Development of Nonlinear Analysis Tools for Concrete Frame Buildings under Extreme Loads

近年来，对极限荷载的非线性分析方法的需求大大增加。例如，恐怖主义威胁的加剧导致许多政府和商业建筑被评估和加固，以防可能发生的炸弹爆炸和车辆撞击。破坏性地震的频繁发生和相关的生命损失要求迅速评估和加固世界各地许多现有建筑物的抗震性。对于极端载荷，有许多分析方法可用，并且通常在工业中使用。这些方法建立在过于简化的理论基础上，忽略了剪切效应。这种方法简化了建模过程，并显著减少了所需的分析时间。因此，具有基本非线性分析知识的结构工程师可以使用这些方法。然而，最近的研究表明，冲击、爆炸和地震载荷会导致显著的剪切破坏，目前工业上使用的方法往往提供不可靠和不准确的结果。文献中以计算机软件的形式提供了许多先进的分析工具来考虑剪切效应。然而，这些工具过于复杂，需要混凝土和剪切建模方面的专业知识。其中一个原因是，它们是许多材料(例如，钢、木材和混凝土)、加载条件(例如，静态、动态和热)以及工程学科(例如，机械、岩土和结构)的通用工具。这需要最终用户做出专家决策，并为要分析的结构定制工具。因此，这些工具大多只适用于学术研究人员。本研究的长期目标是发展能够准确评估混凝土结构在各种荷载条件下的安全性和性能的综合分析方法。我的主要目标是为行业中的结构工程师提供用户友好的非线性分析软件和专门为某些类型的混凝土结构开发的文档。预期的结果是取代目前工业上使用的过于简化的分析方法，并允许进行更准确、更经济和更安全的混凝土结构设计。作为一个重要的里程碑，该研究计划的目标是开发一种冲击、爆炸和地震载荷的分析方法，并通过适合于工业使用的简单建模过程准确地考虑剪切效应。这将通过开发一种仅适用于混凝土框架建筑的专门方法来实现。将预先实施最合适的分析选项和参数，最终用户将不需要为它们作出选择或输入。通过进一步开发以前被证明成功的现有分析程序，将实现准确的剪切和混凝土建模。将开展更多的分析和实验工作，以提高我们对冲击、爆炸和地震载荷的现有知识和建模能力。开发的方法将被应用到一个方便用户的计算机工具中，以促进将开发的知识转移到工业界和研究界。该工具和相关的用户手册将通过互联网向加拿大工程师和研究人员提供，并将与最新的计算机系统兼容。混凝土框架结构仍然是加拿大最常见的建筑体系之一。开发的软件将有助于我们准确分析和评估现有和新框架建筑的安全性和性能，以将冲击、爆炸和地震载荷的破坏性影响降至最低。

The need for nonlinear analysis methods for extreme loads has increased considerably in recent years. Heightened levels of terrorist threat, for example, have resulted in many government and commercial buildings being assessed and strengthened for possible bomb explosions and vehicle impacts. Frequent occurrences of destructive earthquakes and associated loss of life have required prompt assessment and reinforcement of many existing buildings worldwide for earthquake resilience. A number of analysis methods are available and commonly used in industry for extreme loads. These methods are based on overly simplified theories and neglect shear effects. This approach simplifies the modeling process and significantly reduces the analysis time required. Consequently, structural engineers with basic nonlinear analysis knowledge can use these methods. However, recent research studies have demonstrated that impact, blast and earthquake loads result in significant shear damage and the current methods used in industry tend to provide unreliable and inaccurate results. A number of advanced analysis tools, in the form of computer software, are available in the literature to consider shear effects. These tools, however, are overly complex and require expert knowledge on concrete and shear modeling. One reason for this is that they are general purpose tools for many materials (e.g., steel, wood, and concrete), loading conditions (e.g., static, dynamic, and thermal), and engineering disciplines (e.g., mechanical, geotechnical, and structural). This requires end users to make expert decisions and customize the tool for the structure being analyzed. Consequently, these tools are mostly suitable for academic researchers only. The long-term objective of my research is to develop comprehensive analysis methods by which the safety and performance of concrete structures can accurately be assessed under various loading conditions. My main goal is to provide structural engineers in industry with user-friendly nonlinear analysis software and documentation developed specifically for certain types of concrete structures. The anticipated outcome is to replace the overly simplified analysis methods currently used in industry and allow for more accurate, more economical, and safer design of concrete structures. As an important milestone, the objective of this research program is to develop an analysis method for impact, blast and earthquake loads and accurately consider shear effects with a simple modeling process suitable for use in industry. This will be achieved by developing a specialized method for only concrete frame buildings. The most suitable analysis options and parameters will be pre-implemented and end users will not need to make selections or inputs for them. Accurate shear and concrete modeling will be achieved by further developing an existing analysis procedure which was previously proven successful. More analytical and experimental work will be undertaken to advance our current knowledge and modeling capabilities for impact, blast and earthquake loads. The developed method will be implemented into a user-friendly computer tool to facilitate the transfer of the developed knowledge to industry and research communities. This tool and the related users’ manual will be made available over the internet for Canadian engineers and researchers, and it will be compatible with the latest computer systems. Concrete frame structures continue to be one of the most common building systems in Canada. The developed software will contribute to our capability to accurately analyze and assess the safety and performance of existing and new frame buildings to minimize the devastating effects of impact, blast, and earthquake loads.