Non-linear Finite Element Analysis Of The Strengthening R.C. Frame-supporting Stent By Enlarging Section

As a scaffold or platform for industrial equipment stent, R.C. frame-supporting stent is a common structural form. It has been widely used in metallurgy, electric power, machinery, port and other fields. As a result of structural damage and shortage of load bearing capacity in the structure, if many of these structures aren't reinforced immediately, it will bring to people's lives and property can not be unimaginable consequences. Enlarging section method is a traditional and widely-applied reinforcing approach. If the concrete strength is low or it is in some special circumstances, applying enlarging section method for reinforcement is a more feasible option. Applying enlarging section method to increase the whole work capability of R.C. frame-supporting stent is still a lack of research at home and abroad. Therefore, the study of different parameters'impact on the whole work capability of R.C. frame-supporting stent by enlarging section method has important theoretical and practical engineering value.Useing ANSYS software, this paper analyses the whole work capability of R.C. frame-supporting stent under increasing cross-section in monotonic and cyclic loading by taking skeletal structures and meshed section beam-column. On the basis of the existing test data, the paper studies the impact of parameters on R.C. frame-supporting stent mechanical performance and the impact of strengthening cross-section size on the structural plastic hinge through the 4 series of 16 samples.These parameters include concrete strength grade, the diameter of longitudinal reinforcement (reinforcement ratio), stirrup spacing (stirrup ratio) and the stirrup strength grade, the strengthening cross-section size. By the following conclusions: concrete strength grade, stirrup spacing (stirrup ratio) and the strengthening cross-section size are important factors of performance of the overall structure and they should be considered in strengthening design. Difference between inside and outside the concrete strength grade is too large, which can not be very good to work of both inside and outside concrete, and this will make against the overall seismic performance of structures. Surrounding concrete strength grade shall not be less than core concrete strength grade, but also not too high, it is recommended that it is higher two grades up to core concrete strength grade . Reducing stirrup spacing (increasing stirrup ratio) can be effective in promoting the whole work capability of concrete of both inside and outside and improve the bearing capacity. Strengthening cross-section size should not be too big, or it can cause the overall stiffness of the structure to much large, and thus lead to brittle failure. Longitudinal reinforcement (reinforcement ratio) and the stirrup strength grade contribute little to the improvement of horizontal bearing capacity. It can be collocated by configuration. For R.C. frame-supporting stent, strengthening the beam should be not too much and be just to meet the vertical bearing capacity.Too much to strengthen the beam will lead to "strong column-weak beam".This paper systematicly study the performance of R.C. frame-supporting stent in monotonic and cyclic loading.The conclusion and recommendations can provide reference for further research and engineering design.