斜向风作用下倒梯形桁梁桥气动力参数研究

摘要

To study the influences of the aerodynamic parameters on the aerodynamic charac‐teristics of the rail‐cum‐road truss girder bridge with inverted trapezoid section under skew wind , two kinds of the truss girder models with inverted trapezoid sections of different dimensions were selected and the wind tunnel tests for the models under various combined cases of the completed bridge and construction state ,wide range of wind yawed angles (0°~180°) and different wind at‐tack angle flow were carried out .The five‐component force coefficients of the models were meas‐ured and the test values were compared to the results of the traditional skew wind decomposition theory .The results of the tests show that the maximum values of the force coefficients of the transverse bridge direction all appear at the wind yawed angle of about 15° while the maximum val‐ues of the force coefficients of the longitudinal bridge direction appear at the yawed angle of about 60° .For the truss girder bridge with such type of the trapezoid section ,the wind from the trans‐verse bridge direction is not necessarily the worst flow in the calculation of the transverse bridge wind‐induced response and the wind force of the longitudinal bridge direction can not be ignored . The comparison of the wind tunnel test results to the skew wind decomposition theory tells that the ratios of the force coefficients of the transverse and longitudinal bridge directions obtained by the tests and the decomposition theory have certain deviations .%为研究气动力参数对倒梯形断面公铁两用桁梁桥在斜向风作用下气动特性的影响，采用2种不同断面尺寸的倒梯形断面桁梁模型，针对成桥状态与施工状态，在大范围风偏角（0°～180°）与不同风攻角来流条件多种组合工况下进行风洞试验，测量其五分力系数，并将试验值与传统斜向风分解理论结果进行对比。试验结果表明：横桥向力系数最大值均发生在风偏角为15°左右时，顺桥向力系数最大值发生在风偏角为60°左右时；对于此类断面桁梁桥，横桥向风致响应计算时，横桥向来风时不一定是最不利来流，且顺桥向力不能忽略。对比风洞试验结果与斜向风分解理论表明，两者得出的顺桥向力系数与横桥向力系数的比值有一定的偏差。