Analysis and research on prestressed effect in prestressed concrete frame beam
The theoretical and numerical analysis of the prestressed effect in prestressed concrete frame beams was carried out.It was pointed out that the method of simplifying prestressed concrete frame beams into linear members with fixed flange width has limitations.The solid model of beam-slab structure was established,and the vertical load and axial equivalent concentrated force were applied respectively.The normal stress distribution in the slab was analyzed.The results show that when the frame beam is subjected to axial force,there is a significant non-uniform distribution of the normal stress range of the floor along the length direction of the beam,and the commonly used linear frame model cannot accurately reflect the normal stress distribution in the beam.The solid model of the beam-slab structure,the linear frame model of the fixed beam flange width and the beam-slab combined model were established respectively.The prestressed loads were applied on these models and the prestress effect in these three models were compared.The results show that the linear frame model of the fixed beam flange width cannot consider the secondary axial force in the beam caused by the floor constraint,which leads to a large error in the analysis of deformation and crack width.The solid model analysis is accurate but the time cost is too high.Beam-slab combined model can fully consider the secondary axial force effect in the ribbed beam under the plate constraint,and can accurately calculate the internal force and deformation with less analysis cost.
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