What is the typical manufacturing tolerance for the length of a precast beam?

For a beam up to 3 m long, the tolerance is ±5 mm. For lengths between 3 m and 6 m, it is ±8 mm (Table 1).

What is the minimum recommended bearing for a precast slab on a support?

The minimum bearing length should be 75 mm, unless a smaller length is justified by design calculations (Clause 7.3).

How should precast elements be stored on site?

Elements should be stored on firm, level ground using dunnage at specified support points to prevent warping, cracking, or damage (Clause 6.3).

What is the maximum deviation from plumb for a single-storey precast column after erection?

The permissible deviation from plumb per storey height is ±10 mm, with a maximum total deviation of ±25 mm for the full height (Table 2).

IS 10701

: 2019

Code of Practice for Construction of Precast Concrete Structures

CurrentSpecializedCode of PracticeBIMStructural Engineering · Precast and Prefabricated Concrete

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This standard outlines the code of practice for the construction of structures using precast concrete elements. It covers requirements for fabrication, handling, transportation, storage, erection, and connections to ensure structural safety and serviceability.

Covers the general requirements for the design, manufacture, erection and inspection of precast concrete structures and their components.

Quick Reference Values

Permissible tolerance in length for elements up to 3m± 5 mm

Permissible tolerance in cross-section dimensions up to 500mm± 5 mm

Permissible deviation in plumb of columns per storey height± 10 mm

Permissible deviation in level for bearing seating± 5 mm

Minimum bearing length for beams/slabs on supports75 mm

Practical Notes

Strict adherence to specified tolerances (Clause 5) is paramount to avoid fit-up issues during erection, which can cause costly delays and compromise connection integrity.

The design and location of lifting points are critical for safety and to prevent stress-induced damage to the precast element during handling and erection (Clause 6.2).

Proper temporary bracing during erection (Clause 7) is essential to ensure stability of the structure against wind and construction loads until all permanent connections are completed and have gained sufficient strength.