MEME REPLICATION IN TECHNICAL LITERATURE ON THE WTC COLLAPSES

There are popular and regularly recurring memes associated with both the WTC1 and 2 initiation failures and the collapse progression modes.




WTC1 and 2 Collapse Propagation Memeplex and Common Propagation Memes


An excellent example of an interactive collapse propagation memeplex in peer reviewed literature was introduced in section 2.3, step 4..




4 Bazant papers BZ(2002), BV(2007), BL(2008) and BLGB(2008), linked and reviewed here

latest Bazant paper called: Why the Observed Motion History of World Trade Center Towers Is Smooth (2011), linked here.

Frank Greening, Energy Transfer in the WTC Collapse (2006), linked and reviewed here

Keith Seffen, Progressive Collapse of the World Trade Centre: a Simple Analysis (2008), linked and reviewed here

Gordon Ross: Momentum Transfer Analysis of the Collapse of the Upper Storeys of WTC 1 linked here

Cherepanov, Mechanics of the WTC collapse (2006), available through this link

Thomas W. Eagar and Christopher Musso, Why Did the World Trade Center Collapse? Science, Engineering, and Speculation, JEM feature: Special Report (2002), linked here

Equation of Motion Governing the Dynamics of Vertically Collapsing Buildings

by Celso P. Pesce, M.ASCE, Leonardo Casetta, and Fl�via M. dos Santos, linked here.


Every paper without exception has the same limitations and mistakes:



These limitations and mistakes effectively create an underlying environment in which such limits of perception are normalized. These views and this consensus become the 'norm', the dominant meme. Taken as a whole, they can be interpreted to imply 'consensus' among authors. But the consensus is a false one.



There is also a corresponding collapse propagation memeplex in online literature. Many examples were already listed in

3.7: Block Misrepresentations of Collapse Progressions

This meme-plex of online literature is directly related to the meme-plex of the peer-reviewed papers.


Other related popular memes on the WTC1 and 2 collapse progression modes include:









WTC1 and 2 Collapse Initiation Memeplex and Common Initiation Memes


Likewise, a series of memes about the WTC1 and 2 collapse initiation movement and failure mechanisms were started by the NIST in 2005.

These memes have replicated with astounding success even though they are directly contradicted by the visual record of collapse events.

Recall from the opening section of part 6:

Memes are copied by imitation, teaching and other methods. The copies are not perfect: memes are copied with variation; moreover, they compete for space in our memories and for the chance to be copied again. Only some of the variants can survive. The combination of these three elements (copies; variation; competition for survival) forms precisely the condition for Darwinian evolution, and so memes (and hence human cultures) evolve. Large groups of memes that are copied and passed on together are called co-adapted meme complexes, or memeplexes.


From this perspective, the NIST collapse initiation meme started in 2005 is, by far, the dominant meme. Considering that the NIST claim of WTC1 initiation movement flatly contradicts the visual record of the event, the success of this meme has effectively stunted critical thinking on this subject for nearly a decade.





WTC7 Collapse Memeplex

common WTC7 memes

freefall

symmetry





Examination of Common Memes within Technical Literature


Consider a Special Report published in the Journal of Engineering Mechanics in December, 2001:


Why Did the World Trade Center Collapse? Science, Engineering, and Speculation

Thomas W. Eagar and Christopher Musso

Journal of Engineering Mechanics

Feature: Special Report Linked here


Quote from the article:


THE COLLAPSE

...
As the joists on one or two of the most heavily burned floors gave way and the outer box columns began to bow outward, the floors above them also fell. The floor below (with its 1,300 t design capacity) could not support the roughly 45,000 t of ten floors (or more) above crashing down on these angle clips. This started the domino effect that caused the buildings to collapse within ten seconds, hitting bottom with an estimated speed of 200 km per hour. If it had been free fall, with no restraint, the collapse would have only taken eight seconds and would have impacted at 300 km/h.1 It has been suggested that it was fortunate that the WTC did not tip over onto other buildings surrounding the area. There are several points that should be made. First, the building is not solid; it is 95 percent air and, hence, can implode onto itself. Second, there is no lateral load, even the impact of a speeding aircraft, which is sufficient to move the center of gravity one hundred feet to the side such that it is not within the base footprint of the structure. Third, given the near free-fall collapse, there was insufficient time for portions to attain significant lateral velocity. To summarize all of these points, a 500,000 t structure has too much inertia to fall in any direction other than nearly straight down.




