CN106932134B - Based on the Cable force measuring method for waiting generation hinged beam model - Google Patents

Abstract

The present invention belongs to technical field of civil engineering based on the Cable force measuring method for waiting generation to be hinged beam model, and in particular to a kind of vibratory drilling method Cable force measuring method；This method is first according to conventional method, passes through Suo Li T and n rank vibration frequency f corresponding with Suo Li T₁、f₂、...、f_n, obtain the generation such as k ranks hinged beam length L_ak；Then to L_akAverage is taken, obtains a nominal length pervasive to each rankThe L in generation hinged beam method formula will be waited again_akReplace withMeasuring rope power T' and n rank vibration frequency f corresponding with treating measuring rope power T' is treated in foundation₁'、f₂'、...、f_n' new relation, so as to obtain treating measuring rope power T'；This method can not only reduce because Boundary Condition Effect is indefinite and caused by L_akThe problem of error is larger, and can solve by the Boundary Condition Effect generation hinged beam length L such as make each first order mode of drag-line corresponding_akThe problem of inconsistent, improve the measurement accuracy of Cable power.

Description

Based on the Cable force measuring method for waiting generation hinged beam model

Technical field

The present invention is specifically related to based on waiting Cable force measuring method of generation hinged beam model to belong to technical field of civil engineering A kind of and vibratory drilling method Cable force measuring method.

Background technology

Drag-line is the main bearing member of cable system bridge, and the transmission and distribution of power are carried out to cable system bridge.Cable Power is not only one of important parameter of cable system Bridge Design, and is bridge construction control and assessment bridge normal use shape The important indicator of state.As it can be seen that the accuracy of cable force measurement is most important.

In order to improve the measurement accuracy of Cable power, there is waiting generation hinged beam method, such as Harbin Institute of Technology Postgraduate's thesis that Xiao can rush《The experimental study of cable force vibration method measurement》, and equivalent rope length hinged grade for method, Such as the article that yellow emigrant etc. delivers on Southeast China University's journal (natural science edition)《Consider the suspension cable of vibration absorber spring rate Equivalent rope length and cable force measurement》

The principle of both approaches is that each rank mode of oscillation of the drag-line of an Arbitrary Boundary Conditions is equivalent to a root long Spend for L_akHinged girder mode of oscillation, core formula is as follows：

Wherein, T represents Cable power (N), and m represents drag-line line density (kg/m), L_akRepresent that drag-line k first order modes are corresponding etc. For hinged girder model length (m), f_kRepresent the k ranks natural frequency of vibration (Hz), EI represents rope section bending stiffness (Nm2), and π represents circle Frequency.

Although this method can improve Cable power measurement accuracy, but there is problems：Due to boundary condition Influence is still not clear, and live drag-line realistic model is complicated more than ideal situation, therefore L_akCan only be deposited between approximation, with true value In error；In addition, by Boundary Condition Effect, each first order mode of drag-line is corresponding to wait generation hinged beam length L_akAlso it is inconsistent, using phase Same L_akSuo Li is calculated, equally reduces the measurement accuracy of Suo Li.

The content of the invention

To solve the above-mentioned problems, the invention discloses a kind of based on the drag-line cable force measurement side for waiting generation hinged beam model Method, this method can not only reduce because Boundary Condition Effect is indefinite and caused by L_akThe problem of error is larger, and can solve Certainly made each first order mode of drag-line is corresponding to wait generation hinged beam length L by Boundary Condition Effect_akThe problem of inconsistent, be conducive to improve and draw The measurement accuracy of cable force.

The object of the present invention is achieved like this：

Based on the Cable force measuring method for waiting generation hinged beam model, comprise the following steps：

Step a, in bridge construction stretching process, Suo Li T is applied to drag-line, demarcate the Suo Li T and and rope of drag-line to be measured The corresponding n ranks vibration frequency f of power T₁、f₂、...、f_n；

Step b, Suo Li T and n rank vibration frequency f corresponding with Suo Li T are passed through₁、f₂、...、f_n, according to equation below：

Calculate the generation such as k ranks hinged beam length L_ak；

Step c, according to equation below：

To L_akAverage is taken, obtains a nominal length pervasive to each rank

Step d, in bridge operation stage, collection n rank vibration frequency f corresponding with Cable power T' to be measured₁'、f₂'、...、 f_n'；

Step e, the frequency f for obtaining step d₁'、f₂'、...、f_n' it is brought into equation below：

Calculate and n rank vibration frequencies f₁'、f₂'、...、f_n' corresponding rope force value T₁、T₂、...、T_n；

Step f, according to equation below：

Cable power T' to be measured is calculated.

Beneficial effect：

The present invention is first according to conventional method, passes through Suo Li T and n rank vibration frequency f corresponding with Suo Li T₁、f₂、...、 f_n, obtain the generation such as k ranks hinged beam length L_ak；Then to L_akAverage is taken, obtains a nominal length pervasive to each rankAgain will Deng the L in generation hinged beam method formula_akReplace withMeasuring rope power T' and n ranks corresponding with treating measuring rope power T' vibration frequency are treated in foundation Rate f₁'、f₂'、...、f_n' new relation, so as to obtain treating measuring rope power T'；This method can not only be reduced because of boundary condition shadow Ring it is indefinite and caused by L_akThe problem of error is larger, and can solve to correspond to each first order mode of drag-line by Boundary Condition Effect Wait generation hinged beam length L_akThe problem of inconsistent, improve the measurement accuracy of Cable power.

