Behavious Of Steel Bar/Wire Mesh Mortar Strengthening Concrete Columns Under Axial Load

In order to keep the advantages of the RC columns strengthened with wire mesh-mortar and to increase the load bearing capacity of the strengthened RC columns significantly, a thought of strengthening RC columns with steel bar / wire mesh mortar was proposed. Twelve steel bar / wire mesh mortar-strengthening columns and three steel bar mortar-strengthening columns were produced for a comparative experimental study under axial load. The influences of the number of the layers of mesh on the axial bearing properties of the strengthened columns were investigated. The research results indicated that, because of the superior separation of the reinforcement, wire mesh could effectively confine mortar cover, and make wire mesh-mortar failed with the core concrete simultaneously, and the cracks are fine and dense. Therefore, the method of strengthening RC columns with steel bar / wire mesh mortar not only could increase the ultimate compressive bearing capacity of the RC columns significantly, but also could keep their distinct ductility and the advantage easy to be constructed. The results also showed that the number of layers of mesh influenced the ductility of the strengthened columns obviously.Since to strengthen RC columns with FRP is very popular, twelve FRP strengthening RC columns were produced for a comparative experimental study with steel bar / wire mesh mortar-strengthening columns. The results showed that, in regard to increasing the load bearing capacity, the method with FRP had higher efficiency and easier construction; however, the method with steel bar / wire mesh was superior in ductility, durability and heat resistance, and it is obviously low cost.Finally, proper material constitutive models for RC columns strengthened with steel bar / wire mesh mortar were proposed and verified by the nonlinear finite element program ABAQUS against experimental data. Via the numerical analyses, the influence of the wire spacing and the number of layers of mesh on the load bearing capacity of strengthened columns was investigated.In order to obtain a quantitative design method for controling diagonal cracks in cast-in-site concrete floor. Eleven reinforced concrete boards were produced and strengthened with wire mesh for a comparative experimental study. The Effects of the number of layers and the diameter of wire mesh on the crack distance of the strengthened concrete boards were investigated. The test results showed that, the crack spacing could be shortened significantly by increasing the number of layers of mesh, decreasing the wire spacing and increasing the diameter of mesh. The method of increasing the diameter of mesh had the best effect and easiest construction.