Bridge dynamic impact factor extraction method

A technology of dynamic impact and extraction method, applied in force/torque/work measuring instruments, measuring devices, instruments, etc., can solve the problems of difficult filtering and separation, infeasibility, different maximum static response values, etc.

Active Publication Date: 2017-10-03
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The main link of bridge DAF extraction is to obtain the maximum static response. The method of obtaining the maximum static response through direct static test is often affected by many factors such as time and economy and is not feasible.
At present, the more common methods such as the "peak-valley" method use the average of the maximum peak value and the adjacent valley value in the measured dynamic response as the maximum static response, and are subject to the subjective position of the fluctuation point, the test noise, and the valley value (left and right). The maximum static response value calculated by this method is actually not accurate
Obtaining the static response by filtering the dynamic signal is also a commonly used method at present, especially for the situation where the peak and valley values ​​are not obvious, but a reasonable filter setting requires not only the elimination of vibration interference but also the complete preservation of static information. There is often aliasing in frequency between signals, making it difficult to filter and separate
In addition, the above two calculation methods often lead to different maximum static response values ​​under the same vehicle load

Method used

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  • Bridge dynamic impact factor extraction method

Examples

Experimental program
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Embodiment 1

[0086] This embodiment discloses a method for extracting bridge dynamic impact coefficients based on influence lines, which includes the following steps:

[0087] Step 1: Test and extract the actual influence line (IL) of the bridge. It is divided into the following 3 sub-steps:

[0088] (1) Vehicle bridge dynamic response test

[0089] A loading test vehicle with known axle load and wheelbase is used to get on the bridge from one end of the bridge and drive out of the bridge at a lower speed. Record the speed of vehicles passing through the bridge and the dynamic response of bridge setting measuring points, including dynamic strain and dynamic deflection responses.

[0090] From the dynamic response of the vehicle passing the bridge, the response from the first axis on the bridge to the last axis out of the bridge is selected as the research object, which is defined as R. Assuming that the sampling frequency of the data is f, and the total number of data points in this sec...

Embodiment 2

[0180] This embodiment discloses a bridge dynamic impact coefficient extraction method, including:

[0181] Obtain the influence line information reflecting the static characteristics of the bridge;

[0182] Determine the tire-road surface contact force distribution model and the corresponding contact force distribution function according to the vertical contact force between the wheel and the road surface in the vehicle, tire type, and tire pressure factors;

[0183] Based on the information of the inherent influence line of the bridge, combined with the contact force distribution function, the quasi-static response z(x) of the vehicle passing the bridge is calculated, and then IM=max(y) / max(z(x)) -1 Calculate the dynamic impact coefficient of the bridge, where y is the dynamic response obtained from the actual measuring point test;

[0184] Wherein, the quasi-static response z(x) is:

[0185]

[0186] In formula (2), x is the vehicle load action position, num is the num...

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Abstract

The invention relates to the technical field of civil engineering and discloses a bridge dynamic impact factor extraction method to effectively solve the problem of determination of a maximum static value. The method can obtain a more accurate and reasonable bridge dynamic impact factor value, and provides reference for bridge design and management and maintenance and the like. The method comprises the following steps: obtaining dynamic response of a measurement point on a bridge; carrying out piecewise polynomial fitting on the quasi-static portion in the bridge dynamic response, and carrying out superposition fitting on the fluctuation portion in the bridge dynamic response through a series of sine curves; carrying out fitting calculation based on the least squares principle to obtain influence line information reflecting bridge static characteristics; determining a tire-road surface contact force distribution model and a corresponding contact force distribution function; and then, on the basis of the actual bridge inherent influence line information obtained through fitting, and with the contact force distribution function being combined, calculating maximum static response when a vehicle passes the bridge, and calculating the bridge dynamic impact factor.

Description

technical field [0001] The invention relates to the technical field of civil engineering, in particular to a method for extracting bridge dynamic impact coefficients. Background technique [0002] Bridge dynamic impact factor (impact factor, IM) or dynamic amplification factor (dynamic amplification factor, DAF), IM=DAF-1, is caused by dynamic load (such as moving vehicles) and is closely related to bridge design, inspection and maintenance, evaluation, etc. Accurate dynamic impact coefficient is beneficial to the economy and safety of bridge design, and for existing bridges, dynamic impact coefficient is an important parameter associated with bridge management and evaluation. In view of the current background of increasing high-speed and heavy-duty vehicles, it is of great engineering practical value to study the dynamic impact coefficient of expressway bridges. [0003] Up to now, most national bridge design codes have different regulations on the impact coefficient. The...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01L5/00
CPCG01L5/0052
Inventor 王宁波沈炎时名扬张诗洁黄天立李东平
Owner CENT SOUTH UNIV
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