PP-ECC墩柱抗震设计方法初探

Preliminary Study on Seismic Design Method of PP-ECC Pier Column

针对将RC墩柱塑性铰区全截面置换为聚丙烯纤维工程水泥基复合材料(PP-ECC)的墩柱开展了抗震设计方法的研究。基于平截面假定,针对PP-ECC墩柱(将RC墩柱的塑性铰区混凝土置换为PP-ECC)首先推导了其塑性铰区截面弯矩-曲率曲线关键点(屈服弯矩、屈服曲率、峰值弯矩和峰值曲率)的计算方法,然后推导了PP-ECC墩柱力-位移曲线关键点(屈服承载力、屈服位移、峰值承载力、峰值位移)的计算方法,进而提出PP-ECC墩柱的抗震设计方法;基于PP-ECC(抗压强度fpp-c=30 MPa)的单轴力学性能试验确定了其一维拉压本构关系,依据所提出的PPECC墩柱的抗震设计方法计算确定了PP-ECC墩柱模型塑性铰截面的弯矩-曲率关键点值及PP-ECC墩柱模型力-位移曲线的关键点值,并与相应的RC墩柱模型(抗压强度fc=30 MPa)进行了对比分析,结果表明:PP-ECC墩柱相较于塑性铰区采用同等强度混凝土的RC墩柱,其承载力略有提高,且变形能力显著提高。

The aseismic design method of RC pier column with plastic hinge region replacement with polypropylene fiber engineering cement matrix composite (PP-ECCC) is studied in this paper.Based on the assumption of plane section,the key points (yield moment,yield curvature) of the section moment curvature curve in the plastic hinge region of the RC pier column were first deduced for the PP-ECC pier column (replacing concrete in the plastic hinge region with PP-ECC).The calculation method of peak bending moment and peak curvature was derived,and the method of calculating the key points (yield bearing capacity,yield displacement,peak bearing capacity,peak displacement) of PP-ECC pier column was deduced,and the seismic design method of PP-ECC pier column was put forward.Based on the uniaxial mechanical properties test of PP-ECCs (compressive strength f pp-c =30 MPa),a Vera compressive constitutive relation was determined.According to the proposed seismic design method of PP-ECC pier column,the moment curvature key points of plastic hinge section of PP-ECC pier column model and the key point value of force displacement curve of PP-ECC pier column model were determined.Then a comparative analysis was conducted with the corresponding RC pier column model(compressive strength f c=30 MPa).The results show that compared with the RC pier column with the same strength in plastic hinge region,the bearing capacity and the deformation capacity of the 10 PP-ECC pier column are slightly increased and the deformation capacity is obviously improved.