New bridge construction using an innovative hybrid FRP-UHP concrete deck systems

桥梁上部结构由混凝土或钢梁组成，顶部覆盖钢筋混凝土(RC)桥面。在恶劣的环境中，如美国北部或加拿大的气候，甲板上会形成高度腐蚀性的环境，这归因于冬季大量使用除冰盐。超高性能混凝土(UHPC)的发展为工程师提供了一个新的设计水平的机会，以创造更薄的高强度和更长的设计寿命。通过在混合物中添加有机纤维或钢纤维来消除钢筋，简化了超高性能混凝土在建筑中的使用。纤维增强聚合物(FRP)复合材料作为一种新兴的材料，作为钢材的替代品，在新建筑中具有很大的吸引力。玻璃钢桥面系统的重量可能是类似RC桥面的20%左右。然而，尽管FRP具有高强重比、耐腐蚀等优点，但FRP全桥面板系统(相对于RC桥面)较高的初始建造成本仍然是FRPS在桥梁建设市场广泛采用的主要障碍之一。因此，充分利用FRP复合材料的独特性能和超高性能混凝土的独特性能，以混合建筑体系的形式，开发具有成本效益的高性能结构体系是非常必要的。建议的FRP-UHP混杂混凝土截面由一个薄壁玻璃钢拉挤空心箱形截面和一层薄层UHP混凝土组成，在受压区浇筑一层超高强度混凝土，在张拉区粘结一层薄薄的碳纤维或钢纤维片材。高刚度和高强度部分的重量约为同等RC构件的三分之一，从而允许在工作现场快速部署和安装。这项研究计划将调查所提出的系统在室温和低温下的静态、疲劳和长期载荷下的性能。这项研究将为行业带来一项新技术，允许使用和建造耐用的混合桥面系统，这种系统有可能取代传统的钢梁混凝土桥面，或用作自承式短跨度桥梁上部结构。

Bridge superstructures consist of concrete or steel girders topped with a reinforced concrete (RC) deck. In harsh environments, such as those found in northern US or Canadian climates, a highly corrosive environment develops in the decks, attributed to the heavy use of deicing salt during winter weather. The development of Ultra High Performance Concrete (UHPC) provides engineers the opportunities of a new level of design to create thinner sections with high strength and longer design life. The use of UHPC for construction is simplified through the elimination of reinforcing steel by adding organic or steel fibers to the mix. As emerging materials, Fibre Reinforced Polymer (FRP) composites have been introduced as attractive materials for new construction as a substitute for steel. An FRP bridge deck system could weigh about 20% of a similar RC deck. However, in spite of the advantages offered by FRP (such as high-strength to weight ratio, corrosion resistant, etc.,), the higher initial construction cost of full FRP bridge deck systems (relative to RC deck) is still one of the major obstacles for wide-spread adoption of FRPs in the bridge construction market. Therefore, it is essential to develop cost-effective high-performance structural systems that take full advantage of the unique properties of FRP composites and the distinctive properties of UHPC in the form of hybrid construction system. The proposed hybrid FRP-UHP concrete section consists of a thin-walled Glass FRP pultruded hollow box section combined with a thin layer of UHP concrete cast in the compression zone and a thin Carbon FRP or Steel FRP sheets bonded in the tension zone. The high stiffness and strength section could weigh about 1/3 of an equivalent RC member that allows for rapid deployment and installation at the job site. This research program will investigate the performance of the proposed system under static, fatigue, and long-term loading at room and low temperatures. This research will bring a new technology to the industry that permits the use and construction of durable hybrid bridge deck systems that have the potential to replace conventional concrete bridge decks on steel girders, or to serve as a self-supported short span bridge superstructure.