Ethical issues

Earthquake as a contemporary issue in structural engineering

Introduction

New technologies, designs, and innovations have led to construction of more magnificent, sophisticated, and mega structures civil structures around the world. However, the major challenge that remains unresolved is the response of the structures to unprecedented natural calamities such as earthquakes, winds, tsunamis, and landslides. Recent experiences and effects of the calamities, especially earthquakes have proven that more precaution must be taken to mitigate, or reduce their effects on civil structures.

In trying to address challenges caused by earthquakes on structural buildings, engineers and researchers have developed new innovations and technologies to enhance their safety to earthquakes. Many governments have taking new measures in the structural industry to in ensure new civil construction are safer and can withstand natural calamities. One major focus in the research is the development of structural control and measures to reduce the seismic responses of civil structures.

Causes of Earthquake

Earthquakes result from compressional or tensional stresses that built up due to the movement of lithospheric plates of the earth's surface. Sudden release of stress or strain along a fracture in the earth's crust, results in motion of the opposing blocks of rock past one another. The vibrations caused by these movements produce energy that is propagated as waves through and around the earth. The seismic waves reach the earth surface impacts on civil structures.

In other cases, volcanic eruptions, landslides, rock-falls or explosions can also cause a quake, but of a lesser magnitude. Seismic waves emitted by powerful earthquake can trigger smaller quakes in a distant of hundreds of miles away

If the design and strength of the structure cannot contain the amount of energy in wave, they can collapse leading to damage and loss of lives.

Magnitude of earthquake

The magnitude of earthquakes often determined by taking measurement of the amplitude of the seismic waves received on a seismograph. This is put into calculations to obtain the amount of energy released by the earthquake. For a unit increment in magnitude, there is nearly a thirty-fold increment in the energy associated.

The effects of an earthquake on civil structures

There are several effects of earthquake, the effects of the earthquake felt more in a broad area surrounding the epicenter of the earthquake. In most cases, the surface of the earth just above the epicenter cracks due the underlying faults. The magnitude of the vibration and subsequent damage on civil structures in a region is partly dependent on ground features. Earthquake vibrations will last longer with greater magnitude in unconsolidated surface, like a poorly compacted fill. Bedrock areas are less affected. Worst damage occurs in densely populated urban areas where structures are not built to withstand intense shaking.

Falling structures and flying glasses cause even more damage. Flexible structures standing on bedrock generally are less susceptible to earthquake damage compared to structures built on loose soil. A submarine earthquake causes a tsunami, that damage coastal cities.

Reducing effects of earthquakes on civil structures

Newer techniques, technologies and measures have been developed to curb severe effects of earthquake on the surface of the earth. Reforms have been enforced in the construction industry in most counties, especially in countries lying on earthquake prone zones, to implement measures that reduce the impact caused by earthquakes on the environment.

Major precaution measures are:

· Introduction of certification programs to improve competitiveness of constructors

· Embracing new innovations and designs in civic structures that are more adaptive to seismic wave effects

· Developing dander map zones to establish areas with high earthquake risks.

· Employing construction techniques that are seismic resistant.

· Determining sites that are safe for construction through analysis of soil geological structure.

· Making incentives to get rid of unsafe buildings and those in unsafe.

· Training more professionals to curb deficiency of qualified construction professionals, especially in developing counties.

· Establishing and enforcing proper codes and standards for construction of earthquake resistant structures

· Land use controls through zoning.

· Favorable taxation, loans, and subsidies that qualify buildings, methods and sites.

The future of civil structures and earthquakes

Conclusively, despite all the mitigations, earthquakes will continue to occur, and unless more sturdy earthquake-resistant structures are constructed, or improvements on the currently standing structures are made, their effects will continue to cause severe damages. Many reforms in the construction industry currently deployed by government promise better levels of preparedness to earthquake disasters. Several mitigations are put in place to counter attack the problem. This calls for, better engineering practices, new technologies, more professional in the construction industry will lead to better and safer civil structures.

References (2012). A Study on Causesuakes. Retrieved from: http://earthquake.usgs.gov/learn/kids/eqscience.php. Attila O, E. T. (2011). Collapsing Strucures: A study of civil structure practices in Developing Countries.