English：

Tianxingzhou Dedicated Channel Bridge of Changtai Yangtze River Bridge is the world’ slargest⁃span highway⁃railway steel truss arch bridge. Its mid⁃support vertical bearing on the railway sideis a 19000t spherical bearing, currently the heaviest of its kind globally. The construction facedsignificant challenges due to the bearing’s oversized baseplate dimensions, thin grouting layer thickness,extended flow distance of grouting material, and stringent performance requirements for the groutingmaterial that compromised construction quality assurance. To address these issues, grouting experimentalresearch was conducted to develop a novel composite grouting material characterized by high⁃fluidity, low⁃deformation, and high⁃crack resistance, establishing performance parameters for super⁃large bearinggrouting materials. Bubble distribution patterns in the bearing baseplate were investigated, leading toproposed anti⁃bubble measures involving defoaming agent addition and increased venting distance. Amodified vertical⁃shaft mortar mixer was adopted to resolve large⁃volume grouting preparation challenges.A gravity method with step⁃by⁃step grouting process was introduced to enhance grouting flow potential energy. By implementing separate grouting procedures for anchor bolt holes and baseplate groutinglayers, continuous casting of the bearing baseplate grouting layer was achieved,which ensured high⁃quality construction of the bearing grouting system.