碳纤维布加固高温作用后的连续梁试验研究和功能可靠度分析

比较分析了五根混凝土连续梁在碳纤维布加固后的极限荷载、变形、裂缝、延性系数等指标.在实际加固工程中无法对钢筋混凝土连续梁梁项进行加固,因此在试验中采用CFRP来加固梁的跨中,增强其正截面的抗弯承载力,并利用梁支座处出现塑性铰,引起弯矩重分布的特性,来达到加固的目的.为使试验更加接近加固工程实际情况,试验中加固是在持载情况下进行的.试验研究表明：使用碳纤维布提高高温作用后的混凝土连续梁的方法,能有效地抵抗二次火灾的影响;基于试验结果,推导出高温作用后碳纤维布加固的实用设计方法,与试验数据可以较好地吻合.在不能找出加固后梁所有失效模式的情况下,利用分阶段平截面弹塑性分析法求出加固后连续梁的极限挠度,求出了梁的功能（挠度）可靠度.

Experiment Study and Function Reliability Analysis on RC Continuous Beam Subject to High Temperature and Strengthened with CFRP Sheets

The ultimate strength,deformation,crack and ductility capacity of five reinforced concrete continuous beam subject to high temperature and strengthened with Carbon Fiber Reinforced Plastic(CFRP) sheets are compared and analyzed.In some buildings it is unable to apply strengthening measures on the upper surface of the reinforced concrete continuous(RC) beam.Based on the basic characteristics of moment redistribution for RC continuous beam,a new method was proposed to increase the resisting moment capacity of the beam.The CFRP was bonded on beam bottom of the span-mid,the flexural capacity of span-mid was increased,and the plastic joint of beam end was formed.In order to simulate the actual situation,the beam with sustaining load was strengthened,and experimental results showed that the strengthened structure has effective resistance to the subsequent high temperature.A practical design method was proposed leading to good agreement with the experiment results.When the failure pattern of beam strengthened by CFRP cannot be found,the function reliability of beam can be extracted by extracting limited deflection of beam with stage horizontal section elastic plastic analytic method.