This is a comment by Thomas Eagar in December 2001 which repeats many of the popular memes about the WTC1 and 2 collapse progression mode including

1) Crush front acceleration (near free fall) and velocity (increasing to near 200 kph)

2) On why the 'top part' didn't 'fall off' the 'bottom part' during the collapse progression process.

According to the article, there was 'insufficient lateral velocity' due to the 'near freefall acceleration`' of collapse and there was insufficient lateral load to move the 'center of gravity' of the 'upper portion' one hundred feet to any side. In short, 'a 500,000 t structure has too much inertia to fall in any direction other than nearly straight down.'




These authors clearly did not understand of the process sometimes called "ROOSD" when making these comments. These explanations are primitive (and wrong) compared to what is described in the OOS model in section 2.1.







Or consider this PhD thesis on the subject of progressive collapse:



A Method to Assess the Progressive Collapse Vulnerability of Frame Structures

Department of Architecture, Civil Engineering and Environmental Sciences
University of Braunschweig

by Francesco Barni, linked here.




He begins by describing various examples of progressive collapse in chapter 1:


Chapter 1 - What is Progressive Collapse

1.1 Definition of Progressive Collapse

1.2 Opposing Progressive Collapse

1.3 What prompts a Collapse

1.4 Case studies

1.4.1 The Ronan Point Tower

1.4.2 The Hyatt Regency Walkways

1.4.3 The Alfred P. Murrah Federal Building

1.4.4 The World Trade Center

1.4.4.1 Buildings 1 and 2 of the World Trade Center

1.4.4.2 Building 7 of the World Trade Center

1.4.5 The Eads Bridge

1.5 Summary and comments




Each case is described in detail, but when it comes to a description of the WTC1 and 2 collapse progressions, the author describes them by using only one simplified meme made popular by the NIST:

"Global collapse ensued."


Even though the dissertation was written in 2011, the only justification to explain this meme is the argument in Bazant and Zhao, written in 2001. This meme, 'global collapse ensued', was also the only comment on the specifics of the WTC1 and 2 collapse progression modes available in the entire NIST report.


There isn't a single sentence within the dissertation that suggests the author was aware that the mechanism described in section 2.1 occurred in WTC1 or 2.








Consider the following paper written in 2007:



Typology of progressive collapse

by Uwe Starossek
Structural Analysis and Steel Structures Institute, Hamburg University of Technology (TUHH)
Denickestr. 17, 21073 Hamburg, Germany

The paper is linked here.



The abstract, bolding is mine:

"Abstract

A typology and classification of progressive collapse of structures is developed that is founded on a study of the various underlying mechanisms of collapse. Six different types and four classes are discerned, the characteristic features of each category are described and compared, and a terminology is suggested. On this basis, the theoretical treatment of progressive collapse and the development of countermeasures are facilitated because they differ for different types of collapse. Some conclusions drawn here concern analogies that should be pursued further, collapse-promoting features, and possible countermeasures."


The author describes the underlying mechanism of the WTC1 and 2 collapse progressions like this:


2. Types of progressive collapse

2.1 Pancake-type collapse

This type is exemplified by the collapse of the World Trade Center (WTC) towers. The impact of the airplanes and the subsequent fires initiated local failures in the areas of impact. The ensuing loss in vertical bearing capacity was limited to a few stories but extended over the entire cross section of the respective tower [1, 2]. The upper part of the structure started to move downwards and accumulated kinetic energy. The subsequent collision with the lower part of the structure, which was still intact, caused large impact forces which were far beyond the reserve capacities of the structure. This in turn led to the complete loss of vertical bearing capacity in the area of impact. Failure progressed in the same manner and led to a total collapse.

A pancake-type collapse exhibits the following features:

- initial failure of vertical load-bearing elements
- partial or complete separation and fall, in a vertical rigid-body motion, of components"



This is typical of how the WTC collapses are described within much of the literature I have come across. There is no evidence the author can specify the mechanism of collapse progression with any more detail than this general description provides.








