IS 875 Part 2 · Loads
Live Load on Structures — IS 875 Part 2 Complete Guide with 10 GATE MCQs
⏱ 16 min read📅 June 2026✅ IS 875 Part 2:1987🎓 GATE relevant
Live load (imposed load) represents the weight of people, furniture, stored materials, and movable equipment on a floor. Unlike dead load, live load is variable — a room may be empty today and fully furnished tomorrow. IS 875 Part 2 specifies the minimum live loads to be assumed for different occupancy types, and these values directly affect the design of every slab, beam, column, and foundation in the building. This guide covers the complete live load table, reduction factors for large areas and multi-storey columns, three practical examples, and 10 GATE MCQs.
1. Introduction
Every structural design begins with loads. Dead load is fixed once you decide the slab thickness and wall materials, but live load depends entirely on how the building will be used. A hospital corridor must be designed for heavier live loads (4 kN/m²) than a residential bedroom (2 kN/m²), because hospitals may have stretchers, medical equipment, and concentrated groups of people. IS 875 Part 2 provides standardised minimum values so that every engineer uses the same baseline.
2. Concept and Theory
What does live load include?
Live load includes all loads that are not permanently fixed — people, furniture, movable partitions, stored goods, vehicles (in parking), and equipment that can be relocated. It does not include earthquake or wind forces (those are separate lateral loads), dead load (permanent weight of structure and finishes), or construction loads (temporary, handled separately).
Why live loads can be reduced for large areas
The probability that every square metre of a large floor will be loaded to the maximum simultaneously is very low. A 10m² room might be fully occupied, but a 200m² hall is unlikely to have maximum load everywhere at once. IS 875 allows a reduction in live load for floor areas larger than 50m² — this is the floor area reduction factor. Similarly, a ground floor column in a 10-storey building supports the cumulative live load from all floors above, but it is statistically unlikely that all 10 floors are fully loaded simultaneously. IS 875 allows a storey-based reduction for columns.
3. IS Code Background
| Clause | Subject | Plain English |
|---|
| Table 1 | Floor loads | Lists minimum live loads for residential, office, assembly, industrial, hospital, educational, and other occupancies. |
| Cl 3.2 | Concentrated load | Some occupancies require checking for a concentrated load on a small area (e.g., 2.7 kN on 300×300mm for office floors). |
| Cl 3.3 | Reduction for large areas | For floors with area > 50m², live load can be reduced by 5% per 10m² (or as per formula), up to a maximum reduction of 25%. |
| Cl 3.4 | Reduction for columns | For columns/walls supporting multiple floors, live load on floors above can be reduced based on number of floors supported. |
4. Key Formulas
Total Load on a Slab
Total load = DL + LL (kN/m²)
Factored load wu = 1.5 × (DL + LL) for IS 456 limit state
DL includes: slab self-weight + floor finish + partition load
LL from IS 875 Part 2 Table 1 based on occupancy
Live Load Reduction — Large Floor Area
Reduced LL = LL × (1 − reduction%)
Max reduction = 25% for areas > 100m²
No reduction for storage, warehouse, or garage loads
Live Load Reduction — Multi-Storey Columns
Number of floors: 1–2 → no reduction
3–5 floors → 10% reduction
6–10 floors → 20% reduction
Above 10 floors → 30% reduction (max)
Applied to the total live load from all contributing floors
5. Live Load Tables (IS 875 Part 2)
| Occupancy Type | UDL (kN/m²) | Concentrated (kN) |
|---|
| Residential — bedrooms, living rooms | 2.0 | 1.8 |
| Residential — kitchen, toilet, balconies | 2.0 | 1.8 |
| Residential — corridors, stairs | 3.0 | 4.5 |
| Office — general | 2.5 | 2.7 |
| Office — with heavy filing/storage | 5.0 | 4.5 |
| Shop floor (retail) | 4.0 | 3.6 |
| Assembly — with fixed seating (cinema, theatre) | 4.0 | — |
| Assembly — without fixed seating (exhibition hall) | 5.0 | 3.6 |
| Educational — classrooms | 3.0 | 2.7 |
| Hospital — wards | 2.0 | 1.8 |
| Hospital — corridors, operating rooms | 4.0 | 4.5 |
| Industrial — light | 5.0 | 4.5 |
| Industrial — heavy | 10.0 | 9.0 |
| Garages — light vehicles | 2.5 | 9.0 (on 300×300mm) |
| Accessible roof (terrace garden) | 1.5 | — |
| Inaccessible roof | 0.75 | — |
6. Load Calculation Procedure
- Identify occupancy type for each room/zone from architectural drawings.
