Complex 3D moulds for precast plants all over the world

Being one of the world’s most renown mould manufacturers, Construx Weckenmann, developed over time a vast portfolio of moulds that suit precast manufacturers’ needs. In close collaboration with the customer Construx Weckenmann tries to find the most appropriate mould which is in accordance with all technical specifications, which fits the customers’ budget and which copes with the dimensions and numbers of precast elements the customer wants to cast. For companies supplying precast culverts and pods, such as electrical substations and prison cells, Construx Weckenmann conceived over the years a full range of state-of-the-art moulds. Either with a fixed geometry, adjustable or fully automated, 3D moulds are the most complex moulds due to the particular design and technical specifications of these pods and culverts. Being “Top of Mind” in 3D moulds, Construx Weckenmann became a leading supplier for most of the major European precast substation manufacturers. Recently, Construx Weckenmann supplied several different moulds to a number of precast manufacturers all over the world.

Australia: Fully automated culvert moulds

The precast concrete culvert elements, made in these two hydraulically operated moulds, are cast on their side, and turned 90° after demoulding by means of a turning device. Because the elements were going to be placed at the base of a bored tunnel, the dimensions of the moulds had to cope with very strict technical specifications. The tolerance on the joint dimensions (machined shear key soffits and top recess formers with tongue and groove feature) was +/- 0.75mm. The width, height, diagonal and radius had to be within a tolerance of +/- 1.5mm.

Geometrical requirements of the precast Culverts:
• Length: 2380mm + 170mm shear key
• Outside width: 4440mm 
• Overall outside height: 2995mm
• Wall thickness: 300mm
• Roof thickness: 300mm
• Base thickness: 380mm

Seen the large number of units the customer had to manufacture and the high cost of labour in Australia, Construx Weckenmann included a number of features which allowed to reduce the production cost per unit as much as possible, by making the moulds fool-proof and by limiting labour wherever possible. They also included electronic valves and sensors with plc-controls to secure the correct sequence of actions and to ensure a safe working procedure, according to Australian standards.

Special hydraulic and electronic features of the moulds, for making the moulds fool-proof and limiting labour as much as possible:

• Hydraulic opening and closing of the outside panels
• Hydraulic shrinking of the inside core
• Hydraulic securing of the outside panels onto each other
• Hydraulic securing of the outside panels onto the inside core
• Hydraulic securing of the shrinkable inside core
• Hydraulic unit, including tubes, valves, connections and controls
• Electronic valves and sensors with plc-controls
• Remote control for all hydraulic movements

Poland: Fully adjustable substation mould 

These substations are poured upside-down and turned 180° after demoulding. This fully hydraulically and electrically controlled substation mould is conceived to manufacture 4 different lengths and 2 different widths with following possible dimensions:

• Inside length adjustable: 3150mm, 3800mm, 4200mm and 4700mm
• Inside width adjustable: 2600mm and 3000mm
• Inside height steplessly adjustable from 2400mm to 
• 3000mm, 
• Wall thickness adjustable: 90mm and 120mm

Construx also provided 2 different top parts for the inside mould, to be able to make elements with sharp edges between floor and walls or with large chamfers at both ends, a typical feature to accommodate underground duct connections.

The outside mould has hydraulically movable panels. Vibrating the elements is done with high frequency vibrators. The inside mould has a fixed part and several movable parts, according to the above modularity. The intermediate parts can be fit in individually or together. When demoulding, first the 
inside corners are pulled down hydraulically after which the wall panels are also pulled down in the same way, this leaves an 8mm opening on all sides.

Northern Ireland: Communication chambers mould

These so called precast ‘Comms Chambers’ or communications boxes are mainly used in infrastructure works, including airports, railway projects, roads and housing developments. The mould is suitable for manufacturing Comms Chambers with inside dimensions from 1500mm x 1500mm up to 3000mm x 3000mm, with 500mm increments applicable in both directions. The inside height may vary from 400mm up to 2400mm, with 100mm increments. The wall and base slab thickness of the elements can be 200mm, 250mm or 300mm. The mould is suitable to make standard units (with base slab) as well as riser sections (without base slab). The elements will be cast upside-down and be turned 180° after demoulding by means of a turning device, also supplied by Construx 
Weckenmann. Seen the large number of units the customer had to manufacture, and the high cost of labour, the Construx Weckenmann proposal included a number of features which allowed to reduce the production cost per unit as much as possible, by making the moulds fool-proof and by limiting labour as much as possible.

Technical specifications of the standard units:

• Inside dimensions of the units, 10 different sizes:
  • 1500mm x 1500mm, 2000mm, 2500mm and 3000mm
  • 2000mm x 2000mm, 2500mm and 3000mm
  • 2500mm x 2500mm and 3000mm
  • 3000mm x 3000mm
• Units to be poured in any increment of 100mm from 400mm up to a maximum single unit height of 2400mm internal height
• Wall thickness, 3 different possibilities: 200mm, 250mm and 300mm
• Base slab thickness: 3 different possibilities: 200mm, 250mm and 300mm
• Tongue & groove joint to allow riser sections to be added to base unit/riser 
• section
• Rebated joint to allow lids to be added to base unit/riser section
• Tapered toes on both short sides, maximum 500mm x 200mm
• Technical specifications of the riser sections (without base slab):
  • With similar dimensions and features as the standard units
  • Available in 500mm, 750mm and 1000mm heights
  • With spigot (tongue & groove joint) on top and at the bottom

The mould provided by Construx Weckenmann is state-of-the-art, hydraulically operated and equipped with all required safety features. The mould is an adjustable and flexible solution for all different communication chambers and allows for a monolithic cast: walls and base slab at the same time. The hydraulically movable outside panels consisting of 4 main panels plus infill panels to cope with the different required dimensions. The hydraulically shrinkable inside core consists of 4 shrinkable corner parts plus infill panels. Interchangeable top plates for the 10 different sizes of the standard Comms elements are included. These top plates have machined chamfered edges, and they sit on the support structure of the inside core. A height adjustment system allows for inside heights from 400mm up to 2400mm, with 100mm increments. Soffits and top recess formers create very precise tongue and groove features.

