Buckling Property Of Corroded Steel Rebar And Its Influences On Reinforced Concrete Column Sectional Strength

Load-carrying capacity of corroded reinforced concrete columns is one ofthe most important subjects for durability evaluation of concrete structure. Steelbar cross section reduces, mechanical properties degrade and concrete covercracks due to corrosion of reinforced concrete columns. As concrete crosssection is damaged, bond strength between steel and concrete degrades. Whensteel bar is in serious corrosion, hoops may be corroded to break. It results in thereinforced concrete column loses lateral restriction and buckles in compression.Under influences of these factors, load-carrying capacity of the reinforcedconcrete column reduces, and the column breaks without predictive signs. Toevaluate damage level and remaining life of these columns, it is necessary tocalculate load-carrying capacity of the corroded reinforced concrete columns. Asa subitem of the National Natural Science Foundation subject, the researchfocuses on the influences of corroded hoops on sectional strength of reinforcedconcrete frame columns. The main research work and results are as follows:(1) Through electrochemistry method, the commonly used steel bars inreinforced concrete frame column, such as(?)18,(?)20 and(?)22, are corrodedmanually. There are 120 bars and their designed mass corrosion rate is 10%and 20%. Corroded bar test coupons are obtained using this method.(2) In this paper, the uncorroded and corroded steel bars with the sameslenderness ratios are axially compressed. The results of P-â–³curvesdemonstrate bar buckling properties. With experimental data, factorsinfluencing the P-â–³curve are analyzed and a mathematical expressiondescribing characteristics of the P-â–³curves is simulated.(3) With the software ANSYS, the P-â–³curves of compressed bars are simulated.The simulation results are in compare with experimental data, and they arein good agreement. (4) Based on the previous experiment and theoretical analyses, a computationalmodel and the relevant formula of load-carrying capacity are developed forcorroded reinforced concrete columns compressed axially and eccentrically.The work and research results in this paper make a basis for load-carryingcapacity evaluation and reinforcing design of corroded reinforced concretecolumns.