۱- Introduction

۲- Method of strengthening

۳- Numerical modeling

۴- Conclusion

References

Abstract

Concrete structures that are influenced by degradation, overloading, the thawing and freezing cycles, abrasive damage, corrosion of reinforced bars, should be repaired or strengthened. Each of those mentioned influences lead to decreasing the load-carrying capacity of the structure or its member. The damaged structure stops to fulfil the serviceability limit states (SLS) and ultimate limit states (ULS). For this reason, the structure has to be strengthened to increase the load-carrying capacity and elongation of remaining lifetime. One of new method for strengthening vertical members (columns of frame structures) is the using fiber concrete layer and utilization its increased tensile strength in comparison to common concrete.

Introduction

Geometry of structures result from architectural solution. In the last decades, the structures of buildings were changing from low wall structures to higher frame structures stiffened with stiffener walls or cores. The load-bearing system consisted of massive main walls in the past, the floor slabs were supported with these massive walls and created a difficult static system. The main goal was to replace massive structures to subtle structures as skeletal structures or concrete frames, which lead to enlarging utility area (Hruban, K., 1950). The columns are very loaded on the edges of the frame structure, where is the highest bending moment and axial load. The exceeding the design values of structure´s/member´s resistance can be by reasons of the design loads exceeding, mechanical damage (due to explosion, impact load, etc.), change of the structure function and so the increasing of considering loads. Aim of this paper is to show possibility of strengthening the columns by fiber concrete. Distribution and orientation of fibers in fiber reinforced composites are essential for the structural performance of elements and structures (Vítek at all, 2017, Rehacek at all, 2014) and using this method we can achieve the optimal strengthening and technological approach.