| In recent years,some corroded H-section steel columns with large slenderness ratios are confronted with great difficulties in strengthening existing steel structures because they can’t increase the section area significantly.Many studies have shown that partially encased concrete（PEC）is a simple and effective way to strengthen H-section steel column.However,due to leakage of H-section steel column flange plate,there is still a hidden danger of increased corrosion in the subsequent use.Therefore,under the premise of not significantly increasing the cross-section area of steel column,it has become a hot issue in engineering circles to seek a new method of double reinforcement for bearing capacity and durability of H-section steel column.Carbon Fiber Reinforced Polymer（CFRP）has been widely used in the renovation and reinforcement of new buildings and existing structures.On the basis of PEC reinforced H-section steel column,CFRP can be further wrapped to form the structural form of CFRP-PEC reinforced H-section steel column,which can simultaneously meet the strengthening demand of the existing h-section steel column with the double enhancement of bearing capacity and durability.Up to now,there are relatively much research on strengthening H-section steel columns by PEC at home and abroad,but little research on strengthening H-section steel columns by CFRP-PEC,especially on the stability of axial compression.In this paper,tests and finite element simulation are conducted on the mechanical performance of H-section steel columns strengthened by CFRP-PEC under axial compression.Mainly completed the following work:（1）The axial compression loading tests of 15 specimens（3 H-section steel columns,3 PEC columns,3 annular bonded CFRP-PEC columns,3 longitudinal bonded CFRP-PEC columns and 3 mixed bonded CFRP-PEC columns）were completed,and studied how different slenderness ratios and different reinforcement methods influenced the bearing capacity and deformation performance of specimens.The axial compression test results of H-section steel columns reinforced with PEC and CFRP-PEC show that both PEC and CFRP-PEC can greatly improve the bearing capacity of specimens.As the specimen slenderness ratio increased from 4.2 to 12.6,axial compression bearing capacity decreases.（2）Under the same slenderness ratio,compared with PEC reinforcement,mixed CFRP pasting and annular CFRP pasting in CFRP-PEC can still improve the bearing capacity of specimens to a small extent,while longitudinal CFRP pasting has no significant effect on improving the bearing capacity of members.（3）The applicability of the calculation formula of axial bearing capacity proposed by Chen Yiyi,Zhao Gentian,Liang Jiongfeng and Yin Zhanzhong was verified.Based on the superposition principle,a formula for calculating the axial bearing capacity of CFRP-PEC reinforced H-section steel columns is proposed,and the calculated value is in good agreement with the test value.（4）Using finite element software ABAQUS way PEC and CFRP-PEC were used respectively to reinforce the H steel column on the modeling analysis of simulated values coincide well with the test results,and it can provide some reference for the further study of CFRP-PEC reinforced H-section steel columns. |
