GFRP管型钢再生混凝土组合柱轴压性能及承载力计算

Axial compression performance and bearing capacity calculation of GFRP tube filled with steel-reinforced recycled concrete composite column

通过对11根玻璃纤维(GFRP)管型钢再生混凝土组合柱的静力加载试验以研究其轴压性能,主要考虑再生粗骨料取代率、配钢率和长细比、再生混凝土强度等级等设计参数,重点分析试件破坏过程及形态、荷载-位移曲线、荷载-应变曲线和承载力等。结果表明:各试件试验过程及破坏形态相似,型钢先发生屈服,随后内部再生混凝土被压碎,最后外部GFRP管纤维撕裂破坏;试件轴压承载力随着取代率和长细比的增大而逐渐减小,其最大降幅分别为10.8%和9.5%;提高配钢率和再生混凝土强度对组合柱的轴压承载力是有利的,其最大增幅分别为14.1%和6.1%。在GFRP管的约束作用下,内部型钢再生混凝土处于三向受压状态,组合柱的承载力得到了显著提高。在此基础上,采用叠加原理并考虑再生粗骨料取代率及长细比的不利影响,提出GFRP管型钢再生混凝土组合柱的轴压承载力计算公式,计算值与试验吻合较好。

Through the static loading test of 11 GFRP tube filled with steel reinforced recycled concrete composite columns to study their axial compression properties. Design parameters include recycled coarse aggregate replacement percentage, steel ratio, slenderness ratio and strength of recycled concrete. Failure process and mode of all specimens, the load-displacement curves and load-strain curves were mainly analyzed. The test results indicate that the axial compressive force process and failure mode of all specimens are similar, the profile steel yield firstly, then the internal recycled concrete crushing, and finally the external GFRP tube occurs buckling deformation. The axial bearing capacity of specimens decreased with the increase of the recycled coarse aggregate replacement percentage and slenderness ratio, the maximum decrease was 7.6% and 11.7%.Increasing the strength of recycled concrete and steel ratio is beneficial to the axial bearing capacity of columns, the maximum increase is 7.9% and 19.7%. Internal steel-reinforced recycled concrete is subjected to three-way pressure under constraints of GFRP tube, axial bearing capacity of composite columns has been significantly improved. On this basis, the calculation formula of axial bearing capacity for the composite columns is put forward, which adopted the principle of overlay and considered the adversely affect of recycled coarse aggregate replacement percentage and slenderness ratio. The calculated value is in good agreement with the actual bearing capacity of the test.