后张预应力压接装配混凝土框架结构足尺试验研究

为研究预应力压接高效装配式混凝土框架体系(PPEFF体系)的抗震性能和预应力筋锚具意外失效情况下的抗连续倒塌性能，开展了二层三跨足尺平面框架模型的试验研究。框架模型首层层高4.2 m，顶层层高3.5 m，中梁跨度为8.5 m，边梁跨度为7.5 m，按GB 50011—2010《建筑抗震设计规范》中抗震设防烈度8度(0.3 g)进行设计。试验中首先在框架顶部施加低周水平往复荷载，当加载至0.01 rad位移角时，框架梁端和柱脚耗能钢筋屈服；当加载至0.0195 rad位移角时，结构残余位移角为0.005 rad，展现了良好的低损伤和自复位特性；当加载至0.04 rad位移角时，水平荷载达到峰值，预应力筋仍处于弹性工作状态，展现了良好的抗侧能力和耗能能力。详细观测了加载全过程结构的变形、刚度退化、耗能、预应力变化和梁伸长等行为，并进行了数值分析，与试验结果吻合良好。为进一步验证经历强震损伤后梁端受剪承载力和梁跨中局部有黏结构造措施的有效性，在水平加载试验结束后，人为去除框架一层端部预应力筋锚具，对梁端进行了剪切试验，获得了预应力筋有效和失效情况下PPEFF节点梁端受剪破坏模式，验证了PPEFF梁柱节点具有良好的抗剪能力和安全储备。

Full-scale experimental study on post-tensioned prestressed precast frame structures

To study the seismic performance of a novel precast prestressed efficiently fabricated frame (PPEFF) system with prestressed clamped type beam-column connections and the progressive collapse resistance of PPEFFs with accidental failure of anchorage of prestressed tendon, full-scale mock-up tests of a two-story three-span concrete frame were conducted. The heights of the first floor and the top floor were 4.2 m and 3.5 m, respectively. The spans of the middle beam and the side beam were 8.5 m and 7.5 m, respectively. The sections and reinforcements were designed for a seismic fortification intensity of 8 degree (0.3g) according to the GB 50011—2010 ‘Code for seismic design of building’. The horizontal low cyclic load was first applied at the top floor of the frame. The weakened mild steels at the end of the beam and at the bottom of the column yield at a loading drift angle of 0.01 rad. The residual drift angle of the structure reaches 0.005 rad with a drift angle of 0.0195 rad, which shows good low-damage and self-centering characteristics. The horizontal load reaches its peak value with a drift angle of 0.04 rad, while the prestressed tendon is still in elastic with excellent bearing capacity and energy dissipation ability. The deformation, stiffness degradation, energy dissipation, prestress changing and beam elongation behavior of the frame during the test were observed in detail. The numerical simulation was performed whose results were in good agreement with the experimental results. After the horizontal low cyclic load test, the tendon anchor at one end of the first floor was removed artificially and the vertical action was applied at beam ends to verify the shear capacity at the beam ends after severe earthquake and the effectiveness of local bonding measures in the beam span. The failure modes at the beam end of PPEFF joint under the conditions of effective and failure of prestressed tendons were obtained. It is demonstrated that the PPEFF beam-column joint has good shear resistance and safety redundancy.