Structural safety of steel-high strength concrete and steel-normal strength concrete columns

钢-高强混凝土柱和钢-普通强度混凝土柱的结构安全

• 批准号: 1822-2006
• 负责人: Mirza, Sher
• 金额: $ 1.17万
• 依托单位: Lakehead University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=332079
• 关键词: Structural; safety; steel; strength; concrete

During the past couple of decades, several composite steel-concrete structural systems have been used in the construction of bridges and tall buildings. These systems combine the rigidity and formability of reinforced concrete with the strength and speed of construction associated with structural steel. One such system employs composite columns that consist of steel shapes encased in concrete. The concrete used for encasing a structural steel section not only increases its strength and stiffness, but also protects it from the fire damage. As a result, the use of such columns is on the rise in building construction in addition to applications in bridge and marine structures. The load factors included in the 2005 edition of the National Building Code of Canada (NBCC) and the material and member resistance factors specified in the 2004 edition of the Canadian Code for the Design of Concrete Structures (A23.3) are based on investigations of structural steel and reinforced concrete members and may not be applicable to composite steel-concrete columns in which steel shapes are encased in concrete. The objective of this study is to develop safety criteria (material and member resistance factors) for such composite columns based on accurate, elaborate, and comprehensive strength and load-effect modeling procedures, simulation and optimization techniques, and reliability analyses. The safety criteria so developed will be compatible with the A23.3 design expressions and new NBCC load factors, will be applicable to composite columns constructed with high strength concrete as well as with normal strength concrete, and are expected to be better than those currently included in the 2004 edition of A23.3. These criteria will be offered to the structural engineering profession for design office use and to the Code Committee for possible adoption in a subsequent edition of A23.3. The proposed research is needed for the development of A23.3 because the use of composite columns is on the rise as a consequence of damage suffered by many reinforced concrete columns during recent earthquakes around the world. The structural damage caused by Katrina along the US Gulf Coast is likely to further speed up the use of composite columns.

在过去的几十年里，多种钢-混凝土组合结构体系已被用于桥梁和高层建筑的建设。这些系统联合收割机将钢筋混凝土的刚性和可成形性与结构钢的强度和施工速度相结合。一种这样的系统采用由包裹在混凝土中的型钢组成的组合柱。混凝土用于包裹结构钢截面，不仅增加其强度和刚度，而且还保护其免受火灾破坏。因此，除了在桥梁和海洋结构中的应用之外，这种柱在建筑施工中的使用正在增加。2005年版《加拿大国家建筑规范》（NBCC）中包含的荷载系数以及2004年版《加拿大混凝土结构设计规范》中规定的材料和构件抗力系数（A23.3）是基于对结构钢和钢筋混凝土构件的调查，可能不适用于复合钢-型钢包裹在混凝土中的混凝土柱。本研究的目的是开发安全标准（材料和构件阻力系数），这种组合柱的基础上准确，详细，全面的强度和负载效应建模程序，模拟和优化技术，可靠性分析。这样制定的安全标准将与A23.3设计表达式和新的NBCC荷载系数兼容，将适用于用高强度混凝土和普通强度混凝土建造的组合柱，并且预计将优于A23.3 2004版中目前包含的安全标准。这些标准将提供给结构工程专业人员，供设计办公室使用，并提供给规范委员会，以便在A23.3的后续版本中采用。A23.3的发展需要拟议的研究，因为组合柱的使用正在上升，作为许多钢筋混凝土柱在最近的世界各地的地震中遭受破坏的结果。卡特里娜飓风沿着美国墨西哥湾沿岸造成的结构破坏可能会进一步加快复合材料柱的使用。