LOADS

Construction Load

Loads during construction — formwork, scaffolding, stockpiled materials, workers. IS 875 Cl. 3.1.4.

Also callederection loadtemporary load
Related on InfraLens
CODES
IS 875
Definition

Construction loads are loads imposed on a structure during construction — formwork, scaffolding, stockpiled materials, workers, equipment. Distinguished from service loads (live + dead at occupancy), construction loads are temporary but can exceed service loads in some cases. Per IS 875 Part 1 Cl. 3.1.4, construction loads include: (1) Form-work weight and supporting equipment; (2) Stockpiled materials (rebar, cement, aggregates, blocks); (3) Workers and tools; (4) Construction machinery (small cranes, vibrators, welders).

Design considerations: (a) Floor loads during construction often exceed service loads — typical Indian residential floors carry 4-6 kN/m² of construction load (rebar stockpile, formwork supporting upper floor) vs 2 kN/m² service residential live load. (b) Formwork must support the wet concrete weight + supporting frames + workers (typically 5-7 kN/m² for a 150 mm slab). (c) Crane and equipment access — temporary loads on roof or upper-floor edges. (d) Material stockpiles — aggregate piles on slabs designed only for UDL can cause local overload. The most-overlooked aspect: residential slab construction without reinforcement audit — high construction loads on green concrete (before 28-day strength gain) cause cracking that's only visible after the next pour covers it.

Where used
  • Slab and beam design accounting for construction sequence
  • Formwork design for fresh concrete weight + supports
  • Construction equipment loading on roofs and upper floors
  • Material stockpile loads on already-constructed slabs
  • Erection equipment loads on partially-completed structures
Acceptance / threshold
Per IS 875 Part 1 Cl. 3.1.4: construction loads explicitly considered in structural design; formwork supports designed for wet concrete + workers; stockpiles managed within slab capacity; equipment access verified pre-mobilisation.
Site example
Site reality: a Bengaluru commercial project's floor 7 slab developed 25 mm cracks at locations where rebar stockpiles for floor 8 had been placed. Investigation: floor 7 was 14 days old (about 65% of design strength) when 8 tonnes of rebar was stockpiled on a 4 × 4 m area = 5 kN/m² distributed load — exceeding service capacity. Cracks repaired but residual concern. Always verify stockpile loads against current concrete strength; defer stockpiling on green concrete.
Frequently asked
What is construction load?
Construction loads are loads imposed on a structure during construction — formwork, scaffolding, stockpiled materials, workers, equipment. Per IS 875 Part 1 Cl. 3.1.4. Often exceed service loads (e.g., residential floor 4-6 kN/m² during construction vs 2 kN/m² service live load). Must be considered in structural design.
How are construction loads designed for?
(1) Slabs and beams — designed for the larger of construction load envelope or service load. (2) Formwork — supporting fresh concrete + workers (5-7 kN/m² for 150 mm slab). (3) Stockpile loads — managed within slab capacity at current concrete strength (typically 65-100% of design at 14-28 days). (4) Equipment access — verified pre-mobilisation.
Can construction loads damage green concrete?
Yes — concrete at 7-14 days has only 65-90% of design strength. Heavy loads on green concrete (floor stockpiles, rolling cranes, equipment) can cause cracking, deflection, or localised crushing. Indian best practice: defer heavy loading until concrete reaches 28-day design strength; verify with cube tests; use construction sequencing to minimise loading on green concrete.
Related loads terms
Uniform Distributed Load (UDL)
Load spread evenly across length or area (kN/m or kN/m²)
Point Load / Concentrated Load
Load applied at a single point (kN)
Dead Load
Permanent load due to self-weight of structure (IS 875 Part 1)
Live Load / Imposed Load
Variable load due to occupancy/use (IS 875 Part 2). 2-5 kN/m² typical.
Wind Load
Lateral wind pressure on building (IS 875 Part 3). Basic wind speed 33-55 m/s in India.
Seismic / Earthquake Load
Lateral force from earthquake (IS 1893). Zones II–V in India.
Snow Load
Snow accumulation load (IS 875 Part 4)
Load Combinations
DL+LL, 1.5(DL+LL), DL+LL+WL etc per IS 456/IS 800