IS 16700:2017 is the Indian Standard (BIS) for general principles of design for structures. This code provides comprehensive guidelines for ensuring the durability of concrete structures. It introduces a detailed system for classifying environmental exposure conditions and specifies corresponding requirements for concrete constituents, mix proportions, reinforcement cover, and quality assurance to achieve a target service life by mitigating deterioration mechanisms like reinforcement corrosion, sulphate attack, and alkali-aggregate reaction.
Lays down general principles and requirements for the design of structures, including safety, serviceability, and durability.
Criteria for the structural design of tall buildings (> 50 m or > 15 storeys). Drift, accelerations, dynamic analysis.
| Reference | Value | Clause |
|---|---|---|
| Scope — applicability | buildings > 50 m or > 15 storeys | Cl. 1.2 |
| Maximum height covered— above which special studies / wind tunnel | 250 m | Cl. 1.2 |
| Wind tunnel test required | buildings > 150 m or unusual shape | Cl. 4.4.1 |
| Dynamic wind analysis required | all heights covered | Cl. 4.4 |
| Seismic — dynamic analysis mandatory | all heights covered | Cl. 5.2 (refers IS 1893) |
| Storey drift limit — wind (serviceability) | H/500 | Cl. 6.2.2 |
| Storey drift limit — earthquake (design) | 0.004 × storey height | Cl. 6.2.3 (refers IS 1893) |
| Inter-storey drift — sensitive partitions | H/500 | Cl. 6.2.4 |
| Peak occupant acceleration — residential | ≤ 0.15 % g (1-yr return) | Cl. 6.3 (Table 4) |
| Peak occupant acceleration — office | ≤ 0.25 % g (1-yr return) | Cl. 6.3 (Table 4) |
| Damping ratio — RCC tall building | 1.5–2.5 % (lower than 5 %) | Cl. 5.2.6 |
| Damping ratio — composite | 1.5–2 % | Cl. 5.2.6 |
| Aspect ratio — slenderness check | H/B ≤ 6 (no special analysis) | Cl. 4.5.1 |
| P-Δ analysis — when required | stability index θ ≥ 0.05 | Cl. 5.3.2 |
| Concrete grade — minimum (M50+) | M50 typical for vertical members | Cl. 7.2.1 |
| Steel grade — minimum HYSD | Fe-500D (ductile) for SMRF / shear walls | Cl. 7.2.2 (refers IS 13920) |
| Outrigger systems — analysis | explicitly modelled | Cl. 8.4 |
| Base isolation — permitted | Yes (subject to specialist design) | Cl. 9 |
| Time-history analysis — number of records | min 7 (or 3 with 100 % envelope) | Cl. 5.4.3 |
| Performance check — periodic monitoring | vibration / drift sensors recommended | Cl. 12 |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
IS 16700 specifies the structural safety criteria for tall concrete buildings in India — buildings whose height exceeds 50 m or whose height-to-least-base-width ratio exceeds 4 (whichever criterion is met first). It supplements but does not replace the parent design codes (IS 456, IS 13920, IS 1893 Part 1, IS 875 Parts 1-5) — IS 16700 layers on additional analysis, design, and detailing requirements specifically for tall buildings where wind, seismic, gravity P-Δ effects, and serviceability all become governing rather than incidental.
Apply IS 16700 when: - High-rise residential or commercial > 50 m height (typically 15+ storeys) - Slender towers with H/B > 4 - Mixed-use podium + tower complexes where the tower exceeds the threshold - Hotel, office, hospital towers in tier-1 cities with seismic Zone III-V exposure
IS 16700 is the BIS counterpart to international tall-building codes (e.g., LATBSDC in California, CTBUH guidelines). It was published in 2017 to address the rapid growth of high-rise construction in Mumbai, Bangalore, Hyderabad, Delhi-NCR, and similar cities.
Structural system selection (Clause 5): - Up to 50 m: any system per IS 1893 — moment frame, shear wall, dual. - 50-100 m: dual system (frame + shear wall OR frame + core) recommended; pure moment frames generally unsuitable. - 100-150 m: dual system mandatory; outrigger / belt truss often required to control drift. - > 150 m: tube-in-tube, bundled tube, or composite framing typical; outrigger systems standard.
