钢-混组合桥梁栓钉腐蚀疲劳失效及力学性能退化机理试验研究OA北大核心CSTPCD

The stud connectors of steel-concrete composite bridges in corrosive environments may deteriorate due to corrosion-fatigue coupling effect.Three groups of 10 stud push-out specimens were designed and fabricated,and the static and fatigue performance tests and corrosion-fatigue coupling tests were carried out respectively to study the corrosion-fatigue failure and mechanical property degradation mechanism of stud.The results show that corrosion significantly degrades the shear stiffness of the stud;the fatigue life of stud under corrosion-fatigue coupling effect is significantly lower than that after corrosion;the fatigue crack of the stud originates from the stud rod section near the weld toe section on the shear action side,and mainly propagates as a shear crack.When the fatigue crack or corrosion-fatigue crack develops to about 1/2 of the stud diameter,the stud fractures under the combined tensile-shear stress;the main factors affecting stud's damage evolution rate are load ratio,corrosion rate,and corrosion-fatigue coupling effect;the degradation rate of shear stiffness of the stud under the corrosion-fatigue coupling effect is greater than that of the fatigue alone,and the degradation of the shear stiffness includes two stages:rapid degradation and slow degradation,and the former stage accounts for about 20％of the corrosion fatigue life of the stud.