Study on Design method and Fatigue Durability of Cantilever slabs for Highway bridge

本研究的目的是建立一种适合公路桥梁悬臂板的设计方法。为了识别各种类型的板坯在使用极限状态下的真实行为，轮式运行机的疲劳加载方法显得非常重要。加载试验结束后，进行静载试验，研究混凝土裂缝及剩余抗弯刚度的影响。2001年，用滚轮机对钢筋混凝土板和预应力混凝土板的主要板进行了纵向预应力性能测试。2002年试件类型扩展为侧向预应力PC板、半预制预应力混凝土板、钢板与混凝土组合台、槽形PC板。在疲劳加载使其劣化直至使用极限状态后，进行静力加载试验以研究预应力的影响并证实正交异性的发生。由于混凝土裂缝的存在，楼板的性能由各向同性板转变为正交各向异性板，但由于楼板类型的不同，正交两方向的弯矩也发生了变化。通过疲劳试验对正交异性进行了检验。在城市地区，在悬臂板的边缘放置了非常高的庇护所，以减少高速公路上车辆行驶的噪音。当遮阳篷受到强风荷载作用时，会对悬臂板产生较大的弯矩。本文采用特殊的加载设备，对风荷载作用的验证进行了实验研究。试验分别在RC板和钢板-混凝土组合板上进行。在上述试验研究和分析验证的基础上，提出了考虑桥面正交异性的适当设计方法，包括弯矩公式的推导。

The aim of this study is to establish an appropriate design method for the cantilever slabs of highway bridges. To recognize real behavior of various slab types in serviceability limit state, the fatigue loading method with wheel running machines seems to be very important for the slabs. After the loading test, a static loading test was carried out to investigate the effect of cracks of concrete and remaining bending rigidities.In 2001, the essential slabs of RC slabs and PC slab prestressed in longitudinal direction were surveyed their behavior with the wheel running machine. In 2002, the test specimen types were expanded to PC slabs prestressed in the lateral direction, half-precast prestressed concrete slabs, steel plate and concrete composite desks and Channel shape PC slabs. After fatigue loading to give deterioration until serviceability limit states, static loading tests were carried out to investigate the effect or prestressing and to certify the occurrence of orthotropy. Due to the occurrence of cracks in the concrete, the behavior of slabs change from isotropic plate to orthotropic plate but by the type of decks the orthotropy is different from each other and the bending moments in orthogonal two ways change also. Those orthotropy was examined through the fatigue tests.In urban area, very high-rise shelters are placed at the edge of cantilever slab to cut noise from, vehicle running on highway. When the shelters are subjected to strong wind load, it will issue a large bending moment to the cantilever slab. In this study, certification of the effect of wind load was investigated experimentally with special loading equipments. The tests were carried out on a RC slab and a steel plate-concrete composite deck.Based on the above mentioned experimental study and analytical verifications, appropriate design method including deriving bending moment formulae was proposed by taking into account the orthotropy of the decks.