On The Performance Of HPFL Strengthening RC Eccentrically Loaded Column Under Combined Action Of High Temperature And External Load

Owning to the gradually serious situation of building fire, togetherwith the rapid development of structural strengthening technology,fire-resisting of the reinforced structure is becoming an important issuein the structural engineering area. The existing method of strengtheningis mainly using organic structure glue, the fire-resisting effect of whichis not satisfactory. The HPFL strengthening method dealt with by thisarticle has distinctive advantages in structural resisting performance.This is because that the material applied is inorganic gel, which obtaingood fire-proof character and has good compatibility and coordinationwith original concrete. Therefore, the fire-resisting capacity of HPFLstrengthening RC structure is distinctively better than that of organicstructure glue.On the basis of related experiments and theoretic analyses on thefire-resisting performance of eleven HPFL strengthening RCeccentrically loaded column with approximate full scale under combinedaction of high temperature and externally applied load, this article dealswith the issues and makes the conclusions as following:(1) A summary comment on the research work, done by bothChinese and foreigners, on the mechanics performance under hightemperature of concrete, rebar and High-powered composite mortar.(2) A research on the basic laws of column section temperature fieldof HPFL strengthening RC. HPFL back-up coat can effectively reducethe temperature of various points in the column; the changing gradientdecreases gradually from exterior to interior; the temperature of pointsnear the outer face reach the highest and then drop, while temperature ofthe points near the centre rise slowly and the highest is relatively low.(3) A research on the deformation rules of HPFL strengthening RCeccentrically loaded column under and after high temperature. Under thesame high temperature environment, the defection change of HPFLstrengthening RC eccentrically loaded column is apparently smaller thanordinary concrete eccentrically loaded column; ordinary concrete eccentrically loaded column has apparently residual compressiondeformation while HPFL strengthening RC eccentrically loaded columnbarely has. In the whole process with initial load, the midspan defectionof the test specimen protrudes to low-temperature face when the loadplace moves to high-temperature face; when the load place moves tolow-temperature face, big bias specimen’s midspan defection protrudesto high-temperature face while small bias specimen’s midspan defectionprotrude to low-temperature face; when the absolute values ofeccentricity e0are equal, the development of big bias specimen’smidspan defection goes dramatically when the load place is nearing thelow-temperature face.（4）A research on the laws of change of residual bearing capacity ofHPFL strengthening RC eccentrically loaded column after hightemperature: The initial load can distinctly improve it after hightemperature. Furthermore, it puts forward the equivalent section methodto calculate the residual bearing capacity of HPFL strengthening RCeccentrically loaded column after initial load and surrounding hightemperature.