Objective-based equivalent static wind loads for long-span bridges

Author(s):  
Zachary J. Taylor ◽  
Pierre-Olivier Dallaire ◽  
Stoyan T. Stoyanoff

<p>The process to arrive at design wind loads for long-span bridges involves experimental testing and analytical methods. Time domain simulations are becoming increasingly common and many available studies demonstrate results of buffeting response analysis in the time domain. However, there is significantly more to the process than the response analysis to derive wind loads that can be applied practically for design. The current study focuses on two key aspects required to derive design wind loads: prediction of the peak modal deflection and derivation of modal combination coefficients using objective functions.</p>

2013 ◽  
Vol 791-793 ◽  
pp. 370-373
Author(s):  
Hua Bai ◽  
Yue Zhang

In order to solve the problem of traditional buffeting analysis method is complex, the paper summarizes a calculation method of simplifying the suspension bridge buffeting response spectrum which considers the background response by simplifying the vibration mode function. Examples calculation shows that this function is efficient and accurate. With this method the paper analyzes the impact of parameters including structural damping ratio, aerodynamic admittance function, pneumatic self-excited forces, the main beam span and so on on the suspension bridge buffeting response. Results show that: First, the impact of the background response on concrete bridges with larger damping ratio cannot be ignored. Second, when aerodynamic admittance takes Sears function, the buffeting response analysis results may be partial dangerous. Third, the role of the background response on large long-span bridges of more than 2000 m can be ignored.


2017 ◽  
Vol 109 (6) ◽  
pp. 3307-3317
Author(s):  
Afshin Hatami ◽  
Rakesh Pathak ◽  
Shri Bhide

Author(s):  
Giorgio Diana ◽  
Stoyan Stoyanoff ◽  
Andrew Allsop ◽  
Luca Amerio ◽  
Tommaso Argentini ◽  
...  

<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>


2013 ◽  
Vol 540 ◽  
pp. 141-152
Author(s):  
Hang Sun ◽  
De Jun Wang ◽  
Yong Li

Although the seismic response analysis under the multi-excitation was widely focused on the long-span flexible bridges, it is still necessary to pay more attention to this point of continuous girder bridges since the dynamic behavior of this type of bridges are different with either long-span bridges or simple support bridges. Based on the nonlinear dynamic time history analysis, a four-span continuous beam FEM was built, and the effect of excitation types and structure size on seismic response was studied. And results indicate that the structural performance of continuous girder bridges is sensitive with the space correlation of different location of seismic excitation. So its necessary to consider the space effect of excitation while carrying out a seismic design of continuous beam.


2000 ◽  
Vol 126 (1) ◽  
pp. 7-16 ◽  
Author(s):  
Xinzhong Chen ◽  
Masaru Matsumoto ◽  
Ahsan Kareem

1988 ◽  
Vol 110 (1) ◽  
pp. 43-47 ◽  
Author(s):  
J. N. Brekke ◽  
T. N. Gardner

The avoidance of “slack” tethers is one of the factors which may establish the required tether pretension in a tension leg platform (TLP) design. Selection of an appropriate safety factor on loss of tension depends on how severe the consequences may be. It is sometimes argued that if tethers go slack, the result may be excessive platform pitch or roll motions, tether buckling, or “snap” or “snatch” loading of the tether. The results reported here show that a four-legged TLP would not be susceptible to larger angular motions until two adjacent legs lose tension simultaneously. Even then, this analysis shows that a brief period of tether tension loss (during the passage of a large wave trough) does not lead to excessive platform motion. Similarly, momentary tension loss does not cause large bending stress in the tether or significant tension amplification as the tether undergoes retensioning. This paper presents TLP platform and tether response analysis results for a representative deepwater Gulf of Mexico TLP with large-diameter, self-buoyant tethers. The time-domain, dynamic computer analysis included nonlinear effects and platform/tether coupling.


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