The next example is a 188 page PhD thesis written in 2011 on the subject of progressive collapse:

Universit� Libre de Bruxelles Royal Military Academy

Faculty of Applied Sciences Polytechnical

Progressive Collapse Simulation of Reinforced Concrete Structures: Influence of Design and Material Parameters and Investigation of the Strain Rate Effects

By Berta Santaf� Iribarren

Dissertation linked here.



Observe how he describes the collapse of the WTC towers on page 4. He illustrates his conception of the WTC1 collapse as a crush down, then crush up process. This is the illustration he uses:




He then writes:

In short, the fact that the most representative examples of progressive collapse have occurred in the last decades has led to both American and
European general building codes to include guidelines for the evaluation of the potential for progressive collapse. However, most of these documents are based on simplified analysis approaches or they merely give general recommendations for the mitigation of the consequences of a structural local failure. Hence, increasing interest is being drawn in the civil engineering research community to derive new specific design rules against progressive collapse. Nevertheless, it appears to be a very ambitious task to propose a general analysis procedure applicable to every loading scenario and building type.



Specific design rules in specific cases can only be formulated by having a specific understanding of past examples of progressive collapse.

If the papers linked in this section offer the most specific conceptions of the collapse progressions of WTC1 and 2 being propagated throughout technical circles, it is easy to see why the recommendations are so general.





Yet another example:



University of Sydney, Civil Engineering Department

linked here


Once one storey collapsed all floors above would have begun to fall. The huge mass of falling structure would gain momentum, crushing the structurally intact floors below, resulting in catastrophic failure of the entire structure. While the columns at say level 50 were designed to carry the static load of 50 floors above, once one floor collapsed and the floors above started to fall, the dynamic load of 50 storeys above is very much greater, and the columns at each level were almost instantly destroyed as the huge upper mass fell to the ground.



No, the flooring is stripped from the columns. This is yet another example of an author who does not know anything about the specifics of the collapse mode of the Twin Towers.

He is propagating a common meme of buckling columns






Why did the building fall so quickly?

The buildings did fall quickly - almost (but not exactly) at the same speed as if there was no resistance. Shouldn't the floors below have slowed it down? The huge dynamic loads due to the very large momentum of the upper floors falling were so great that they smashed through the lower floors very quickly. The columns were not designed to carry these huge loads and they provided little resistance.




The collapse mode did not have much to do with columns, but with column-to-floor connections. The actual collapse fronts moved with near constant velocity through the OOS regions into the basements.

He repeats the common meme of column buckling and adds a common meme about freefall and acceleration.

The progression fronts did slow down, hence the near constant velocity of the collapse fronts and the highly regulated, tightly confined processes. Constant velocity at about 8 floors per second cannot be achieved without a resistive component.




The way the building collapsed must have been caused by explosions.
One demolition expert on the day of the collapse said it looked like implosion but this is not very strong evidence. Implosion firstly requires a lot of explosives placed in strategic areas all around the building. When and how was this explosive placed in the building without anyone knowing about it. Second, implosion required more than just explosives. Demolition experts spend weeks inside a derelict building planning an event. Many of the beams are cut through by about 90% so that the explosion only has to break a small bit of steel. In this state the building is highly dangerous, and there is no way such a prepared building could still be running day to day like WTC was.



False choice based on ignorance of the actual progressive collapse mechanisms and ignorance of the nature and locations of column-to-column connection locations.



The Structural System

The structural system, deriving from the I.B.M. Building in Seattle, is impressively simple. The 208-foot wide facade is, in effect, a prefabricated steel lattice, with columns on 39-inch centers acting as wind bracing to resist all overturning forces; the central core takes only the gravity loads of the building. A very light, economical structure results by keeping the wind bracing in the most efficient place, the outside surface of the building, thus not transferring the forces through the floor membrane to the core, as in most curtain-wall structures. Office spaces will have no interior columns. In the upper floors there is as much as 40,000 square feet of office space per floor. The floor construction is of prefabricated trussed steel, only 33 inches in depth, that spans the full 60 feet to the core, and also acts as a diaphragm to stiffen the outside wall against lateral buckling forces from wind-load pressures."




