塑性铰区采用纤维增强混凝土柱抗震性能试验研究

Experimental investigation on seismic behavior of columns with fiber-reinforced concrete in potential plastic region

为了提高钢筋混凝土柱的抗震性能,考虑在其潜在的塑性铰区采用纤维增强混凝土(FRC)代替普通混凝土。设计6个剪跨比为3、柱内箍筋配置较少的钢筋混凝土柱试件,其中5个试件的潜在塑性铰区采用了FRC,另外1个试件的潜在塑性铰区未采用FRC,并对其进行拟静力试验。通过改变FRC区高度和强度以及柱轴压比,观测试件在低周反复水平荷载作用下的裂缝开展和破坏过程,研究其滞回特性、变形能力及耗能能力。结果表明,与普通钢筋混凝土柱相比,塑性铰区采用FRC且柱内箍筋配置较少的柱,其破坏形态为纵向受力钢筋屈服后的剪切破坏,具有较好的变形能力和损伤容限;在材料强度、柱轴压比不变时,FRC区高度增加1倍,位移延性系数、极限位移角分别提高45%和21%,耗能能力提高81%;局部使用FRC可以减少约束箍筋和抗剪箍筋用量。

In order to improve the seismic behavior of the reinforced concrete column, the fiber-reinforced concrete （FRC） was applied in the potential plastic region of the column instead of ordinary concrete. A series of six reinforced concrete column specimens with shear span ratio of 3 and little stirrup were designed, where five specimens were made of FRC in the potential plastic region, and one was conventional concrete column for comparison. By means of quasi- static tests, the cracking and damage process of the specimens were studied under low cyclic reversed lateral loads. The hysteretic behavior, deformability and energy dissipation capacity were analyzed for various FRC region, axial load ratio and concrete strength. The results show that, combined with normal concrete columns, the column with FRC in the potential plastic region and little stirrup exhibits shear failures after the longitudinal reinforcement yielding with better ductile characteristics and damage tolerance. As the height of FRC region doubled, the displacement ductility ratio and drift ratio increased by 45% and 21% respectively, and energy dissipation capacity increased by 81%. The column with FRC in the part of column can reduce the amounts of confining reinforcements and shear stirrups.