scholarly journals Rigid-Plastic Analysis of Seismic Resistant T-Frame considering Moment-Shear Interaction

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ghader Bagheri ◽  
Payam Ashtari ◽  
Farhad Behnamfar
Keyword(s):  
Energy Dissipation ◽  
Collapse Mechanism ◽  
Rigid Plastic ◽  
Soft Storey ◽  
Collapse Mechanisms ◽  
Plastic Mechanism ◽  
Plastic Analysis ◽  
Seismic Resistant ◽  
Global Collapse ◽  
The Moment

To select a seismic resistant system, in addition to strength and stiffness, ductility and energy dissipation are important to be considered. Structures have nonlinear behavior under the influence of moderate and strong earthquakes. One of the primary aims in designing seismic resistant structures is to prevent the formation of undesirable collapse mechanisms such as the collapse in only a few storeys of the structure that leads to low energy dissipation. In order to achieve a global collapse mechanism, modern seismic codes provide simple rules for design, which is called the hierarchy criteria. Although these simple criteria could prevent the formation of a soft storey mechanism, they could not lead to an optimal global collapse mechanism. In these mechanisms, the energy dissipation zones include all the yielding zones such as beams, while all other parts of the structure have remained in the elastic range. TRF (T-resisting frame) is an innovative lateral resistant system introduced for architectural reasons and to provide more energy dissipating capability. This system has several collapse mechanisms due to the moment, shear, or moment-shear behavior of its members. In this paper, within the framework of the theory of plastic mechanism control, the rigid-plastic analysis of the TRF system to achieve the desired collapse mechanism is used by considering the moment-shear interaction. According to these analyses, which are performed on a single storey frame, simple hierarchy criteria are developed to create the desired collapse mechanism. Also, these criteria prevent undesired collapse mechanisms in order to have more energy dissipation and more ductility. Finally, the validity of the proposed criteria has been verified by the pushover analysis.

Assessment of the Seismic Vulnerability of Existing RC Buildings and Effect of the Irregular Position of the Masonry Panels on the Fragile Collapse Mechanisms

2012 ◽  
Vol 602-604 ◽  
pp. 1555-1565 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis ◽  
Vittorio Pasquino
Keyword(s):  
Seismic Performance ◽  
Seismic Vulnerability ◽  
Effective Interaction ◽  
Frame Structure ◽  
Collapse Mechanism ◽  
Seismic Zone ◽  
Soft Storey ◽  
Collapse Mechanisms ◽  
Masonry Infills ◽  
Displacement Based

The present work deals with the evaluation of the level of seismic vulnerability of reinforced concrete existing buildings situated in high seismic zone and designed for only gravitational loads. For assessing seismic performance, a Displacement Based Approach (DBA) is adopted and in particular the N2-metohd is used, according to Italian seismic code NTC 2008. The effect of the masonry infills on the seismic response of the structure is considered and a nonlinear model is adopted for all the panels considered in effective interaction with the frame structure. It is shown that the effect of the masonry infills, if improperly located within the building, can give rise to a worsening of the seismic performance of the structure. In fact particular locations of the masonry infills within the building can give rise to a fragile structural behavior due to a collapse mechanism of soft storey. A comparative analysis of a building is performed by considering the effects of the masonry infills and by considering the bare structural frame and it is shown that fragile collapse mechanisms can occur depending on the location of the effective masonry infills within the building. Consequently it is discussed how in a vulnerability analysis the procedure of neglecting the masonry infills not always is a procedure which operates for the benefit of security.

scholarly journals Evaluation of the Seismic Capacity of Existing Moment Resisting Frames by a Simplified Approach: Examples and Numerical Application

2021 ◽  
Vol 11 (6) ◽  
pp. 2594
Author(s):  
Rosario Montuori ◽  
Elide Nastri ◽  
Vincenzo Piluso ◽  
Paolo Todisco
Keyword(s):  
Collapse Mechanism ◽  
Eurocode 8 ◽  
Seismic Capacity ◽  
Numerical Application ◽  
Simplified Approach ◽  
Soft Storey ◽  
Moment Resisting Frames ◽  
Inelastic Analysis ◽  
Plastic Mechanism ◽  
Moment Resisting

