预应力混凝土框架结构的抗震设计探讨

Discussion on Aseismic Design of Prestressed Concrete Frame Structures

在设计多层多跨预应力混凝土框架结构时,一般按抗裂度控制条件计算预应力筋后再按允许的预应力度确定普通钢筋的数量,则节点抗剪强度不足和“强梁弱柱”难以避免;如果满足梁的截面相对受压区高度的结构位移延性规定,则梁的抗裂度不易满足。建议放松受压区高度、抗裂度控制条件,选取合适的预应力度,选取内节点处强梁弱柱,增加柱尤其是中柱的箍筋,在边柱中加配预应力筋,内节点附近梁加腋,在罕遇地震作用下将多层多跨预应力混凝土框架结构设计成“混合耗能机制”的有限延性框架。

In the design of the multi-story and multi-span prestressed concrete frame structures （PCFS）, tendons of frame beams usually were designed by crack resistance capacity and it was hard to avoid “strong beam-weak column” and “strong element-weak joint” around inner beam-column joints. Crack resistance capacity was difficult to satisfied, if tendons of frame beams were designed by displacement ductility resistance capacity. By comparing it with that of design codes （GB50010 and GB50011 ）, the authors gave the detailing measures such as “strong beam-weak column”, adding tendons in the outer columns, haunching in height of beams around inner joints, increasing stirrup quantity near plastic hinges of columns, especially inner columns etc.. It is necessary and rational that reasonable mixed energy dissipation mechanisms （EDM） of limited displacement ductility are applied for the PCFS＇s aseismic design with conditions of major earthquakes.