Abstract
Traditional methods fail to predict the pumping pressure loss of high-performance concrete properly in super high-rise pumping situations due to complex changes of concrete properties. Therefore, it is imperative to propose a relative accurate method for pumping pressure estimation in super high-rise buildings. This paper builds the simplified pressure calculation method “pressure induced by the gravity plus pressure along the pipe line.” The later one is gained by establishing topology optimized model based on computational fluid dynamics and considering the lubrication layer formation. The effect of rheological properties and flow rate is analyzed based on this model in detail. Furthermore, the developed calculation method is verified by the measured pumping pressure during the super high-rise building construction of the Shanghai Tower (the tallest building in China recently). The relative differences between the calculation results and the measured data in situ are less than 6%, indicating the applicability of this method for predicting the pressure loss of the super high-rise pumping.
Highlights
Concrete pumping has been adopted in formwork casting for decades
To solve the above-mentioned problems, this study aims to establish a simplified pumping pressure estimated method based on mechanical analysis and measurement on spot. e pumping force per meter is attained by computational fluid dynamics. e effects of various factors such as flow rate, lubrication layer thickness, yield stress, and viscosity on the lubricating effect are studied
As the pressure calculation method is no longer suitable for concrete pumping in present codes, a simplified calculation method which combines the concrete pumping pressure measurement in situ and computational fluid dynamics (CFD) simulation is established in this paper. e following conclusions could be drawn: (1) e simplified method developed in this paper can be applied to predict the pumping pressure in the super high-rise pumping cases. e relative difference between the calculated pressure loss and the recorded pressure loss in situ can be controlled within 13%. e key factor of this method is pressure loss coefficient, which is determined by interpolation according to the discharge rate and the plastic viscosity
Summary
Concrete pumping has been adopted in formwork casting for decades It is widely used for concrete conveying during skyscraper construction because it is time-saving and environment-protecting. How to avoid pipeline leakage is still a bottleneck in the long-distance pumping process, such as super high-rise buildings, super long bridges, and long-distance tunnels, in which the pumping pressure plays a crucial role. Is is mainly because both mixture design of fresh concrete and equipment selection depend on the prediction of pumping pressure, especially for super high-rise pumping. Ese specifications play a crucial guiding role in the traditional concrete pumping construction, but they are not suitable for the pressure prediction of high-performance concrete [3].
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