If the actual collapse progression modes were identified, one may not be so impressed with the design. The current tenants of the I.B.M. building in Seattle may want to consider the actual collapse progression modes of the Twin Towers before renewing their leases.

Once again, yet another technical author demonstrates they have no concept of the collapse mechanism described in section 2.1 of this book.







Another example:

The World Trade Center Disaster: Analysis and Recommendations

by Jeremy Abraham Kirk, Masters thesis

From the paper:
linked here

Many engineering professionals have undertaken to provide an explanation of the collapse mechanism, but opinions vary widely. The Federal Emergency Management Agency produced a review of the event and a summary of much of the data collected following the event (FEMA 2002). This report formed the basis for much of the following research by others. The National Institute of Standards and Technology (NIST) picked up the task where FEMA left it, and is currently undertaking the most comprehensive study of the disaster (NIST 2004). Many other engineers and researchers have published the results of their own analyses. In this thesis comparisons will be made among the various hypotheses, with intent to identify the most probable cause of global collapse. Additionally, a summary will be made of various proposed methods to prevent global collapse in similar future events.


A common collapse progression meme repeated:

One further note of interest addressed by the authors is a response to the common question of why the towers did not fall sideways. First of all, the buildings were 95% air. In addition to this, the center of gravity of the tower would have to move 100 feet to the side to create an overturning moment. Such motion could not be created even by the high velocity impact of the aircraft.


The paper was written in 2005. This description of the WTC1 collapse initiation has been the dominant meme on this subject since a least 2005.

In the north tower (WTC 1), the damage from the initial aircraft impact included severed columns from floors 93 to 98 in theexterior tube framing, damaged floor framing, and damaged core columns through the entirewidth of the core from north to south. One column on the exterior south face was also severed. The perimeter structure on the north face above the impact zone sagged down after the impact. Loads redistributed immediately so that the north and south faces of the tube carried 7% less gravity load, the east and west faces carried 7% more load, and the core carried only 1% more. The ensuing fires caused further damage. During the phase of fire damage, core columns experienced a net negative strain (shortening). The thermal expansion in these columns was overcome by high thermal creep and elastic strains. The loads produced by the axial shortening were distributed up to the hat truss and transferred to the perimeter tube structure. The redistribution of loads in this stage resulted in a 10% increase of the loads carried by the north and south faces of the building, a 25% increase in the east and west faces, and a 20% reduction of load in the core. The increases in load were still not significant enough to fail the columns. This thermal degradation phase also affected the floor assembly. Sagging of floors 95-99 occurred. These floors then contracted on the north side as the fire cooled in this area. Fires reached the south side later in the event, causing similar sagging in the floors there. Seat connections were weakened by the fire, and about 20% of the connections failed on floors 97 and 98 as the floors pulled inward on the columns. The columns on the south face bowed in due to the tension in the floors as well as temperature differentials within the columns themselves (see Figure 11). The collapse initiation phase began as the perimeter columns on the south face bowed and lost stability. Load was removed from the south wall and resolved to the core through the hat truss, and also around the perimeter corners to the east and west walls of the tube by means of the spandrel beam. The structure above the impact zone tilted rigidly 8' to the south. Column instability rapidly progressed from the south face to the east and west faces. The change in potential energy produced by this motion was more that could be absorbed by the structure, and collapse ensued.






Another example:

Study of Structural Redundancy of High-Rise Steel Building Due to the Effect of Heat and Loss of Vertical Structural Members

by Akira Wada, Kenichi Ohi, Hiroyuki Suzuki, Yoshifumi Sakumoto, Mitsumasa Fushimi, Hisaya Kamura, Yukio Murakami, Masamichi Sasaki, and Kazunari Fujiwara

linked here



3. PREVENTION OF PROGRESSIVE COLLAPSE

3.1 Mode of Progressive Collapse

The committee classifies progressive collapse into two modes as shown in Fig. 1, and is promoting research into the conditions that will prevent progressive collapse for each of the modes. Mode 1 of Fig. 1 illustrates propagation of story collapse to the lower stories. This mode represents the case where a collapse occurs on a certain story (called initial collapse story - it can be more than one story), all stories above this story fall perpendicularly in a mass, and the vertical load resistant members (columns) of the story or stories just beneath cannot sustain the impact. Mode 2 represents progressive collapses that occur on stories above the initial collapse story. If a vertical element of the load-bearing strength of the initial collapse story is lost and load transfer occurs, and if the members adjacent to the lost vertical resistance can sustain the rearranged loads, the progressive collapse of this mode does not occur. This mode occurred to the exterior columns of the WTC towers. In the case of the WTC towers, a Mode 1 collapse occurred following the Mode 2 collapse. The WTC tower case is being evaluated without a clear distinction being made between these two modes, because these two modes of collapse occurred consecutively.








