BBR VT CONA CMF flat anchorage post-tensioning system
The European approved CONA® CMF post-tensioning system (bonded or unbonded) is a multi-strand technology for internally post-tensioned applications where the anchoring has to be carried out in very thin concrete cross-sections, such as slabs. The standard tendon sizes range from 2 to 4 strands. Typical applications include car parks, apartment buildings, commercial office space, retail centers and distribution warehouses.
CONA CMF tendons are also used for suspended slabs of hospitals and stadia as well as slabs on ground for terminal facilities, hangars and sporting venues, or bridge decks. BBR Network Members offer design of slab PT structures and have sound engineering knowledge backed by many years of experience in order to maximize the benefits for all building stakeholders.
The main components in the anchor zone of the CONA CMF system are the wedges, anchor head, load transfer element and trumpet. For the load transfer to the concrete, the CONA CMF BT (bearing trumplate) is used, which makes use of an advanced and proprietary three plane load transfer especially developed for anchoring in thin cross section. This allows for very small centre and edge distances at the anchorages, as well as application of the full post-tensioning load at very low concrete strengths.
Fixed and stressable couplers
CONA CMF tendons can be coupled using propriety Type H sleeve couplers. The coupler can serve as a stressing/active anchorage coupler (Type S) or fixed/passive anchorage coupler (Type F) bearing against the bearing trumplate or as movable couplers (Type B) along the length of the tendon.
The strand bundle is enclosed in a corrugated BBR VT plastic round or flat duct or steel duct utilizing either steel or plastic material. For special applications, such as loop tendons, smooth round steel or plastic ducts can be used. The filling of the tendons in bonded applications is carried out using a high performance BBR grout. For unbonded applications the duct can be injected with grease/wax or circulating dry air.
Cast-in bond anchorage
For terminating the CONA CMF tendon at the passive end a cast-in CONA CMO bonded anchorage can be used to minimise material costs and improve site productivity. This anchorage does not require any local anti-bursting reinforcement in the anchorage zone and is capable of fully transferring the post-tensioning forces from the strand into the concrete structure.