部分预应力混凝土梁相对界限受压区高度取值分析

Analysis of Bounding Relative Height of Compression Zone for Partially Prestressed Concrete Beam

钢筋混凝土构件和预应力混凝土构件相对界限受压区高度相差很大,同一截面尺寸构件,当由相对界限受压区高度控制时,预应力混凝土梁与普通混凝土梁相比,承载力降低约17%。本文根据预应力钢绞线拉伸应力-应变试验曲线,分析了预应力钢绞线条件屈服强度取值对相对界限受压区高度的影响。对预应力筋和非预应力筋配筋强度基本相同的部分预应力混凝土梁进行计算,分析了弯矩-曲率关系。计算结果表明,适当提高界限受压区高度,在保证部分预应力混凝土构件延性的前提下承载力可提高10%以上。

There is a big difference in the bounding relative height of compression zone between reinforced concrete beam and prestressed concrete beam,and the ultimate bearing capacity of prestressed concrete beam is about 17 percent less than the capacity of steel concrete beam with the same section size when the design is controlled by the limitation of the bounding relative height.The experimental stress-strain curves of the prestress strands in tension were given in the paper,and the effects of the conditional yield strength on the bounding relative height of the compression zone of prestressed concrete beam were analysed.The moment-curvature relation of a partially prestressed concrete beam with steel bars and prestressed strands mostly same is calculated.The calculation shows that the ultimate bearing capacity of the partially prestressed concrete beam can be increased by more than 10% on the premise of ensuring certain ductility.when the bounding relative height of compression zone is properly increased.