The Collapse Times of Tall, Multi-story Buildings of Constant Cross-section

Bradford Howland

linked here

The mechanics of the collapse were previously considered in detail by Bazant and Verdure (2007). However, these authors assumed that the destruction occurs in two sequential phases, first a "crush down" phase and then, in their words, "After the l ower crushing front hits the ground, the upper crushing front of the compacted zone can begin propagating into the falling upper part of the tower...". In contrast , as will be seen below, we believe that both types of crushing occurred simultaneously in the fall of the twin towers. This is because the stories above the fracture are in free fall until they strike the compacted zone (which we term the "agglomeration") and the agglomeration is falling with an acceleration less than that of gravity due to the reduction of velocity each time the agglomeration strikes an underlying stationary story. It was pointed out to us as we prepared the final draft of this paper that a model formulated along the same lines as ours, but less complete, could be found on a website (Kuhn,2008). We note the differences between that model and ours at the appropriate point below.









Mathematical Models of Progressive Collapse and the Question of How Did the World Trade Centers Perish

Charles M. BECK

linked here







Collapse Time Analysis of Multi-Story Structural Steel Buildings

Robert M. Korol, K.S. Sivakumaran and Frank R. Greening

linked here









An article about James Quintiere and his thoughts on the NIST investigation is linked here.


"James Quintiere, Ph.D., former Chief of the Fire Science Division of the National Institute of Standards and Technology (NIST), has called for an independent review of NIST's investigation into the collapses of the World Trade Center Towers on 9/11.

Dr. Quintiere made his plea during his presentation, "Questions on the WTC Investigations" at the 2007 World Fire Safety Conference. "I wish that there would be a peer review of this," he said, referring to the NIST investigation. "I think all the records that NIST has assembled should be archived. I would really like to see someone else take a look at what they've done; both structurally and from a fire point of view."

"I think the official conclusion that NIST arrived at is questionable," explained Dr. Quintiere. "Let's look at real alternatives that might have been the cause of the collapse of the World Trade Towers and how that relates to the official cause and what's the significance of one cause versus another."

Dr. Quintiere, one of the world's leading fire science researchers and safety engineers, also encouraged his audience of fellow researchers and engineers to scientifically re-examine the WTC collapses. "I hope to convince you to perhaps become 'Conspiracy Theorists', but in a proper way," he said.

In his hour-long presentation, Dr. Quintiere discussed many elements of NIST's investigation that he found problematic. He emphasized, "In every investigation I've taken part in, the key has been to establish a timeline. And the timeline is established by witness accounts, by information from alarm systems, by any video that you might have of the event, and then by calculations. And you try to put all of this together. And if your calculations are consistent with some of these hard facts, then perhaps you can have some comfort in the results of your calculations. I have not seen a timeline placed in the NIST report."

Dr. Quintiere also expressed his frustration at NIST's failure to provide a report on the third skyscraper that collapsed on 9/11, World Trade Center Building 7. "And that building was not hit by anything," noted Dr. Quintiere. "It's more important to take a look at that. Maybe there was damage by the debris falling down that played a significant role. But other than that you had fires burning a long time without fire department intervention. And firefighters were in that building. I have yet to see any kind of story about what they saw. What was burning? Were photographs taken? Nothing!"




This person used to lead the Fire Science Division at the NIST. He followed the NIST WTC investigation and his (very critical) comments are included in the 2005 congressional transcripts on the results of the NIST report.



It would be interesting to know if the most prominent members of the Skyscraper Safety Campaign are aware of what we call ROOSD. A fellow poster mentioned commenting on this subject to James Quintiere. This is what a poster wrote about an exchange he had with Dr Quintiere:

"I attended a seminar at John Jay College a number of years ago at the Christian Regenhard Center. Quintierre, Ms Regenhard, Prof. Glenn Corbett were among those who attended. The seminar was to examine the response and investigation of NIST. They looked at official responses to large fires in the past, egress issues and so on.

