INTRODUCTION TO EARTHQUAKE ENGINEERING Earthquake engineering is the science of the performance of buildings and struc- tures when subjected to seismic loading. It also assists analyzing the interaction be- tween civil infrastructure and the ground. One of the most important aims of earth- quake engineering is the proper design and construction of buildings in accordance with building codes, so as to minimize dam- age due to earthquakes. It is the earthquake resonant wave frequencies of seismic engineer who ensures proper design of waves, thus reducing the damaging effects. buildings, so they will resist damage due to Thus, the structure is protected from the earthquakes, but at the same time not be damaging consequences of an earthquake unnecessarily expensive. by decoupling the structure from the shak- ing ground. Today in this technical era this sub-stream Research on Earthquake Engineering is also nowhere behind. There are many In order to properly understand how build- technologies developed in this field which is ings and structures can stand up to earth- not only a grandeur but also is a necessity quakes, extensive research has also been for safety of structures. conducted on earthquakes. In order to obtain an in depth knowledge Seismic Vibration Control Technologies concerning the initiation and behavior of earthquakes, it is essential to ascertain the The purpose of these technologies is to mechanical properties and frictional charac- minimize the seismic effects on buildings teristics of the crust of the earth. Observa- and other infrastructure by the use of seis- tions from space have clarified the complete mic control devices. When seismic waves cycle of earthquake, including the silent ac- start penetrating the base of the buildings cumulation of strain, transfer of stress be- from the ground level, the flow density of tween faults, release of strain, and failure their energy reduces due to reflections and of faults. Measurements on boundary other reasons. However, the remaining zones of tectonic plates have explained the waves possess significant potential for dam- interaction of faults across hundreds of age when they reach the superstructure. kilometers. Study of the stress transients that take place after earthquakes will deter- Vibration control devices assist in the re- mine the possibility of future earthquakes duction of the damaging effects, and en- at other sites in the system. These studies hance the seismic performance characteris- have provided scientific explanations relat- tics of the building. When the seismic ed to earthquake engineering and resulted waves penetrate a superstructure, these are in revision of concepts and practical appli- dissipated by the use of dampers, or dis- cation. persed in a wide range of frequencies. Mass - dampers are also employed to absorb the Advancements in technology- DEVELOPMENT or DESTRUCTION?

We live in an age of technology. In the world here, yet again. In 373 BCE, historians record- that we have carved for ourselves, it is tough, or ed that animals, including rats, snakes and wea- rather impossible to imagine a day without tech- sels, deserted the Greek city of Helice, days be- nology in any sphere of life. fore an earthquake devastated the place. There In the wake of recent earthquakes in Japan, have been several documented cases of strange Philippines and Indonesia; and with an expo- animal behavior prior to the earthquake- as in nential growth in our technology, it becomes case of dogs, excessive barking and irregular important to find the vague link (if it exists) be- behaviour such as biting can be taken as signs tween the development in technology and natu- of forecast. Here again, nature proves its su- ral disasters. premacy over mankind and its developments- while the whole of technology put together The seismic activity of these areas is credited to has never been able to predict the calamities, their location which coincides with the Pacific something as simple as the change in the be- Ring of Fire. Pacific Ring of Fire, also known havior of animals can help make very accurate as Circum Pacific belt is an area of intense vol- forecasts. Before the deadly earthquake in Indo- canic and seismic activity, just along the edges nesia, it was observed that snakes came out of of the Pacific Ocean-home to 452 volcanoes their habitats before the completion of their hi- (over 75% of the world’s active and dormant bernation cycle. It could later be realized that volcanoes). Nearly 80% of the world’s earth- they could feel the shocks generated by the quakes occur in the Ring of Fire belt. The natu- seismic waves and hence the behaviour. This ral cause of the disasters being stated, let us way, Nature again stands undefeated. delve deeper and have a close look at the techno- logical scenario which contributes heftily to the Any destruction occurs when there is a lapse in causes of the disasters. someone’s part in bearing one’s responsibility. And destructions occur when man refuses to Mankind has exploited Mother Nature, to the acknowledge his responsibility towards the na- extent that she is forced to retaliate in the forms ture. Notwithstanding, it is never too late. Let of natural calamities. Reckless industrialization, us take care of our nature, the way it takes care deforestation, over mining, excavations, unnec- of our needs. essary dam constructions, fracking and various such activities are adding up to the sources of Each effort counts. Let us make ours count. disasters. And this indiscriminate usage of our nature and its resources by man for his selfish needs has provoked the nature to the extent that wrath of nature is too common a sight for all of us these days. Also, in spite of all the progress that we have - made today, we can still not predict our calami- ties accurately. And nature defeats technology The earthquake-resistant bridge- CHENAB BRIDGE

An under-construction railway bridge over in consultation with the Defence Research the in and Kashmir’s and Development Organization (DRDO),” a district, billed to be the world’s high- senior engineer working on the project est, can withstand earthquakes measuring said, without explaining further. up to eight on the Richter scale and high- The bridge, a part of the -Reasi- intensity blasts. Anantnag-Srinagar- railway pro- The arch bridge, a part of an ambitious ject, can withstand a blast of 30kg of ex- railway project connecting Kashmir to the plosives, the engineer said. The overall rest of the country, will have a “security length of the bridge is 1,315 metres, hav- setup” against possible terror threats and ing 17 spans, of which the main steel arch quakes, the officials said. The work on the portion across the Chenab river is of 476 Rs 1,250-crore bridge, which will be 359 metres in length, and its height is 359 me- metres above the Chenab river bed and tres above the river bed. stand 30 metres taller than the iconic Eiffel “There are certain unique and unparalleled Tower in Paris, will be completed by May features in the under-construction bridge. 2019. It is for the first time in that a con- As Jammu and Kashmir is faced with terror crete-filled steel arch is being used as the main arch,” he said. He said that the work activities and prone to earthquakes, M K on the viaduct portion of the bridge at Sri- Gupta, Member (Engineering) of the Rail- nagar end was nearing completion. The way Board, said that the railways “will put project work is being carried out by in place a security setup against any such AFCONS Construction Company through threat in consultation with defence forces”. Konkan Railway. The Udhampur-Srinagar- “The bridge has been designed in such a Baramulla Rail Link (USBRL) Project will way that it will withstand an earthquake be completed by March 2021. measuring eight on the Richter scale. - There will be no damage to the bridge,” A workshop on Building Information Modelling (BIM) said Gupta, who began the work on putting and Revit will be conducted soon. For more infor- the main arch on November 5. mation, visit our facebook page: facebook.com/ceabits He said that a detailed, site-specific seismic analysis had been carried out by experts Our Team: from the Indian Institute of Technology Raghav Agrawal, Amisha Srivastava, Rakshit (IIT), Roorkee, and the Indian Institute of Mishra, Umang Agarwala, Aditya Bhanja, Science (IISc), Bangalore. “The bridge has Chirayu Tank also been designed with anti-terror features