06.STRUCTURAL SAFETY



PROVISIONS FOR STRUCTURAL SAFETY  

6.1 Structural design and safety

For any building under the jurisdiction of these regulations 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 competent authority as per Table 6.1 wherever applicable.

6.1.1 Additional provisions in building regulations/ bye-laws for natural hazard prone areas

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 6: Structural D–sign -

Section– 1 Loads, Forces and Effects

Section– 2 Soils and Foundations,  

Section– 3 Timber and Bamboo,  

Section– 4 Masonry,  

Section– 5 Concrete &  

Section– 6 Steel  

Section– 7 Prefabrication Systems, Building and Mixed /Composite Construction of National Building Code of India (NBC), taking into consideration the Indian Standards as given below:  

For General Structural Safety

1) IS: 456:2000 “Code of Practice for Plain and Reinforced Concrete.

2) IS: 800-2007 “Code of Practice for General Construction in Steel. ]

3) IS: 801-1975 “Code of Practice for Use of Cold Formal Light Gauge Steel Structural Members in General Building Construction.

4) IS 875 (Part 2):1987 Design loads (other than earthquake) for buildings and structures Part2 Imposed Loads. (Reference to Table 4.1- “Occupant Load” may be considered for design load)

5) IS 875 (Part 3):1987 Design loads (other than earthquake) for buildings and structures Part 3 Wind Loads.

6) IS 875 (Part 4):1987 Design loads (other than earthquake) for buildings and structures Part 4 Snow Loads.

7) IS 875 (Part 5):1987 Design loads (other than earthquake) for buildings and structures Part 5 special loads and load combination.

8) IS: 883:1994 “Code of Practice for Design of Structural Timber in Building.

9) IS: 1904:1986 (R 2005) “Code of Practice for Structural Safety of Buildings: Foundation”

10) IS 1905:1987 “Code of Practice for Structural Safety of Buildings: Masonry Walls.

11) IS 2911(Part 1): Section 1: 2010 “Code of Practice for Design and

Construction of Pile Foundation Section 1

Part 1:    Section 2 Bored Cast-in-situ Piles

Part 1:    Section 3 Driven Precast Concrete Piles

Part 1:    Section 4 Bored Precast Concrete Piles

Part 2:    Timber Piles

Part 3:    Under Reamed Piles

Part 4:    Load Test on Piles

For Cyclone/Wind Storm Protection

12) IS 875 (3):1987 "Code of Practice for Design Loads (other than Earthquake) for Buildings and Structures, Part 3, Wind Loads"

13) Guidelines (Based on IS 875 (3)-1987) for improving the Cyclonic Resistance of Low rise houses and other building. For Earthquake Protection

14) IS: 1893 (Part 1)-2002 "Criteria for Earthquake Resistant Design of Structures (Fifth Revision)"

15) IS:13920-1993  "Ductile  Detailing  of  Reinforced  Concrete  Structures subjected to Seismic Forces - Code of Practice"

16) IS:4326-2013 "Earthquake Resistant Design and Construction of Buildings - Code of Practice (Second Revision)"

17) IS:13828-1993   "Improving   Earthquake   Resistance   of   Low   Strength Masonry Buildings - Guidelines"

18) IS:13827:1993 "Improving Earthquake Resistance of Earthen BuildingsGuidelines"

19) IS:13935-2009 "Seismic Evaluation, Repair and Seismic Strengthening of Buildings -Guidelines” For Protection of Landslide Hazard

20) IS 14458 (Part 1): 1998 Guidelines for retaining wall for hill area: Part 1 Selection of type of wall.

21) IS 14458 (Part 2): 1997 Guidelines for retaining wall for hill area: Part 2 Design of retaining/breast walls

22) IS 14458 (Part 3): 1998 Guidelines for retaining wall for hill area: Part 3 Construction of dry stone walls

23) IS 14496 (Part 2): 1998 Guidelines for preparation of landslide – Hazard zonation maps in mountainous terrains: Part 2 Macro-zonation.  

Note:  Whenever an Indian Standard including those referred in the National Building Code or the National Building Code is referred, the latest revision of the same shall be followed except specific criteria, if any, mentioned above against that code

6.1.2 Structural Design Basis Report (SDBR)

In compliance of the design with the above Indian Standard, the Structural Engineer on Record will submit a structural design basis report in the Proforma attached herewith covering the essential safety requirements specified in the Standard.

