ACT / ACT Systems
Reinforced concrete fails at its connections — where a bar is bent, lapped or welded, and where a member is asked to carry more than it was detailed for. These five systems each remove one of those weak points. All are patented, all are published, and all are available for licensing.
System 01 — MST
Active external confining pressure is applied along the length of a column or beam through steel angles and plates, then locked in permanently by welded strips. The member gains strength and ductility without gaining size or weight, and without the concrete section being cut into.
US 6,718,723 EG 21,647 EG 23,111 CA 2,325,706
System 02 — Karma
A light, low-cost structural system for walls and floors: precast panels made of a lightweight core between two thin layers of reinforced concrete or cement mortar, each with a light reinforcing mesh. The longitudinal rib reinforcement projects beyond the panel so that, on site, ribs of cast concrete tie the panels together and transfer load between wall, slab and floor.
EG application 2009101449
Karma slabs
The floor version of the system. Panels are cast in a mould where a vibrating loading head forms rows of voids through the section, so the slab loses most of its dead weight but keeps a full grid of ribs. The panel leaves the yard partially cast: the lower mesh and the lower part of the ribs are in concrete, the upper part of the rib reinforcement is deliberately left exposed.
On site the segments are placed in their design sequence, resting on a steel beam fixed between two columns, and further reinforcement is inserted in situ. The exposed rib steel, the inserted bars and the topping are then cast together, and the segments are stressed to one another with post-tensioning tendons. What was a set of light precast pieces becomes one monolithic, prestressed floor plate.
System 03 — hybrid truss beams
A steel truss skeleton with simple mechanical joints replaces the reinforcement cage of a beam. Because the truss is a structure in its own right, it carries its own weight and the weight of the fresh concrete during casting — so the formwork and the propping under it can go.
The joints are bolted, not welded. Welding a truss node burns the bar and leaves a brittle heat-affected zone exactly where the force concentrates; a mechanical joint does not touch the metallurgy of the bar.
Two joint types; the assembled truss before casting.
System 04 — beam–column joints
In a frame corner, the main tension bars are bent around the joint. The tensile force pushing through that bend produces radial compression, the concrete cover splits, and the joint fails in a brittle way — long before the members either side of it have given what they are capable of.
The bend is replaced by a mechanical L-coupler. The bar arrives straight, is coupled at the corner, and never gets work-hardened. Ductility, stiffness and load capacity all rise, and joint efficiency goes to 170% against 144.5% for the bent-bar reference.
ACI Structural Journal 118(2), 2021.
Two parallel trusses run through the beam, the joint and the column, with diagonal tension and compression members crossing inside the corner. The force on the bent main bar drops from 6.38P to 2.8P, the diagonal strut force from 9.02P to 4P, and the failure moves out of the joint into the column.
Applied Mechanics 7(2), 2026, article 49.
System 05 — mechanical coupler
Reinforcing bars carry outward circumferential ribs. Those ribs are what makes a mechanical coupler difficult: they cut down the contact surface available to transfer load between the bar and the inside of the sleeve, so most couplers end up long, heavy and expensive.
The ACT coupler works on the double action of screw elements. The sleeve is machined with female grooves that interlock with the bar ribs, and screw elements tighten against the bar without threading, enlarging or undercutting it. As the screws bite, the bar ribs are pressed into direct contact with the inner surface of the sleeve and the spaces between them are eliminated.
WO 2023/098965 A1 PCT/EG2021/000039
Two sleeve halves plus an outer pipe whose internal diameter is slightly less than the outside of the halves. The bar ends are seated in the female grooves, then the pipe is driven over the assembly — enough pressure to stop the two bars splitting apart.
The sleeve halves are given a gentle outward slope towards each end. Two tapered locks with the same internal slope are driven on from either side, closing the halves onto the bars.
Two coupler halves with protruding sides and bolt holes. The bars are seated in the grooves and the threaded bolts on the protruding sides are tightened — the version that needs no press on site.
That is the only result a coupler needs to produce. If the bar fails away from the connection, the connection is stronger than the bar — and the designer can treat a coupled bar as continuous.
All five systems are available for licensing and joint development, including the laboratory programme needed to qualify them in a new market.