Empirical Mode Decomposition Application for Structural Seismic Responses

2012 ◽  
Vol 256-259 ◽  
pp. 2096-2101 ◽  
Author(s):  
Ri Dong Du ◽  
Yong Bo Yuan ◽  
Miao Chen
Keyword(s):  
Empirical Mode Decomposition ◽  
Large Mass ◽  
Displacement Curve ◽  
Seismic Responses ◽  
Long Span Bridges ◽  
Long Span ◽  
Long Span Bridge ◽  
Mode Decomposition ◽  
Geological Conditions ◽  
Large Mass Method

Large mass method is used to calculate structural seismic responses of long-span bridges. Due to the inherent characteristics of large mass method, the larger scale of long span bridge, different geological conditions, seismic input time delay of different foot stall, the displacement curve of seismic responses will be drifted and distorted from the normal. In this paper, Empirical Mode Decomposition（EMD) based on the large mass method is proposed to remove pseudo component and drift displacement. Then displacement response curve is reconstructed using the remaining components, the drift and distortion of structural seismic responses is successfully removed by this method.

Super-long span bridge aerodynamics: on-going results of the TG3.1 benchmark test – Step 1.2

2019 ◽  
Author(s):  
Giorgio Diana ◽  
Stoyan Stoyanoff ◽  
Andrew Allsop ◽  
Luca Amerio ◽  
Tommaso Argentini ◽  
...  
Keyword(s):  
Numerical Models ◽  
Experimental Tests ◽  
Numerical Comparison ◽  
Aeroelastic Stability ◽  
Turbulent Wind ◽  
Long Span Bridges ◽  
Buffeting Response ◽  
Long Span ◽  
Long Span Bridge ◽  
Sectional Model

<p>This paper is part of a series of publications aimed at the divulgation of the results of the 3-step benchmark proposed by the IABSE Task Group 3.1 to define reference results for the validation of the software that simulate the aeroelastic stability and the response to the turbulent wind of super-long span bridges. Step 1 is a numerical comparison of different numerical models both a sectional model (Step 1.1) and a full bridge (Step 1.2) are studied. Step 2 will be the comparison of predicted results and experimental tests in wind tunnel. Step 3 will be a comparison against full scale measurements.</p><p>The results of Step 1.1 related to the response of a sectional model were presented to the last IABSE Symposium in Nantes 2018. In this paper, the results of Step 1.2 related to the response long-span full bridge are presented in this paper both in terms of aeroelastic stability and buffeting response, comparing the results coming from several TG members.</p>

Numerical Simulation of Wind-Driven Rain on a Long-Span Bridge

2019 ◽  
Vol 19 (12) ◽  
pp. 1950149
Author(s):  
Shenghong Huang ◽  
Qiusheng Li ◽  
Man Liu ◽  
Fubin Chen ◽  
Shun Liu
Keyword(s):  
Numerical Simulation ◽  
Wind Engineering ◽  
Multiphase Model ◽  
Rain Intensity ◽  
Long Span Bridges ◽  
Long Span ◽  
Long Span Bridge ◽  
Extreme Rain ◽  
Section Model ◽  
Bridge Spans

Wind-driven rain (WDR) and its interactions with structures is an important research subject in wind engineering. As bridge spans are becoming longer and longer, the effects of WDR on long-span bridges should be well understood. Therefore, this paper presents a comprehensive numerical simulation study of WDR on a full-scale long-span bridge under extreme conditions. A validation study shows that the predictions of WDR on a bridge section model agree with experimental results, validating the applicability of the WDR simulation approach based on the Eulerian multiphase model. Furthermore, a detailed numerical simulation of WDR on a long-span bridge, North Bridge of Xiazhang Cross-sea Bridge is conducted. The simulation results indicate that although the loads induced by raindrops on the bridge surfaces are very small as compared to the wind loads, extreme rain intensity may occur on some windward surfaces of the bridge. The adopted numerical methods and rain loading models are validated to be an effective tool for WDR simulation for bridges and the results presented in this paper provide useful information for the water-erosion proof design of future long-span bridges.

