Studies On The Problem Of Temperature Compensation Of Strain Measurement In The Detection Process Of Concrete Bridge

In the process of strain measurement of bridge structure,the temperature effect seriously affected the accuracy of strain measurement results all the way.However,the present compensation of temperature strain can not eliminate the effects of strain measurement in the process of bridge detection which made by temperature completely,mainly emboding in two aspects:firstly, the temperature field of the strain gauge of temperature compensation is different from that of the measurement strain gague.secondly,the temperature compensation at the present stage has not considered the influences of secondary As a result,raising a more effective and reliable method of temprerature compensation in order to improve the accuracy of strain measurement has become an important research subject.The text analyses the temperature field changes of box bridge in sunshine effect is based on loading test which is based on loading test through by carrying out s field monitoring to strain in each measure point of test section in the middle of 2~3#bridge span of disanjiao bridge,analysing comparatively the influence degree made by temperature of test point in different position and the curve fitting of temperature compesation produced by temperature of loading test when the changes of environment temperature presents curve.the results of the experiment are as follows:first,for box bridge,it mainly exists vertical temperature gradient and temperature gradient inside and outside the box room.the vertical temperature of bridge mainly exists in the section from roof to bridge floor;in normal circumstances,the internal temperature of the box room is relatively stable,the temperature changes in test point is bigger than the internal temperature inside the box room;second,the strain measurement of test point at roof is mainly influenced by vertical temperature gradient;The strain measurement of test point at beam bottom is mainly influenced by temperature gradient inside the box room;third,although the difference of temperature strain of each test point made by linear temperature effect is small,but temperature can make a big difference to the influence degree of test result of each test point for the load plan of unbalance loading.Therefore,in the temperature compensation,considering heating-up time(or temperature fall time),the compensation of eachtest point in beam bottom of small box bridge can make a proportional reduce(or increase)through a curve parabola fitting to the strain of each test point in the process of strain measurement,.Researching the temperature effect in each measure point of test section in the middle of 2~3#bridge span of disanjiao bridge can provide proofs for further optimization of the temperature compensation method of strain measurement in the process of bridge detection.