Brief description of the drawings

Fig. 1 is the schematic cross-section of PES7-139 type drag-lines.

Fig. 2 is inhaul cable vibration auto-power spectrum spectrogram.

Embodiment

The specific embodiment of the invention is described in further detail below in conjunction with the accompanying drawings.

Specific implementation profit one

The Cable force measuring method based on grade generation hinged beam model of the present embodiment, comprises the following steps：

Step a, in bridge construction stretching process, Suo Li T is applied to drag-line, demarcate the Suo Li T and and rope of drag-line to be measured The corresponding n ranks vibration frequency f of power T₁、f₂、...、f_n；

Step b, Suo Li T and n rank vibration frequency f corresponding with Suo Li T are passed through₁、f₂、...、f_n, according to equation below：

Calculate the generation such as k ranks hinged beam length L_ak；

Step c, according to equation below：

To L_akAverage is taken, obtains a nominal length pervasive to each rank

Step d, in bridge operation stage, collection n rank vibration frequency f corresponding with Cable power T' to be measured₁'、f₂'、...、 f_n'；

Step e, the frequency f for obtaining step d₁'、f₂'、...、f_n' it is brought into equation below：

Calculate and n rank vibration frequencies f₁'、f₂'、...、f_n' corresponding rope force value T₁、T₂、...、T_n；

Step f, according to equation below：

Cable power T' to be measured is calculated.

Specific implementation profit two

The stream of profit one is embodied based on the Cable force measuring method for waiting generation hinged beam model, foundation in the present embodiment Journey, carries out actual measurement, the schematic cross-section of the drag-line is as shown in Figure 1 to PES7-139 types drag-line.The technical parameter of the drag-line It is as follows：Rope long l=68.89m, line density m=44kg/m, sectional area A=5349mm², limit Suo Li T_lim=8993kN, conversion Bending stiffness EI=455.37kNm.

This method is as follows：

Step a, in bridge construction stretching process, Suo Li T are applied to drag-line, by inhaul cable vibration as shown in Figure 2 certainly Power spectrum spectrogram, demarcates the Suo Li T and n rank vibration frequency f corresponding with Suo Li T of drag-line to be measured₁、f₂、...、f_n, such as the institute of table 1 Show：

1 Suo Li of table and vibration frequency tables of data

Step b, Suo Li T and n rank vibration frequency f corresponding with Suo Li T are passed through₁、f₂、...、f_n, according to equation below：

Calculate the generation such as k ranks hinged beam length L_ak, result of calculation is as shown in table 2：

2 each rank of table etc. is for hinged girder length data table

Step c, according to equation below：

To L_akAverage is taken, obtains a nominal length pervasive to each rankResult of calculation is：

Step d, in bridge operation stage, collection n rank vibration frequency f corresponding with Cable power T' to be measured₁'、f₂'、...、 f_n'；Wherein, the theoretical value 1799kN of Cable power T' to be measured, obtained n rank vibration frequencies f₁'、f₂'、...、f_n' such as table 3 It is shown：

The Cable power to be measured of table 3 and vibration frequency tables of data

Step e, the frequency f for obtaining step d₁'、f₂'、...、f_n' it is brought into equation below：

Calculate and n rank vibration frequencies f₁'、f₂'、...、f_n' corresponding rope force value T₁、T₂、...、T_n, result of calculation such as table 4 It is shown：

Table 4 treats measuring rope force value calculation result data table

Step f, according to equation below：

Cable power T'=1792kN to be measured is calculated.

Finally, the Suo Li result of calculations 1792kN tried to achieve according to the method for the present invention and theoretical value 1799kN is contrasted, Relative error is very small, should be the result shows that the Suo Li result of calculations and actual value deviation very little that the method for the present invention obtains, can be used for Actual cable force measurement.

The foregoing is only a preferred embodiment of the present invention, but protection scope of the present invention be not limited thereto, Any one skilled in the art the invention discloses technical scope in, technique according to the invention scheme and its Inventive concept is subject to equivalent substitution or change, should be covered by the protection scope of the present invention.

Claims (1)

1. based on the Cable force measuring method for waiting generation hinged beam model, it is characterised in that comprise the following steps：

Step a, in bridge construction stretching process, to drag-line apply Suo Li T, demarcate drag-line to be measured Suo Li T and with Suo Li T couple The n rank vibration frequencies f answered₁、f₂、...、f_n；

Step b, Suo Li T and n rank vibration frequency f corresponding with Suo Li T are passed through₁、f₂、...、f_n, according to equation below：

Calculate the generation such as k ranks hinged beam length L_ak；Wherein, T represents Cable power, and m represents drag-line line density, L_akRepresent drag-line k ranks The corresponding grade of the vibration shape is for hinged girder model length, f_kRepresent the k rank natural frequencies of vibration, EI represents rope section bending stiffness, and π represents circumference Rate；

Step c, according to equation below：

To L_akAverage is taken, obtains a nominal length pervasive to each rank；

Step d, in bridge operation stage, collection n rank vibration frequency f corresponding with Cable power T' to be measured₁'、f₂'、...、f_n'；

Step e, the frequency f for obtaining step d₁'、f₂'、...、f_n' it is brought into equation below：

Calculate and n rank vibration frequencies f₁'、f₂'、...、f_n' corresponding rope force value T₁、T₂、...、T_n；

Step f, according to equation below：

Cable power T' to be measured is calculated.