The Research On Bearing Performance Of Corroded Reinforced Compressive Concrete Members

Recent engineering investigations show that there are more and more destruction cases induced by the descent in durability of reinforced concrete structures. And reinforcement rustiness is very common in these cases. The damage caused is huge; A great many research revealed that reinforcement corrosion is one of the most important factors influencing structural durability. The reduction of effective diameter of reinforcement bars, the loss of bond between steel and concrete and the microcrack of concrete due to the expansion of the bars by the rust products are the principal aspects of the corrosion damage. This shows that reinforcement corrosion problem is not just an economic issue, it is also a relationship to the structural safety problems. Therefore the research on corroded reinforced concrete structures on the mechanical properties is particularly important.Combining with the National Natural Science Foundation of China(No.50478032), following researches were done in this thesis:1) The variation regularity of the ultimate anti-bending capacity of the rectangular-sectioned beam with different corrosion has been obtained through the qualitative analysis of 39 columns (Axial compression columns, reinforced concrete columns with large-eccentric compression and reinforced concrete columns with small-eccentric compression each 13) with accelerated corrosion;2) Test found that steel corrosion may change the member's damage shape. Then proposed a formula for calculating the limits of great or small eccentric compression----the height of boundary compression area, and combine with the test established finite element method to verify it;3) The conclusion has been obtained that the strain of corroded steel bar and concrete no longer fit in with the assumption of plane section through the analysis of the strain data, the strain relation of steel bar and concrete in the mid-span section of variously corroded beams at ultimate has been obtained. Through the building of new geometric relation, the formula with corrosion rate as the main variable for the anti-compressing capacity of the small eccentric compression corroded reinforced concrete columns has been suggested and verified by experiment;4) Steel corrosion decline the bond performance, further decline the ability to work synergies between the steel and the concrete. Through introduction of coordination coefficient to establish a ultimate compressing capacity model of the great eccentric compression corroded reinforced concrete column, and through test data to verify.