A generalized Pareto distribution–based extreme value model of thermal gradients in a long-span bridge combining parameter updating

2016 ◽  
Vol 20 (2) ◽  
pp. 202-213 ◽  
Author(s):  
Guang-Dong Zhou ◽  
Ting-Hua Yi ◽  
Bin Chen ◽  
Huan Zhang
Keyword(s):  
Pareto Distribution ◽  
Generalized Pareto Distribution ◽  
Extreme Value ◽  
Thermal Gradients ◽  
Long Span Bridges ◽  
Long Span ◽  
Generalized Pareto ◽  
Long Span Bridge ◽  
Extreme Value Model ◽  
Value Model

Estimating extreme value models with high reliability for thermal gradients is a significant task that must be completed before reasonable thermal loads and possible thermal stress in long-span bridges are evaluated. In this article, a generalized Pareto distribution–based extreme value model combining parameter updating has been developed to describe the statistical characteristics of thermal gradients in a long-span bridge. The procedure of excluding correlation and the approach of selecting a proper threshold are suggested to prepare samples for generalized Pareto distribution estimation. A Bayesian estimation, which has the capability of updating model parameters by fusing prior information and incoming monitoring data, is proposed to fit the generalized Pareto distribution–based model. Furthermore, the Gibbs sampling, which is a Markov chain Monte Carlo algorithm, is adopted to derive the Bayesian posterior distribution. Finally, the proposed method is applied to the field monitoring data of thermal gradients in the Jiubao Bridge. The extreme value models of thermal gradients for the Jiubao Bridge are established, and the extreme thermal gradients with different return periods are extrapolated. The results indicate that the generalized Pareto distribution–based extreme value model has a strong ability to represent the statistical features of thermal gradients for the Jiubao Bridge, and the Bayesian estimation combining parameter updating provides high-precision generalized Pareto distribution–based models for predicting extreme thermal gradients. The predicted extreme thermal gradients are expected to evaluate and design long-span bridges.

Research on Design Vehicle Load for Long-Span Bridges

2011 ◽  
Vol 90-93 ◽  
pp. 909-914
Author(s):  
Da Lin Hu ◽  
Ding Ding ◽  
Long Gang Chen ◽  
Chun Mei Xia
Keyword(s):  
Simulation Analysis ◽  
Extreme Value Distribution ◽  
Bending Moments ◽  
Long Span Bridges ◽  
Long Span ◽  
Vehicle Load ◽  
Long Span Bridge ◽  
Load Effects ◽  
Vehicle Loads ◽  
Characteristic Values

This paper presents simulation analysis of load effects of bridges under random fleet. Based on actual data of vehicle loads on Guangzhou-Shenzhen Expressway and relevant statistical results, mid-span bending moments of long-span virtual simple-supported beams are calculated. Then probability distribution of the bending moments and extreme value distribution of the load effects within design reference period are obtained. Finally, characteristic values of mid-span bending moments and recommended values of design lane load are calculated, sequentially. The results studied in this paper can be as a reference for long-span bridge design, and also can be a reference for overloading control or weight charge policy.

scholarly journals Damage detection of long-span bridge structures based on response surface model

2020 ◽  
Vol 24 (3 Part A) ◽  
pp. 1497-1504 ◽  
Author(s):  
Shujun Fang
Keyword(s):  
Damage Detection ◽  
Response Surface ◽  
Element Model ◽  
Response Surface Model ◽  
Surface Model ◽  
Long Span Bridges ◽  
Long Span ◽  
Long Span Bridge ◽  
The Finite Element Model ◽  
Fourth Order Polynomial

In order to solve the problem of high risk and low precision of existing damage detection methods for long-span Bridges, a new method based on fourth-order polynomial response surface model is proposed. Response surface model is constructed by using fourth order polynomial function. The parameters of the finite element model of the bridge are modified according to the response surface model. Based on the finite element model, the modal strain energy before and after the damage of the element was calculated, and the damage index of the element was obtained, so as to realize the damage detection of the long-span bridge structure. Experimental results show that the proposed method can accurately detect the damage location of long-span Bridges under different damage conditions, and the detection error of damage degree is less than 1%, which has a broad application prospect.

