03.SAFETY AND SERVICES
STRUCTURAL SAFETY AND SERVICES
27. STRUCTURAL DESIGN
For any building construction work under the jurisdiction of these bye-laws, structural design/retrofitting shall only be carried out by a Structural Engineer on Record (SER) or Structural Design Agency on Record (SDAR). Proof checking of various designs/reports shall be carried out by the Authority as per Table-VI wherever applicable. Generally, the structural design of foundations, elements of masonry, timber, plain concrete, reinforced concrete, pre-stressed concrete and structural steel shall conform to the provisions of part VI Structural Design Section-1 Loads, Section-2 foundation, Section-3 wood, Section-4 Masonry, Section-5 Concrete & Section-6 Steel of National Building Code of India (NBC), taking into consideration the Indian Standards as given below.
27.1For General Structural Safety:
i) IS: 456:2000”Code of Practice for Plain and Reinforced Concrete
ii) IS: 800-1984 “Code of Practice for General construction in Steel
iii) IS: 801-2975 “Code of Practice for Use of Cold formal Light Gauge Steel Structural Members in General Building Construction
iv) IS 875 (Part
2): 1987 Design Loads (other than earthquake) for buildings and structures Part 2 Imposed Loads
v) IS 875 (Part 3): 1987 Design Loads (other than earthquake) for buildings and structures Part 3 Wind Loads
vi) IS 875 (Part 4): 1987 Design Loads (other than earthquake) for buildings and structures Part 4 Snow Loads
vii) IS 875 (Part 5): 1987 Design Loads (other than earthquake) for buildings and structures Part 5 special Loads and Load Combination viii) IS: 883:1966 “Code of Practice for Design Structural Timber in Building
ix) IS: 1904:1987 “Code of Practice for Structural Safety of Buildings: foundation”
x) IS: 190:1987 “Code of Practice for Structural Safety of Buildings: Masonry Walls
xi) IS: 2911 (Part I): Section 1: 1979 “Code of Practice for Design and Construction of Pile Foundation Section 1 Part 1: Section 2 Based Cast-in-situ Piles Part 1: Section 3 Driven Pre-cast concrete Piles Part 1: Section 4 Based Pre-cast Concrete Piles Part 2: Timber Piles Part 3: Under Reamed Piles Part 4: Load Test on Piles
27.2 For Cyclone/Wind Storm Protection:
xii) IS: 875 (3)-1987 “code of Practice for Design Loads (other than earthquake) for Buildings and Structures, Part 3, Wind Loads” xiii) Guidelines (Based on IS 875 (3)-1987) for improving the Cyclonic Resistance of Low rise houses and other building
27.3 For Earthquake Protection:
xiv) IS: 1893-2002 “Criteria for Erthquake Resistant Design of Structures (Fifth Revision)’
xv) IS: 13920-1993 “Ductile Detailing of Reinforced Concrete Structures subjected to Seismic forces-Code of Practice”
xvi) IS: 43261993 “Earthquake Resistant Design and Construction of Buildings-Code of Practice (Second Revision)”
xvii) IS: 13828-1993 “Improving Earthquake Resistant of Low Strength Masonry Buildings-Guidelines”
xviii) IS: 138271993 “Improving Earthquake Resistant of Earthen Buildings-Guidelines”
xix) IS: 13935-1993 “Repair and Seismic Strengthening of Buildings-Guidelines”
27.4 For Protection of Landslide Hazard:
xx) IS: 14458 (Part 1): 1998 Guidelines for retaining wall for hill area: Part 1 Selection of type wall.
xxi) IS: 14458 (Part 2): 1997 Guidelines for retaining wall for hill area: Part 2 Design of retaining/breast wall.
xxii) IS: 14458 (Part 3): 1998 Guidelines for retaining wall for hill area: Part 3 Construction of dry stone walls
xxiii) IS: 14496 (Part 2): 1998 guidelines for preparation of landslide-Hazard zonation maps in mountains terrains: Part 2 Macro-zonation.
