FIELD OF THE INVENTION:
The present invention relates to construction formwork systems, and more particularly to a positively controlled, synchronized, and shock-free hydraulic lowering of column-hung modular deck formwork system capable of supporting fresh concrete loads and without ground-supported shoring. The invention specifically concerns a controlled hydraulic lowering ’mechanism integrated with column-mounted support, wherein lowering is governed by regulated hydraulic actuation rather than gravity release or manual mechanical adjustment.
BACKGROUND OF THE INVENTION AND PRIOR ART:
Conventional slab construction typically employs ground-supported shoring systems which restrict access, increase labour dependency, and prolong construction cycles.
Suspended or column-hung formwork systems are known in the art (IPC E04G11/04); however, such systems generally depend on either purely mechanical release arrangements or purely hydraulic lifting or striking devices, each presenting inherent limitation (IPC E04G11/50, E04G11/54).
Existing hydraulic striking systems typically rely on direct load take-over without controlled counterbalancing, leading to potential shock loading, non-uniform lowering, and risk of slab damage. Such systems often lack a defined pre-lowering load transfer phase and operate without precise synchronization across multiple supports.
Conversely, screw jack-based systems permit load holding but do not enable regulated, synchronized, and continuous lowering of large deck assemblies and are inherently labour-intensive.
Accordingly, there exists a technical need for a column-hung formwork system in which lowering of the slab, formwork is governed primarily by a controlled hydraulic mechanism, incorporating progressive load transfer, flow-regulated descent, and synchronized actuation across multiple supports, while maintaining mechanical stability during load-bearing phases.

OBJECTIVES OF THE INVENTION:
The objective of the invention is to provide a Lowering of column-hung modular deck formwork system supported by the bracket that: - Eliminates ground-supported staging. - Safely supports full wet concrete load. - Enables controlled and synchronized lowering. - Avoid shock during slab separation. - Allows rapid reuse with reduced workmen.
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SUMMARY OF THE INVENTION:
The present invention provides a Lowering mechanism of column-hung modular deck formwork system intended for use in Larger thick slab construction, which eliminates the requirement for ground-supported staging or shoring and enables safe, mechanized, and reusable formwork operations. The system is particularly suited for repetitive slab construction in high-rise buildings, podium slabs, transfer slabs, and similar structures.
In accordance with the invention, the formwork system comprises a plurality of column-mounted bracket assemblies, each bracket assembly being securely fixed to a permanent structural column at a predetermined elevation corresponding to the slab soffit level. Each column-mounted bracket assembly integrates both a mechanical screwjack and a hydraulic jack, arranged substantially along a common vertical axis, thereby providing a dual load-path mechanism for load support and controlled lowering.
During slab casting, a modular deck structure comprising primary girders, secondary beams, and decking or sheathing panels is supported on the column-mounted bracket assemblies. In this stage, the mechanical screwjack functions as the primary load­bearing element, supporting the entire load arising from fresh concrete, reinforcement, formwork components, and construction live loads, while the hydraulic jack remains in an inactive or standby condition.
After completion of concreting and upon attainment of a predetermined stripping strength of the slab, hydraulic pressure is gradually applied to the hydraulic jack in each bracket assembly. The applied hydraulic pressure progressively transfers load from the mechanical screwjack to the hydraulic jack, thereby establishing a counter-

