CAJ | 학술논문

为合理确定主跨680 m 的莫桑比克马普托大桥的主梁形式，利用节段模型风洞试验，分别研究了扁平钢箱梁、钢箱叠合梁和工字型叠合梁的气动性能。结果表明：扭转刚度较弱的工字型叠合梁颤振风速远低于检验风速，且涡激振动也不满足舒适性要求，在设计中不宜采用；钢箱叠合梁尽管颤振风速较高，但其在钢箱顶面凸起的混凝土桥面板会造成气流分离和漩涡脱落，可能存在较大涡激振动振幅的隐患，可在设计中选择性采用；扁平钢箱梁断面颤振临界风速高，且无明显涡激振动，为该大跨度悬索桥的优选主梁形式。试验结果还显示，若设置宽0．5 m 的风嘴导流板可进一步提高钢箱梁断面的颤振临界风速，但由于导流板直接影响造价并增加后期养护费用，而节段模型试验结果一般偏于保守，因此最后的取舍需要参考三维颤振计算或全桥气弹模型风洞试验结果。若在其斜腹板上外挂直径90 cm 的过桥水管，将显著弱化颤振性能和涡振性能，因此在设计中不宜采用。
위합리학정주과680 m 적막상비극마보탁대교적주량형식，이용절단모형풍동시험，분별연구료편평강상량、강상첩합량화공자형첩합량적기동성능。결과표명：뉴전강도교약적공자형첩합량전진풍속원저우검험풍속，차와격진동야불만족서괄성요구，재설계중불의채용；강상첩합량진관전진풍속교고，단기재강상정면철기적혼응토교면판회조성기류분리화선와탈락，가능존재교대와격진동진폭적은환，가재설계중선택성채용；편평강상량단면전진림계풍속고，차무명현와격진동，위해대과도현색교적우선주량형식。시험결과환현시，약설치관0．5 m 적풍취도류판가진일보제고강상량단면적전진림계풍속，단유우도류판직접영향조개병증가후기양호비용，이절단모형시험결과일반편우보수，인차최후적취사수요삼고삼유전진계산혹전교기탄모형풍동시험결과。약재기사복판상외괘직경90 cm 적과교수관，장현저약화전진성능화와진성능，인차재설계중불의채용。
To select a rational main girder type for the Maputo Bridge in Mozambique which is projected to have a main span of 680 m ,the aerodynamic behavior of three types of main girder ,in-cluding the flat steel box girder ,steel-concrete composite box girder and I-shaped composite girder were examined by the sectional model wind tunnel test .The results of the test indicate that the I-shaped composite girder with intrinsic low torsional stiffness is not a favorable solution in the de -sign ,for its flutter wind speed is much smaller than the testing wind speed and its vortex -induced vibration is not able to meet the requirements of physical and psychological comfort as well .The steel-concrete composite box girder can withstand higher flutter wind speed ,but the concrete deck slab humps on top of the steel box are prone to cause airflow separation and the concrete deck slab is likely to be shed by vortex flow ;therefore ,this type of main girder faces the latent risk of large-amplitude vortex-induced vibration ,which can be taken as an alternative solution in the design . The cross section of the flat steel box girder can bear a higher critical flutter wind speed and no sig -nificant vortex-induced vibration was found on it ,in this sense ,the flat steel box girder is regarded as the optimal main girder type for long-span suspension bridges .From the test results ,we also find that the critical flutter wind speed for the cross section of the steel box girder can be further improved by installing the 0 .5 m thick guide vanes .However ,the adoption of guide vanes will di-rectly influence the cost and will increase the later maintenance cost ,furthermore ,the results of the sectional model test are usually conservative ,thus ,the final decision should be made based on the three-dimensional flutter calculation and the results of the aeroelastic model wind tunnel test for the overall bridge .If the 90 cm diameter cross-the-bridge water pipes are hung outside the ob-lique webs ,the capacity of the main girder to counter flutter and vortex-induced vibration would be significantly weakened ,therefore this solution should be omitted in the design .