The “Structural Design Basis Report (SDBR)”consists of four parts (FormNo.6, MHA Expert Committee Report)

Part 1:    General Information/ Data      

Part 2:    Load Bearing Masonry Buildings    

Part 3:   Reinforced Concrete Buildings  

Part 4:    Steel Buildings

i) Drawings and Documents to be submitted for approval of appropriate authorities shall include SDBR as detailed bow:  

Part 1:   Completed  

Part 2:   (if applicable) – completed  

Part 3:  (if applicable) – undertaking that completed Part 3 will be submitted   before commencement of construction.

Part 4:   (if applicable) – undertaking that completed Part 4 will be submitted before commencement of construction.

ii) SDBR as detailed below shall be submitted to the appropriate authority as soon as design of foundation is completed, but not later than one month prior to commencement of construction.  

Part 1:    Completed  

Part-2, Part-3 or Part-4:    (if applicable) Completed

6.1.3 Seismic strengthening/retrofitting

Prior to seismic strengthening/retrofitting of any existing structure, evaluation of the existing structure as regards structural vulnerability in the specified wind/seismic hazard zone shall be carried out by a RSE/RSDA. If as per the evaluation of the RSE/RSDA 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:  

1. For masonry buildings reference shall be made to IS 4326 and IS 13935  

2. For concrete buildings and structures reference shall be made to IS15988: 2013 Seismic evaluation and strengthening of existing RCC buildings.  

6.1.4 Buildings with Soft Storey

In case buildings with a flexible storeys, such as the ground storey consisting of open spaces for parking that is “Stilt buildings” or any other storey with open halls, special arrangements are to be made to increase the lateral strength and stiffness of the soft/open storey such as Steel bracing / Shear walls / Brick infills between columns.

Dynamic analysis of building is to be carried out including the strength and stiffness effects of infills and inelastic deformations in the members, particularly, those in the soft storey, and the structural members are to be designed accordingly.

Alternatively, the following design criteria are to be adopted after carrying out the earthquake analysis, neglecting the effect of infill walls in other storeys:

a. The columns and beams of the soft storey shall be designed for 2.5 times the storey shears and moments, calculated under seismic loads specified in the other relevant clauses; or,

b. Besides the columns designed and detailed for the calculated storey shears and moments, shear walls shall be placed symmetrically in both directions of the building as far away from the centre of the building as feasible; to be designed exclusively for 1.5 times the lateral storey shear force calculated as before. For details of design and provisions, IS 1893, Part 1 shall be referred.  

6.1.5 Review of structural design

i) The Competent Authority shall create a Structural Design Review Panel (SDRP) consisting of senior SER’s and SDAR’s whose task will be to review and certify the design prepared by SER or SDAR 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-6.1 gives requirements of SDRP for different seismic zones namely III, IV and V and for structures of different complexities.

iv) In seismic Zone II, buildings & structures greater than 40m in height will require proof checking by SDRP as per detail at Sl. no.3 of Table 6.1

Table 6.1 Proof Checking Requirements for Structural Design

Sl. No.  Type of Structure Submission from SER or SDAR  To be Proof Checked 
1 Load Bearing Buildings upto three storeys  SDBR- Not to be checked
2 Buildings upto seven storeys (R.C.C/Steel framed structure) SDBR To be checked
Preliminary design To be checked
3 Building greater than seven storeys (R.C.C/Steel framed structure)  SDBR To be checked
Preliminary design To be checked
Detailed structural design and structural drawings To be checked
4 Special Structures  SDBR To be checked
Preliminary design To be checked
Detailed structural design and structural drawings To be checked

* SDBR – Structural Design Basis Report  

Notes:

1. Table 4.1 may be referred for Occupant Load/Live load for different building types.

2. At the preliminary proposal stage of a project, the objective is to undertake feasibility study/comparison of a number of possible alternatives of structural schemes and determine the most cost effective one, detailed structural calculations are not necessary for each alternative scheme. However, it is necessary to determine the member sizes and reinforcement content in order to determine the cost. By making conservative assumptions it is possible to derive simplified calculations for both analysis and design. This is called “Preliminary or approximate analysis, and design”.

After the most cost effective scheme is selected and signed-off by the Client, the detailed calculations are performed on the selected scheme to determine the precise structural members and composition (size, dimension and stress behavior), and this is called the “Detailed structural design”. In the aforesaid, the design of structural members is typically assumed to account for all the stress loads identified from section xx to be applicable in the given project.

3. Special structure means large span structures such as stadium, assembly halls, or tall structures such as water tanks, TV tower, chimney, etc. 

