Numerical Code for Seismic Collapse Analysis of Framed Structures

In the conventional design of a building, only static analysis in the horizontal and uniaxial directions is commonly carried out, in order to minimize calculation costs. This approach can ensure the structural strength of the building, if there is sufficient strength to support the load in the vertical direction. For a similar reason, the mass system model replaces the building layer in dynamic analysis, and the complicated dynamic behavior of the structure at the member level becomes difficult to be examined sufficiently. Therefore, the development of a more precise and more efficient dynamic analysis code is strongly desired.

Recently, significant advances in the field of computers have been eliminating the calculation cost restrictions, and various dynamic analysis codes are being developed. Among those codes, there are some codes applicable to dynamic collapse problems which contain strong nonlinearities and discontinuities, such as the Distinct Element Method (DEM) or the Discontinuous Deformation Analysis (DDA). These codes have been applied to demolition analyses and seismic collapse analyses. However, the above-mentioned discrete numerical methods are computationally intensive and need detailed modeling. Therefore, they are suitable only for detailed analyses of either two-dimensional or small three-dimensional models.

On the other hand, the Finite Element Method (FEM), which is based on continuum material equations, has been successfully applied to a wide range of engineering problems including structural analyses of large-scale structures. However, the FEM is generally limited to analyses of relatively small displacements and it needs complicated modifications to simulate fracture occurring in structural members or joints. The main objective of this study is to develop a finite element code, which can simulate dynamic behaviors with such strong nonlinearities and discontinuities and is efficiently applicable to seismic collapse analyses of framed structures.

Toi and Isobe developed the Adaptively Shifted Integration (ASI) technique for the linear Timoshenko beam and the Bernoulli-Euler beam elements, which can be easily implemented into the existing finite element codes. In this technique, the numerical integration point is shifted immediately after the occurrence of a fully plastic section in the element so that a plastic hinge is formed exactly at that section. As a result, the ASI technique gives more precise elasto-plastic solutions than the conventional schemes, and has become able to simulate dynamic behaviors with strong nonlinearities by using only a small number of elements for a member. Structurally discontinuous problems have also become easily handled, by shifting the numerical integration point of the linear Timoshenko beam element to an appropriate position, and by releasing the resultant forces in the element simultaneously However, when the number of elements per member is very small, it still lacks accuracy in the elastic range compared to the converged solution, due to the low-order displacement function of the linear Timoshenko beam element.

To improve the accuracy in elastic range, Isobe and Lynn modified the ASI technique into an ASI-Gauss technique. The accuracy in elastic range is improved by placing the numerical integration points of the two consecutive elements forming an elastically deformed member in such a way that stresses and strains are evaluated at the Gaussian integration points of the two-element member, where the accuracy of bending deformation is mathematically guaranteed for two-point integration. The rest of the shiftings are done according to the flow of the ASI technique.

In this study, the ASI-Gauss technique is implemented into the finite element code in order to develop a more precise and less-calculation-time-consuming seismic collapse analytical tool. The purpose of this study is to verify the validity of the ASI-Gauss technique in seismic collapse analysis and to construct a highly efficient structural design tool for framed structures. An analysis involving member fracture and contact is performed on a large-scale framed structure to show the practicability of the scheme.

Seismic collapse anslysis of 8-story framed structure (150%JMA-Kobe three-dimensional wave)

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Related papers (Journals):

Y.Toi and D.Isobe: Adaptively Shifted Integration Technique in the Finite Element Collapse Analysis of Framed Structures, Journal of the Society of Naval Architects of Japan, Vol.171, (1992), pp.363-371, in Japanese. abstract

Y.Toi and D.Isobe: Adaptively Shifted Integration Technique for Finite Element Collapse Analysis of Framed Structures, International Journal for Numerical Methods in Engineering, Vol.36, (1993), pp.2323-2339. abstract

Y.Toi and D.Isobe: Finite Element Analysis of Buckling Collapse Behaviors of Framed Structures by Using Adaptively Shifted Integration Technique, Journal of the Society of Naval Architects of Japan, Vol.174, (1993), pp.469-477, in Japanese. abstract

Y.Toi and D.Isobe: Finite Element Analysis of Dynamic Collapse Behaviors of Framed Structures by the Adaptively Shifted Integration Technique, Journal of the Society of Naval Architects of Japan, Vol.175, (1994), pp.299-306, in Japanese. abstract

Y.Toi and D.Isobe: Finite Element Analysis of Quasi-Static and Dynamic Collapse Behaviors of Framed Structures by the Adaptively Shifted Integration Technique, Computers and Structures, Vol.58, No.5, (1996), pp.947-955. abstract

D.Isobe and Y.Toi: Finite Element Analysis of Dynamic Collapse Behaviors of Brittle Framed Structures by the Adaptively Shifted Integration Technique, Journal of the Society of Naval Architects of Japan, Vol.180, (1996), pp.471-478, in Japanese. abstract

D.Isobe and Y.Toi: Analysis of Structurally Discontinuous Reinforced Concrete Building Frames Using the ASI Technique, Computers and Structures, Vol.76, No.4, (2000), pp.471-481. abstract

D.Isobe: Seismic Damage Analysis of Reinforced Concrete Buildings Considering Member Fracture, Journal of the Mechanical Behavior of Materials, Vol.11, Nos.1-3, (2000), pp.63-68. abstract

D.Isobe and M.Tsuda: Development of Seismic Collapse Analysis Code for RC Framed Structures Using Finite Element Method, Journal of Structural Engineering, Vol.48B, (2002), pp.385-394, in Japanese. abstract

