广州白云国际机场二号航站楼预应力混凝土柱结构设计

Prestressed concrete column design of Guangzhou Baiyun International Airport Terminal 2

我国的《建筑抗震设计规范》(GB 50011—2010)及《高层建筑混凝土结构技术规程》(JGJ 3—2010)规定钢筋混凝土框架结构的弹性层间位移角限值为1/550。对于层高较大的框排架结构,如机场航站楼、铁路站房、体育馆等建筑,柱顶铰接,排架结构的位移比框架结构大,层间位移角限值往往成为柱截面的控制因素。这些建筑的围护结构多为金属或玻璃幕墙,能承受较大的变形,如混凝土柱仍按1/550的层间位移角限值设计,柱截面往往偏大。如为满足位移角限值而采用钢柱或钢管混凝土柱,则经济代价较大。在广州白云国际机场二号航站楼工程中,对支撑钢屋盖的混凝土柱施加预应力,当结构的弹性层间位移角限值放宽至1/350时,预应力混凝土柱仍基本处于弹性状态,柱截面尺寸得到优化,建筑效果和经济效益显著。

Chinese design standard Code for seismic design of buildings(GB 50011—2010) and Technical specification for concrete structures of tall building(JGJ 3—2010) stipulate that the limitation for the elastic inter-story displacement angle of reinforced concrete frame structure is 1/550. For frame-bent structures such as airport,railway station and gymnasium,because hinge joints exist at the top of the columns and the displacement of bent structure is much larger than that of frame structure,the limitation value of inter-story displacement angle usually becomes the critical factor for determining their column sizes. Most of the exterior protected structure of these frame-bent structures buildings are metal or glass curtain wall which can sustain large deformation. If the concrete columns are chosen for the frame-bent structures and are designed following the limit value of inter-story displacement angle as 1/55,the column sizes will be over-large; while if the steel columns or the steel tube concrete columns are adopted,the cost will be expensive. In order to overcome the dilemma,in Guangzhou Baiyun International Airport Terminal 2 building,prestressing technique is applied to the concrete columns that support roof. In this case,the prestressed concrete column performed elastically even when the elastic inter-story displacement angle is around 1/350. Using this approach could reduce the column size,and improve significantly the aesthetic aspects and economic benefits of the building.