FORCES AND EFFECTS AND CALCULATION FOR THE DESIGN VALUES.

LOADS AND FORCES:--In structural design , account shall be taken of the dead , live and wind loads and forces such as those caused by earthquake ,and effects due to shrinkage ,creep , temperature,etc where applicable. Dead loads shall be calculated on the basis of unit weights which shall be established taking into consideration the materials specified for construction uses . Alternatively the dead loads may be calculated on the basis of unit weights of the material given in IS:1911-1967, unless more accurate calculations are warranted, the unit weights of plain concrete and reinfoced concrete made with sand and gravel or crushed natural stone aggregate may be taken as 24000 N per cubic metre and 25000N /cubic metre respectively. Live loads and wind loads shall be assumed in accordance with IS :875 -1964 .The earthquake forces shall be calculated in accordance with IS :1893 -1975 .In case of shrinkage,creep and temperature effects ,if the effects are liable to effect materially the safety and serviceability of the structure,these shall be taken into account in the calculations.In the case of ordinary building infrastructure effects due to temperature fluctuations and shrinkage and creep can be ignored in the design calculations .Other forces and effects if they are liable to effect materially the safety and serviceability of the structure ,shall be taken in to account, foundation movement (IS :1904-1978), elastic axial shortening,Soil and fluid pressures (IS:875-1964),Vibration , fatigue,Impact (IS:975-1964), erection loads  IS:875-1964 and Stress concentration effect due to point loads and the like .

Combination of loads : The combination of loads shall be taken as given by IS:875-1964 and the dead load counteracting other loads and forces in a Structural member or joint , special care shall be exercised by the design engineer to ensure adequate safety for possible stress reversals.Design load is the load tobe taken for use in the appropriate method of design ,it is the characteristics load in case of working stress method and characteristic load with appropriate partial safety factors for limit state design .