| Steel Tube-Confined Concrete(STCC) is a kind of new composite material.Due to its outstanding performance and characteristics, STCC has achieved rapiddevelopment in terms of construction in our country during the last30years,especially for arch bridge construction. However, according to statistics, the voidproblem appeares ubiquitously in the actual application process of STCC structure,which is a potential threat to the safety of the structure and restricts the developmentof STCC structure. So it is significant to study and analysis of the void problem.Based on the influence of the void to the thermal performance of STCC structure,two aspects of the void problem are mainly studied in this paper:(1) the influence ofvoid to the structure’s temperature field;(2) the research of the void identificationmethod based on boundary element method.STCC structure in the natural environment is considered as the research object.Firstly, the solar load model of CFD software is employed to simulate the sectiontemperature field of STCC structure which is mainly affected by solar radiation. Byanalyzing the difference of temperature field distribution between STCC’s normalsection and void section in the case of different time, weather conditions andseasons, the influence of the void to the structure’s temperature field is studied. Theresults show that the void enhances the nonlinear distribution of the structure’stemperature field under the effect of solar radiation, and the wall temperature of thevoid area will rise, and so does the wall temperature range of the void section, andboth of which will rise with the increase of the void area. The void area’s walltemperature difference of the two types of cross section reaches to the maximumvalue at13PM and14PM under the summer sunny weather condition.The wall temperature of STCC is unstable under the action of naturalenviroment factors, and the influence of void to the wall temperature is susceptibleto the temperature measurement error, which overthrew the original idea that carriesout the void identificaton of STCC based on the wall temperature under naturalconditions. Thus the night condition is considered and a heating plate is decoratedon the wall of STCC to achieve a relatively stable state. According to the walltemperature under this condition, this paper carries out the structure’s voididentification based on the boundary element method. The average relative error ofvoid identification is only0.88%, which indicates the feasibility of the voididentification under this condition.Finally, the influence of different parameters on the void identification of theSTCC is analyzed, including the location, size and the heat flux of the heating plate,temperature measurement error and the number of temperature measurement points. The results show that when the heating plate is decorated on the void area, the voididentification is more accurate. The increase of the area and heat flux of heatingplate and the number of wall temperature measurement points will improve theaccuracy of the void identification. The temperature measurement error has greaterinfluence on the void identification. When the actual temperature measurement error1K is considered, the average relative error of the void identification reaches6%inthe case of this paper. In some external conditions, as the size of STCC’s void areadecreases, the accuracy of the corresponding void identification also decreases. Inorder to achieve good precision of void identification, it needs to select the aboveparameters reasonably. |
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