Research On The Mechanical Properties Of The Reinforced Concrete Slab Which Is Strengthened By The High Performacne Ferrocement Laminate After The Fire

In recent years, a increasing number of fires bring huge losses to people’s lives and property,and building damage is inevitable. As a result, it is much important for us to pay attention to structure reinforcement and repair. As a new type of structure reinforcement, High Performance Ferrocement Laminate has more irreplaceable advantages than traditional reinforcement methods, and now is widely used in structural reinforcement and repair fields. In this thesis, this method is uesd to do a research on the mechanical properties of fire-damaged reinforced concrete slab. According to existing specification, a simple and practical formula of bearing capacity of normal section of Strengthening fire-damaged reinforced concrete(RC) slab with High Performance Ferrocement Laminate is derived. As a result, lots of help is provided for engineers and technicians in reinforcement design. The main contents and results are listed below:(1)A series of traditional methods of reinforced concrete structure reinforcement and repair in domestic and foreign were summarized. The advantages and disadvantages of the various of traditional reinforcement methods had been made analysis and comparison, including their application scope. The background of the High Performance Ferrocement Laminate was introduced in details.(2)The research results on the mechanical properties and thermal performance of the steels and concrete at high temperatures by domestic and foreign scholars were summarized and contrasted. And the calculation assumptions and models used in this thesis were given.(3)In this thesis, finite element analysis software called ANSYS was used to simulate the cross-section temperature field of different thicknesses (h=100mm,110mm,120mm) concrete slab at different heating-up time (t=30min,60min,90min,120min).By analyzing the results under different conditions, A variation of the internal isotherm line of300℃and800℃was obtained, and temperature charts of concrete slab under different fire resistance were made so that people could use it directly when they need.(4)ANSYS was used to simulate the deflection of reinforced concrete slab at high temperatures, and the effect of different conditions to the deflection of reinforced concrete slab were found. At the same time, the variation of mechanical properties of reinforced concrete slab at high temperatures was obtained. Also, a practical calculation method of remaining bearing capacity of the normal section of fire-damaged reinforced concrete slab was proposed. This method was based on second-order model, combined with the temperature chart under different fire resistance. The remaining bearing capacity of the normal section of fire-damaged reinforced concrete slab was turned from a complex non-linear analysis into a simplified calculation.(5)On the basis of the plane section assumption and the equivalent reduction model of a T-shaped slab, a practical and simplified formula about bearing capacity of the normal section of Strengthening fire-damaged Reinforced Concrete Slab with High Performance Ferrocement Laminate was deduced.(6)Finally, a simplified practical formula of structure reinforcement using in the actual project was introduced in this thesis.