For a country prone to disasters such as India, disaster management is a crucial subject. For successful management, capacity building along with understanding the topography of the land and proper organization and planning of cities is vital. Non-structural elements though will help in the preparedness, the importance of structural elements cannot be overlooked. The structural aspect of disaster management is where the role of Civil Engineers come in. This blog deals with the interrelationship between disaster management and civil engineering and some general details about disaster management.
A disaster is a sudden, calamitous event that seriously disrupts the functioning of a community or society and causes human, material, and economic or environmental losses that exceed the community’s or society’s ability to cope using its own resources. Though often caused by nature, disasters can have human origins.
The majority of damage in the event of a disaster is due to improper city planning, failure of structural design, poor infrastructural facilities, ignorance of building norms, low quality substitutes of building materials and lack of site investigations. This is where the expertise of a civil engineer is highly demanded.
A structural engineer need to play an active role in preparing the development plan of an area. Specifications should be followed, structural analysis should be done using the latest techniques and advanced methods like performance based designs must be followed rather than simple code based approaches. Materials such as High Performance Concrete, Fiber Reinforced Concrete, Self-Compacting Concrete, Fiber Reinforced Polymers etc. should be preferred in the construction of new buildings; and floating columns, soft stories and other irregularities should be avoided. Civil engineering involves designing structures on the ground and thus the study of the ground behavior is a must. Detailed examination of the subsoil by a Geotechnical engineer is a very important criteria in construction works, ensuring the structure will not give in the face of a calamity and to understand the site specific response. Landslides may occur due to modification of slopes for construction works, overloading of slopes or due to alteration of the natural drainage, all of which can be avoided if proper soil knowledge is available. Geological conditions leading to the failure of dams, channels are of common occurrence, making related studies essential. A hydraulic engineer can provide information about bridges and dam construction and also suggest flood control measures. A construction manager must ensure that the quality of the construction material doesn’t compromise the safety and the stability of the structure; proper construction strategies should be worked upon and building and safety codes and regulations should be complied with. City planners must keep in mind the vulnerability of a specific area to disasters. Specifications and guidelines should be issued for construction activities in these areas. Third party checks and by the Local Authority for the compliance of the project with all the requirements must be conducted before issuing the Building Use permission and also regular investigations should be conducted after the completion.
Base isolation is one of the most efficient method used in protecting a structure against earthquakes. It is a collection of structural elements which should substantially decouple a superstructure from its substructure resting on a shaking ground, thus protecting the building. Normally, excavations are made around the building and the building is separated from the foundations. Steel or reinforced concrete beams replace the connections to the foundations, while under these, the isolating pads, or base isolators, replace the material removed. While the base isolation tends to restrict transmission of the ground motion to the building, it also keeps the building positioned properly over the foundation.
Viscoelastic dampers are another type of dampers that are used in structures to control their vibrations during an earthquake. They are materials which possess the properties of both a viscous material, which resists the motion and of an elastic body, which has a tendency to return to its original position. These two properties combined offer reliable seismic protection.
Sausage groynes are long cylindrical structures which are placed along the bank of the slopes of streams to help improve the slope stability. Gabion/Mattress Groynes are used in the faster moving streams, where erosion is occurring at a faster rate. They trap soil particles to allow a buildup of soil, thus encouraging the growth of vegetation.
Heath of a structure is very crucial in determining the way it will act during a natural disaster, it affects the economy of the country and the lifestyles of the people. The challenge faced by engineers is to maintain the security and safety of large civil infrastructures such as bridges, dams, skyscrapers, nuclear power plants during the event of a natural disaster or a terrorist attack. Until recently, the main obstacle was the lack of sensors which would be easy to install, economical, and be harsh environment resistant. Recent developments in the fields of nanotechnology and MEMS (micro-electro mechanical system) have proved to provide an innovative solution. These have led to wireless, inexpensive, compact, high density data collection systems. Systems working with these concepts have been able to provide real time condition assessment of structures, and assess their integrity after attacks. It also provides identification of incipient damage in structures experiencing long term deterioration. Till date, systems based on nanotechnology and MEMs-based systems have been able to wirelessly detect and monitor different damage mechanisms in concrete structures and monitor critical structures’ stability during floods and barge impact.
Hydrologic Modelling System (HEC-HMS) is a software developed to simulate the precipitation runoff processes of dendritic watershed systems. The program has a graphical user interface which makes the study of water availability, urban drainage, flow forecasting, future urbanization impact, reservoir spillway design, flood damage reduction, floodplain regulation, and systems operation user friendly. Supplemental analysis tools are provided for parameter estimation, depth area analysis, flow forecasting, erosion and sediment transport, and nutrient water quality. This system was successfully used in the Damodar Basin in eastern India.
Response, Recovery and Reconstruction include the Post-disaster initiatives taken in response to a disaster
The contribution of engineering has been important in the setting of engineering codes and standards, and in the development of engineering resources, tools, and methodologies for use in mitigating the impacts of natural and technological hazards on the built environment However, engineered-hazard mitigation options alone do not guarantee protection from natural and other hazards. Therefore, a holistic multi hazard perspective that integrates social, economic, and environmental issues to hazard reduction is preferred. The engineering professionals, who contribute to hazard reduction, will be increasingly required to work across disciplines, and with many actors and stakeholders.
AAKAAR aims at creating a platform to compete, learn and promote Civil Engineering amongst the education fraternity through Competitions, Events and ICES, IIT Bombay (research paper conference) and also to make a festival of all and for all the Civil Engineering students.