芳纶纤维筋有黏结部分预应力混凝土梁受弯性能研究

Experimental study on flexural behavior of partially prestressed concrete beams with bonded AFRP tendons

对以芳纶纤维筋为有黏结预应力筋、环氧涂层钢筋为非预应力筋的部分预应力混凝土梁的受弯性能进行研究,共进行了10根梁从混凝土开裂、裂缝开展直至梁受弯破坏的全过程试验。测定了梁的开裂弯矩,梁截面应变分布,变形的发展,裂缝出现、发展及分布情况,提出区分芳纶纤维筋破断及混凝土压坏的界限等效配筋率或界限中和轴高度,推导出芳纶纤维筋拉断和混凝土压坏同时发生,混凝土压坏、芳纶纤维筋未拉断及芳纶纤维筋拉断、混凝土未压坏等情况的受弯承载力计算方法,并提出芳纶纤维筋有黏结部分预应力混凝土梁短期刚度及裂缝宽度的计算方法。

This study deals with the flexural behavior of partially prestressed concrete beams with bonded AFRP tendons and epoxy coated steel bars. A full-range of tests was conducted by loading l0 beam specimens all the way to initial cracking of concrete, leading to eventual failure. In these tests, bending moment at the on-set of crack, corresponding strain distribution, deflections of the beams, crack initiation and its growth were measured. The critical equivalent reinforcement ratio, or the critical height of neutral axis, was proposed to distinguish between AFRP tendons rupture and concrete compression failure. A method for calculating the flexural load-bearing capacity in different failure modes, including concrete compression failure, AFRP tendon rupture and simultaneous concrete compression failure and AFRP tendon rupture, are proposed. The method is also capable of calculating the short-term stiffness and crack width of the concrete beam.