385m超高跨越输电塔电梯井筒的阻力系数研究

Drag Coefficients of Elevator Shaft of Ultra-High Long-Span Transmission Tower with Height of 385 Meters

针对大跨越输电塔电梯井筒的风荷载采用节段模型和整塔模型的风洞试验进行研究,分析有无爬梯、有无塔体干扰对井筒阻力系数的影响,并与各国规范中圆柱阻力系数的规定值对比,最后给出了井筒阻力系数的设计建议值。研究表明:有爬梯井筒的阻力系数大于无爬梯井筒的阻力系数;有塔体干扰下井筒阻力系数随风向变化显著,在45°达到最小值,在35°达到最大值;节段模型试验和整塔模型试验获得的井筒气动力系数比较接近;给出了电梯井筒在有塔体干扰下阻力系数随风向角的建议值,无爬梯井筒最大的阻力系数为0.93,与GB 50009—2012《建筑结构荷载规范》推荐的光滑圆柱0.9的阻力系数比较接近。

Wind tunnel tests were conducted on sectional models and whole tower models to obtain the wind loading on the elevator shaft of long-span transmission towers. The influence of climbing ladders and interference of tower body on the drag coefficient of the elevator shaft was analyzed. The test results were compared with those regulated in different countries’ codes. Finally, the drag coefficients of the elevator shaft were recommended for the design. The results showed that the drag coefficients of elevator shaft with climbing ladder was larger than that of shaft without climbing ladder. With the interference effect of tower body, the drag coefficients significantly varied with the wind azimuth, reaching their maximum value at 35 degree and their minimum value at 45 degree. The aerodynamic coefficients of the shaft obtained from sectional model and whole tower model tests were almost equaled. The drag coefficients of the shaft with respect to wind azimuth under the interference of tower body were recommended. The maximum value of elevator shaft without climbing ladder was 0.93, which was quite close to 0.9 that was the drag coefficient of smooth circular cylinder recommended by Load Code for the Design of Building Structures(GB 50009-2012).