Evaluation of Dynamic Collapse Behavior of Steel Moment Frames Damaged by Blast

2011 ◽  
Vol 82 ◽  
pp. 404-409
Author(s):  
Kyung Koo Lee ◽  
Lan Chung ◽  
Sang Hyun Lee ◽  
Tae Won Park ◽  
Jieun Rho
Keyword(s):  
Progressive Collapse ◽  
Mitigation Strategies ◽  
Analysis Method ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Strain Rate Effects ◽  
Collapse Analysis ◽  
Alternate Path Method ◽  
Collapse Behavior ◽  
Progressive Collapse Analysis

Blast effects on structures and blast mitigation strategies have been vigorously studied in the world. The alternate path method, or common progressive collapse analysis method, of structures assumes the threat-independent removal of vertical load-carrying elements. However, in reality, a blast-induced column-missing event will produce the damage on adjacent structural elements and the rapid dynamic response of the structures. In this study, the strain rate effects on the dynamic collapse behavior of steel moment frames are investigated by performing the blast-induced sequential progressive collapse analysis. Then, the improvement of the progressive collapse analysis method is discussed based on the numerical results.

scholarly journals Strain Rate Effect on the Progressive Collapse Analysis of RC Frame Structure under Earthquake

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Wenming Wang
Keyword(s):  
Strain Rate ◽  
Progressive Collapse ◽  
Strain Rate Effect ◽  
Frame Structure ◽  
Rc Frame ◽  
Strain Rate Effects ◽  
Rc Frame Structure ◽  
Rate Effects ◽  
Collapse Analysis ◽  
Progressive Collapse Analysis

The strain rate effect can influence the seismic responses of reinforced concrete (RC) structures because the constitutive relationship of concrete and rebar is rate-dependent. This paper carries out progressive collapse analysis to research the influence of strain rate effects on collapse-resistant capacity, collapse mode, and collapse path of the RC frame structure. A progressive collapse simulation program for the reinforced concrete (RC) structure with a static and dynamic constitutive relationship is coded individually using the user subroutine VUMAT and then implemented in the advanced finite element program ABAQUS. The good agreement between experimental and simulation results proves that the coded subroutine is reliable. With the coded subroutine, by conducting progressive collapse analyses of a four-story RC frame structure under earthquake, the effect of strain rate on the response is investigated. The numerical results demonstrate that the collapse-resistant capacity of the structure is underestimated when the strain rate effect is neglected. It is shown that strain rate effects influence the collapse mode and collapse path of the structure. Therefore, strain rate effects should be considered in the progressive collapse analysis of the RC frame structure.

Effect of fully restrained beam-to-column connection on the progressive collapse strength of steel moment frames

2020 ◽  
Vol 23 (8) ◽  
pp. 1656-1668
Author(s):  
Alireza Salmasi ◽  
Mohammad Reza Sheidaii ◽  
Mohammad Saghaie Sahebalzaman ◽  
Saeed Tariverdilo
Keyword(s):  
Structural Integrity ◽  
Progressive Collapse ◽  
Nonlinear Effects ◽  
Frame Structure ◽  
Moment Frames ◽  
Steel Moment Frames ◽  
Plastic Hinges ◽  
Dynamic Increase Factor ◽  
Collapse Strength ◽  
Alternate Path Method

The beam-to-column connection has been identified as a key element for steel frame structures to maintain the structural integrity during progressive collapse phenomenon. In the current study, in order to assess the effects of beam-to-column connection type on the progressive collapse strength of steel moment frames, the progressive collapse behavior of a steel intermediate moment frame structure was evaluated with 10 different types of fully restrained connections. The progressive collapse strength of these buildings against sudden removal of a column was separately studied using nonlinear static alternate path method presented in Unified Facility Criteria progressive collapse guideline. To consider the nonlinear effects in the structural modeling, plastic hinges for beam and column members and connections were defined and modeled according to the ASCE 41 standard. The results of the progressive collapse analyses indicated that if the plastic hinges of connections are separately defined in addition to the plastic hinges of beams and columns, the structure will have lower progressive collapse strength, and the calculated dynamic increase factor will grow. Among the studied types of connections, the free flange connection had the best performance and the highest strength against progressive collapse.

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