I.S Codes on Earthquake Resistant Building Design
Earthquake resistant building design guidelines are provided by set of Indian Standard codes (IS Codes). After observing Indian earthquakes for several years Bureau of Indian Standard has divided the country into five zones depending upon the severity of earthquake. The list of Indian codes for earthquake design of structures include IS 1893–2002, IS 4928–1993, IS 13827–1992, IS: 13920–1997, IS: 13935–1993. These codes take several parameters into considerations for instance local seismology, accepted level of seismic risk, building typologies, construction materials, and methods used in construction.
The role that codes of earthquake design structures play is of utmost important. This is because structures that designed and constructed in accordance with the specifications, procedures, and recommendations of these codes are capable of resisting seismic forces and associated deformations to certain extent. These codes are the guidance of designers to plan, design, detail, and construct buildings to withstand earthquakes. Finally, it should be known that, similar to other codes around the world, structures design based on these codes do not entirely immune from damages during earthquake of all magnitude. However, such buildings are able to withstand sizeable intensities without total collapse.
I.S on Earthquake Resistant Building Design
- IS 1893 (Criteria for Earthquake Resistant Design of Structures).
- It is divided into five different parts.
- Part 1 Presents provisions that are general in nature and applicable to all structures. It deals with assessment of seismic loads on various structures and earthquake resistant design of buildings. Additionally, it provides specifications related to buildings only.
- The other parts of IS 1893 including Part 2, 3, 4, and 5 need to be read in combination with this part.
- Part 2 cover liquid retaining structures including elevated and ground supported structures. Guidance is also provided on seismic design of buried tanks.
- Part 3 deals with bridge and retaining walls.
- Part 4 contains industrial structures including stack like structures.
- Part 5 provide design and construction guidance on dams and embankments.
- IS 4326 (Code of Practice for Earthquake Design Resistant Design and Construction of Buildings).
- This code covers general principles for earthquake resistant buildings.
- It deals with the selection of materials and special features of design and construction for different types of buildings such as timber constructions, masonry constructions using rectangular masonry units, and buildings with prefabricated reinforced concrete roofing/flooring elements.
- IS 13827 (Improving Earthquake Resistance of Earthen Buildings)
- The guidelines provided in IS 13827 deals with the design and construction aspects for improving earthquake resistant design of earthen houses without the utilization of stabilizers for instance cement, admixtures, lime, and asphalt.
- The provisions of this standard are applicable for seismic zones III, IV and V.
- No special provisions are considered necessary in Zone II.
- IS 13828 (Improving Earthquake Design of Low Strength Masonry Buildings).
- It provides general principles of design and special construction features for improving earthquake resistance of buildings of low-strength masonry. This masonry includes burnt clay brick or stone masonry in weak mortars, like clay-mud.
- The provisions of this standard are applicable in all seismic zones. No special provisions are considered necessary for buildings in seismic zone II.
- Low strength masonry dealt with based on this standard is termed non-engineered, and are not totally free from collapse under seismic shaking intensities VIII (MMI) and higher.
- IS 13920 (Code of Practice for Ductile Detailing of Reinforced Concrete Structures Subjected to Seismic Forces).
- This standard provides requirements for designing and detailing of reinforced concrete structures in order to equip them with adequate toughness and ductility to withstand serious earthquake shocks without collapse.
- The provisions for reinforced concrete construction given in this standard apply specifically to monolithic reinforced concrete construction. Precast and/or prestressed concrete members may be used only if they can provide the same level of ductility as that of a monolithic reinforced concrete construction during or after an earthquake.
- IS 13935 (Seismic Evaluation, Repair and Strengthening of Masonry Buildings – Guidelines)
- These guidelines cover general principles of seismic strengthening, selection of materials, and techniques for repair/seismic strengthening of masonry and wooden buildings.
- The code provides a brief coverage for individual reinforced concrete members in such buildings, but does not cover reinforced concrete frame or shear wall buildings as a whole. Some guidelines are also laid down for non-structural and architectural components of buildings.