They did not discuss engineering at all. I had the honor to speak with A few of the presenters including Quintiere and Ms Regenhard (She did not present)... and did an over view to Quintierre about ROOSD. He was interested but said he was not an structural engineer and not competent to evaluate its veracity. We corresponded a bit after that.








Searching and Reviewing the Written Record

Lists of all academic papers, ASCE peer reviewed papers and literature on the WTC collapses can be seen at this link. Just as the visual record can be gathered and inspected, so the large body of written history over the last decade can be gathered together and examined for common recurring patterns and mistakes. With the improved body of knowledge now available, one can look back over the entire body of these written descriptions of the events over the last 11 years in the form of technical papers in professional publications and spot quite a few recurring errors.





A large representative sample of the best search results, first 20 pages of results for google, yahoo, bing is reproduced below1, extracted on May 6, 2012.



Typology of Progressive Collapse by Uwe Starossek

JOM, Why did the World Trade center collapse? Eager and Musso

World Trade Center, some engineering aspects, University of Sydney

Sideplate design systems

RETROFIT OF FLAT-SLAB COLUMN CONNECTIONS USING CFRP STUDS TO RESIST PUNCHING-SHEAR FROM CYCLIC LOADING
http://www.cee.hawaii.edu/reports/UHM-CEE-08-03.pdf
Dom Joavanni O. Cueva and Ian N. Robertson
Research Report UHM/CEE/08-03
December 2008

Macro and Micro Nonlinear Analysis Methods to Assess Progressive Collapse Potential in Steel Frame Buildings
as a Function of Beam-to-Column Connection Behavior
http://206.220.211.182/blog/wp-content/saviac-74th-paper-with-figures.pdf
Jesse E. Karns, S.E. and David L. Houghton, S.E.
Myers, Houghton & Partners, Inc. �" Structural Engineers

Wikipedia entry on progressive collapse

Structural Systems for Progressive Collapse Prevention
http://www.nibs.org/client/assets/files/mmc/Burns%20paper.pdf
Joseph Burns, John Abruzzo, Mark Tamaro
Thornton-Tomasetti Engineers

Progressive Collapse of Structures
http://www.thomastelford.com/books/SampleChapters/Progressive%20collapse%20intro.pdf
Uwe Starossek
Hamburg University of Technology

(sample chapters of book)

Mitigation of Post 9-11 Realities in Steel Frame Structures
As a Function of the Choice of Connection Geometry
http://www.mabs.ch/spiezbase/mabs17/17-8-10.pdf
David L. Houghton1, M.S., S.E. and Jesse E. Karns2, S.E.
17th International Symposium on Military Aspects of Blast and Shock
Las Vegas, Nevada
June 10-14, 2002

(A powerpoint presentation on) Comparing Progressive Collapse Due To Fire In Different Structural Systems
here

UNIFIED FACILITIES CRITERIA (UFC)
DESIGN OF BUILDINGS TO RESIST PROGRESSIVE COLLAPSE 2009, 2010
http://www.wbdg.org/ccb/DOD/UFC/ufc_4_023_03.pdf

Study on the design methods to resist progressive collapse for building structures

Xinzheng Lu1,2, Yi Li1,2, Lieping Ye1,2 Yifei Ma1,2 and Yi Liang1,2

¹ Department of Civil Engineering, Tsinghua University, Beijing 100084, P.R. China

Phys.org Construction strategies to avoid progressive collapse

Seminar on introduction to progressive collapse by Ms. Margaret Tang, Weidlinger Associates in 2011






ASCE database search results:

Found 177 Records with the keyword term of "Progressive collapse"

Displaying 100 records - please modify your search for better results.

