DETERMINATION OF THE FAILURE MODE AND BEARING CAPACITY OF CONCRETE COLUMNS WITH MESH REINFORCEMENT

Abstract

Paper deals with the results of experimental test of reinforced concrete columns withmesh reinforcement. Experimental investigations of columns were performed using hydraulic presswith a maximum load level of 480 tones. On the basis of previous theoretical research three series ofexperimental samples which are represented with simply concrete columns (BS-0), concrete columnsin mesh holder (BS-P) and concrete columns in mesh holder with additional reinforcement rings (BSPS)were produced. The height of all samples is 1000mm and the diameter is 450mm. There threeschemes of experimental tests were considered: static loading using press’ plates (I), monocycle (II)and static (III) loading using additional round steel plates. The results of tests were obtained in theform of failure mode and breaking forces for three series of samples. According to the results of testsover the first scheme, it is obtained that the destruction of columns with mesh reinforcement goesmore slowly than concrete columns. The appearance of cracks started at the level of loading equalto 100 tones for BS-0 samples and 200-250 tones – for BS- and BS-PS samples. The level of breakingforces for BS-P samples and for BS-PS samples is 18-26 % and 21-28 % higher than for BS-0 samplesrespectively. After monocycle loading it is obtained that breaking forces for BS-P and BS-PS samplesare 5 % and 23 % higher than BS-0 samples. It is noted that cracking processes for all samplesstarted near the moment of total destruction, so the failure of samples was brittle and sharp.According to the third scheme of loading the difference between breaking forces for BS-0 and BS-Psamples is about 5 %, BS-0 and BS-PS is 7 %. Failure mode for third scheme is similar to secondscheme, but it is also mentioned multistage destruction of columns when after achieving the level ofbreaking force level of loading falls and increases several times. It is recommended to apply loadover whole cross section of column in real structures, because it plays a significant role in increasingof bearing capacity. The results of experimental tests were compared with results of numericalanalysis, which showed qualitative and quantitative coincidence.