Joints | Provision & Necessity of joints a large Building - Ishwaranand

Ishwaranand News

Joints | Provision & Necessity of joints a large Building

Joints

Provision/necessity of joints in a large building

Joints, Provision/necessity of joints in a large building, Location of Construction, position for construction joints, as per I.S.3414-1168
  • All building materials expand about contract due to change in temperature including variation in moisture content.
  • That magnitude of such expansion about contraction depends upon the type of material used in construction and the range of variation in some temperature including moisture content.
  • Components of a structure are not allowed free movements, therefore, internal stresses will be set up which may result in the formation of cracks.
  • To control either isolate thermal including other movements to avoid danger over a structure.
  • To break the continuity of a structure.
  • Joints sub-divide each building toward smaller units including also permit free movement of an individual unit.
Joints, Provision/necessity of joints in a large building, Location of Construction, position for construction joints, as per I.S.3414-1168

The recommended spacing of expansion joints for different types of works as per I.S.3414-1168

  1. For load-bearing walls with cross-walls at intervals. A traditional type of one-brick thick or more. =30m
  2. Walls of warehouse-type construction (without cross walls.) =30 m
  • Chajja’s, balconies and parapets. = 6 to 12 m
  • Ordinary roof slabs of R.C.C. 20 to 30 m intervals and at protected by layers of mud changes in direction as in phuska or other insulating media in L, T, H &U shaped struct.un-framed construction.
  • The unprotected slabs. =15 m
  • Frames:- At 30 m intervals and at corners of L, T, H, and U shaped structures.
  • Copings:- Corresponding to joints in the roof slabs.

Location of Construction Joints for Different Members

Some recommended position during construction joints into different structural components is as supporting.

Joints, Provision/necessity of joints in a large building, Location of Construction, position for construction joints, as per I.S.3414-1168

For slabs

  • In the case of slabs supported on two sides, the construction joints should be vertical at support.
  • It can also, be provided at the middle of the span at right angles to the main reinforcement
  • Inside the case of two-way slabs, the joint tin be provided near the centre of the either span

For Beams

Joints, Provision/necessity of joints in a large building, Location of Construction, position for construction joints, as per I.S.3414-1168

For columns

  • In case of columns, the construction joint should be formed horizontally by stopping the concrete in a column about 75 mm below its junction with the lowest soffit of the beam 
  • The operation of concreting over the construction joint should be exerted up after a break of at least 4 hours
Joints, Provision/necessity of joints in a large building, Location of Construction, position for construction joints, as per I.S.3414-1168

For walls

No comments