Collaborative Research: Transforming Building Structural Resilience through Innovation in Steel Diaphragms

美国依靠坚固和有弹性的建筑存量，将地震和飓风等极端自然灾害对其公民的伤害和对其经济的损害降至最低。过去，结构工程师将注意力集中在创造更坚固、更有延展性、更可靠的横向抵抗系统上，这些系统可以用在建筑物的墙壁内，以抵御与这些自然灾害相关的极端要求。对于楼层系统在抵制这些要求方面的作用，人们相对较少关注。楼面横隔板起到了关键作用，它将建筑物在极端事件期间产生的需求分配给侧向阻力系统，并最终分配给建筑物基础。钢桥面是多层钢结构建筑中最常用的横隔板之一，通常由混凝土填充的波纹薄板组成。该项目的目标是：将钢桥面横隔板作为整体建筑性能的综合结构系统，发展对三维建筑模型中楼板系统精确建模的改进策略，并开发钢桥面横隔板的新解决方案，以增强建筑的整体结构弹性。目前对楼板横隔板系统缺乏了解，阻碍了建筑设计方法从专注于二维框架设计到在三维建筑设计中实现创造性解决方案的必要演变。在建筑物中，作为能量耗散系统的横隔膜的利用尚未得到利用或优化。该项目将开发一系列适用于钢桥面横隔板的建筑原型。将在连接和隔膜尺度上进行综合实验计划，包括用于揭示测试过程中的损伤和变形的新的非接触式测量方案，以弥合目前阻碍建筑三维建模和设计的关键知识空白。为了探索能量耗散隔膜的新解决方案，该项目将对结构熔断器进行测试，并开发将这些熔断器集成到钢质隔膜系统中的原型。该项目还将完成高保真材料和几何非线性有限元模型，以便能够详细研究隔膜内以及隔膜与所有连接部件之间的力流动。将开发一系列低保真度、降阶模型，适用于选定建筑原型的整个建筑分析。将对横隔板在建筑响应中的作用进行正式优化，包括一种新的两级优化方案。总而言之，这些活动将为建筑横隔板的设计提供最先进的技术。通过与工业界的全面接触，这些发现将被转移给工程师，并用于提高国家建筑的结构弹性。

America relies on a robust and resilient building stock to minimize harm to its citizens and damage to its economy due to extreme natural hazards such as earthquakes and hurricanes. In the past, structural engineers have focused their attention on creating stronger, more ductile, more reliable lateral-resistance systems that can be used within the walls of buildings to resist the extreme demands associated with these natural hazards. Comparatively little attention has been paid to the role of the floor systems of buildings in resisting these demands. The floor diaphragm acts as a critical element that distributes the demands developed in a building during an extreme event to the lateral-resistance systems and eventually to the building foundation. Steel deck, i.e., thin corrugated steel panels typically with concrete fill, forms one of the most commonly used diaphragm elements in multi-story steel buildings. This project has as its objectives: to develop fundamental understanding of steel deck diaphragms as structural systems integrated within the overall building performance, to develop improved strategies for accurate modeling of floor systems within three-dimensional building models, and to develop new solutions for steel deck diaphragms that enhance the overall structural resilience of buildings.Current lack of knowledge about floor diaphragm systems impedes a needed evolution for building design approaches from focusing on two-dimensional frame design to enabling creative solutions within three-dimensional building design. The utilization of the diaphragm as an energy dissipating system has not been harnessed nor optimized in buildings. This project will develop a series of building archetypes appropriate to steel deck diaphragms. An integrated experimental program will be conducted at the connection and diaphragm scale, including novel non-contact measurement schemes for revealing damage and deformations during testing, to bridge critical knowledge gaps that currently impede three-dimensional modeling and design of buildings. To explore new solutions for energy-dissipating diaphragms, this project will perform testing of structural fuses and develop prototypes for integrating these fuses into steel diaphragm systems. This project will also complete high fidelity material and geometric nonlinear finite element models to enable detailed investigations of the flow of forces in diaphragms and between the diaphragm and all connected components. A series of lower fidelity, reduced order models will be developed, appropriate for whole building analysis of selected building archetypes. Formal optimization of the role of the diaphragm in building response, including a novel two-level optimization scheme, will be performed. Taken together, these activities will provide a significant advancement in the state-of-the-art for design of building diaphragms. Through a comprehensive outreach effort with industry, the findings will be transferred to engineers and utilized to improve the structural resilience of the nation's buildings.