The capacity of a structure can be assessed using inelastic analysis, requiring sophisticated numerical procedures such as pushover and incremental dynamic analyses. A simplified method for the evaluation of the seismic performance of steel moment resisting frames (MRFs) to be used in everyday practice has been recently proposed. This method evaluates the capacity of buildings employing an analytical trilinear model without resorting to any non−linear analysis. Despite the methodologies suggested by codes, the assessing procedure herein described is of easy application, also by hand calculation. Furthermore, it constitutes a suitable tool to check the capacity of the buildings designed with the new seismic code prescriptions. The proposed methodology has been set up through a large parametric analysis, carried out on 420frames designed according to three different approaches: the theory of plastic mechanism control (TPMC), ensuring the design of structures showing global collapse mechanism (GMRFs), the one based on the Eurocode 8 design requirements (SMRFs), and a simple design against horizontal loads (OMRFs) without specific seismic requirements. In this paper, some examples of the application of this simplified methodology are proposed with references to structures supposed to exhibit global, partial and soft storey mechanism.

Plastic Collapse of a Thin Annular Disk Subject to Thermomechanical Loading

2013 ◽  
Vol 80 (5) ◽  
Author(s):  
Sergei Alexandrov ◽  
Elena Lyamina ◽  
Yeau-Ren Jeng
Keyword(s):  
Analytic Solution ◽  
Hydrostatic Stress ◽  
Yield Criterion ◽  
The Other ◽  
Collapse Mechanism ◽  
Plastic Collapse ◽  
Thermomechanical Loading ◽  
Annular Disk ◽  
Collapse Mechanisms ◽  
Inner Radius

A semi-analytic solution for plastic collapse of a thin annular disk subject to thermomechanical loading is presented. It is assumed that the yield criterion depends on the hydrostatic stress. A distinguished feature of the boundary value problem considered is that there are two loading parameters. One of these parameters is temperature and the other is pressure over the inner radius of the disk. The general qualitative structure of the solution at plastic collapse is discussed in detail. It is shown that two different plastic collapse mechanisms are possible. One of these mechanisms is characterized by strain localization at the inner radius of the disk. The entire disk becomes plastic according to the other plastic collapse mechanism. In addition, two special regimes of plastic collapse are identified. According to one of these regimes, plastic collapse occurs when the entire disk is elastic, except its inner radius. According to the other regime, the entire disk becomes plastic at the same values of the loading parameters at which plastic yielding starts to develop.

Energy-Dissipation Mechanisms and Seismic Design Recommendation of Eccentrically Braced Steel Frames

2011 ◽  
Vol 71-78 ◽  
pp. 3662-3665
Author(s):  
Bao Cheng Zhao ◽  
Qiang Gu
Keyword(s):  
Plastic Deformation ◽  
Energy Dissipation ◽  
Seismic Design ◽  
Steel Frames ◽  
Shell Element ◽  
Elastic Stiffness ◽  
Collapse Mechanism ◽  
Finite Element Program ◽  
Earthquake Load ◽  
Element Program

Eccentrically braced steel frames are a lateral load-resisting system which apply high intensity area and it can provide the high elastic stiffness that met higher steel building drift requirement. This paper first provides an introduction of Forces in links and Energy dissipation mechanisms of eccentrically braced steel frames. In that Eccentrically braced steel frames will collapse after the link beams go into plastic deformation under earthquake load, A new analytical model which include shell element apply to link beams with large deformation and plastic deformation and beams element apply to other parts of structure is presented in this paper for analyzing eccentrically braced steel frames energy-dissipation behavior and collapse mechanism. Computer program is complied. After this paper applies nonlinear finite element program to analyze the behaviors of eccentrically braced steel frames under cyclic load, the seismic design recommendations of eccentrically brace are presented.

Sign in / Sign up

Export Citation Format

Share Document