During the exploitation and dissemination Workshop at the training Campus Weeze from 16.-17. April 2018 LUAS presented the BCB to end-users. The program was distributed to the visitors on give-away memory sticks. The end-users simply moved the content of the memory stick to a folder on their laptops or Mac´s (The BCB works cross-platform) and started Blender (the Fracture Modifier including BCB) directly, because no installation is needed. First we presented the simulation process step-by-step on a simple structure. Then the end-users were invited to open and simulate a prepared model of the H-shaped rehearsal building at the Weeze site . It was nice to see an Inachus partner with Blender experience to be engaged in own simulations from scratch after our presentation.
This video shows the simulation of the H-shaped rehearsal building at the Weeze site under an earthquake event. It is a processed simulation that includes the distribution of dummies. This feature is new in the BCB and was implemented after the pilot in Weeze. The distribution of large amount of human figures is made with the help of Blender´s particle system, a new preset group ‘Victims’ has been added in the BCB element groups for this purpose. Note, that the simulation of masonry structures is not yet sufficiently studied and the simulation results still may lack plausibility.
The 9th plenary meeting was successfully held in the Weeze training base at the German-Dutch border on April 16-17, 2018. The plenary meeting was followed by the exploitation and dissemination Workshop on Wednesday 18th and Thursday 19th. The partners had a chance to present their work to end users. Fifteen urban search and rescue (USaR) professionals from Sweden, the Netherlands, United Kingdom and UN-OCHA attended.
We have finally published a series of three tutorials that introduce the BCB. This series offers something for everyone: users without any Blender experience, people who want to take on the challenge to dive into the BCB methodology and for those who just want to see results fast.
1. Guide for BCB Installation & Simple Collapse Simulation
– installation instruction and introduction into a simple collapse simulation
2. Guide to Simulate a Multi-Family House with Standard Blender
– Introduction of the BCB fundamentals with standard Blender
3. Guide to Simulate a Multi-Family House with Fracture Modifier
– Introduction into a speed optimized variant with the FM
Have fun! And please post us your own simulation results.
Video: by courtesy of Kostack Studio
Blender and the BCB were used to model and simulate the bridge that collapsed in Miami in a speed modeling challenge. Due to the lack of precise technical drawings the Bridge was reconstructed on the basis of high resolution drone images. The element properties were estimated from close up photographs of the bursted reinforcement. The bridge was built and simulated in Blender in just 24 hours.
Even though the bridge model is only estimated and the BCB has not yet formulation for pre-stressed concrete it is interesting that the damage occurred about at the same location as it happened in reality. It is to be expected that under evenly distributed loading damage happens at the truss diagonals with the biggest internal angle, see image below.
On 15th of March 2018, a 53 m long recently-erected bridge section collapsed under its own weight. At the moment of the accident construction workers were working on the north end of the bridge section, re-tightening internal cables to strengthen the diagonal members- cracks in the structure were noticed short time before.
The bridge applied a new method, called “Accelerated Bridge Construction”, prefabricated bridge elements are hereby prepared in a factory, then shipped to the site and put together at the scene to minimize the impact on the local traffic. The exact reasons of the collapse are still being investigated.
This is the latest student assignment that has spun off INACHUS at Laurea University of Applied Sciences this year. Our student Juha Penttinen took on the task to proof that an effective training tool for first responders that focuses on the fast pre-sorting of victims is possible. The pre-sorting is done based on the popular smart triage sorting algorithm that was created to tag patience with a color code to direct the ambulance at first to the victims with the most severe injuries.
The special task in this educational game is to find victims deploying various search devices like phone finder, chemical trail detector, IR- and night vision etc. All the victims in the debris need to be found and tagged correctly in the shortest possible time.
The collapsed building structure used in this game is a result of the DEM simulations (performed by the BCB software) of the Vitruv building library.
The game can be freely downloaded from here: Training game for fast victim sorting
The BCB has delivered valuable results when it was used to simulate the
destruction of the Pyne Gould Corporation building in Christchurch and
the collapse of the apartment block in Chennai. Both cases have been
described in this blog earlier. Now, a third collapse simulation comes
along as another validation case, it further emboldens us to believe
that the BCB delivers noteworthy results. Kostack studio used the BCB to
simulate the collapse of the World Trade Center 7 that occurred after
the terror attack in New York in 2001. This collapse is still furiously
disputed to prove or disprove conspiracy theories that claim that the
collapse happened by controlled demolition. Kostack studio procured the
detailed construction drawings and built an accurate model
with all relevant structural members in Blender. For the initiating
collapse event the findings of the NIST (National Institute of Standards
and Technology) investigation report were used. According to this report
the failure occurred due to the intense fires that were triggered by the
debris from the other two towers. The sprinkler system in WTC7 did not
work properly. The fire caused the thermal expansion of steel beams that
caused a girder to slide and loose its bearing which in turn caused a
vital pillar (column number 79) to buckle. In the Blender model column
79 was removed.
The load bearing structure of the WTC7 was made of steel. The steel
members were bonded with screws. To replicate these connections the
strength formulas in the BCB perform a rough approximation of the ratio
of the total screw area section and member contact area.
The Blender simulation replicates a peculiarity that is not evident when
watching the actual video footage from the collapse. The building’s
structure was a typical tube-frame design, the facade columns and beams
formed a rigid frame that delivered a strong structural membrane along
the exterior of the building. After the implied column failure the
structure collapsed from within and left the hollow membrane staying for
a while before the latter was caving in on itself as well.
This simulation is a sober re-creation of the alleged damages caused due
to the fires that were stated in the NIST report. It is not meant to
comment on any of the claims regarding the conspiracy theories.
WTC7 technical drawings: