Cement Energy and Environment

• Cobalt concentration in soil is 5,006 mg/kg in the 2004 report; the 2011 report says it is 1,153 mg/kg • To Know more, please log on to www . downtoearth.org.in . Courtesy: Down to Earth, 1-15 Apri/ 2011,Pp27-31 STRICT BUILDING CODES PROVE SAVIOUP IN JAPAN Strict adherence to building codes saved many lives in Japan following worst tsunami and earthquake that hit Japan's coastal areas. Japan has outfitted its buildings with advanced devices called base isolation pads and energy dissipation units to dampen the ground's shaking. The dissipation units are built into a building skeleton. They are hydraulic cylinders that elongate and contract as the building sways, sapping energy. The country has built concrete seawalls in many communities, some as high as 40 feet, which amounted to its first line of defence. In coastal towns, networks of sensors are set up to set off alarms in individual residences and automatically shut down floodgates when an earthquake strikes to prevent waves from surging upriver. These precautions along with earthquake and tsunami drills are routine in the country, that is why Japan is the best prepared country for disaster practices that saves lives and keep damage to the buildings and structures at minimal level. In Japan, the building codes have long been much more stringent on specific matters like how much a building may sway during a quake. But still ~ystems deployed were not foolproof as tsunami roared over embankments, washing out cars, ships and damaging buildings, which according to an estimate rose to over 85,000 and the scale of the tragedy indeed colossal. There could have been devastation worse than this if the country was not adequately prepared for such nature's furry. ' This should prompt us about our preparedness for such eventualities. The Indian subcontinent is prone to dangerous earthquakes with five having already taken place . Development of better building codes and strict enforcement of existing ones which in most cases are breached rather than observed are the measures calling for immediate action. Courtesy: NBM&CWApri/ 2011, P48. Flexible Towers 'Base isolation pads' are installed between the foundation and structural steel framework of many Japanese highrises. SteelAttachment Plate Alternating Layers of Stiffening Steel and Rubber e Foundation In aquake, the frame of a fixed-base building-without pads-will lean and its shape will distort, causing damage. Isolation Pads flex for the buildings, keeping the frame upright. ......... Fixed Base Pads ·~-- Ground Motion--•• Source: Multi disciplinary Center for Earthquake Engineering Research, SUNY-Buffalo 45