Study On Axial Pressure Behavior Of Reinforced Concrete Columns Cooled By High Temperature Water

Fire cause damage or collapse of reinforced concrete structures or components,causing huge losses to the society and people.Therefore,the study of the mechanical properties of reinforced concrete structures or members under fire(high temperature)has attracted more attention from scholars from various countries and they do many experimental research and theoretical analysis for it.In this paper,through the experimental study of reinforced concrete columns,the axial stress of reinforced concrete column is studied under the influence of different high temperature,cooling mode,longitudinal reinforcement diameter and stirrup spacing.A total of 57 reinforced concrete columns were designed in this test.54 samples were subjected to high temperature test and cooled by natural cooling and water spray cooling after high temperature,and then cooled with normal temperature test pieces.Comparative analysis,57 specimens were statically loaded and analyzed for mechanical properties.Through the test,the characteristics of the high temperature were obtained,characteristics of the loss rate and the apparent condition under the influence of different cooling modes were analyzed.Through the static load test of the test piece,the failure mode of the test piece was observed,and the characteristic parameters such as peak load and peak displacement of the test piece were obtained.Analysis and research:different temperature,cooling methods,longitudinal reinforcement diameters,the spacing of the stirrups affects the mechanical properties of the axial compression of the column after temperature.The results show that the surface color of the test piece is deepened with the high temperature.The water-cooled test piece is darker than the natural cooling test piece;The more obvious the crack is,the burning loss rate increases with the increase of temperature,the burning loss rate of the water spray cooling test piece is greater than the burning loss rate of the natural cooling test piece;the peak displacement of the water spray cooling test piece and natural cooling test piece.The shape of the load curve tends to be generally consistent,it has experienced three stages of ascending,descending and gradually gradual;the temperature has the most obvious influence on the axial pressure performance of the column,followed by the cooling mode,and the influence of the reinforcement ratio and stirrup spacing is small.Finally,according to the current formula of the bearing capacity of the column axial compression bearing capacity,combined with the material strength change after high temperature,the bearing capacity of the test piece is calculated,and the calculated results are in good agreement with the experimental results.