D.Isobe and M.Tsuda: Seismic Collapse Analysis of Reinforced Concrete Framed Structures Using the Finite Element Method, Earthquake Engineering and Structural Dynamics, Vol.32, No.13, (2003), pp.2027-2046. abstract

Related papers (Proceedings):

M.Tsuda and D.Isobe: Development of Seismic Collapse Analytical Scheme for RC Space Framed Structures Using Finite Element Method, Proceedings of the Conference on Computational Engineering and Science, Vol.6, No.2, (2001), pp.463-466, in Japanese. abstract

D.Isobe and M.Tsuda: Development of Seismic Damage Finite Element Code for Reinforced Concrete Framed Structures, CD-ROM Proceedings of the 2nd International Conference on Advances in Structural Engineering and Mechanics ASEM'02, (2002), Busan, Korea. abstract

T. Ine, D. Isobe, N. Katahira and K. Kajiwara: Dynamic Collapse Analysis for Elasto-Plastic Behaviors of the Steel Frame under Seismic Loads using ASI-Gauss Technique, Part 1: Development of Dynamic Collapse Analysis Code, Proceedings of the 77th Architectural Research Meetings, Kanto Chapter AIJ, (2007), pp.165-168, in Japanese. abstract

T. Ine, D. Isobe, N. Katahira and K. Kajiwara: Dynamic Collapse Analysis for Elasto-plastic Behaviors of the Steel Frame under Seismic Loads using ASI-Gauss Technique, Abstracts of the International Conference on Computational Methods (ICCM2007), (2007), Hiroshima, Japan. abstract

T. Ine, D. Isobe, N. Katahira and K. Kajiwara: Dynamic collapse analysis for the steel framed structures using ASI-Gauss technique, Proceedings of the Conference on Computational Engineering and Science, Vol.12, No.1, (2007), pp.387-390, in Japanese. abstract

D. Isobe and N. Katahira: A Dynamic Finite Element Code for Analyzing Collapse Behaviors of Framed Structures under Seismic Loads, CD-ROM of the ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COMPDYN2007), (2007), Crete, Greece. abstract

T. Ine, D. Isobe, N. Katahira and K. Kajiwara: Seismic Collapse Analysis of the Steel Framed Structure using ASI-Gauss Technique, Summaries of Technical Papers of Annual Meeting Architectural Institute of Japan 2007 B-1, (2007), pp.257-258, in Japanese. abstract

N. Katahira, D. Isobe, T. Ine and K. Kajiwara: Seismic Collapse Analysis of Large Framed Structure using ASI-Gauss Technique, Summaries of Technical Papers of Annual Meeting Architectural Institute of Japan 2007 B-1, (2007), pp.259-260, in Japanese. abstract

N. Katahira, D. Isobe, T. Ine and K. Kajiwara: Development of Seismic Collapse Analysis System using ASI-Gauss technique -Verification of Analytical Code-, Proceedings of the 20th JSME Computational Mechanics Conference, No.07-36, (2007), pp.343-344, in Japanese. abstract

N. Katahira, D. Isobe, T. Ine and K. Kajiwara: Development of Seismic Collapse Analysis Code for Framed Structures under Three-Dimensional Excitation, Proceedings of the 57th National Congress of Theoretical and Applied Mechanics, (2008), pp.241-242, in Japanese. abstract

N. Katahira, D. Isobe, T. Ine and K. Kajiwara: Seismic Collapse Analysis of Large Framed Structure under Three-Dimensional Excitation, Summaries of Technical Papers of Annual Meeting Architectural Institute of Japan 2008 B-1, (2008), pp.395-396, in Japanese. abstract

N. Katahira, D. Isobe, T. Ine and K. Kajiwara: Development of Macro-Model Seismic Collapse Simulator for Framed Structures using ASI-Gauss Technique, CD-ROM Proceedings of the 14th World Conference on Earthquake Engineering (14WCEE), (2008), Beijing, China. abstract

N. Katahira, D. Isobe, T. Ine and K. Kajiwara: Verification of Macro-Model Seismic Collapse Analysis Code for Framed Structures, Proceedings of the 21th JSME Computational Mechanics Conference, No.08-33, (2008), pp.63-64, in Japanese. abstract

M. Ohsaki, T. Miyamura, M. Kohiyama, D. Isobe, H. Akiba, M. Hori, K. Kajiwara and T. Ine: High-Precision Finite Element Analysis of Elastoplastic Seismic Responses of Steel Building Frames, Proceedings of the Conference on Computational Engineering and Science, Vol.14, No.2, (2009), pp.829-832, in Japanese. abstract

T. Miyamura, M. Ohsaki, M. Kohiyama, D. Isobe, H. Akiba, M. Hori, K. Kajiwara and T. Ine: Virtual Shaking-Table Test of Super-Highrise Steel Frame and 4-Story Steel Frame Using Prototype of E-Simulator, Summaries of Technical Papers of Annual Meeting Architectural Institute of Japan 2009 B-1, (2009), pp.399-400, in Japanese. abstract

T. Miyamura, M. Ohsaki, M. Kohiyama, K. Onda, D. Isobe, H. Akiba, M. Hori, K. Kajiwara and T. Ine: High-Precision Finite Element Analysis of 4-Story Steel Frame Discretized by Solid Elements, Proceedings of the 22th JSME Computational Mechanics Conference, No.09-21, (2009), pp.218-219, in Japanese. abstract

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