scholarly journals PROGRESSIVE COLLAPSE MECHANISM OF STEEL FRAMED-STRUCTURES SUBJECTED TO A MIDDLE-COLUMN LOSS

2021 ◽  
Keyword(s):  
Progressive Collapse ◽  
Collapse Mechanism ◽  
Framed Structures ◽  
Middle Column

Experimental study on the progressive collapse mechanism in the braced and tied-back retaining systems of deep excavations

2020 ◽  
Author(s):  
Gang Zheng ◽  
Yawei Lei ◽  
Xuesong Cheng ◽  
Xiyuan Li ◽  
Ruozhan Wang
Keyword(s):  
Large Scale ◽  
Large Deformations ◽  
Load Transfer ◽  
Progressive Failure ◽  
Progressive Collapse ◽  
Collapse Mechanism ◽  
Bending Moments ◽  
Failure Path ◽  
Transfer Mechanisms ◽  
Very High

Collapses of braced or tied-back excavations have frequently occurred. However, the influence of the failure of some retaining structure members on the overall safety performance of a retaining system has not been studied. Model tests of failures of retaining piles, struts or anchors were conducted in this study, and the load transfer mechanisms underlying these conditions were analysed. When failures or large deformations occurred in certain piles, the increasing ratios of the bending moments in adjacent piles were much larger in the braced retaining system than in the cantilever system and more easily triggered progressive failure. When the strut elevation was lower or the excavation depth was greater, the degree of influence and range of pile failures became larger. When certain struts/anchors failed, their loads transferred to a few adjacent struts/anchors, possibly leading to further strut/anchor failure. The influence mechanisms of strut or anchor failure on piles were different from those of pile failure. As the number of failed struts or anchors increases, the bending moments of the piles in the failure zone first decrease and then increase to very high values. Therefore, the progressive failure path extends from struts/anchors to piles and will lead to large-scale collapse.

scholarly journals Experimental and Theoretical Investigations on Progressive Collapse Resistance of the Concrete-Filled Square Steel Tubular Column and Steel Beam Frame under the Middle Column Failure Scenario

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Wei Xuan ◽  
Lai Wang ◽  
Changjiang Liu ◽  
Guoqi Xing ◽  
Lili Zhang ◽  
...  
Keyword(s):  
Progressive Collapse ◽  
Theoretical Models ◽  
Steel Beam ◽  
Load Path ◽  
Loading Test ◽  
Structural Resistance ◽  
Failure Scenario ◽  
Beam Frame ◽  
Collapse Process ◽  
Middle Column

A static loading test was carried out on a 1/3-scale concrete-filled square steel tubular column-steel beam frame (CFSTSBF) specimen with 2 spans to study its progressive collapse behaviors under the middle column failure scenario using the alternate load path method and to examine the failure mode and load transfer and main resistance mechanisms of the residual structure. Then, theoretical models of the specimen, involving the whole collapse process, were developed, and the resistance and deformation relationships of each model were calculated and validated with test results. The results indicated that the specimen collapse process includes the elastoplastic stage, plastic stage, transfer stage, and catenary stage, the beam mechanism and catenary mechanism were the principal mechanisms for the structure against progressive collapse, and catenary action can significantly strengthen structural resistance. The modified theoretical models with higher practical accuracy could be used to assess structural performances against progressive collapse.

scholarly journals Progressive Collapse Assessment: A review of the current energy-based Alternate Load Path (ALP) method

2019 ◽  
Vol 258 ◽  
pp. 02012 ◽  
Author(s):  
Nur Ezzaryn Asnawi Subki ◽  
Hazrina Mansor ◽  
Yazmin Sahol Hamid ◽  
Gerard Parke
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Progressive Collapse ◽  
Structural Response ◽  
Steel Frame ◽  
Collapse Mechanism ◽  
Load Path ◽  
Acceptance Criterion ◽  
Current Energy ◽  
Collapse Assessment

The Alternate Load Path (ALP) is a useful method that has generated a considerable recent research interest for the assessment of progressive collapse. The outcome of the ALP analysis can be assessed either using the force-based approach or the energy-based approach. The Unified Facilities Criteria (UFC- 4- 023-03) of progressive collapse guideline - have outlined that the force-based approach can either be analysed using static or dynamic analysis. The force-based approach using static analysis is preferable as it does not require a high level of skill and experience to operate the software plus no effort is required in scrutinising the validity of the analysis results output. However, utilising the static approach will eliminate the inertial effect in capturing the actual dynamic response of the collapsed structure. In recent years, the development of the energy-based progressive collapse assessment is attracting widespread interest from researchers in the field; as the approach can produce a similar structural response with the force-based dynamic analysis by only using static analysis. Most of the current energy-based progressive collapse assessments are developed following the requirements which are given in the progressive collapse guidelines provided by the Unified Facilities Criteria. However, little attention is given to the development of the energy-based approach using the Eurocode standards as a base guideline. This article highlights the merits of utilising the energy-based approach against the force-based approach for a collapsed structure and explains the collapse mechanism of a steel frame in the perspective of the energy concept. The state of the art of energy-based progressive collapse assessment for a structural steel frame is reviewed. The comprehensive review will include insights on the development of the energy-based method, assumptions, limitations, acceptance criterion and its applicability with the European standards. Finally, potential research gaps are discussed herein.

scholarly journals A Review on Progressive Collapse of Building Structures

2014 ◽  
Vol 8 (1) ◽  
pp. 183-192 ◽  
Author(s):  
Hao Wang ◽  
Anqi Zhang ◽  
Yi Li ◽  
Weiming Yan
Keyword(s):  
Design Method ◽  
Progressive Collapse ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Collapse Mechanism ◽  
Building Structures ◽  
Wide Range ◽  
Collapse Behavior ◽  
Element Method

Progressive collapse of building structures is generally triggered by a local failure due to accidental actions, followed by subsequent chain effect of the structures which may result in wide range failure or even collapse of the entire buildings. Since the “911” event, progressive collapse of building structures has been widely concerned by engineers and researchers. This paper assesses the current researches on this issue from experimental study, numerical simulation and theoretical analysis. Given the limitation of costs and difficulties of experimental tests, the experimental studies investigate the collapse mechanism, such as development of stress/strain and damage/failure of materials, mainly via the scaled down specimens of structural components and substructures. On the other hand, the collapse behavior of entire building structures is analyzed via the numerical methods, such as the finite element method and the discrete element method. Further, the collapse resistance demand and the robustness assessment for building structures are theoretically studied in depth in which the simplified theoretical models of the collapse-resisting demand and the collapse risk assessment are proposed respectively. At last, the design method to prevent progressive collapse for building structures is also discussed.

Sign in / Sign up

Export Citation Format

Share Document