In this type of tie, the tie member contains threaded ends so, the external members can be removed without any breaking or pulling. Internal disconnecting ties are classified into two types as follows.

#1 She-Bolt Tie

#2 Coil Tie

#1 She-Bolt Tie

She-bolt tie system contains one inner tie rod and two she-bolt members. Both ends of the inner tie rod are threaded up to some distance.

She-bolt contains one normal threaded end and one tapered end with a threaded hole.

The tapered end is placed internally into the forms and ties rod is screwed into the threaded holes of she-bolts on both sides.

Externally threaded ends of she-bolts are used to secure the forms by a wing nut and washer arrangement.

After the hardening of concrete, the inner tie rod remains in concrete and she-bolts can be removed and reused.

#2 Coil Tie

The coil tie contains two members, inner tension member, and the external holding member.

Inner tension member consists of two helical coils welded to the ends of two or four steel struts. This member remains in concrete after hardening.

External holding member consist of two bolts which are screwed into the coils on both ends and these bolts are supported by washer and wale arrangement. These bolts can be removed after hardening and reused.

Two strut coil is used for medium works and four strut coil is used for heavy works.

If required, plastic or wood cones can be provided at each end of the coil to act as form spreaders.

If the thickness of the wall is too large, two inner members connected by a threaded rod can be used.