Analysis Of Force Performance And Safety Margin Indices For Unbonded Partially Prestressed Concrete Beams With High Strength Reinforcement

The unbonded prestressed construction process has many advantages such as significantly improving structural bearing capacity,improving performance,convenient construction,good durability,etc.,and unbonded prestressed component with high strength steel bars instead of ordinary reinforcement can not only improve the load-bearing capacity of components,but also save steel consumption to achieve the purpose of energy saving and environmental protection.Therefore,a systematic analysis of the load-bearing capacity and deformation capacity of such components is useful for the actual engineering.The main research contents and achievements of this article are as follows:(1)Research on the bearing capacity of unbonded partially prestressed concrete beams with high-strength steel barsThrough the experimental study,the influence of the non-prestressed steel bar strength and the comprehensive reinforcement index on the flexural performance of the component were compared and analyzed,and the prestressed ultimate stress calculation methods were compared and analyzed.The results show that the addition of high-strength steel bars can significantly increase the ultimate stress of the prestressed tendons and the flexural bearing capacity;the improvement of the comprehensive reinforcement index is conducive to limiting the development of cracks,and the flexural rigidity and bearing capacity of the member Increase;the increment of the limit stress value of the prestressed tendon increases with the increase of the strength of the non-prestressed reinforcement,and decreases with the increase of the comprehensive reinforcement index.(2)Deformation performance of unbonded partially prestressed concrete beams equipped with high-strength steel barsThe three-stage stiffness calculation method of the component is analyzed,and the calculation results of the formulas are compared and analyzed.The results show that the data calculated are in good agreement with the measured values,and the theory of the component The deflection curve is in good agreement with the actual deflection curve.(3)Safety reserve analysis of unbonded partial prestressed concrete members with highstrength steel barsAlthough the ductility index of this type of component often does not meet the ductility requirements,the addition of high-strength steel bars improves the load-bearing capacity and safety reserve capacity of the component.In this paper,a variety of safety reserve indicators are used to analyze the safety reserve of the component.The effective safety reserve and the bearing capacity safety reserve index have increased,and the deformation safety reserve has been reduced.The safety reserve of such components can be analyzed using the equivalent safety reserve indicator and the basic bearing capacity safety reserve indicator(4)Finite element analysis of unbonded partially prestressed concrete members with high-strength steel barsThe finite element analysis software is used to numerically simulate the component,and the effects of the comprehensive reinforcement index and prestress degree on the component are additionally analyzed.The results show that the simulation results are in good agreement with the measured data.The increase in the prestress of the component can effectively improve the load-bearing capacity of the component,but at the same time there is a certain limit to the deformation capacity of the component.