Crane accidents can be caused by mechanical failures or human failures in the operations of the cranes. Even the mechanical failures can be a result of improper supervision or maintenance and all point to lack of training and required attention to crane operations by field managers. The Need for Cranes and the Risks Involved Cranes…
Disaster is a natural calamity which may be in the form of • Drought • Flood • Cyclone • Forest fire • Landslide • Earthquake • Volcanic eruption etc. DISASTER PREVENTION STRATEGY Construction of dams can prevent flood havoc. Identify the rivers and construct dams to regulate flow of water during heavy rainfalls. Spreading the…
It is reported that in USA fire kills more people each year than all other natural disasters combined including floors, cyclones and earthquake. The fire load in a building should be kept to the minimum possible. The term fire load indicates the amount of heat liberated in kilo joules per square metre (kJ/m2) of floor…
A cyclone is a storm accompanied by high speed whistling and howling winds. It brings torrential rains. A cyclone storm develops over Tropical Ocean and blows at speed as high as 200–240 km/hour. It is usually accompanied by lightning, thunder and continuous downpour of rain. Cyclones extend from 150 km to 1200 km in lateral…
Tall buildings are subjected to heavy horizontal forces due to inertia during earthquake. Hence they need shear walls. A shear wall is a R.C.C. enclosure within the building built to take shear forces. It is usually built around lift room. These shear walls must be provided evenly throughout the buildings in both directions as well…
The earthquake resistance of small buildings may be increased by taking some precautions and measures in site selections, building planning and constructions as explained below: 1. Site Selection: The building constructions should be avoided on (a) Near unstable embankments (b) On sloping ground with columns of different heights (c) Flood affected areas (d) On subsoil with…
Seismograph is an instrument for measuring oscillation of earth during earthquakes. It has three major components—the sensor, the recorder and the timer. Figure 20.2 shows a typical seismograph. The pendulum mass, string, magnet and support together constitute the sensor. The drum, pen and chart paper constitute the recorder. The motor that rotates the drum at…
EARTHQUAKES RESISTANT BUILDINGS An earthquake is a sudden, rapid shaking of the earth surface caused by the breaking and shifting of rocks beneath. During earthquake, ground motion occurs in a random fashion in all directions radiating from a point within earth crust, called epicentre. It causes vibrations of structures and induce inertia forces on them….
Applying mortar coats on the surfaces of walls, columns, ceiling etc. to get smooth finish is termed as plastering. Mortar used for plastering may be lime mortar, cement mortar or lime-cement mortar. Lime mortar used shall have fat lime to sand ratio of 1 : 3 or 1 : 4. If hydraulic lime is used mix proportion…
Air entrained concrete has microscopic air bubbles in the concrete. Air bubbles provide durability for concrete exposed to freezing and thawing. These air bubbles help to improve the workability of the concrete and reduce the slump. Concrete entrained air testing is a must to maintain quality. The Advantage of Air Entrained Concrete Air entrainment is the…