It will be seen from the Table 6.1 above that there is a wide range of structure typology, and the requirement by the Competent Authority for third party verification will depend on the type of structure.

6.1.6 Certification regarding structural safety in design

Structural Engineer on Record (SER) or Structural Design Agency on Record (SDAR) shall give a certificate of structural safety of design as per proforma given in Form-3 and Form 14 (of the MHA Expert Committee Report) at the time of completion.

6.1.7 Constructional safety

6.1.7.1 Supervsion  

All construction except 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) for various seismic zones.

6.1.7.2 Certification of structural safety in constrution  

CER/ CMAR shall give a certificate of structural safety of construction as per proforma given in Form-13 (of the MHA Expert Committee Report) at the time of completion.

6.1.8 Quality control and inspection  

All material and workmanship shall be of good quality conforming generally to accepted standards of Public Works Department and Indian standard specification and codes as included in Part-V Building Materials and Part-VII Construction practices and safety of National Building Code of India.

6.1.8.1 Inspection

All the construction for high-rise buildings higher than seven storeys, 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) in seismic zones IV & V.

6.1.8.2 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 Form-15. Quality Inspection Programme to be carried on the site shall be worked out by QAR/ QAAR in consultation with the owner, builder, CER / CMAR.

Note: Sections 6.1.7 and 6.1.8 shall not be applicable for Government buildings that are designed and constructed under the supervision of in-house architects/engineers.

6.1.9 Control of signage & outdoor display structures, cellphone towers and telephone towers.  

Following provisions shall apply for telecommunication infrastructure-

a) Location: The Telecommunication Infrastructure shall be either placed on the building roof tops or on the ground or open space within the premises subject to other regulations.

b) Type of structure

i) Steel fabricated tower or antennae’s on M.S. pole. 

ii) Pre-fabricated shelters of fibre glass or P.V.C. on the building roof top / terrace for equipment.

iii) Masonry Structure/ Shelter on the ground for equipment.

iv) D.G. Set with sound proof cover to reduce the noise level.

c) Requirement:

i) Every applicant has to obtain/ procure the necessary permission from the “Standing Advisory Committee on Radio Frequency Allocation” (SACFA) issued by Ministry of Telecommunications.

ii) Every applicant will have to produce the structural safety & stability certificate for the tower as well as the building from the Structural Engineer on Record (SER) which shall be the liability of both owner and SER.

iii) Applicant has to produce / submit plans of structure to be erected.

d) Projection: No Pager and/or Telephone Tower shall project beyond the existing building line of the building on which it is erected in any direction.

6.2 Structural requirements of low income housing

Notwithstanding anything contained herein, for the structural safety and services for development of low income housing, the relevant provisions of applicable IS:8888 Part 1 shall be enforced alongwith Annex C of Part 3 NBC, 2005.  

6.3 Inspection

The general requirement for inspection of the development shall also include the following regulation.

6.3.1 General Requirements

The building unit intended to be developed shall be in conformity with Regulation on requirement of site. Generally all development work for which permission is required shall be subject to inspection by the Competent Authority as deemed fit. The applicant shall keep a board at site of development mentioning the survey No, city survey No, Block No, Final Plot No., Sub plot No., etc. name of owner and name of Architect on Record, Engineer on Record, Developer, Structural Engineer on Record, Construction Engineer on Record.

6.3.2 Record of Construction Progress

a) Stages for recording progress certificate and checking:-

i) Plinth, in case of basement before the casting of basement slab.

ii) First storey.

iii) Middle storey in case of High-rise building.

iv) Last storey.

b) At each of the above stages, the Owner / Developer / Builder shall submit to the designated officer of the Competent Authority a progress certificate in the given formats (Form No. 7-10, of the MHA Expert Committee Report). This progress certificate shall be signed by the Construction Engineer on Record.

c) The progress certificate shall not be necessary in the following cases:

i) Alteration in Building not involving the structural part of the building.

ii) Extension of existing residential building on the ground floor upto maximum 15 sq mt. in area.

d) Completion Report

i) It shall be incumbent on every applicant whose plans have been approved, to submit a completion report in Form No.11 (of the MHA Expert Committee Report)

ii) It shall also be incumbent on every person / agency who is engaged under this Development Control Regulations to supervise the erection or reerection of the building, to submit the completion report in Form No.12 and 13 (of the MHA Expert Committee Report) prescribed under these Development Control Regulations.

iii) No completion report shall be accepted unless completion plan is approved by   the Competent Authority.

e) The final inspection of the work shall be made by the concerned Competent Authority within 21 days from the date of receipt of notice of completion report.