2011 Alternate Path Progressive Collapse Analysis of Steel Stud Bearing Wall Structures

2011 Analytical Load and Dynamic Increase Factors for Progressive Collapse Analysis of Building Frames

2011 DoD Research and Criteria for the Design of Buildings to Resist Progressive Collapse

2011 Finite Particle Method for Progressive Failure Simulation of Truss Structures

2011 Large-Scale Experimental Evaluation of Building System Response to Sudden Column Removal

2011 New Methods for Progressive Collapse Testing and Simulation

2011 Probabilistic Robustness Assessment of Pre-Northridge Steel Moment Resisting Frames

2011 Progressive Collapse Analysis of RC Structures Including Beam Axial Deformation

2011 Progressive Collapse Resistance of an Actual 11-Story Structure Subjected to Severe Initial Damage

2011 Punching Shear Failure in Progressive Collapse Analysis

2011 Testing and Analysis of Steel and Concrete Beam-Column Assemblies under a Column Removal Scenario

2011 Three-Dimensional Effects in Progressive Collapse Modeling

2010 Building Robustness Research during World War II

2010 Disproportionate Collapse: Terminology and Procedures

2010 Dynamic Analysis of Gap Closing and Contact in the Mixed Lagrangian Framework: Toward Progressive Collapse Prediction

2010 Effects of Random Imperfections on Progressive Collapse Propagation

2010 Experimental and Analytical Assessment on Progressive Collapse Potential of Two Actual Steel Frame Buildings

2010 Krylov Subspace Accelerated Newton Algorithm: Application to Dynamic Progressive Collapse Simulation of Frames

2010 Linear and Nonlinear Static Analysis for Assessment of Progressive Collapse Potential of Multistoried Building

2010 Parallel Axial-Flexural Hinge Model for Nonlinear Dynamic Progressive Collapse Analysis of Welded Steel Moment Frames

2010 Progressive Collapse Mechanisms of Brittle and Ductile Framed Structures

2010 Progressive Collapse Resistance of Steel-Concrete Composite Floors

2010 Seismic Progressive Collapse Analysis of Reinforced Concrete Bridges by Applied Element Method

2009 Applicability of Prescribed Robustness and Design Approaches to Building Classes for Disproportionate Collapse Resistance

2009 Behavior of Varied Steel Frame Connection Types Subjected to Air Blast, Debris Impact, and/or Post-Blast Progressive Collapse Load Conditions

2009 Comparison and Study of Different Progressive Collapse Simulation Techniques for RC Structures

2009 Design-Oriented Approaches for Progressive Collapse Assessment: Load-Factor vs. Ductility-Centred Methods

2009 Development and Application of Linear and Non-Linear Static Approaches in UFC 4-023-03

2009 Development of 3D Models of Steel Moment-Frame Buildings for Assessment of Robustness and Progressive Collapse Vulnerability

2009 Development of Reduced Structural Models for Assessment of Progressive Collapse

2009 Discussion of Examples Using the Revised DOD Progressive Collapse Design Requirements

2009 Disproportionate Collapse Research Needs

2009 Dynamic Energy Based Method for Progressive Collapse Analysis

2009 Evaluation of an Existing Steel Frame Building against Progressive Collapse

2009 Evaluation of Missing Column Analyses in Progressive Collapse Design Codes

2009 Investigation of Progressive Collapse-Resisting Capability of Steel Moment Frames Using Push-Down Analysis

2009 Methodologies for Progressive Collapse Analysis

2009 Overview of the Revised DOD Progressive Collapse Design Requirements

2009 Performance as a Measure of Robustness

2009 Probabilistic Approach to Progressive Collapse Prevention. Physics Based Simulations

2009 Progressive Collapse: Failure Criteria Used in Engineering Analysis

2009 Progressive Collapse Nomenclature

2009 Progressive Collapse of Cable-Stayed Bridges

2009 Progressive Collapse Simulation of Reinforced Concrete Buildings Using Column Models with Strength Deterioration after Yielding

