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:
This video shows the simulation of the second building from the building library. Two damage scenarios were examined: a pillar removal due to explosion and an earthquake. The pillar removal did not lead to collapse. The video displays the reaction when the strong earthquake time history was applied.
The building library collects a range of typical building structures (9-10 buildings) including structural details. Prone to collapse risks are examined and the collapse shapes are exported from the simulations in a digital exchange format DXF and OBJ. The building library can be used in a real collapse case to estimate the probable location of cavities.
The removal of these two pillars did not lead to collapse.
Here is a video and download link for the virtual training tool prototype created using Unreal Engine 4. The building model is from a collapse simulation of the Pyne Gould Corporation building in Christchurch, New Zealand. The simulation was made by Laurea UAS as a part of INACHUS´ software validation cases .
At the current stage of the prototype, the user will try to find and evacuate all victims in the scene. The prototype will hopefully be improved further by another student, so it can be brought to a point where it could be used as a virtual training tool to reduce costs in Urban Search and Rescue training. For example adding first aid, techniques and decision making according to the USaR principles could be implemented in the tool.
The project was done by Ville Tiira as an internship and thesis, which are a part of the Bachelor’s degree in Business Information Technology in Laurea UAS.
On 28th of June 2014 around 4:40 PM IST one of two under construction buildings collapsed at a suburb of Chennai, in the Indian state of Tamil Nadu. The collapse happened during heavy rain and a thunderstorm with lightning. The building site was still busy. Workers and casual uninvolved searched shelter from the rain and frequent lightning. This is the reason the accident claimed many victims, altogether 61 casualties. Many of the survivors delivered eye witness reports. According to those reports the building collapsed directly after a lightning stroke. This might be the first documented case where a lighting caused the complete collapse of a building.
The debris pattern is most unusual, since the building was split into two halves and each half shifted to the respective side. The simulation, made by Virtual Validation Corporation Kostack & Walter, reproduces this extraordinary dynamics very well. The software was developed at Laurea University of Applied Sciences.
Now, that we are able to successfully simulate the collapse of big building structures, the software Blender gives its splendid support to exploit the simulation results for interactive walk throughs. Blender´s powerful features facilitate educational tools for rescue workers and paramedics. A training program could teach them in localizing victims within the debris, estimating their physical condition and applying first aid measures.
We have reached an impressive milestone. Our BCB add-on has evolved into a serious simulation tool: One of the software validation cases in our Inachus research has been the collapsed Pyne Gould Corporation building in Christchurch. The building was destroyed in a devastating earthquake, on 22 February 2011. The Blender add-on was able to simulate the debris pattern fairly accurately as it can be seen from the video and the still images at the end of it.
Only the simulation of concrete structures is possible at the moment. Much remains to be done, such as the simulation of deformable building elements like steel structures. The bases is laid with the introduction of spring constraints. But the working of springs in Blender needs yet thorough investigation.
This video is a first test to see if our simulation results can be used in an interactive walk through environment. The collapsed blender model is exported into the unreal game engine. Here a character can walk around, climb the debris or search inside for cavity spaces. This technology would be perfectly suitable for the education of rescue personnel. It is for example possible to apply physical behavior to debris fragments so that trainees can move pieces and experience the subsequent collapse.