Feasibility Study of Super-Long Span Bridges Considering Aerostatic Instability by a Two-Stage Geometric Nonlinear Analysis

2020 ◽  
pp. 2150033
Author(s):  
Jiunn-Yin Tsay
Keyword(s):  
Wind Speed ◽  
Nonlinear Analysis ◽  
Two Stage ◽  
Long Span Bridges ◽  
Critical Wind Speed ◽  
Long Span ◽  
Main Cable ◽  
Geometric Nonlinear ◽  
Long Span Bridge ◽  
Geometric Nonlinear Analysis

To meet the need of constructing fixed cross strait links, super-long span bridge with a main span over 2 000[Formula: see text]m is considered as a candidate for their ability to cross deep and wide straits. To this end, some super-long span bridges with proper cable and girder systems were previously proposed and studied. The major design considerations are aimed at adopting new cable material, increasing the entire rigidity of the bridge, stabilizing the dynamic characteristics, strengthening the deck sections, etc. In this paper, a brief review of main cable and girder system is first given of the concepts previously proposed for the design of super-long span bridges. Then some typical examples are studied, focused on various issues related to the design of super-long span bridges, including composite cable, the unstressed length and tension force of the main cable, the stiffness and mass effects of the deck on critical wind speed, and the critical wind speed of various cable systems. The most challenges in super-long span bridges are to solve aerostatic and aerodynamic instability at required design wind speed. In this connection, the wind-induced aerostatic instability of super-long span bridges is studied by a two-stage geometric nonlinear analysis for dead loads and wind loads. The developed program adopted herein for geometric nonlinear analysis was verified and confirmed before. The proposed methods (i.e. composite cable, slotted girder, increasing deck stiffness and mass, cable layout, etc.) obtained for all the examples are in agreement with this study, which indicates applicability of the design approaches presented.

Seismic Response Analysis of Long Span Cable-Stayed Bridge under Non-Uniform Excitation

2012 ◽  
Vol 246-247 ◽  
pp. 131-135
Author(s):  
Bao Fu Wang ◽  
Zhong Ren Feng ◽  
Xiong Jiang Wang ◽  
Bai Ben Chen
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Ground Motions ◽  
Time History ◽  
Large Mass ◽  
Response Analysis ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
History Analysis ◽  
Large Mass Method

In this paper, non-uniform dynamic analysis of a cable-stayed bridge is carried out using the large mass method. The Ed Yangtze River highway bridge, constructed in Hubei province, is chosen as a numerical example. In the non-uniform dynamic analysis, various wave velocities are used for the travelling ground motion. Displacements and internal forces solutions obtained for the spatially varying ground motions are compared with those of the uniform excitation. It is observed that the velocity of the ground motion greatly influences the response of the bridge and the variability of the ground motions should be included in the time-history analysis of cable-stayed bridges.

APPLICATION OF EMPIRICAL MODE DECOMPOSITION IN STRUCTURAL HEALTH MONITORING: SOME EXPERIENCE

2009 ◽  
Vol 01 (04) ◽  
pp. 601-621 ◽  
Author(s):  
JUN CHEN
Keyword(s):  
Structural Health Monitoring ◽  
Data Processing ◽  
Parameter Identification ◽  
Empirical Mode Decomposition ◽  
Health Monitoring ◽  
Structural Parameter ◽  
Raw Data ◽  
Structural Health ◽  
Long Span ◽  
Mode Decomposition

The installation of long-term structural health monitoring (SHM) system on super-tall buildings, long span bridges and large space structures has become a worldwide trend since last decade to monitor loading conditions, to detect damage, to assess structural safety and to guide maintenance during their service life. The core part of an SHM system is the function of data processing and structural parameter/damage identification that extracts useful information from huge amount of raw data and provides reliable knowledge for proper decision. Recently emerged data processing technique empirical mode decomposition (EMD) in conjunction with Hilbert transform (HT) provides a more better and powerful tool for SHM. This paper summarizes some research experience gained from application of EMD + HT in SHM with focuses on pre-processing raw data, structural parameter identification and damage detection. In particular, EMD is applied to determining time varying mean wind speed for wind data and to extract multipath effect from GPS data. For structural parameter identification, the EMD + HT approach is employed to identify natural frequencies and modal damping ratios of long span bridge during passage of strong typhoon and of structures with closely spaced modes of vibration. The results manifest the advantages of EMD + HT over traditional FFT-based methods in damping estimation. Furthermore, experimental investigation has been carried out to study the applicability of EMD for identifying structural damage caused by a sudden change of structural stiffness. It is concluded from all these investigations that EMD approach is a promising tool for structural health monitoring of large civil structures. Finally, some issues concerned for further practical application of EMD are highlighted and discussed based on these academic researches.

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