地震造成的建筑物倒塌是引起重大人員傷亡的主要原因,對結構進行抗倒塌設計意味著生命的拯救。除自然災害外,結構倒塌也可能是由疏忽大意或故意破壞造成的。另一方面,只有少數(shù)人能夠負擔得起建筑進行防倒塌設計的昂貴成本。因此,采用經(jīng)濟、實用和有效的方法對結構進行防倒塌設計是十分必要的。地震作用下鋼結構的安全儲備是可量化的,然而,將其融合到結構設計中仍然是一個亟待解決的問題。本論文嘗試進行支撐體系的優(yōu)化研究,并進一步將安全儲備的概念拓展至連續(xù)倒塌領域,這個過程提供了理解需求能力比(DCR)自身以及其與結構構件行為狀態(tài)之間相互關系的全新視角。該研究特別是將安全儲備的概念融入到支撐體系這個過程,對鋼結構的設計和加固具有重要意義,使得支撐體系由側向荷載耗能構件的初始角色成為防止結構倒塌的主要結構構件。本論文的研究內容如下:1)分析了對稱布置的中心支撐鋼框架的地震倒塌安全儲備。研究表明,支撐的布置方式和截面形式?jīng)Q定著支撐提高結構安全性的效率。從數(shù)值算例來看,最佳的加固方案不能兼得最高的結構安全性和最低的造價,而是在安全性和造價之間取得平衡。結合選取最優(yōu)加固方案的三個參數(shù)來看,在給定結構的最佳加固方案中性能水...

【文章頁數(shù)】：172 頁

【學位級別】：博士

【文章目錄】：
Abstract
摘要
Table of Major Symbols and Units
1 Introduction
    1.1 Research Background and Significance
        1.1.1 Background
        1.1.2 Research Significance
    1.2 State-of-the-Art for Safety Margin Analysis and Design Optimization of Building Structures
        1.2.1 Causes of Structural Collapse
        1.2.2 Methods for Assessing Seismic Collapse Capacity
        1.2.3 Review of Progressive Collapse
        1.2.4 Review of Optimization Design for Bracing Systems
        1.2.5 Problem Statement
    1.3 Research Topics
2 Seismic Collapse Margin Analysis of Steel Frame Structures with Symmetrically Placed Concentric Braces
    2.1 Introduction
    2.2 Structural Collapse Resistance
    2.3 Collapse Margin Ratio
    2.4 Performance Index
        2.4.1 Location of Braces
        2.4.2 Number of Braces
        2.4.3 Optimal Brace Cross Section
    2.5 Retrofitting Cost
    2.6 Modeling using OpenSees
    2.7 Case Study
    2.8 Summary
3 Collapse Safety Margin-Based Design Optimization of Steel Structures with Concentrically Braced Frames
    3.1 Introduction
    3.2 Brace Schemes using Probabilistic Analysis of Multi-Element Removal
        3.2.1 Designable Matrix
        3.2.2 Matrix brace locations
        3.2.3 Matrix Brace Sections
    3.3 Optimal Discrete Brace Sections Derived from Base-Shear Method
        3.3.1 Overview and Assumptions
        3.3.2 Flexure Displacement
        3.3.3 Optimal Shear Displacement
        3.3.4 Total Optimal Brace Section
        3.3.5 Optimal Discrete Brace Section
    3.4 Optimal Design of Bracing Systems using Collapse Safety Assessment
        3.4.1 Optimization Overview
        3.4.2 Collapse Safety Evaluation
        3.4.3 Optimal Brace Scheme
    3.5 Numerical Examples
        3.5.1 Modeling using OpenSees
        3.5.2 Building Models
        3.5.3 Results and Discussions
    3.6 Summary
4 Vertical Collapse Safety Margin Assessment for Steel Frames against Earthquake-Induced Loss of Column
    4.1 Introduction
    4.2 CMR_V Assessment
        4.2.1 Important Parameters for Assessing CMRV

        4.2.2 Proposed Classification of the Vertical Earthquakes
        4.2.3 Performance Analyses of the Archetypes
    4.3 CMR_V Formulation
        4.3.1 Limitation of Data
        4.3.2 Nonlinear Regression Equation for the CMR
        4.3.3 Validation of the Proposed Formulation
    4.4 Estimation of the Minimum CMR_V

        4.4.1 CMR_V,min Based on Reduction of Potential for Progressive Collapse
        4.4.2 CMR_V,min Based on Beam Deformation States under Column Loss
    4.5 Summary
5 Design of Buckling-Restrained Braces in Retrofit of Steel Frames Considering Different V/H Ratios
    5.1 Introduction
    5.2 Seismic Collapse Assessment of Braced Structures
        5.2.1 Structural Collapse under Seismic Loads
        5.2.2 Proposed Procedure to Assess Seismic Collapse
        5.2.3 Structural Parameters Influencing the Seismic Structural Collapse
    5.3 Assessment of Structural Parameters
        5.3.1 Effect of the Column Removal on the Structural Strength
        5.3.2 Influence of the V/H Ratio on the Structural Vulnerability
        5.3.3 Relation of the Beam Length to the Structural Strength
        5.3.4 Influence of the Brace Configuration
    5.4 Proposed BRB Design against Seismic Structural Collapse
        5.4.1 Proposed Design of BRB
        5.4.2 Optimal Utilization of the BRB
    5.5 Summary
6 Conclusions and Future Work
    6.1 Conclusions
    6.2 Abstract of Innovation Points
    6.3 Future Work
References
Published Papers during PhD Period
Acknowledgement
About the Author



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