Dominant Factor in the Collapse of WTC-1

Miamis, K.; Irfanoglu, Ayhan; Sözen, Mete A.

doi:10.1061/(asce)cf.1943-5509.0000014

Cited by 4 publications

(7 citation statements)

References 7 publications

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“…This is confirmed by the observations that the tower remained structurally intact after impact and load on the remaining columns was tolerable as demonstrated by the observed behavior of the structure. Note that the factor of safety of the perimeter framing and the interior core against existing axial loads are estimated to be approximately 5.4 and 2.8, respectively (Miamis et al, 2009).…”

Section: B767–200er Wtc‐1 Impact Simulationmentioning

confidence: 99%

“…Miamis (2007) provides a detailed and comparative study of the information gathered from the first two sources. Miamis et al (2009) summarizes the results from the study of the thermal response of WTC‐1 at Purdue University.…”

Section: Thermal Response Of Wtc‐1mentioning

confidence: 99%

“… Total capacity of the core at 95th story at different metal temperatures. Instability limited to one story (Miamis et al, 2009). …”

Section: Buckling Of the Core Columns As A Collapse Initiation Mechmentioning

confidence: 99%

“…Triggered by the September 11, 2001 attacks, the physics of high‐velocity solid and fluid impact on structural elements and systems is investigated at Purdue University through laboratory tests (Krahn and Pujol, 2007) as well as numerical analyses and simulations with particular attention on the response of the Pentagon building (Hoffmann et al, 2004) and the World Trade Center Tower‐1 (WTC‐1) (Irfanoglu and Hoffmann, 2008) with additional work on thermal response of the WTC‐1 structural system (Miamis et al, 2009). Furthermore, to assist in illustrating the vast amount of information generated by the large‐scale computer simulations, tools for realistic visualization have been developed (Popescu and Hoffmann, 2005; Rosen et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Using Numerical Simulations and Engineering Reasoning under Uncertainty: Studying the Collapse of WTC‐1

Irfanoglu

2010

Computer aided Civil Eng

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A series of numerical aircraft crash simulations and thermal behavior analyses were made at Purdue University to study the response of the World Trade Center Tower 1 (WTC-1) on September 11, 2001. The process included accuracy verification for the computational tools using available experiment data. Numerical models for the Boeing 767-200ER aircraft and the structural system for the top 20 stories of WTC-1 were developed for the simulations. A second aircraft model, simpler yet comparable in effect, was developed and used for a parametric sensitivity analysis. Results from these simulations and published by other researchers indicate that while the observed impact damage to tower exterior framing can be estimated accurately, the unseen impact damage to the core structure of the tower could not be estimated with high confidence. Although the computational tools helped in developing an understanding as to what might have happened as the aircraft penetrated and disintegrated into the structure, they were not able to reduce the uncertainty in the core damage estimate. However, reflecting insight from the behavior of the Pentagon building under the impact loads it received on the same day and studying the effects of elevated temperature on mechanical properties of steel in light of experimental data, the uncertainty in the core structural damage estimate was found to be of negligible importance with regards to the ultimate fate of the tower. It is demonstrated that through use of numerical simulations and engineering reasoning, a dominant factor in the collapse of the tower could be proposed with confidence. It was the loss of fire-proofing in the tower core during aircraft impact * To whom correspondence should be addressed. Email: ayhan@ purdue.edu. that left the core vulnerable to ensuing thermal loads and resulted in the eventual collapse of the tower.

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Section: B767–200er Wtc‐1 Impact Simulationmentioning

confidence: 99%

Section: Thermal Response Of Wtc‐1mentioning

confidence: 99%

“… Total capacity of the core at 95th story at different metal temperatures. Instability limited to one story (Miamis et al, 2009). …”

Section: Buckling Of the Core Columns As A Collapse Initiation Mechmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Using Numerical Simulations and Engineering Reasoning under Uncertainty: Studying the Collapse of WTC‐1

Irfanoglu

2010

Computer aided Civil Eng

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“…Even though the impact may have caused significant damage in the core area, the researchers found that the uncertainty in the damage level became immaterial when the effects of elevated temperature, due to ensuing fire and missing steel thermal insulation, on the strength and stiffness of steel members were taken into consideration . The damage inflicted by aircraft impact on the insulation of the core framing was the dominant factor in the collapse of the structure …”

Section: Introductionmentioning

confidence: 99%

Response of reinforced concrete beams to high‐velocity fluid impact. Part I: Experiments

Korucu

Irfanoglu

2018

Structural Concrete

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Thirty‐two reinforced concrete beams were tested under static and fluid impact loads. Hoop (rectangular) and spiral transverse reinforcement of various configurations were used to confine the specimens. The objectives were to observe the effect of shape of beams and configuration of confinement reinforcement on the impact resistance, and to estimate the limiting fluid velocity that causes total failure.

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Learning from failures in an emblematic building in Valencia, Spain

Adam

Buitrago

2018

Engineering Failure Analysis

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On many occasions advances have been made in science and engineering thanks to the knowledge gained from failures. In the particular case of structural engineering the study of actual failures makes it possible to advance and define new theories, concepts and designs, for example, the changes and improvements that appeared after some of the "classical" failures such as the Ronan Point building, Quebec Bridge, Murrah Federal Building, Tacoma Narrows Bridge and the World Trade Center. This paper describes a teaching method used with structural engineering students at the Universitat Politècnica de València based on the study of cases of damage to buildings in the Valencia, Spain. Due to its special characteristics, one of the buildings studied is the Príncipe Felipe Science Museum. Some of its main characteristics are: 1) it is one of Valencia's emblematic buildings, 2) its considerable dimensions required huge quantities of concrete, 3) it has a complex structure and an innovative architectural design, 4) the wide variation in the type of damage detected, which make it a particularly valuable teaching aid. The most important damage detected has been classified and described during the visits to the Príncipe Felipe Science Museum. The damage mechanisms are widely diverse and include: those due to the behaviour of the concrete itself (e.g. shrinkage and early age thermal cracking), those due to the presence of damp, those whose origin can be traced back to the construction phase, and others due to corroded reinforcement and to the loads acting on the structure. The paper has a double value since on one hand it describes a highly successful teaching aid for the training of specialists 2 in structural engineering, while on the other it classifies and describes the existing damage in one of the most important modern buildings in Spain and perhaps in Europe.

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Dominant Factor in the Collapse of WTC-1

Cited by 4 publications

References 7 publications

Using Numerical Simulations and Engineering Reasoning under Uncertainty: Studying the Collapse of WTC‐1

Using Numerical Simulations and Engineering Reasoning under Uncertainty: Studying the Collapse of WTC‐1

Response of reinforced concrete beams to high‐velocity fluid impact. Part I: Experiments

Learning from failures in an emblematic building in Valencia, Spain

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