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设计制作了2根配置500 MPa细晶粒(HRBF500)钢筋的预应力高强混凝土T形梁,通过实测预应力损失与理论计算比较,得出实测预应力损失大于理论计算值。基于疲劳荷载的试验,绘出HRBF500钢筋应力、钢绞线应力及梁跨中挠度曲线,分析配有细晶粒钢筋的预应力混凝土梁的疲劳性能。结果表明,在一定幅度的疲劳荷载(等幅)作用下,配有HRBF500钢筋的预应力高强混凝土梁,其钢筋、预应力钢绞线及跨中挠度均满足使用阶段规范的限值,即在HRBF500钢筋拉应力大于150 MPa条件下,经过250万次疲劳荷载作用后仍满足设计要求。
Two prestressed high-strength concrete T-beams with 500 MPa fine grain (HRBF500) steel bars are designed and manufactured. The measured prestress loss is compared with the theoretical calculation, and the measured prestress loss is greater than the theoretical value. Based on the fatigue load tests, the HRBF500 steel bar stress, strand stress and mid-span deflection curve are plotted, and the fatigue behavior of prestressed concrete beams with fine-grained steel bars is analyzed. The results show that the prestressed high-strength concrete beams with HRBF500 rebar under the action of a certain range of fatigue loads (equal amplitude) can meet the requirements of the specification of the use stage for the steel bars, prestressed steel strands and mid-span deflections, HRBF500 steel tensile stress greater than 150 MPa conditions, after 2.5 million times the fatigue load still meet the design requirements.