Note: Whenever an Indian Standard including those referred in the National Building Code or the Indian National Building Code is referred; the latest revision of the same shall be followed except specific criteria, if any, mentioned above against that code
28. Structural Design Basis Report:
In compliance of the design with the above Indian Standard, the Structural Engineer on Record will submit a structural design basis report in the format given in Appendix-B covering the essential safety requirements specified in the Standard.
29. Seismic Strengthening/Retrofitting:
Prior to seismic strengthening/retrofitting of any existing structure, evaluation of the existing structure as regards vulnerability in the specified wind/seismic hazard zone shall be carried out by a Registered Structural Engineer/Registered Structural Design Agency. If as per the evaluation of the Registered Structural Engineer/Registered Structural Design Agency, the seismic resistance is assessed to be less than the specified minimum seismic resistance as given in the note below, action will be initiated to carry out the upgrading of the seismic resistance of the building as per applicable standard guidelines.
Note: (a) for masonry buildings reference is to be made to IS:4326 and IS: 13935 and (b) for concrete buildings and structures reference to be made to BIS code on evaluation and seismic strengthening for retrofitting of RCC buildings under preparation at present.
30. Review of Structural Design:
(i) The Competent Authority shall create a Structural Design Review Panel (SDRP) consisting of Senior Structural Design Engineers on Record and Structural Design Agencies on Record, whose task will be to review and certify the design prepared by Structural Engineer on Record or Structural Design Agency on Record whenever referred by the competent authority.
(ii) The Reviewing Agency shall submit addendum to the certificate or a new certificate in case of subsequent changes in structural design
(iii) Table-VI Gives requirements of SDRP for structures of different complexities.
TABLE-VI PROOF CHECKING REQUIREMENTS FOR STRUCTURAL DESIGN
|TYPE OF STRUCTURE
||SUBMISSION FROM SER OR SDAR
||TO BE PROOF- CHECKED
||HIGHRISE BUILDING, BUILDINGS ABOVE 2000M2 PLINTH AREA AND MORE THAN GROUND + 3 (RCC/STEEL FRAME STRUCTURE)
||TO BE CHECKED
||TO BE CHECKED
||TO BE CHECKED
||PUBLIC BUILDINGS WITH MORE THAN 1000 M2 PLINTH AREA GROUND + 3 AND ABOVE
||TO BE CHECKED
||TO BE CHECKED
||TO BE CHECKED
||A. SPECIAL STRUCTURES
B. SPECIAL BUILDINGS
||TO BE CHECKED
||TO BE CHECKED
||TO BE CHECKED
SDBR- STRUCTURAL DESIGN BASIS REPORT
• Public building means assembly of large number of people including schools, hospitals, courts etc.
• Special structure means large span structures such as stadium, assembly halls, or tall structures such as water tanks, TV tower, chimney, etc. and the requirement by the Competent Authority for third party verification will depend on the type of structure.
All construction including load bearing buildings upto 3 storeys shall be carried out under supervision of the Construction Engineer on Record (CER) or Construction Management Agency on Record (CMAR).
32. Structural Requirements of Low Cost Housing:
Notwithstanding anything contained herein, for the structural safety and services for development of low cost housing, the relevant provisions of applicable IS Codes shall be enforced.
33. QUALITY OF MATERIALS AND WORKMANSHIP
All materials and workmanship shall be of good quality conforming generally to accepted standards of Bureau of Indian Standards Specification and codes as included in Part V Building Materials and part VIII Constructional Practices and Safety of National Building Code of India 2005.
34. QUALITY CONTROL AND INSPECTION
34.1. Inspection: - All the construction for buildings in Grade I and II, public buildings and special structures shall be carried out under quality inspection program prepared and implemented under the Quality Auditor on Record (QAR) or Quality Auditor Agency on Record (QAAR).
34.2. Certification of safety in quality of construction: - Quality auditor on Record (QAR) or Quality Auditor Agency on Record (QAAR) shall give a certificate of quality control as per proforma given in Appendix-D. Quality Inspection Programme to be carried on the site shall be worked out by Quality Auditor on Record/Quality Audit Agency on Record, in consultation with the owner, builder, Construction Engineer on Record/Construction Management Agency on Record.
35. BUILDING SERVICE
The planning, design and installation of lifts and escalators shall be carried out in accordance of part VIII Building Services, section 2 Electrical Installations, Section3Air Conditioning and heating, Section V Installation of lifts and Escalators of National Building Code of India 2005.
