The joints of water tank are majorly divided into 3 types:
1) Movement joints
2) Construction joints
3) Temporary open joints
1) Movement joints: Special types of materials are required to maintain water tightness while accommodating relative movement between the side of joints. Movement joints are of 3 types:-
i. Contraction joints: - A contraction joint is a typical movement joint which accommodates the contraction of the concrete.
-It is of 2 types: - complete contraction joint- discontinuity of both steel and concrete
Partial contraction joint- discontinuity of concrete only
- These are usually applied after construction or just before the reservoir is put into service by pouring in hot & cold state.
ii. Expansion joints: - It is a movement joint with complete discontinuity in both reinforcement and is intended to accommodate either expansion or contraction of the structure
Joint fillers are used to fill the initial gap provided in the joint and are usually a compressible sheet or strip materials used as spaces.
iii. Sliding joint: - Sliding joint is a movement joint with complete discontinuity in both reinforcement and concrete at which special provision is made to facilitate relative movement in place of the joint.
-This joint is provided between wall & floor in some cylinder tank designs
2) Construction joints: - A construction joint is a joint in the concrete introduced for convenience in construction at which special measures are taken to achieve subsequent continuity without provision for further relative movement.
3) Temporary open joints:- A temporary open joint is a gap temporarily left between the concrete of adjoining parts of a structure which after a suitable interval and before the structure is put into use, is filled with mortar or concrete completely or provided below with the inclusion of jointing material.