Innovative Steel Braced Frame Systems for Tall Buildings in Seismic Active Regions

地震活跃地区高层建筑的创新钢支撑框架系统

• 批准号: RGPIN-2021-04367
• 负责人: Tremblay, Robert
• 金额: $ 3.79万
• 依托单位: École Polytechnique de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754677
• 关键词: Innovative; Steel; Braced; Frame; Systems

Steel braced frames are widely used to resist wind and earthquake lateral loads for building structures in Canada. The system is easy to design, fabricate and erect. It represents the most cost-effective solution to achieve the lateral strength and stiffness under winds and small earthquakes. However, the system can exhibit poor performance under strong earthquakes such as large inelastic deformations and significant permanent deformations. For tall buildings, it can be prone to concentrations of storey drifts that can lead to global instability and structural collapse. Measures have been implemented in codes to achieve proper seismic response and safety to the public, including higher design seismic loads and stringent height limits. Those have increased construction costs and limited the application of the system. In addition, building owners are likely to face long downtime periods and high repair/reconstruction costs after a major seismic event, which may lead to significant losses for the Canadian economy. The research will focus on the development of two new steel bracing systems that can achieve superior seismic performance, with no or limited damage after an extreme earthquake, such that functionalities can be quickly restored, and repair costs are minimized. The first system is an innovative hybrid bracing system in which an elastic brace and a nonlinear brace are coupled with an elastic beam to generate a positive post-yielding stiffness that ensures stable seismic response and self-centering capabilities. The system can be coupled with an elastic segmental spine system to achieve more uniform storey drift demand over the structure height. The second system builds on the controlled rocking braced frame system that has been developed in the last two decades to eliminate structural damage and permanent structural deformations after a strong earthquake event. The original contribution from the proposed project is a new self-centering storey shear fuse that diminishes the force demand on the structure to reduce its initial cost. This novel shear fuse is inspired from the hybrid braced frame system described in the first project. Both studies will be conducted with the objective of developing braced steel frames suitable for tall buildings located in seismic active regions of eastern and western Canada. The research are expected to lead to effective structural configurations and design methodologies that will have been validated through advanced nonlinear seismic analysis. Shake table experiments and full-scale cyclic tests are also planned to validate the response of the proposed systems. Research will also be conducted to improve design provisions for braced frames using braces with intentional eccentricity and slotted hidden brace connections for HSS members. Testing and numerical simulations will also be performed to assess the plastic rotation capacity of beam-to-column connection in the gravity frame of building structures.

钢支撑框架在加拿大建筑结构中被广泛应用于抵抗风和地震的横向荷载。该系统易于设计、制造和安装。它代表了最具成本效益的解决方案，以实现在风和小地震下的横向强度和刚度。然而，该系统在强震下可能表现出较差的性能，例如大的非弹性变形和显著的永久变形。对于高层建筑，它可能容易出现楼层漂移集中，从而导致全球不稳定和结构倒塌。守则已实施多项措施，包括提高设计地震荷载和严格的高度限制，以确保公众获得适当的地震反应和安全。这些都增加了建设成本，限制了该系统的应用。此外，在发生重大地震事件后，建筑物所有者可能面临长时间的停机时间和高昂的维修/重建成本，这可能会给加拿大经济带来重大损失。研究将集中于开发两种新的钢支撑系统，它们可以实现优越的抗震性能，在极端地震后没有或仅有有限的破坏，从而能够迅速恢复功能，并将维修成本降至最低。第一个系统是一种创新的混合支撑系统，其中弹性支撑和非线性支撑与弹性梁耦合，以产生正的屈服后刚度，确保稳定的地震反应和自定心能力。该系统可以与弹性节段脊梁系统相结合，以实现结构高度上更均匀的楼层漂移要求。第二个系统建立在可控摇摆支撑框架系统的基础上，该系统是在过去20年中开发的，目的是消除结构破坏和强烈地震后的永久结构变形。该项目最初的贡献是一种新型的自定心层剪力保险丝，它减少了对结构的受力需求，从而降低了初始成本。这种新型的剪切保险丝的灵感来自于第一个项目中描述的混合支撑框架系统。这两项研究的目标都是开发适用于加拿大东部和西部地震活跃地区的高层建筑的支撑钢框架。预计这项研究将导致有效的结构配置和设计方法，并将通过先进的非线性地震分析进行验证。还计划进行振动台试验和全尺寸循环试验，以验证所提出的系统的响应。还将进行研究，以改进使用故意偏心的支撑和开槽隐藏支撑连接的支撑框架的设计规定。还将进行试验和数值模拟，以评估建筑结构重力式框架中梁柱连接的塑性转动能力。