Damper placement for seismic control of super-long-span suspension bridges based on the first-order optimization method

2010 ◽  
Vol 53 (7) ◽  
pp. 2008-2014 ◽  
Author(s):  
Hao Wang ◽  
AiQun Li ◽  
ChangKe Jiao ◽  
Billie F. Spencer
Keyword(s):  
Optimization Method ◽  
Suspension Bridges ◽  
First Order ◽  
Seismic Control ◽  
Long Span

Damper Optimization for Long-Span Suspension Bridges

2013 ◽  
pp. 112-125
Author(s):  
Hao Wang ◽  
Aiqun Li ◽  
Zhouhong Zong ◽  
Teng Tong ◽  
Rui Zhou
Keyword(s):  
Seismic Response ◽  
Optimization Method ◽  
Sensitivity Analyses ◽  
Suspension Bridges ◽  
Seismic Responses ◽  
Control Effect ◽  
Analytic Hierarchy ◽  
First Order ◽  
Traveling Wave Effect ◽  
Long Span

Long-span suspension bridges are becoming prevalent globally with the rapid progress in design methodologies and construction technologies. Although with apparent progress, the balance between excessive displacement and inner forces, under dynamic loads, is still a main concern because of increased flexibility and low structural damping. Therefore, effective controllers should be employed to control the seismic responses to ensure their normal operation. In this chapter, the combination of the analytic hierarchy process (AHP) and first-order optimization method are formulated to optimize seismic response control effect of the Runyang suspension bridge (RSB) under earthquakes, considering traveling wave effect. The compositive optimal parameters of dampers are achieved on the basis of 3-dimensional nonlinear seismic response analyses for the RSB and parameters sensitivity analyses. Results show that the dampers with rational parameters can reduce the seismic responses of the bridge significantly, and the application of the AHP and first-order optimization method can lead to accurate optimization effects.

Control of Vibrations due to Moving Loads on Suspension Bridges

2006 ◽  
Vol 11 (3) ◽  
pp. 293-318 ◽  
Author(s):  
M. Zribi ◽  
N. B. Almutairi ◽  
M. Abdel-Rohman
Keyword(s):  
Bridge Deck ◽  
Suspension Bridge ◽  
Lyapunov Theory ◽  
Dynamic Responses ◽  
Suspension Bridges ◽  
Control Force ◽  
Moving Loads ◽  
Hydraulic Actuator ◽  
Long Span ◽  
Suspended Cables

The flexibility and low damping of the long span suspended cables in suspension bridges makes them prone to vibrations due to wind and moving loads which affect the dynamic responses of the suspended cables and the bridge deck. This paper investigates the control of vibrations of a suspension bridge due to a vertical load moving on the bridge deck with a constant speed. A vertical cable between the bridge deck and the suspended cables is used to install a hydraulic actuator able to generate an active control force on the bridge deck. Two control schemes are proposed to generate the control force needed to reduce the vertical vibrations in the suspended cables and in the bridge deck. The proposed controllers, whose design is based on Lyapunov theory, guarantee the asymptotic stability of the system. The MATLAB software is used to simulate the performance of the controlled system. The simulation results indicate that the proposed controllers work well. In addition, the performance of the system with the proposed controllers is compared to the performance of the system controlled with a velocity feedback controller.

Vibration Serviceability of Long Span Cable Bridges using Long-term Monitoring Data

2019 ◽  
Author(s):  
Eui-seung Hwang ◽  
Sun-Kon Kim ◽  
Do-Young Kim ◽  
Ki-Jung Park
Keyword(s):  
Monitoring Data ◽  
Suspension Bridges ◽  
Span Length ◽  
Bridge Design ◽  
Long Span ◽  
Vibration Serviceability ◽  
Long Term Monitoring ◽  
Deflection Limit ◽  
Term Monitoring