2009 Revision of the Tie Force and Alternate Path Approaches in the DOD Progressive Collapse Design Requirements

2009 Structural Robustness Evaluation

2008 Assessment of Progressive Collapse Residual Capacity Using Pushdown Analysis

2008 Blast Testing of Steel Frame Assemblies to Assess the Implications of Connection Behavior on Progressive Collapse

2008 Effect of Progressive Failure on Measured Shear Strength of Geomembrane/GCL Interface

2008 Finite Element Simulation on Progressive Collapse Resistance of Reinforced-Concrete Frame

2008 Foundation Design against Progressive Collapse of Buildings

2008 Inelastic Dynamic Progressive Collapse Analysis of Truss Structures

2008 Macro Models for Progressive Collapse Analysis of Steel Moment Frame Buildings

2008 Macromodel-Based Simulation of Progressive Collapse: RC Frame Structures

2008 Macromodel-Based Simulation of Progressive Collapse: Steel Frame Structures

2008 A Model for Progressive Collapse of Conventional Framed Buildings

2008 Nonlinear Analysis for Progressive Collapse Investigation on Reinforced Concrete Framed Structures

2008 Progressive Collapse Analysis and Retrofit Design Using the Unified Facilities Criteria

2008 Progressive Collapse Analysis of a Steel Building with Pre-Northridge Moment Connections

2008 Progressive Collapse Analysis, Retrofit Design, and Costs for Existing Structures

2008 Progressive Collapse and Earthquake Resistance

2008 Progressive Collapse of a 2-story Reinforced Concrete Frame

2008 Progressive Collapse of the World Trade Center: Simple Analysis

2008 Progressive Collapse Resistance of Hotel San Diego

2008 Progressive Failure of a Dam Abutment: A Fracture Mechanics Analysis

2008 The Role of Foundation Design in Progressive Collapse of Buildings

2008 System Safety Performance Metrics for Skeletal Structures

2008 Towards Modeling Progressive Collapse in Reinforced Concrete Buildings

2008 Unified Progressive Collapse Design Requirements for DOD and GSA

2007 Experimental and Numerical Study of Uplift Behavior of Shallow Circular Anchor in Two-Layered Sand

2007 Mechanics of Progressive Collapse: Learning from World Trade Center and Building Demolitions

2007 On Potential Progressive Failure of Large-Panel Buildings

2006 Behavior and Design of Commercial Multistory Buildings Subjected to Blast

2006 Comparison of Various Procedures for Progressive Collapse Analysis

2006 Global System Considerations for Progressive Collapse with Extensions to Other Natural and Man-Made Hazards

2006 Mitigating Risk from Abnormal Loads and Progressive Collapse

2006 Modeling the Impact of Failed Members for Progressive Collapse Analysis of Frame Structures

2006 Murrah Building Bombing Revisited: A Qualitative Assessment of Blast Damage and Collapse Patterns

2006 Preventing Disproportionate Collapse

2006 Progressive Collapse �" An Implosion Contractor’s Stock in Trace

2006 Progressive Collapse of Structures: Annotated Bibliography and Comparison of Codes and Standards

2006 Static Equivalency in Progressive Collapse Alternate Path Analysis: Reducing Conservatism While Retaining Structural Integrity

2006 Strong Diagonals

2006 Study of Mitigation Strategies for Progressive Collapse of a Reinforced Concrete Commercial Building

2005 Can Strengthening for Earthquake Improve Blast and Progressive Collapse Resistance?

2005 Development of An Analytical Database to Support a Fast Running Progressive Collapse Assessment Tool

2005 Multi Hazard Approach to Progressive Collapse Mitigation

2005 Prediction of Injuries to Building Occupants From Column Failure and Progressive Collapse With the Bicads Computer Program

2005 Progressive Collapse: Case studies Using Nonlinear Analysis

2005 Progressive Collapse of Moment Resisting Steel Frame Buildings

2005 Progressive Collapse of Precast Panel Buildings Subjected to External Loading

2005 SDOF Model for Progressive Collapse Analysis

2005 Stability of the World Trade Center Twin Towers Structural Frame in Multiple Floor Fires

2005 Strategies for Mitigating Risk of Progressive Collapse

2005 A Study of Progressive Collapse in Multi-Storey Steel Frames

2004 Defensive Design: Blast and Progressive Collapse Resistance in Steel Buildings

2004 Possibility of Postliquefaction Flow Failure due to Seepage

2004 Progressive Analysis Procedure for Progressive Collapse

2004 State-of-the-art vs. State-of-the practice in Blast and Progressive Collapse Design of Reinforced Concrete Structures

2004 U.S. General Services Administration Progressive Collapse Design Guidelines Applied to Concrete Moment-Resisting Frame Buildings






On to part 6.2: Meme Replication in Mass Media

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