【摘要】 该文进行了3根体外预应力混凝土简支梁的动力试验,试验表明:在张拉阶段,试验梁的自振频率随预加力的增大而提高,这是与传统的线弹性理论分析结论相反的;张拉开裂之后,试验梁的自振频率明显下降。为了和试验结果进行对比,运用相关文献中体外预应力梁的频率计算公式,对试验梁的自振频率进行了计算,计算结果与试验结果在梁频率的变化趋势及数值上均有较大的出入。该文以试验为基础,结合混凝土是一种复合材料的这种特性,提出了新的计算方法。计算表明:该文提供的方法具有较好的适用性,理论分析和试验结果吻合较好。更多还原

【Abstract】 Dynamic tests on three simply supported beams with external prestressing were carried out. The expermental results indicated that natural frequencies of species increased with the growth of prestressing at the stage of stretching, which is contrary to what derived from classical linear-plastic theories. Also, natural frequencies of species decreased significantly after crack occurs. Natural frequencies of species were calculated with existing formulas and compared with test results, and significant difference was observed between the values of natural frequencies, as well as their varying tendencies. Based on test results and considering concrete as a composite material, a new calculation method of natural frequencies is presented, which generates consistant results with testing observations.更多还原