黑龙江交通科技

以江西省南韶高速公路昌宁段预应力混凝土T梁桥为研究对象，对火灾后的桥梁开展了系统的灾后检测与承载能力评估研究。通过综合运用外观检查、锤击法、混凝土超声测速和回弹测试、碳化深度等检测技术手段，结合混凝土高温性能特征分析，量化评估了火灾对桥梁结构的损伤程度，分析了火灾后的材料性能及结构承载能力。通过对全桥进行模态试验测量桥梁结构的振动特性，结果表明：一阶竖弯实测频率4.949 Hz，理论值3.931 Hz，比值1.26；二阶竖弯实测频率5.647 Hz，理论值4.535 Hz，比值1.25。阻尼比分别为2.105%和1.200%。实测频率均高于理论值，表明桥梁的整体刚度未见明显损伤。

This study investigates a post-fire assessment and load-bearing capacity evaluation of a prestressed concrete T-beam bridge located on the Nanchang-Shaoguan Expressway(Changning Section) in Jiangxi Province. A systematic post-damage inspection was conducted employing integrated techniques, including visual examination, hammer sounding, ultrasonic pulse velocity testing, rebound hammer tests, and carbonation depth measurement. By combining these findings with an analysis of the properties of concrete under high temperatures, the extent of fire-induced damage to the bridge structure was quantitatively assessed, and the residual material properties as well as structural load-bearing capacity were analyzed. Modal testing performed on the entire bridge to measure its vibration characteristics revealed the following results: the measured first-order vertical bending frequency was 4.949 Hz(theoretical value: 3.931 Hz), yielding a ratio of 1.26; the measured second-order vertical bending frequency was 5.647 Hz(theoretical value: 4.535 Hz), with a ratio of 1.25. The corresponding damping ratios were 2.105% and 1.200%, respectively. The consistently higher measured frequencies compared to their theoretical counterparts indicate no significant degradation in the overall stiffness of the bridge.