关于钢管混凝土浇筑产生气泡问题的试验研究

EXPERIMENTAL RESEARCH OF BUBBLES GENERATED BY CONSTRUCTION OF POURING CONCRETE IN STEEL-TUBE

在大连期货大厦采用的小截面(600mm×600mm)方钢管混凝土柱框筒结构体系中,钢管混凝土浇筑施工工艺是项目施工组织的重要课题之一。由于截面过小,内部横隔板等结构复杂,采用传统浇筑法及顶升法均不可行,经综合分析,项目拟采用高抛免振工艺浇筑自密实混凝土。在等比例浇筑试验的过程中,发现方钢管内部构件横隔板节点下方存在气泡。针对气泡的产生机制及对结构的影响,通过进一步的试验验证以确定能否采用及如何采用高抛免振的浇筑工艺。从问题背景出发,详述试验设计、实施、结果分析及所得结论,验证减少气泡的方法以及气泡对结构受力影响不大两方面内容,为采用高抛免振的混凝土浇筑施工工艺提供重要实证依据。

The Dalian Futures Building is the combination of steel structure frame outside and core tube shearing force wall inside. In the steel framework outside, concrete filled steel tubes with small cross-section （600 mm× 600 mm） were used. So the concrete pouring process of the project is one of the important issues of construction organization. As the tubers cross-section is too small with complicated internal structure, using traditional casting methods and jacking method are not feasible. So the high-throw and non-vibrating concrete technique is proposed to apply. During the experiment, there are air a few bubbles below the diaphragm in the square steel tubes. Whether the vibration-free high throw pouring process is applied or not and how to use it is determined by further validation tests aimed at the mechanism for the bubble＇s generation and the impact on the structure. On such background above, details about the experimental design, implementation, results and conclusions are described, and two aspects about how to reduce the bubbles and the bubbles effect on the structure force are proved. These conclusions provide important empirical basis for applying the high-throw and non-vibratin~ concrete technique for the project.