Study On Flexural Performance Of A Large-Span Beam Based On Post-Prestressed Side Lateral Superposition Reinforcement

Studies show that pre-stressing reinforcement and steel-concrete composite technology enhance the structural performance of large-span reinforced concrete beams effectively.A number of study on non-bonded pre-stressing reinforcement have been carried out,while study on bonded pre-stressing reinforcement is inadequate.Even though studies on steel-concrete beam reinforcement in the vertical direction are sufficient,mechanical models and designs based on lateral reinforcement remain limited.To reinforce large-span beams with height restrictions,strict deflection limitations,and seismic performance requirements,the implementation of pre-stressing reinforcement technology and extension of composite technology to beam sides are crucial.This study will cover the following research contents:(1)Building on a four-story reinforced concrete frame structure renovation project and meeting requirements such as beam height and seismic performance,the prestressed side composite reinforcement method was selected after evaluating alternatives.Real-time construction monitoring was conducted,obtaining strain and displacement data during the three-stage prestressed tensioning process,as well as the final deformation-stable displacement data.The analysis reveals that the deformation on both sides of the composite surface of the large-span concrete beam reinforced with the prestressed side composite reinforcement method is consistent.The stress levels of concrete and steel bars during the construction phase are low,with small vertical and horizontal displacements,ensuring the beam’s safety and stability.Upon completion of the reinforcement and stabilization of deformation,vertical displacement is minimal,indicating a successful reinforcement effect.(2)MIDAS FEANX software was employed to simulate the construction scenario of applying the prestressed side composite reinforcement method to the reinforcement of large-span beams.The simulation results were compared with monitoring data,revealing that the numerical analysis results closely align with the monitoring data,thus validating the rationality of the finite element model parameters.(3)Numerical simulation was utilized to compare stress,displacement,and crack distribution changes of large-span beams before and after reinforcement based on the prestressed side composite reinforcement method.The results indicate that postreinforcement stress levels significantly decrease,the tensioned area of the concrete is reduced,effectively improving the stress distribution of the large-span beam.Vertical displacement is reduced after reinforcement,and variations along the beam span become smoother,effectively controlling the vertical displacement of the large-span beam.The crack distribution area and maximum crack width decrease after reinforcement,effectively enhancing the crack resistance of the large-span beam.(4)Numerical analysis was employed to compare the reinforcement effects of the prestressed side composite reinforcement method and traditional reinforcement methods.The Technique for Order of Preference by Similarity to Ideal Solution(TOPSIS)was used for scheme optimization in specific reinforcement conditions.The results demonstrate that the prestressed side composite reinforcement method is suitable for large-span beam reinforcement under various conditions,particularly when component height cannot be increased,offering a significant advantage.(5)Based on the engineering case,combined with numerical and field experimental research results,it is evident that the prestressed side composite reinforcement method possesses notable advantages and application potential when existing buildings require high levels of vertical displacement control,crack control,seismic performance,durability,and ductility for the beam.