Analysis requirements (Clause 6): - 3D dynamic analysis mandatory (response spectrum minimum; time-history analysis for buildings > 150 m or irregular plan/elevation) - Account for P-Δ effects when stability index θ > 0.10 (Clause 6.4) - Diaphragm flexibility analysis when L/B > 3 in floor plan or when floor has large openings - Cracked-section properties: 0.7 × I_g for beams, 0.5 × I_g for slabs, 0.7 × I_g for walls (Clause 6.5)
Wind design (cross-reference IS 875 Part 3): - Tall slender buildings: dynamic analysis for along-wind response (gust factor method, IS 875 Part 3 Annex) - Across-wind and torsional response: required for H/B > 4 OR fundamental period > 1 s (vortex shedding check) - Wind tunnel testing required (IS 16700 Clause 7.5) for buildings > 150 m, complex shapes, or multi-tower complexes with aerodynamic interference
Seismic design (cross-reference IS 1893 Part 1 and IS 13920): - Performance-based seismic design (PBSD) recommended for buildings > 100 m in Zones IV-V - Mass and stiffness eccentricity must be checked for plan irregularity (IS 1893 Clause 7) - All RC walls and frames in seismic zones III-V must follow IS 13920:2016 ductile detailing
Drift / deflection limits: - Inter-storey drift under wind (serviceability): H/500 (Clause 7.6) - Inter-storey drift under design earthquake (DBE): H/250 per IS 1893 Clause 7.11 - Acceleration at top floor under wind (occupant comfort): 15-25 milli-g for residential / hotel, 25-40 milli-g for commercial (IS 16700 Annex C)
Concrete grades (Clause 8): - Minimum M30 for all structural elements in tall buildings (vs M20 in IS 456 general) - Vertical members in lower 1/3 of building: M40-M60 typical - Walls and core: M50-M80 in 100 m+ buildings (matched to required axial capacity and creep limits) - Mix design per IS 10262:2019; admixtures per IS 9103:1999
Steel grades: - Reinforcement: Fe 500D minimum (IS 1786:2008); Fe 550D in seismic zones IV-V high-confinement zones - Structural steel (composite or steel members): IS 2062:2011 E 350+ grade
Slab system: - Flat slab + drop common; punching shear governs near columns (IS 456 Clause 31) - Post-tensioned slabs widely used to reduce slab depth and weight - Span-to-depth ratio limit per IS 456 Clause 23; IS 16700 tightens for vibration control
Shear wall design (Clause 9): - Boundary elements (confined ends) per IS 13920 Clause 9 - Wall thickness ≥ 200 mm (IS 13920 minimum); typically 300-500 mm in tall buildings - Minimum reinforcement: 0.25 % each direction, 0.40 % vertical at boundary elements
Foundation (Clause 10): - Raft + piles common for tall buildings - Differential settlement limit: < L/1000 between adjacent columns (more stringent than IS 1080) - Pile load tests per IS 2911 Part 4 mandatory - Soil-structure interaction analysis required for buildings on soft soil (Class C or D site per IS 1893)
1. Treating IS 16700 as optional 'guideline'. It is mandatory once height or slenderness thresholds are crossed. Approving authorities (BMC, BBMP, TPMS, GHMC) increasingly require IS 16700 compliance certificates. 2. Skipping wind tunnel testing on > 150 m or unusual-shape buildings. The code-based wind loads from IS 875 Part 3 are tied to standard rectangular plans. Twisted, bent, or stepped towers have very different actual wind response. 3. Static-only seismic analysis on tall buildings. IS 1893 mandates dynamic analysis (response spectrum at minimum) for buildings > 40 m. Equivalent static method is invalid. 4. Ignoring P-Δ effects. Stability index θ > 0.10 (Clause 6.4) requires P-Δ in analysis; θ > 0.20 indicates the structure is too flexible — redesign for stiffness, not just for additional moment. 5. Inadequate diaphragm modelling on flat-slab buildings with large openings. Rigid-diaphragm assumption breaks down; lateral forces don't distribute as intended. Use semi-rigid or flexible diaphragm in 3D model. 6. Cracked-section stiffness ignored in serviceability drift checks. Using gross section gives drift estimates 30-50 % too low. Apply IS 16700 Clause 6.5 reduced stiffness factors. 7. Outrigger floors not modelled correctly. Outrigger trusses have major effect on building period and drift; their stiffness must be modelled accurately, including connection flexibility. 8. Pile group settlement not differentiated from single-pile capacity. Tall building rafts on piles develop group action — the group settles more than a single pile of the same load. Run group settlement analysis. 9. Wind-induced acceleration not checked for occupant comfort. Top-floor acceleration > 25 milli-g causes nausea / dizziness in occupants. Specify and verify per IS 16700 Annex C / ISO 6897. 10. Skipping irregularity penalty for asymmetric stiffness or mass. IS 1893 Clause 7 requires response-spectrum analysis to capture torsion; symmetric assumption + plan irregularity = unsafe design.