Belgium: Fully automated and hydraulically operated substation mould

Because the main walls of the substations are straight and only the basement walls, both inside and outside, are tapered, the demoulding needs to be done hydraulically. The mould has 2 hydraulically shrinkable inner cores and 4 hydraulically movable outside panels. Not only shrinking and moving are hydraulic, but also securing the outside panels is done with a hydraulic wedge system. Before the outside panels can be opened completely, they are slightly pushed backwards by means of a hydraulically operated eccentric device. The actual demoulding of the element is initiated by pushing the bases up and consequently lifting the element out of the mould by means of 6 perfectly synchronized hydraulic rams and 6 air vents. Construx provided the complete mould with electronic valves, sensors and a control panel, thus controlling all movements and securing the right sequence of movements, which resulted in a fool-proof system.

List of sensors:
• On every corner joint: check wedge open or wedge closed
• On every wall: check wall open or not
• On every corner of the shrinking core: check core completely out or core completely in 
• On the push-up system: check system out or system in / bottom in or bottom out

Sequence of demoulding operations:
• Pulling wedges on the outside corners
• Pushing walls slightly open

Opening walls completely
• Shrinking of inner core
• Pushing up the concrete element
Sequence of closing operations:
• Expansion of inner core
• Closing outside panels (pushers retracted)
• Securing the outside panels by closing the wedge connections

An audio signal and a flashing light indicate when the mould is in operation.

The elements are poured upside-down with self-compacting concrete. To facilitate the turning of the element, Construx supplied a special frame connecting the mould onto the customers’ turning device. All the outside panels have working platforms, one of which is equipped with a stair and the 3 others have access ladders. Construx also supplied a roof mould. Dimensions of the substation:

Length 3525mm x Width 2380mm x Height 2780mm
• Upper part wall thickness: 80mm
• Inside and outside basement walls with various tapers

Australia: Fully adjustable box mould

This fully adjustable mould is conceived to manufacture elements with 6 different lengths and 3 different widths with following possible dimensions:

Inside length adjustable: from 2500mm up to 5000mm, with 500mm increments
• Inside width adjustable: 2200mm, 2500mm and 3800mm

Height: steplessly adjustable from 1350mm to 2600mm
• Wall thickness adjustable: 150mm, 175mm, 200mm and 250mm

The outside panels have wheels and sit on rails, as they can be opened and closed by hand using a gear drive. The long outside panels have a 1500mm stroke: 700mm demoulding + 800mm adjustability. The short outside panels have a 1750mm stroke: 700mm demoulding + 1050mm adjustability. The two long lateral outside panels are 6000mm wide and the two short transverse outside panels are made of a main 2200mm wide panel plus two add-on parts, one of 300mm and another of 1600mm. The inside mould has shrinkable corner panels with interchangeable intermediate panels. Steel bases of 4 different widths sit on height adjusters. Obviously, there are no tie-bars through the concrete elements, only over the top and underneath.

USA: Fully automated mono-box mould

The system is suitable to make mono-boxes. These elements come with a fixed width and different lengths, forming a minimum size box of 6’ x 6’ and a maximum size of 6’ x 20’ Inside width: 6’
• Inside length: 6’ to 20’ in steps 1’
• Wall thickness: 8”, 10” and 12”

The idea of the mould is to start with a stable chassis with integrated rails on which all components can roll into position. Outside panels are also rolling on this frame and height adjusters fit on the chassis. The fixed part of the core consists of a fixed end segment made up of two hydraulic shrinkable 
corners and a fixed roof plate. A second end segment sits on wheels and is longitudinally movable on the frame. In this way the core can be extended with intermediate segments. Both connected end segments form the minimum box size: 6’ x 6’. When adding infill segments in between the end segments, 
any other internal length can be achieved. The 2 transverse outside panels of 6’ long have 4 extra extensions of 2” and 4 extra extensions of 4” on both sides, to make the 3 different thicknesses. These 2 transverse panels roll between the 2 longitudinal panels of 22’. The panels can be connected to make 
all combinations of wall thicknesses and core dimensions. All panels can open 800mm for demoulding and easy access to put rebar and box-outs. Opening and closing the outside panels is done hydraulically. All infill segments and the movable end segments are equipped with a hydraulic lock. This 
hydraulic locking device consists of 3 individual pins which each have a hydraulic cylinder to activate them. The hydraulic lock avoids workers having to go inside the core when assembling it. All outside panels are equipped with safety floors and access ladders, and Construx also supplied an extra working 
platform between outside panels and inside core

Shaping the Future of Concrete

Construx Weckenmann meets the requirements of their customers, in order to obtain the most appropriate solution to manufacture their precast culverts and pods. The outcome of achieving such an objective is always a very satisfied customer. Construx Weckenmann is an engineering-driven manufacturing company relying on the commitment, creativity and experience of its employees. Their aim is to establish a partnership, rather than to be a supplier, in providing turnkey solutions for precast and on-site formwork issues.