【作者】 周亮；

【导师】 王海东；

【作者基本信息】 湖南大学 ， 结构工程， 2013， 硕士

【摘要】 本文对一种新型RC柱抗震加固方法—低预应力钢带箍加固展开试验研究，考察该新型加固方法的加固效果以及加固柱的抗震性能。通过对3根采用低预应力钢带箍横向约束加固的钢筋混凝土柱及2根对比柱进行低周反复试验，研究较高轴压比下采用横向预应力钢带箍加固RC柱的抗震性能。试验以轴压比和钢带箍的布置为主要参数，研究（a）在较高轴压比下采用低预应力钢带箍加固RC柱的抗震性能的变化规律；（b）钢带箍的关键布置位置。通过对试件的破坏形态、滞回特性、骨架曲线和延性等重要抗震性能指标综合分析，得出以下结论：（1）低预应力钢带箍加固能有效提高较高轴压比下高配箍率RC柱的抗震性能，对于抗震设防要求较高的结构或构件有着较为明显的加固效果。（2）低预应力钢带箍加固使混凝土处于三向受压状态，可对试件斜裂缝的产生和发展起抑制作用，能有效改善高配箍率RC柱的变形能力和抗震性能（3）低预应力钢带箍加固基本不会增大被加固RC柱的初始刚度和截面尺寸，对加固前后的地震作用影响极小。（4）低预应力钢带箍能与箍筋共同工作，使二者在破坏之前充分发挥约束作用。且钢带箍应变高于箍筋应变，其发挥的约束作用更加直接有效。（5）相同轴压比条件下，采用低预应力钢带箍加固的约束柱的延性系数比对比柱提高40%左右，承载力提高超过15%。运用通用有限元软件Ansys，建立了合理的有限元模型，对本文研究的试件进行了较为准确的数值模拟。通过对比计算结果和试验结果可知，计算所得的水平承载力和延性系数与试验结果吻合较好。在验证有限元模型合理的基础上，进一步探讨了钢带箍的最佳布置方式。分析结果表明，仅在根部250mm范围内满布钢带箍可使试件达到理想的水平承载力和延性水平。这一结论也可为后续试验提供参考和借鉴。更多还原

【Abstract】 A new retrofitted method that makes use of low-prestressed steel belts intransverses direction of RC columns is studied on the paper to check the effect of thenew method and the seismic performance of the retrofitted columns.Three circular columns confined by low-prestressed steel belts and two normalcolumns have been tested under axial and cyclic lateral force to investigate theeffectiveness of external low-prestressing in transverse direction of circular columns.The main parameters of the test were axial compression ratio and arrangement of s teelbelts. The main objectives of the study were to obtain information on:(a) the seismicperformance of RC columns confined by low-prestressed steel belts under high axialcompression ratio;(b) the key position of the arrangement of the steel belts.Based onthe test results, the failure mechanism, bearing capacity, hysteretic behavior, skeletoncurve and ductility were comprehensively analyzed and conclusions were as follows:(1) The retrofitted method with low-prestressed steel belts can effectivelyimprove the seismic performance of RC columns with high stirrup ratio under highaxial compression ratio, and the retrofitted effect for structures or members withhigher seismic requirement is obivious.(2) The low-prestressed steel belts strengthening can make the concrete in a stateof triaxial compression, and it can also inhibit the development of oblique cracks andeffectively improve the deformability and the seismic performance of RC columnswith high stirrup ratio.(3) The new retrofitted method studied in the paper will not increase the initialstiffness and cross-sectional dimension of retrofitted columns, so it affect the seismicaction minimally.(4) The low-prestressed steel belts can work together with stirrups, which canmake both fully participate in the work before the destruction.(5) Under the same axial compression ratio, the ductility index of confinedcolumns increases by about40%, and bearing capacity by more than15%.The FEM model of the RC columns retrofitted by low-prestressed steel beltswere established and the elastic-plastic analysis were carried out using versatile FEMsofeware-ANSYS. The comparison between the FEM analysis and experimental resultindicates that: the calculated horizontal bearing capacity and ductility index h ave a good agreement with the experimental result. The optimal arrangement of thespecimen is studied based on reasonable FEM analysis. It is suggested fullarrangement of steel belts within the scope of250mm height on the root of the columncan provide the the specimen the desired level of capacity and ductility. Thisconclusion can be referenced for the further experimental study.更多还原