Typical tall-building design cascade:
1. Concept — architectural form, target height, plan dimensions, slenderness ratio. Determine if IS 16700 applies. 2. Structural system — moment frame / shear wall / dual / outrigger / tube selection per height (IS 16700 Clause 5). 3. Preliminary design — gravity load take-down, member sizing for axial capacity. 4. Geotechnical investigation — borings, SPT, c_u; raft / pile / mixed foundation choice. 5. 3D structural model — stiffness inputs include cracked sections (IS 16700 Clause 6.5). 6. Wind analysis — IS 875 Part 3 gust factor + dynamic; wind tunnel for height > 150 m or unusual shape. 7. Seismic analysis — response spectrum (IS 1893); time-history for buildings > 150 m or Zones IV-V critical. 8. Drift and acceleration check — H/500 wind (SLS), H/250 seismic; occupant comfort acceleration (Annex C). 9. Member design — IS 456 + IS 13920; verify boundary elements and confinement. 10. Foundation design — raft / pile per IS 1080 / IS 2911; settlement limit L/1000. 11. Pile load testing — initial + routine per IS 2911 Part 4. 12. Detailed reinforcement drawings — every joint detailed per IS 13920. 13. Construction QA — concrete acceptance per IS 456, integrity tests on piles, regular inspection per project QA plan. 14. Post-construction — vibration / acceleration monitoring on instrumented buildings; periodic structural health review.
IS 16700 is the layer that ties these all together for the > 50 m / H/B > 4 regime. For shorter buildings, the conventional IS 456 + IS 13920 + IS 1893 trio suffices.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Design Working Life | 100 years (Clause 5.3) | 50 years for standard buildings; 100 years for monumental buildings. | EN 1990:2002 |
| Trigger for Mandatory Wind Tunnel Test | Building height > 150 m (Clause 7.2.2) | Based on susceptibility to wind effects (e.g., flexible structures), not a single height threshold. | ASCE/SEI 7-16 |
| MCE Inter-Story Drift Limit | 0.004h (0.4%) for Life Safety (Clause 11.2.2) | Can be up to 0.025h - 0.03h (2.5% - 3%) for Collapse Prevention. | CTBUH Technical Guide 2017 |
| Primary Seismic Analysis for MCE | Non-linear Time History Analysis (NLTHA) is required (Clause 8.3.3) | NLTHA is the standard for Performance-Based Design, which is typical for landmark tall buildings. | CTBUH Technical Guide 2017 |
| Load Factor for Dead Load (DL) + Seismic (E) | 1.2 (DL + IL + E) or 1.5 (DL + E) or 0.9 DL + 1.5 E (ref IS 1893) | (1.2 + 0.2*SDS)*DL + 1.0*E (specific combinations vary) | ASCE/SEI 7-16 |
| Requirement for Peer Review | Mandatory for all aspects of structural design (Clause 12.1) | Commonly required by Authorities Having Jurisdiction for complex PBD projects; not universally mandated by the code itself. | General Practice with ASCE/SEI 7-16 |