钢筋混凝土双曲拱桥墩上结构的控爆拆除

介绍桂林市解放桥墩上结构爆破拆除的设计与施工。该桥是一座长 180m、宽15m、4墩 5跨、7肋 6波的双曲拱桥。桥下水深 2～ 7m不等。根据其受力和结构特点 ,采用控爆与机械吊装相结合的方法 ,按照平衡对称、均衡卸载的原则 ,先拆除拱上结构预制件 ,然后对拱肋、拱顶平台等拱圈部分进行全面钻孔、一次爆破 ,使其向河面方向整体塌落。总计钻孔约 85 0 0个 ,装填乳化炸药 76 5kg ,使用导爆管 1 18万发 ,导爆索 10 0 0m。用挖泥船 ,配合其他船只 ,进行水中清碴 ,用 15天时间就把主航道疏通。

CONTROLLED BLASTING DEMOLITION OF THE STRUCTURE ON ABUTMENTS OF A REINFORCED-CONCRETE HYPERBOLIC ARCH BRIDGE

In this paper, design and construction of the blasting for demolition of Jiefang Bridge in Guilin, Guangxi were introduced. It is a hyperbolic arch bridge with length of 180m, width of 15m, 4 abutments, 5 spans, 7 ribs and 6 waves. The depth of river under the bridge varies from 2 to 7 m. According to the characteristics of its load bearing and structure, the bridge was demolished by the method of combining controlled blasting with craning hauling. In the light of the principles of balanced and symmetrical unloading, the readymade units on the arch were firstly removed by use of craning hauling method. Then, the arch rings inclusive of the ribs and the vault platform were collapsed to water face by one shot drilling and blasting. For the blasting, about 8500 holes had been bored, emulsion explosive of 765 kg loaded, 11800 Nonel detonators and detonating fuse of 1000m used. A small dredger and other boats were used for remove of broken concrete in water. The dredge of the main channel was finished only in 15 days.