- Look up UDL from IS 875 Part 2 Table 1.
- Calculate dead load: slab self-weight (25×D kN/m²) + floor finish (typically 1.0–1.5 kN/m²) + partition load (0.5–1.5 kN/m² for lightweight).
- Combine: total service load = DL + LL.
- Factor: wu = 1.5 × (DL + LL) for limit state design.
- Apply reductions if applicable (large area, multi-storey columns).
7. Worked Examples
Example 1 — Residential Slab Load (Beginner)
A 150mm thick slab for a residential bedroom. Floor finish = 1.0 kN/m².
Dead Load
Slab = 25 × 0.15 = 3.75 kN/m²
Finish = 1.0 kN/m²
Total DL =
4.75 kN/m²Live Load
LL = 2.0 kN/m² (residential bedroom)
Factored Load
w
u = 1.5 × (4.75 + 2.0) =
10.125 kN/m²
Example 2 — Office Building Column Load (Intermediate)
Interior column in a G+6 office building. Each floor area tributary to column = 25m². Slab = 150mm, finish = 1.5 kN/m², LL = 2.5 kN/m². Calculate axial load on ground floor column.
Load per Floor
DL = (25×0.15 + 1.5 + 2.0 beam/wall estimate) × 25 = 8.25 × 25 = 206.25 kN
LL = 2.5 × 25 = 62.5 kN per floor
Total from 7 Floors (G + 6 upper)
Total DL = 7 × 206.25 = 1443.75 kN
Total LL = 7 × 62.5 = 437.5 kN
LL reduction for 7 floors = 20% → reduced LL = 0.8 × 437.5 =
350 kNFactored Column Load
P
u = 1.5 × (1443.75 + 350) =
2691 kN
Example 3 — Hospital vs Residential Comparison (Conceptual)
Compare factored slab loads for a hospital corridor (LL=4 kN/m²) vs residential room (LL=2 kN/m²). Same 150mm slab, 1.0 kN/m² finish.
Residential
w
u = 1.5 × (4.75 + 2.0) =
10.13 kN/m²Hospital Corridor
w
u = 1.5 × (4.75 + 4.0) =
13.13 kN/m²Impact
Hospital corridor load is
30% higher — this means thicker slabs or closer-spaced reinforcement. A slab designed for residential use must NOT be used for a hospital without re-checking.
8. GATE MCQs
Q1. Live load for a residential building (bedrooms) as per IS 875 Part 2 is:
- (a) 1.5 kN/m²
- (b) 2.0 kN/m²
- (c) 3.0 kN/m²
- (d) 4.0 kN/m²
Answer: (b)
IS 875 Part 2 specifies 2.0 kN/m² for residential rooms (bedrooms, living rooms, kitchens).
Q2. Live load on an inaccessible roof as per IS 875 is:
- (a) 0.5 kN/m²
- (b) 0.75 kN/m²
- (c) 1.5 kN/m²
- (d) 2.0 kN/m²
Answer: (b)
Inaccessible roofs = 0.75 kN/m². Accessible roofs = 1.5 kN/m². Frequently tested in GATE.
