time and enhance the accuracy of the predictions, this article proposes a novel data-driven method to predict the laterally seismic response based on the estimated lateral stiffness. The proposed method integrates the machine learning (ML) approach with the hysteretic model, where ML is used to compute the parameters that govern the nonlinear properties of the lateral response of target structural components directly from a training set composed of experimental data (i.e. data-driven procedure) and the hysteretic model is used to directly output the lateral stiffness based on the computed parameters and then to perform the seismic analysis. We apply the proposed method to predict the lateral seismic response of various types of RC columns subjected to cyclic loading and ground motions. We present the detailed model formulation for the application, including the developments of a modified hysteretic model, a hybrid optimization algorithm, and two data-driven seismic response solvers. The results predicted by the proposed method are compared with those obtained by classical methods with the experimental data serving as the ground truth, showing that the proposed method significantly outperforms the classical methods in both generalized prediction capabilities and computational efficiency.

Dynamics of Closed Circuit Hydraulic Model Loops

2002 ◽  
Author(s):  
Bjo̸rnar Svingen ◽  
Morten Kjeldsen ◽  
Roger E. A. Arndt
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Response ◽  
Theoretical Work ◽  
Current Theory ◽  
Water Tunnel ◽  
Post Processing ◽  
Global System ◽  
Pressure Transducers ◽  
Response Data ◽  
Cavitating Hydrofoil

This paper reviews the issue of making unsteady measurements involving cavitating flow in traditional test loops. Measurements of the dynamic response of a water tunnel during testing of a partially cavitating hydrofoil are presented and reviewed in the context of current theory. Data were collected from an array of pressure transducers that were distributed around the tunnel loop. In the post processing of these data, gain and phase response data were calculated. Theoretical analysis consisted of splitting the system into different elements, and included the compressibility of water in the physics used to describe each element. While solving the global system an eigenvalue solution was found, thus no node specific solution is obtained. This work is currently being extended with the aim of obtaining node specific values such that a more direct comparison between the experimental and theoretical work can be made.

Seismic Response for a Reinforce Concrete Specimen Considering Corrosive Hazards

2015 ◽  
Vol 764-765 ◽  
pp. 1124-1128 ◽  
Author(s):  
Wei Ting Lin ◽  
Yuan Chieh Wu ◽  
An Cheng ◽  
Tzu Ying Lee
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Response ◽  
Seismic Response ◽  
Corrosion Test ◽  
Natural Frequencies ◽  
Response Spectrum ◽  
Open Circuit ◽  
Reinforced Concrete Frame ◽  
Accelerated Corrosion ◽  
Accelerated Corrosion Test

This study is aim to evaluate the dynamic response variation of the scale-down reinforced concrete frame specimen under accelerated corrosion conditions. The specimens achieved the accelerated corrosion test by immersing in the accelerated corrosion test. Open circuit potential, corrosion rate, natural frequencies, displacements, accelerations and response spectral curves were tested and discussed. Test results presented that the corroded reinforced concrete specimens presented the changes in the dynamic response especially natural frequencies and response spectrum. This study provided further insight on the variation of seismic response behaviors in the deteriorated reinforced concrete structures and hoped to useful for structural assessments and appraisals applied to full-scale structures.

THE EFFECTS ON SHAPE-MODELING OF CONCRETE GRAVITY DAMS IN EARTHQUAKE RESPONSE ANALYSES

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Tatsuo Nishiuchi
Keyword(s):  
Seismic Response ◽  
High Elevation ◽  
Earthquake Response ◽  
Basement Rock ◽  
Gravity Dams ◽  
3D Fem ◽  
Fem Model ◽  
Concrete Gravity Dams ◽  
Contraction Joints ◽  
Non Linear

To clarify the effects of seismic response of concrete gravity dams under large earthquake, finite element method (FEM) analyses were carried out. In analyses, the height of dam and material properties of concrete and basement rock are same. The 2-dimensional (2D) and the 3-dimensional (3D) FEM model were made and used in earthquake response analyses. The contraction joints between dam block are concerned in 3D non-linear FEM analysis. In the case of same height of dam, the numerical results of damage states and placements in dam are different between 2D FEM model and 3D FEM model, due to the effect of difference in vibration mode of dam. In the 2D FEM model, the damage of top in cross-section becomes remarkable. In the 3D FEM model, the damage of attachment between dam body and basement rock at high-elevation becomes remarkable. The damage of 3D FEM model is smaller than that of 2D FEM model for the same acceleration level of earthquake. The influence of seismic response on contraction joints of 3D non-linear FEM dam model is smaller, which is as same as that of 3D linear FEM dam model. From the above results, the 2D FEM model gives a conservative assessment compared to the 3D FEM model.

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