load balancing condition in which the load is substantially shared between the two jack mechanisms. This gradual load transfer prevents sudden release of load and ensures stability of the deck during the transition phase.
Once counter-load balancing is achieved, the mechanical screw jack is released or disengaged, and the hydraulic jack assumes full responsibility for supporting the deck structure. The deck formwork is then lowered uniformly and in a controlled manner by regulated hydraulic actuation across all bracket assemblies, enabling synchronized and shock-free separation of the formwork from the slab soffit.
Through the integration of column-mounted support, mechanical load bearing, hydraulic lowering, and counter-load balancing, the invention provides a safe, efficient, and reusable formwork system that significantly reduces workmen dependency, shortens construction cycles, improves site safety, and enhances construction quality compared to conventional formwork systems.
BRIEF DESCRIPTION OF DRAWINGS:
- Figure 1: Plan view of Modular Formwork layout - Figure 2: Sectional view of Modular Formwork with Bracket - Figure 3: Typical Cross sectional view of Bracket - Figure 4: Load Balancing & Lowering Sequence - Figure 5: Construction cycle stages (3D Images) - Figure 6: Construction Sequence (7 Pages) - Figure 7: Modular Formwork Setting out (2 Pages) - Figure 8: Modular Formwork Section details - Figure 9: Bracket arrangement for Modular Formwork
DETAILED DESCRIPTION OF THE INVENTION:
The present invention relates to a column-hung modular deck formwork system intended for slab construction, particularly in multi-storey buildings, podium slabs, transfer slabs, and other structures requiring repetitive and mechanised formwork operations. The invention provides an integrated system capable of supporting full construction loads during concreting and subsequently enabling hydraulically governed, synchronized, and shock-free lowering, without the use of ground- supported staging or shoring.

General Arrangement of the System:
The system according to the invention comprises a plurality of column-mounted bracket assemblies fixed to permanent structural columns, and a modular deck structure supported on said bracket assemblies. Each bracket assembly incorporates both a mechanical screwjack and a hydraulic jack, arranged in a common load axis, to provide a dual load-path mechanism for load support and controlled lowering.
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The modular deck structure comprises primary load-bearing members, secondary support members, and decking or sheathing panels, arranged to form a continuous slab soffit surface.
Column-Mounted Bracket Assembly:
Each column-mounted bracket assembly is securely fixed to a reinforced concrete column at a predetermined elevation corresponding to the slab soffit level. Fixing of the bracket assembly to the column is achieved using mechanical anchors, through- bolts, or equivalent fastening means, designed to safely transmit construction loads from the formwork system into the permanent structure.
The bracket assembly comprises a structural steel bracket frame, preferably fabricated from plates, box sections, or rolled steel sections. The bracket frame is configured to project outwardly from the column and to support vertical loads from the deck system.
Adjustable seating or alignment provisions may be incorporated in the bracket frame to facilitate accurate leveling of the deck prior to concreting.
Mechanical Screw Jack:
Mounted on each bracket assembly is a mechanical screwjack, which functions as the primary load-bearing component during slab casting. The mechanical screw jack comprises a high-tensile threaded spindle and a corresponding load-bearing nut arrangement. The screwjack is configured to support the entire load arising from fresh concrete, reinforcement steel, formwork components, and construction live loads during the concreting stage.
The mechanical screw jack allows fine vertical adjustment to ensure precise deck leveling and maintains positional stability under full load with minimal deflection.
During concreting, the screwjack remains fully engaged, and all vertical loads from the modular deck are transmitted through the screwjack and the bracket assembly into the structural column.

Hydraulic Jack:
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Coaxially arranged with the mechanical screw jack in each bracket assembly is a hydraulic jack, which is provided for controlled lowering of the deck after casting. The hydraulic jack is mounted such that its line of action substantially coincides with the axis of the mechanical screwjack, thereby ensuring axial load transfer and avoiding eccentric loading.
During slab casting, the hydraulic jack remains in inactive or standby condition and does not carry any substantial portion of the slab load. The hydraulic jack is connected to a hydraulic power source through suitable hoses and fittings, and may be provided with flow control valves, non-return valves, and pressure relief valves to ensure safe and synchronized operation across multiple bracket assemblies.
Modular Deck Structure:
The modular deck structure supported on the bracket assemblies comprises primary girders extending between adjacent bracket assemblies and secondary beams supported on the primary girders. A plurality of decking or sheathing panels, such as plywood panels, are fixed to the secondary beams to form a continuous slab soffit.
The modular nature of the deck structure allows it to be adapted for different slab spans and geometries and enables repeated reuse for successive floor levels. Loads from the deck structure are transferred directly to the bracket assemblies through the mechanical and hydraulic jack arrangement
Operation During Concreting:
During slab construction, the modular deck structure is assembled and supported on the bracket assemblies, and the mechanical screw jacks are adjusted to achieve the required slab soffit level. Reinforcement is placed, and concrete is poured onto the deck.
Throughout the concreting operation, the entire construction load is supported by the mechanical screw jacks, while the hydraulic jacks remain inactive. The bracket assemblies and screwjacks collectively transfer the load into the structural columns.
Load Balancing and Lowering Operation:
After concreting, the slab is allowed to cure until it attains a predetermined stripping strength sufficient to permit removal of the formwork without causing damage to the slab. Upon attainment of this strength, hydraulic pressure is gradually applied to the hydraulic jack in each bracket assembly.

