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[Anupds]

An article By Anup D Shirhatti Dtd. 27-08-2021  


             One of the major aspects in civil engineering is disaster management. Disasters like Earthquake, flood, Tsunami,etc. pose great challenges to Humanity. A lot of research is done on earthquake. Earthquake is sudden shaking of the ground due to which the buildings suffer damage. Earthquakes are common near tectonic plates. However if the building is designed for earthquake it generally performs better.
  
           Recently, we saw in Orrissa, west bengal, Mumbai during cyclones we anticipate rain and heavy wind. During Heavy wind the tall structures are some times fail as they are not able to sustain load. Generally light structures like trussed roofs, Hoardings, etc are suceptible.  However concrete buildings designed for  earthquake it generally performs better.

            Fire is also a very important aspect, Recently we heard that a cracker factory got burnt making damage to people and property.  Fire requires the exhaustible material & initiator so combustible material and initiator like short circuits, etc to be avoided as far as possible.Also since large buildings have come up, exit routes with directions is necessary also lot of times smoke kills more than fire so ventilation is very necessary.  and all in all precaution is better than cure.
       
         In last couple of years we have seen lot of news that flood occurs the downstream area gets flooded with water. Generally cities are constructed, irrigation of land all require water and during summer there is requirement of water but During monsoon when the dams get filled during short time after a threshhold the water has to be left into the Downstream area in view of safety of dam structures after giving notice to people. After the flood recedes things come back to normal but is a great discomfort.
     
         Although Disasters are not able to be estimated prior, precautions like Earthquake design and ductile detailing in High wind and Earthquake zones is necessary. Emergency exits and ventilation and fire exhausting services are necessary. The structures must also be designed for cyclones. draught and floods occurs which are not under human control. The key is to be prepared and reconstruct.

[vikram.jeet]

NATURAL DISASTERS

The article by Er Anup D , is nicely presented giving information on on Earthquakes , Wind /storms , FIRE , FLOODS  as Natural happenings and preparedness to minimise damages .

To add in this phenomenon are instances of LIGHTENINGS killing hundreds of people at various locations , even in India this year Lightening killed many , tourists visiting some fort in Rajasthan were killed, farmers working in fields were burnt to death, some people taking refuge under trees were got killed by lightening which fell on tree.

Also the instances of  TORNADOS, the high speed swirling winds occur , it damage everything on its path. In 1978 a tornado occured in Delhi following a path from Delhi University towards Kingsway Camp and Towards Radio colony. Many vehicles on its route got lifted, parapet walls of Colleges were damaged, and Communication Towers of MTNL were totally bent down on tornados path.

ALL THESE ARE SOMETIMES REFERRED AS ACTS OF GOD

[vikram.jeet]

NATURAL DISASTERS

in this List we must add CLOUD BURSTS INSTANCES happening every year in Hilly areas damaging villages and villages killing people . The suuden discharge of water from clouds suddenly fall on hilly slopes taking with it debris, stones and hitting everything on way ,finally falling into close by river , causing sudden floods and damages on  downstream without any warning.

[vikram.jeet]

NATURAL DISASTERS

Article by Er Anup D also lists fire . Instances of fire in buildings are due to shear  negligence on part of humans , but happenings of FOREST FIRE are also the natural disasters , could also be due to negligence of people living around forest areas. Once fire broke out , it is very difficult to control . Even in Countries like America , the WILD FIRE has become a challenge .

[vikram.jeet]

NATURAL DISASTERS

Further to add in list of disasters are :

Slope Failures in hilly areas
Avalanche s in Snowbound hills

Slope failures , mostly during monsoon season are very common occurances  with no concrete solution to address these problems .
These are partly natural , but partly man invited disasters. Deforestations , Road widening s , damage to natural landscape of hills for development  of projects , and many other human interferences to NATURE are the reasons behind these disasters .
Slope failure zones needs to be identified for remedial  measures like strengthenings .

Avalanches are natural disasters , and such zones are identified and tourists are cautioned at such locations .

[VPandya]

Dear SEFI friends,

We all must watch damage to structures due to :

"  Hurricane IDA in New Orleans , USA . "

In year 2005 Hurricane KATRINA did lots of damage,  such that US Building Codes were UPGRADED . Le us see the effects of Hurricane IDA .  Hope for the best.

Regards .

Vasudeo Pandya   P.E.
Structural Engineer

[Dr. N. Subramanian]

[VPandya]

Dear Dr. Subramanian,


Thanks for your comments . I agree that Levees , Sea-Walls and Pump Houses done after Hurricane Katrina did reduced the damage due IDA to a great extent , but about 1  million people of Louisiana , are without Power . They  will not get their power restored for another 3 weeks. We have to do a better job of Designing  Electric Power Lines  for Hurricane type IDA.  How one can function without Electric Power ?


Regards.


Vasudeo Pandya  P.E.
Structural Engineer

[Dr. N. Subramanian]

Dear Er Pandya,


Yes. I agree with you that the people in Louisiana are without power( one of my relatives is also affected). It is because of trees falling on power lines and some transmission line towers collapsing( I saw such collapses in TV). It may be because of the extreme wind speed of Hurricane Ida, which I believe reached 150 Mpa. Not sure whether the towers were designed for such a speed.

In USA, there is no underground cable system and all lines are carried overhead using wooden poles. This also may be one of the reasons. The governments here are interested in making laws to banning abortion and preventing people from freely voting and not interested in strengthening infrastructure. You may be aware that the 2021 infrastructure report card of ASCE has included stormwater infrastructure for the first time in its grading and received D grade. The grading in other areas are also not that impressive.

Warm regards
Subramanian