Analysis of building collapse under blast loads

Computationally efficient macromodels are developed for investigating the progressive collapse resistance of seismically designed steel moment frame buildings. The developed models are calibrated using detailed finite-element models of beam-column subassemblages and account for the most important physical phenomena associated with progressive collapse. The models are utilized to compare the collapse resistance of two-dimensional, ten-story steel moment frames designed for moderate and high seismic risk according to current design specifications and practices. The simulation results show that the frame designed for high seismic risk has somewhat better resistance to progressive collapse than the system designed for moderate seismic risk. The better performance is attributed to layout and system strength rather than the influence of improved ductile detailing. The alternate path method is shown to be useful for judging the ability of a system to absorb the loss of a critical member. However, it is pointed out that the method does not provide information about the reserve capacity of the system and so its results should be carefully evaluated.

Macromodel-Based Simulation of Progressive Collapse: Steel Frame Structures

Progressive collapse analysis of seismically designed steel braced frames

SUMMARY
Collapse resistance of high-rise buildings has become a research focus because of the frequent occurrence of strong earthquakes and terrorist attacks in recent years. Research development has demonstrated that numerical simulation is becoming one of the most powerful tools for collapse analysis in addition to the conventional laboratory model tests and post-earthquake investigations. In this paper, a finite element method based numerical model encompassing fiber-beam element model, multilayer shell model, and elemental deactivation technique is proposed to predict the collapse process of high-rise buildings subjected to extreme earthquake. The potential collapse processes are simulated for a simple 10-story RC frame and two existing RC high-rise buildings of 18-story and 20-story frame–core tube systems. The influences of different failure criteria used are discussed in some detail. The analysis results indicate that the proposed numerical model is capable of simulating the collapse process of existing high-rise buildings by identifying potentially weak components of the structure that may induce collapse. The study outcome will be beneficial to aid further development of optimal design philosophy. Copyright © 2012 John Wiley & Sons, Ltd.

/pdf/collapse-simulation-of-reinforced-concrete-high-rise-2lz9i1rp22.pdf

Collapse simulation of reinforced concrete high‐rise building induced by extreme earthquakes

Nonlinear dynamic simulations of progressive collapse for a multistory building

The present study is concerned with the improvement of the previously proposed ‘shifted integration technique’ for the plastic collapse analysis of framed structures using the linear Timoshenko beam element or the cubic beam element based on the Bernoulli-Euler hypothesis. In the newly proposed ‘adaptively shifted integration technique’, the numerical integration points for the evaluation of the stiffness matrices are automatically shifted immediately after. the occurrence of plastic hinges according to the previously established relations between the locations of numerical integration points and those of plastic hinges. By using the adaptively shifted integration technique, sufficiently accurate solutions can be obtained in the non-linear frame analysis by two-linear-element or only one-cubic-element idealization for each structural member. The present technique can easily be implemented in the existing finite element codes utilizing the linear or the cubic beam element.

Adaptively shifted integration technique for finite element collapse analysis of framed structures

A new finite element code using the Adaptively Shifted Integration (ASI) technique with a linear Timoshenko beam element is applied to the seismic collapse analysis of reinforced concrete (RC) framed structures. This technique can express member fracture as a plastic hinge located at either end of an element with simultaneous release of the resultant forces in the element. Contact between members is also considered in order to obtain results that agree more closely with actual behavior, such as intermediate-layer failure. By using the proposed code, sufficiently reliable solutions have been obtained, and the results reveal that this code can be used in the numerical estimation of the seismic design of RC framed structures. Copyright © 2003 John Wiley & Sons, Ltd.

Seismic Collapse Analysis of Reinforced Concrete Framed Structures Using the Finite Element Method

Computationally efficient framework for probabilistic collapse analysis of structures under extreme actions

https://www.kz.tsukuba.ac.jp/~isobe/104.pdf

Structural collapse analysis of framed structures under impact loads using ASI-Gauss finite element method

The objective of this study is to develop a dynamic finite element code that can effectively cope with strong non-linearities and discontinuities common in impact collapse problems, and whose calculation cost is sufficiently low to enable dynamic analyses of full-model large-scale structures. The adaptively shifted integration (ASI) technique is modified into the ASI-Gauss technique to further reduce calculation cost. Algorithms considering member fractures and elemental contact are also presented. Impact collapse analysis is conducted to simulate the aircraft impact with the World Trade Center South Tower (WTC2), and the analytical results showed good agreement with the observed data. Copyright © 2006 John Wiley & Sons, Ltd.

Daigoro Isobe

Papers

Adaptively shifted integration technique for finite element collapse analysis of framed structures

Seismic Collapse Analysis of Reinforced Concrete Framed Structures Using the Finite Element Method

Computationally efficient framework for probabilistic collapse analysis of structures under extreme actions

Structural collapse analysis of framed structures under impact loads using ASI-Gauss finite element method

Finite element code for impact collapse problems of framed structures