As hydraulic pressure is increased, the hydraulic jack progressively takes up load from the mechanical screw jack, thereby establishing a counter-load balancing condition in This gradual load transfer prevents any sudden or uncontrolled release of load.
Once the load has been substantially transferred to the hydraulic jack, the load-bearing nut of the mechanical screwjack is released or disengaged. The hydraulic jack then assumes full responsibility for supporting the deck and is actuated in a controlled manner to lower the modular deck formwork by a predetermined distance.
The lowering operation is carried out in a synchronized and gradual manner across all bracket assemblies, ensuring uniform separation of the deck from the slab soffit.
Shock-Free Slab Separation and Reuse: The combination of the mechanical screwjack, the hydraulic jack, and the counter­load balancing mechanism ensures shock-free slab separation, thereby preventing cracking, spalling, or surface damage to the newly cast slab. After lowering, the deck components may be disengaged, repositioned, and reused for subsequent slab construction cycles.

Technical Effect and Advantages:
The invention ensures
- Elimination of ground-supported staging. - Dual safety through mechanical and hydraulic paths; - Controlled and synchronized formwork lowering; - Reduced Workmen dependency and construction time; and - Improved safety and quality in slab construction
INDUSTRIAL APPLICABILITY:
The invention is industrially applicable to high-rise buildings, podium slabs, transfer decks, and infrastructure projects requiring repetitive slab construction.

1. A column-hung modular deck formwork system comprising: (a) a plurality of column-mounted bracket assemblies fixed to structural columns; (b) a modular deck structure supported by said bracket assemblies; (c) at least one mechanical screw jack provided in each bracket assembly and configured to support the entire wet concrete and formwork load during slab casting; and (d) at least one hydraulic jack integrated coaxially with the mechanical screw jack; wherein load is transferable from the mechanical screw jack to the hydraulic jack through a counter-load balancing mechanism prior to lowering, enabling controlled and shock-free lowering of the modular deck formwork without ground-supported shoring.
2. The system as claimed in claim 1, wherein the mechanical screwjack comprises a high-tensile threaded spindle having a diameter of about 80 mm. 3. The system as claimed in claim 1, wherein the hydraulic jack has a rated capacity of about 100 tonnes and a stroke of 75-100 mm. 4. The system as claimed in claim 1, wherein the hydraulic jack remains idle during concreting and is activated only after the concrete achieves stripping strength. 5. The system as claimed in claim 1, wherein the counter-load balancing mechanism comprises gradual pressurization of the hydraulic jack to substantially equalize load between the jacks.
6. The system as claimed in claim 1, wherein the bracket assemblies are fabricated from structural steel conforming to IS 2062 or equivalent. 7. The system as claimed in claim 1, wherein lowering of the deck is carried out at a controlled rate of approximately 1 mm per second. 8. A method of striking a slab formwork using the system as claimed in claim 1, comprising the steps of supporting slab load on the mechanical screwjack, balancing load using the hydraulic jack, releasing the mechanical screwjack, and lowering the deck in a controlled manner.