On Monday, January 15, 2018, we were shocked by an incident collapse on the BEI floor. This veranda is actually designed to be just a traffic lane and not a place where people hang around for a long time. Many people ask what causes the collapse. People's assumptions are different and many say it's "because there's a lot of cuts here's money", "the building is old", and some say "the cause is because of the earthquake". But what is the main cause of the collapse of IDX veranda ?
The exact cause of the collapse of the veranda IDX still investigated up to now. However, the author will try to predict the cause of the veranda IDX it collapsed. After collecting data for a few days, the author can discuss this incident.
Veranda that exists in the IDX, have made of construction steel frame as the lobby floor and steel cables to hold the end farthest from the object of the veranda. Can be seen in Figure 2, this is a photo of the IDX veranda that hasn't collapsed.
Figure 3 is a fraction of the video frame of the collapse of the IDX veranda. In Figure 4 is a diagram of the construction of the IDX veranda. It can be seen that the crowd stood at the end close to the steel cable and caused the corridor to collapse. Casualties inflicted due to this incident as many as 77 people with the condition of the victims suffered broken bones.
In the science of statics and the mechanics of the strength of the material, see figure 3, point A is a type of pedestal and the end of the steel frame rod (point B) is supported by steel wire attached to the point C. The steel cable aims to reduce the amount of deflection (bent) which occurred at the end of the steel frame rod. So the construction of the steel framework of the veranda will still look straight and stable and will not lobby sloping if passed.
The building of IDX was built in 1997-1998 and based on existing data, has not done maintenance. Conceivable for 20 years in use, this hallway has different loading conditions and repeats every day. This repetitive load condition can cause fatigue in one part of the construction of this hall and is aggravated by the fault of the parties associated with the absence of maintenance for this construction.
In engineering, this is called a failure by fatigue. This type of fatigue failure of the most frequent and common expression in construction. In the case of this veranda, seen on the video frame, many people stood and gathered on one of the sides of this veranda. Therefore, this veranda had a concentration load and the load will be over.
This concentrated load condition causes the binding parts in each of these hallways to fail and the hall is collapsed. Moreover, point B (see figure 3) is a point of deflection and high-stress concentration. This affects the point C that serves to hold the point B so that there is a failure due to excessive load at point C. The failure of steel cable binder at point C can be seen from the condition of the fall of the basement on the video.
It can be concluded that the condition of fatigue occurs at point C. The failure of the steel cable hook causes the loss of pedestal ability in holding the existing load and at this point serves to support the end of the steel frame rod at point B from the condition of excessive deflection. The high stress and fatigue conditions that lead to the breakdown of these constructs.
Hopefully, this review adds to our knowledge. Remember! always prioritize safety in everyday life. Do not neglect and underestimate the small things.
References :
[1] https://metro.tempo.co/read/1050597/selasar-bei-ambruk-ini-daftar-77-korban.
[2] https://news.detik.com/berita/d-3816384/selasar-ambruk-tower-ii-bei-belum-pernah-direnovasi.