36. PLUMBING SERVICES
The planning, design, construction and installation of water supply, drainage and sanitation and gas supply system shall be in accordance with Part IX Plumbingservices Section I-Water supply, section 2-Drainage and sanitation and Section 3 – Gas supply of National Building Code of India 2005.
37. FIRE SAFETY DETECTION AND EXTINGUISHING SYSTEM
(i) The Authority while according permission shall follow the Code of Practice and Standards of Requirements recommended in the National Building Code of India. (ii) Fire protection and extinguishing system shall conform to accepted standards and shall be installed as recommended in the National Building Code of India and to the satisfaction of Directorate of Fire Services.
38. PROTECTION AGAINST HAZARDS
38.1. PROTECTION OF AREAS FROM EARTHQUAKES
i) In those areas where there are no dangers of soil liquefaction or settlements or landslides, all building structures and infrastructures in such areas should be designed using the relevant Indian Standards as provided in the Building Regulations and the National Building code.
ii) Soils subjected to liquefaction potential under earthquake shaking can be improved by compaction to desired relative densities, so as to prevent the possibility of liquefaction.
iii) Buildings and structures could be founded on deep bearing piles going to non- liquefiable dense layers.
iv) Steep slopes can be made more stable by terracing and construction of retaining walls and breast walls, and by ensuring good drainage of water so that the saturation of the hill slope is avoided.
v) Any other appropriate engineering intervention to save the building structures or infrastructure from the fury of the earthquake.
Note: The protective action given under (ii) and (v) will usually involve large amount of costs and should only be considered in the case of large and costly structures. For ordinary buildings the cost of improvement of the site will usually be uneconomical, hence bad sites should be excluded by Land Use Zoning.
38.2. PROTECTION FROM CYCLONIC WIND DAMAGE
i) Buildings, structures and infrastructures in the cyclone prone areas should be designed according to the Indian Standards and Guidelines as provided in the Regulations and the National Building code.
ii) Light utility structures used for electrical transmission and distribution and towers for communications, chimney stacks of industrial structures require special design considerations against the cyclonic wind pressure, suctions and uplifts.
iii) In case the buildings, structures and infrastructures are founded on marine clay deposits it will be advisable to adopt either under-reamed or long piles which should penetrate the marine clay layer and rest on dense sand stratum, or individual column footing with a reinforced concrete beam located at the level of the ground, or a continuous reinforced concrete strip footing, using a very low bearing pressure.
iv) Wherever the topsoil could become slushy due to flooding, the top layer of 30 cm depth of soil should not be considered for providing lateral stability.\ v) In storm surge prone areas, it will be preferable to construct the community structures, like schools, cyclone shelters, etc. by raising the level of the ground protected by provision of retaining walls at sufficient distance away from the building taken to such depth that no erosion takes place due to receding storm surge. Alternatively, construct the community structures on stilts with no masonry or bracing upto the probable maximum surge level.
38.3. PROTECTION OF AREAS FROM FLOODS
this may require one or more of the following actions:
i) Construction of embankments against the water spills from the source of flooding like rivers, large drains etc.
ii) Construction of high enough embankments/bund around the planning area.
iii) Raising the planning area above the high flood level.
iv) Construction/improvement of drainage paths to effectively drain the water from the planning area.
v) Construction of buildings and structures on deep foundations going below the depth of scour or on stilts with deep enough foundations under water.
vi) Flood proofing works such as the following: Providing Quick Drainage facility, consisting of •
Revitalization of secondary and primary drainage channels after establishing the drainage blockage points;
• Provision of additional waterways;
• Clearing of clogged cross drainage works; Providing Human and Animal Shelters for population living within embankments in the form of raised platform or use of available high ground. vii) Anti-erosion actions in affected areas.
viii) Any other suitable measure. Note: Similar protection methods could be used against flooding caused in cyclone prone areas by high intensity rains or by the storm surge. The concept of land zoning should be kept in mind for areas where protection works are taken up to decide inter-se priority for location of structures considering possibility of failure of protection works during extreme disaster events.