Q3. The maximum permissible reduction in live load for large floor areas is:
- (a) 10%
- (b) 15%
- (c) 25%
- (d) 50%
Answer: (c)
Maximum reduction = 25% for areas exceeding 100m² (Cl 3.3).
Q4. Live load reduction for a column supporting 8 floors is:
- (a) 10%
- (b) 20%
- (c) 30%
- (d) No reduction
Answer: (b)
6–10 floors → 20% reduction. 3–5 floors → 10%. Above 10 → 30%.
Q5. Live load for a classroom in an educational building is:
- (a) 2.0 kN/m²
- (b) 2.5 kN/m²
- (c) 3.0 kN/m²
- (d) 4.0 kN/m²
Answer: (c)
Classrooms = 3.0 kN/m² as per IS 875 Part 2.
Q6. Live load IS 875 Part 2 does NOT apply to:
- (a) Residential buildings
- (b) Wind loads
- (c) Office buildings
- (d) Hospital wards
Answer: (b)
Wind loads are covered by IS 875 Part 3, not Part 2. Part 2 covers only imposed (live) loads due to occupancy.
Q7. The load factor for live load in IS 456 limit state design (DL + LL combination) is:
- (a) 1.0
- (b) 1.2
- (c) 1.5
- (d) 1.6
Answer: (c)
IS 456 Table 18: γf = 1.5 for both DL and LL in the basic combination 1.5(DL + LL).
Q8. For a parking garage for light vehicles, the concentrated load to consider is:
- (a) 2.7 kN
- (b) 4.5 kN
- (c) 9.0 kN
- (d) 1.8 kN
Answer: (c)
Light vehicle garages have a UDL of 2.5 kN/m² but a concentrated load of 9.0 kN on a 300×300mm area — representing a heavy wheel load.
Q9. Partition load in a residential building is typically accounted as:
- (a) Part of live load
- (b) Part of dead load as UDL (1.0–1.5 kN/m²)
- (c) Ignored for low-rise buildings
- (d) Part of seismic weight only
Answer: (b)
Lightweight partitions whose positions may change are treated as additional dead load — IS 875 Part 2 Note suggests adding 1/3 of the partition weight as UDL on the slab.
Q10. If floor area reduction is applied, it should NOT be used for:
- (a) Office spaces
- (b) Assembly halls
- (c) Storage and warehouses
- (d) Residential corridors
Answer: (c)
Storage loads are actual loads (stacked goods) and don't reduce with area — every square metre may actually be loaded to the maximum.
9. Common Mistakes
Mistake 1: Using wrong occupancy category. A residential corridor (3.0 kN/m²) has 50% more live load than a bedroom (2.0 kN/m²). Read the table carefully — different rooms in the same building have different loads.
Mistake 2: Applying area reduction to storage loads. Storage loads represent actual weight of stored goods. Reduction is not permitted.
Mistake 3: Forgetting floor finish and partition dead loads. Floor finish adds 1.0–1.5 kN/m², partitions add 0.5–1.5 kN/m². Ignoring these underestimates the total load by 15–25%.
Mistake 4: Confusing IS 875 parts. Part 1 = dead load, Part 2 = live load, Part 3 = wind, Part 4 = snow, Part 5 = special loads. Students sometimes cite the wrong part.
10. Quick Revision Summary
Memorise:
- Residential: 2.0 kN/m² (rooms), 3.0 (corridors/stairs)
- Office: 2.5 kN/m² (general), 5.0 (heavy storage)
- Assembly: 4.0 (fixed seating), 5.0 (without seating)
- Hospital: 2.0 (wards), 4.0 (corridors, OT)
- Classroom: 3.0 kN/m²
- Roof: 0.75 (inaccessible), 1.5 (accessible)
- Area reduction: max 25%, not for storage
- Column reduction: 10% (3-5 floors), 20% (6-10), 30% (>10)
- IS 875 Parts: 1=DL, 2=LL, 3=Wind, 4=Snow, 5=Special
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