<p>Along with building slender and longer span structures, vibration serviceability becomes more important considerations in bridge design and maintenance. In this study, vibration serviceability and deflection limit for long span cable bridges are investigated using long-term monitoring data such as accelerations and displacements of bridges. Exampled bridges are Yi Sun-Sin Grand Bridge (suspension bridge, main span length=1,545m) and 2<sup>nd</sup> Jindo Grand Bridge (cable stayed bridge, main span length=344m). Long-term data are analyzed and compared with various design codes, guidelines, and other research results. Probability of exceedance are calculated for each criterion. Regarding on deflection limits, Korean Bridge Design Code (Limit State Design) specifies L/400 and L/350 for cable stayed and suspension bridges, respectively. Saadeghvaziri suggested deflection limit based on natural frequency, acceleration limit of 0.5 m/s² and vehicle speed. Various human comfort criteria on vibration are also applied including ISO standards. The results of this study are expected to be useful reference for the design, the proper planning and deflection review of the long span cable bridges around the world. Further researches are required to find the optimum deflection or vibration criteria for long span bridge and their effects on bridge clearance and elevation.</p>

Nonsmooth Optimization Method for Image Restoration

1995 ◽  
Author(s):  
Kazufumi Ito ◽  
Karl Kunisch
Keyword(s):  
Image Restoration ◽  
Nonsmooth Optimization ◽  
Numerical Optimization ◽  
Augmented Lagrangian ◽  
Energy Criterion ◽  
Optimization Methods ◽  
Optimization Method ◽  
Augmented Lagrangian Methods ◽  
Active Set ◽  
First Order

Abstract In this paper we discuss applications of the numerical optimization methods for nonsmooth optimization, developed in [IK1] for the variational formulation of image restoration problems involving bounded variation type energy criterion. The Uzawa’s algorithm, first order augmented Lagrangian methods and Newton-like update using the active set strategy are described.

Seismic Performance of the Buckling-Restrained Brace Central Buckle for Long-Span Suspension Bridges

2018 ◽  
Vol 12 (05) ◽  
pp. 1850015 ◽  
Author(s):  
Wei Guo ◽  
Jianzhong Li ◽  
Nailiang Xiang
Keyword(s):  
Seismic Performance ◽  
Design Procedure ◽  
Suspension Bridges ◽  
Preliminary Design ◽  
Viscous Dampers ◽  
Buckling Restrained Brace ◽  
Long Span ◽  
Parametric Analyses ◽  
Yield Force ◽  
Central Buckle

In this paper, a novel central buckle composed of buckling-restrained braces (BRBs) is developed for long-span suspension bridges, and its preliminary design procedure is presented. Seismic performance of suspension bridges equipped with BRB central buckles is investigated and compared with those with conventional central buckles (e.g. rigid or flexible central buckles). Furthermore, the effect of BRB yield force, as well as the effectiveness of BRB central buckles combined with viscous dampers, is evaluated using parametric analyses. The results indicate that the BRB central buckle is more effective than other central buckles in reducing both the longitudinal girder displacements and force demands on towers during an earthquake. Furthermore, the combination of BRB central buckles and viscous dampers is a superior option for mitigating the seismic response of long-span suspension bridges.

Nonlinear Multiresponse Parameter Estimation Using Simplex Optimization Method

2015 ◽  
Vol 1105 ◽  
pp. 299-304
Author(s):  
A. Al Saleh Mohammad ◽  
A. Yussuf Abdirahman
Keyword(s):  
Probabilistic Models ◽  
Length Distribution ◽  
Simulated Data ◽  
Optimization Method ◽  
Sequence Length ◽  
Distribution Data ◽  
Multiple Site ◽  
First Order ◽  
Site Type ◽  
Market Requirements

Polyolefin molecular architectures are designed according to customer needs and demands. Hence, it is essential to determine the catalytic behavior that gives the polymer the characteristics it needs to meet the market requirements. Today most of the industrial polyolefin production depends on multiple-site-type catalysts such as Ziegler-Natta catalysts. In this work a methodology to estimate parameters for polyolefin multiple-site-type catalysts was presented. The sequence length distribution data were simulated using Zeroth-order and First-order Markovian models. These simulated data were used to test the robustness of the optimization method. The optimization method used was able to retrieve and comprehend the proper probabilistic models and provide acceptable polymerization parameters estimates.

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