© 2022
Ramaswami Ashok Kumar
Invocation
https://m.youtube.com/watch?v=OF2QCl3-6BM&list=RDMM31vQFHBhJoQ&index=11
Demolition of RCC structures requires extraordinary safety features because of Uranium dust.
1.0 Demolishing RCC Structures creates dangerous radioactive contaminants, like the heavy metal Uranium-238(1). The uranium dust so created enters living beings through lungs, skin. Within settled communities where buildings still have a life of 50y or more, the premature demolition of little used structures of a housing complex creates impossible conditions where the neighbours have nowhere to go. This is because the uranium which has an atomic weight of 92 has great affinity for the phosphate backbone of our DNA and binds itself to the DNA. The uranium enhances natural background ionising radiation by the 4th power of the ratio of its atomic weight and tissue. This factor is (92/7.5)^4=22642(2). Thus the background ionising radiation which normally has a value of 2490 microsieverts/year is multiplied by 22642 and becomes 56377473 microsieverts/y, more than 4 orders of magnitude fold! That is 56 Sieverts/y at the uranium location. The uranium converts this enhanced photon energy to photoelectrons which are like beta rays causing damage to the cells at infinite biological effectiveness. Uranium is known to cause cancer in animals and genomic damage at very low concentrations.
ECRR 2010 details the deadly effects of uranium 238 in chapters 6, 9 and 12.
Apply the precautionary principle and stop such demolitions for which we have to make the Supreme sacrifice.
Haiku on the demo(litio)n
Say bei bei to life!
You are being bombarded
With uranium
Uranium with
Infinite effectiveness
Biological
Say bye bye to life
Demolishions persisting
Of homes once lived in
Forcefully destroyed
Involuntarily hit
From body's inside
Ingested and inhaled
Uranium sits on cells
Sending deadly rays!
2.0 Structural safety of adjacent buildings adversely affected.
But health of citizens though the primary concern is not the only disastrous effect. The health of structures of the neighbouring building complexes is also seriously affected.
The brief research conducted by me below points out the extremely serious nature of the issue.
Demolition of buildings: The forces on adjacent structures
1. Chunk of concrete falling from the roof.
A chunk of concrete of 2mx2mx1m fell from a height of 18m on to the cement concreted ground of housing(hsg) society A
from hsg socoety A under demoliition
adjacent to a housing society B during redeveloment demolition of the hsg complex A.
The energy with which the chunk of 4 m^3 fell was mgh= 4m^3* 2273kg/m^3*9.81 m/s/s* 6*3= 1605465.36 Nm
The impulse force on the pavement lasted 0.1s
This was immediately transmitted to the adjacent building B’s pile foundation
This would at 2000 Joules/kg/DegK cause a shock temperature input of
802.73268 deg K in 100 millisecs,
The force was mg= 4m^3 x2273kg/m^3*9.81
Force= 89192.52 N.
The acceleration shock input on 1kg of the foundation was Force/mass 89192.52 m/s/s
Thus the buildings would experience an uplift and this was indeed experienced by us in Building No.1
on 18 Oct 2022 in a similar demolishing situation.
Shear modulus is 1.19*10^10= 11900000000 Pa(Ref 3).
Shear stress(SS) when shear modulus is reached is 1.19*10^10 Pa is
SS= Vertical Force/Shear Area 4*2273*9.81/shear area
Shear Area= Vertical Force /SS = 7.49517E-06 m^2.
Let us assume a cube of side l m
Thus 4l 7.49517E-06 or l=
The coefficient of linear expansion of concrete Coefficient of Linear Expansion for concrete is 12 (10^-6 K^-1) (Ref 4).
Change in length = (coefficient of linear expansion) (initial length) (change in temp).
Let us assume a cube of side l m
Thus 4l 7.49517E-06 or l= 1.87379E-06 or 1.8738 microm
New length= 1.89184E-06
New Vol 6.77103E-18
Old Vol of cube= 6.57907E-18
New Vol/Old Vol= 1.029177642
2. Vibrations caused by use of the demolition hammer giving 1000 punches per minute at a maximum input power to the tool of 2000 W per hammer(Ref 5). What is the shock temperature rise developed after 8 hrs in a day at 1 kg of the foundation of hsg society B at 30m mean distance with 10 hammers vibrating simultaneously at the roof of demolition building complex A? Also what is the ratio of the volume of 1 kg of this foundation after the shock input temperature rise compared to that at the commencement of the drilling cum hammering operation?
Force on 1 kg of adj bldg.(B) fndn using hand drills for demolishing houses= 9920000 N
Shear area = Shear Force transmitted to the 1 kg of building of B= Shear Force/Shear Stress= 9920000N/11900000000= 0.000833613 m^2
As before let us assume a cube of length l for the 1 kg foundation.
Shear area =4l.
Thus l = 0.000833613/4= 0.000208403 m.
New length= 12*10^-6*original length*shock input rise in temperature+original length= 0.000580528 m
New Volume of the 1kg foundation= New lenghth^3= 1.95646E-10 m^3.
Original volume of the cube= 0.000208403^3= 9.05137E-12 m^3.
Vibration Vol after shock input temp rise/Vibration Vol before shock temp rise= 21.61505084
The 1kg of foundation experiences a temperature shock input rise of 148800 Kelvin (See calculations below) .
The implications of such a temperature rise and increase of volume of 1kg of foundation in a highly compressed status are profound.
The foundation may melt and distort where the huge volume increase of 21 fold may lead to an explosion and fire.
3. Computations of shock input temperature rise of 1 kg of foundation of adjacent building.
High impact performance due to 62 joules of impact energy and 1000 blows per minute 62*1000 62000 J/min
Interval between blows 60/1000 0.06 secs 60 msecs
62000 Joules per min per blow for 8hrs 29760000 Joules
10 drills = 297600000 Joules at 10000 blows per minute for 8 hours.
Temp shock rise per day on a kg of adj building foundation 148800 Kelvin .
Force = Energy/distance of drills in the mean K81/30m = 9920000 N
4. Conclusions.
One should not demolish a building complex which was hardly lived in after a decade or two in the midst of a settled community because of unacceptable health consequences of both the residents and the residential complex.
5. References
