环境腐蚀对预应力桥梁疲劳性能影响试验研究

STUDY ON THE INFLUENCE OF ENVIRONMENTAL CORROSION ON FATIGUE PERFORMANCE OF PRESTRESSED BRIDGE

为深入研究腐蚀环境下预应力桥梁结构的疲劳性能,对不同腐蚀率试验梁进行了等幅疲劳试验,探讨试验梁的疲劳寿命、最大位移、混凝土最大压应变和残余应变的发展规律,并分析裂缝对腐蚀后试验梁的自振频率的影响。研究结果表明:在等幅疲劳荷载作用下,腐蚀率的增加会导致试验梁的疲劳寿命骤然减小;腐蚀率越大,梁的最大位移增长速度越快,腐蚀后的试验梁受压区混凝土残余应变与疲劳试验次数符合双对数线性关系;裂缝宽度对结构自振频率有明显影响,随着最大裂缝宽度的增大,试验梁的自振频率降低。

In order to further study prestressed bridge structure fatigue performance under corrosive environment, constant amplitude fatigue tests of beams with different corrosion rate were conducted. It was discussed the law of development of the test beam fatigue life, the maximal displacement, concrete maximum compressive strain and residual strain, and the influence of cracks on the natural vibration frequency of the test beam was analyzed. The results showed that under constant amplitude fatigue load, the increase of corrosion rate can lead to a sharp decrease in fatigue life. The corrosion rate increased, the maximum displacement of the beam would grow faster. After the corrosion,residual strain of compressive zone of concrete and fatigue cycle numberconform to double logarithm linear relationship. Structural natural vibration frequency was affected obviously by the crack width. With the increase of maximum crack width, the natural frequencies of the test beam were reduced.