Fatigue cracking induced by vehicle load is a prevalent problem in orthotropic steel decks. In addition, pavement debonding in steel bridge decks is another familiar issue resulting from low slip resistance in the faying surface between the steel and asphalt concrete. The present study proposed a strengthening method that uses ultra-high performance concrete to stiffen a repeatedly maintained cable-stayed bridge in order to help address these two problems. The existing issues of the real bridge and the corresponding causes were investigated. Following this, an ultra-high performance concrete paving system was designed to improve the stiffness of the orthotropic steel decks. For this paving system, a 45-mm ultra-high performance concrete layer was connected to the deck by welded shear studs. The local stresses at the typical vulnerable fatigue cracking points were determined by means of a finite element model and of a field loading test to evaluate the strengthening effect. The results showed that this strengthening method can prevent the propagation of fatigue cracks. The local stresses of the U-ribs and diaphragms were reduced by 45.4% and 40.0%, respectively. The repaired bridge has sufficient resistance against fatigue cracking based on the in situ observations.

中文翻译：

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使用超高性能混凝土加固斜拉桥钢桥面：案例研究

车辆载荷引起的疲劳开裂是正交各向异性钢甲板的普遍问题。此外，钢桥面板中的路面脱粘是另一个常见问题，原因是钢和沥青混凝土之间的接合面的防滑性低。本研究提出了一种使用超高性能混凝土加固反复维护的斜拉桥的加固方法，以帮助解决这两个问题。对实际桥梁存在的问题及相应原因进行了调查。在此之后，设计了一种超高性能混凝土铺路系统，以提高正交各向异性钢桥面板的刚度。对于这个铺路系统，一个 45 毫米的超高性能混凝土层通过焊接剪力钉连接到甲板上。通过有限元模型和现场加载试验来确定典型易受疲劳裂纹点处的局部应力，以评估强化效果。结果表明，这种强化方法可以防止疲劳裂纹的扩展。U 形肋和隔膜的局部应力分别降低了 45.4% 和 40.0%。根据现场观察，修复后的桥梁具有足够的抗疲劳开裂能力。