Innovative Design for Sustainable Bridges and Other Structures

可持续桥梁和其他结构的创新设计

• 批准号: RGPIN-2014-04683
• 负责人: ElBadry, Mamdouh
• 金额: $ 1.46万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=636459
• 关键词: Innovative; Design; Sustainable; Bridges; Other

The proposed research aims at providing innovative design for sustainable performance of concrete bridge and building structures. Focus will be placed on two projects:1) Development of a Hybrid Corrosion-Free Bridge System: An innovative corrosion-free system for short and medium span bridges is proposed. The system consists of precast prestressed concrete truss girders and a cast-in-place or precast deck slab. The girders have top and bottom concrete chords made of glass fibre reinforced polymer (FRP) hollow sections filled with concrete. The chords are connected by precast vertical and diagonal truss members made of concrete-filled GFRP tubes. The vertical members are mainly in compression and connected to the chords using GFRP dowels. The diagonals are in tension and connected to the chords by GFRP double-headed bars. The bottom chord is pretentioned with carbon FRP strands. The FRP hollow sections are produced by filament winding. They and the tubes serve as stay-in-place formwork, confine the concrete in compression, and provide tensile and shear reinforcement. Short GFRP double-headed studs are used in the girders top chords to connect to the deck slab. The girders can be post-tensioned by external CFRP tendons to balance the slab weight and to provide continuity in multi-span bridges. The new system has the advantages of reduced self-weight and enhanced durability. The light weight reduces the load on the supports and allows for longer spans, resulting in reduction in the size of substructure and in the number of supporting piers in multi-span bridges and, hence, reduction in the initial cost. The improved durability reduces the maintenance cost and extends the structure's life span. Computer models will be developed to investigate an optimum design of the truss girder. Such design should result in the lightest girder with best performance. The models will be used to determine the optimum girder depth for different spans and the optimum dimensions of the truss chords, amount of prestressing, size of the web members, and number and size of headed bars needed to connect the diagonals to the chords. Full-scale specimens will be fabricated and tested under static, fatigue, and sustained load in order to verify the optimum design. The long-term objective is to develop guidelines and procedures for design and construction of the new bridge system.2) Novel Reinforcing Details in Dapped Ends of Precast Girders for Strength and Durability: The ends of precast girders often have reduced depth over short lengths in the form of dapped ends. Girders with dapped ends are frequently used in bridges and parking structures. Because of the reduced depth at the girder ends, the shear stresses are high, and, therefore, design of dapped ends requires special consideration. Dapped ends are typically reinforced with conventional steel closely-spaced stirrups and longitudinal reinforcing bars, which require hooks and bends and even welded plates to ensure sufficient anchorage. Recent research by the applicant has shown that reinforcing dapped ends with single and double headed steel studs eliminates congestion and provides efficient anchorage to concrete without the need for external anchor plates. Bridges and parking structures are exposed to harsh environment in which corrosion of steel is a major source of deterioration. This project aims at investigating the efficiency of reinforcing dapped-end zones with FRP headed bars in lieu of steel studs to achieve higher strength and better durability. Static load and fatigue tests will be conducted on series of dapped-end beams reinforced with FRP headed bars of different layouts. Analytical studies will be carried out to develop guidelines for design of dapped ends reinforced with FRP headed bars.

拟议的研究旨在为混凝土桥和建筑结构的可持续性提供创新设计。将重点放在两个项目上：1）开发无混合腐蚀的桥梁系统：提出了用于短和中跨度桥梁的无创新腐蚀系统。该系统由预制的预应力混凝土桁架梁和现场或预制甲板板组成。大梁具有由玻璃纤维增​​强聚合物（FRP）空心截面制成的顶部和底部混凝土和弦，里面装有混凝土。和弦通过由充满混凝土的GFRP管制成的预制垂直和对角线桁架成员连接。垂直成员主要是压缩的，并使用GFRP销钉连接到和弦。对角线处于张力，并通过GFRP双头杆连接到和弦。底部的和弦用碳FRP链假定。 FRP空心截面是通过细丝绕组产生的。它们和管子充当现场模板，将混凝土限制在压缩中，并提供拉伸和剪切钢筋。腰带顶部和弦中使用短的GFRP双头螺柱连接到甲板板。大梁可以在外部CFRP肌腱后进行张紧，以平衡平板重量并提供多跨度桥的连续性。新系统具有降低自重和增强耐用性的优势。轻质的重量减少了支架上的负载并允许更长的跨度，从而减少了子结构的大小以及多跨度桥梁中支撑码头的数量，从而减少了初始成本。提高的耐用性降低了维护成本，并延长了结构的寿命。将开发计算机型号来研究桁架梁的最佳设计。这样的设计应以最佳性能导致最轻的梁。这些型号将用于确定不同跨度的最佳小梁深度以及桁架和弦的最佳尺寸，预应力量，Web成员的尺寸以及将对角线连接到和弦所需的头条杆的数量和大小。全尺度标本将在静态，疲劳和持续负载下制造和测试，以验证最佳设计。长期目标是制定新桥系统设计和建造的准则和程序。2）预制梁的末端增强细节以提高力量和耐用性：预制梁的末端通常以淡淡的末端形式的短长度减少了深度。桥梁和停车结构经常使用带有末端的大梁。由于梁末端的深度减小，剪切应力很高，因此，底端的设计需要特别考虑。通常用传统的钢紧密间隔的马rup和纵向加固条加固，这些钢筋需要钩和弯曲，甚至焊接板以确保足够的锚固。申请人的最新研究表明，用单头和双头钢螺柱加强末端的末端消除了拥塞，并为混凝土提供了有效的锚固，而无需外部锚固板。桥梁和停车结构暴露于严酷的环境中，钢的腐蚀是恶化的主要来源。该项目旨在调查用FRP头杆代替钢螺柱增强末端区域的效率，以实现更高的强度和更好的耐用性。静态负载和疲劳测试将对用不同布局的FRP头杆加固的一系列dapped末端梁进行。将进行分析研究，以制定用FRP头条杆增强的dapped端设计指南。