6.3.3 Permission for Building Occupancy and Certification

The Authority issuing occupancy certificate before doing so shall ensure that following are compiled from consideration of safety against natural hazard:

i) Certificate of lift Inspector has been procured & submitted by the owner, regarding satisfactory erection of Lift.

ii) The Certificate of Competent Authority and or fire department for completion and or fire requirements as provided in these regulations has been procured and submitted by the owner.

iii) If any project consists of more than one detached or semi detached building/buildings in a building unit and any building / buildings thereof is completed as per provisions of D.C.R. (Such as Parking, Common Plots, Internal Roads, Height of the Building, Infrastructure facilities, lift and fire safety measures), the competent authority may issue completion certificate for such one detached or semi detached building / buildings in a building unit.

iv) The occupancy certificate shall not be issued unless the information is supplied by the Owner and the Architect on Record/ Engineer on Record concerned in the schedule as prescribed by the Competent Authority from time to time.

6.3.4 Maintenance of Buildings  

In case of building older than fifty years, it shall be the duty of the owner of a building, to get his building inspected by a Registered Structural Engineer (RSE) within a year from the date of coming into force of these regulations. The Structural Inspection Report (Form No.16, of the MHA Expert Committee Report) shall be produced by the Owner to the Appropriate Authority. If any action, for ensuring the structural safety and stability of the building is to be taken, as recommended by SER, it shall be completed within five years. For other buildings, the owner shall get his building inspected after the age of building has crossed forty years. The procedure shall be followed as per above regulation. 

6.3.5 Protective Measures in Natural Hazard Prone areas 

In natural hazard prone areas identified under the land use zoning regulations, structures buildings and installations which cannot be avoided, protective measures for such construction/development should be properly safeguarded based on the suggestion given in the Report of the MHA Expert Committee - Volume I. 

6.3.6 Registration of Professionals 

Presently, the legislation for the profession of architecture is applicable in the country in the form of Architects Act 1972, an Act of the Parliament of India. Accordingly, the qualifications, competence and service conditions followed in the profession of architecture are in accordance with the provisions of the said Act and the rules made thereunder. For other professions and professionals like engineers, structural engineers, landscape architects, urban designers, building supervisors, electrical engineers, developers/promoters there is no legislative frame available/applicable. Therefore, for appropriate qualifications, competence and responsibilities of professional involved in different types of development proposals shall be applicable as per Appendix ‘E’ Registration: Qualifications and Competence of Professionals  and methods of determination of  professional fees are suggested in clause 6.3.7. 

6.3.7 Professional fees for SER/SDAR and CER/CMAR

Selection of professionals and determination of professional charges shall be done by the Authority, considering the following:

i) Structural safety of a building is the responsibility of the “SER/SDAR” for proper design and the “CER/CMAR” for proper construction, therefore it is imperative that selection and appointment of these professionals is made after verification of their antecedents.

ii) The fees to be paid to SER/SDAR for structural design may be specified keeping in view the size and complexity of the project.

iii) Similarly, fees for construction management to CER/CMAR may be specified keeping in view the size and complexity of the project and the duration for which construction management services have to be provided on the basis of the total cost of the project.

iv) Proof checking: Fees for Proof checking where carried out may vary based on the cost of the structural items enumerated in (ii) above

6.3.8 Appointment of Professionals

The Owner/Developer shall appoint Town Planner on Record (TPR), Architect on Record (AR), Engineer on Record (ER), Structural Engineer on Record (SER), Structural Design Agency on Record (SDAR), Geotechnical Engineer on Record (GER), Construction Engineer on Record (CER), (CMAR), and Quality Auditor on Record (QAR) and Quality Audit Agency on Record (QAAR) as required. Details of qualification and requirement of registration shall be as given in Appendix ‘E’. Proper written agreement(s), in standard format(s), shall be entered upon with such professional(s) engaged

6.4 Alternative Materials, Methods of Design and Construction and Tests 

The provision of the Bye-Laws are not intended to prevent the use of any material or method of design or construction not specifically prescribed by the bye-law provided any such alternative has been approved. The building materials approved by B.I.S. or any statutory body will form part of the approved building material and technology as part of the Bye-Laws.  

The Authority shall promote and encourage use of Pre-fabricated factory made building components for medium to large scale projects that have significant impact. The use of ready mix concrete (RMC) shall also be encouraged for in-situ concrete constructions.  

Section 10.2.5 may be referred for further aspects of Sustainability and incentivized promotion of alternative materials, methods in construction. 

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