坡面摩擦低预应力自复位混凝土框架结构的抗震性能分析

Analysis of Seismic Performance of Self-Centering Concrete Frame Structures Characterized by Low Prestressing and Slope Friction

传统自复位混凝土框架的刚度和耗能能力不易满足结构的大震需求,使结构在地震过程中的层间位移角过大。且为满足结构的完全复位,须对预应力筋进行高张拉,进一步降低了结构的耗能比β。提出的坡面摩擦低预应力自复位混凝土(SF-SCPC)框架结构将低预应力和高耗能比β引入到自复位混凝土框架中,允许结构出现一定的残余位移,从而实现结构在罕遇地震下的高耗能。以某8度设防地区的钢筋混凝土结构为原型,分别设计了低预应力坡面摩擦半自复位混凝土(SF-PSCPC)框架、带平面摩擦耗能器的半自复位混凝土(PF-PSCPC)框架和带坡面摩擦耗能器的完全自复位混凝土(SF-CSCPC)框架。对结构进行设防烈度地震、罕遇地震和极罕遇地震下的非线性动力时程分析,研究了耗能器形式与初始预应力等参数对层间位移角、残余层间位移角和梁柱损伤等结构抗震性能指标的影响。结果表明:在预应力自复位混凝土框架中充分结合坡面摩擦耗能机制和低预应力复位机制可有效降低结构的层间位移角,减少主体构件的损伤;SF-PSCPC框架中的节点滞回曲线面积明显大于PF-PSCPC框架和SF-CSCPC框架,表现出较高的耗能能力;SF-PSCPC结构在罕遇地震下虽有一定的残余位移,但均小于结构经济可修的限值。

Due to the difficulty in meeting major earthquake demands with the stiffness and energy tion dissipa-capabilities of traditional self-centering prestressed concrete(SCPC)frames,the inter-story drift of the structure becomes excessively large during seismic events.Additionally,to achieve full re-centering of the structure,high tensioning of steel strands is required,which further reduces the energy dissipation ratio(β)of the structure.A self-centering prestressed concrete frame with low prestressing and slope friction(SF-SCPC)was proposed,low prestressing and a high energy dissipation ratioβwere incorporated into the self-centering prestressed concrete frame,allowing for some residual displacement in the structure to chieve a-high energy dissipation under large earthquakes.Using a reinforced concrete structure in an gree 8-de-seismic fortification area as a prototype,semi-self-centering prestressed concrete frames with low tressing pres-and slope friction(SF-PSCPC),semi-self-centering prestressed concrete(PF-PSCPC)frames with planar friction energy dissipating,and fully self-centering prestressed concrete frames with slope tion fric-energy dissipating(SF-CSCPC)were designed.Nonlinear dynamic time-history analysis was ted conduc-on the structures under design intensity,rarely occurred,and extremely rarely occurred earthquakes to study the impact of energy dissipator forms and initial prestressing parameters on the seismic performance indicators such as inter-story drift,residual inter-story drift,and beam-column damage.The results ted indica-that effectively combining the slope friction energy dissipation mechanism and low prestressing tering re-cen-mechanism in self-centering prestressed concrete frames could significantly reduce the inter-story drift and decrease damage to main components.The hysteresis curve area of connections in the SF-PSCPC frame is significantly larger than that of the PF-PSCPC and SF-CSCPC frames,indicating higher energy tion dissipa-capacity.Although the SF-PSCPC structure exhibited some residual displacement under rarely occurred earthquakes,it remained within the economically repairable limit of the structure.