In exemplary implementations of this invention, a nozzle sprays foam, layer by layer, to fabricate a fabricated object according to a CAD model, and a subtractive fabrication tool removes material from the fabricated object according to a CAD model. The fabricated object comprises a mold or an interior form. The foam may be low-density, high strength and fast-curing. The foam may be used for large-scale 3D printing. For example, the foam may be used to 3D print molds for walls of homes. The foam molds may be left in place, after casting concrete in the molds, to serve as insulation. Or for example, the foam may be used to 3D print on site an internal form for a large wind turbine blade. The wind turbine blade may then be produced on site by depositing fiberglass on the outside of the internal form.

A method of tensioning concrete is disclosed.

In exemplary implementations of this invention, a nozzle sprays foam, layer by layer, to fabricate a fabricated object according to a CAD model, and a subtractive fabrication tool removes material from the fabricated object according to a CAD model. The fabricated object comprises a mold or an interior form. The foam may be low-density, high strength and fast-curing. The foam may be used for large-scale 3D printing. For example, the foam may be used to 3D print molds for walls of homes. The foam molds may be left in place, after casting concrete in the molds, to serve as insulation. Or for example, the foam may be used to 3D print on site an internal form for a large wind turbine blade. The wind turbine blade may then be produced on site by depositing fiberglass on the outside of the internal form.

Disclosed is a method for preparing a concrete-filled steel tubular edge-constrained laminated shear wall, belonging to the field of prefabricated buildings. The method allows for integrated hoisting during installation, leading to a simple working procedure and easy quality control. During manufacturing, an interior wythe board is flipped and placed on supporting members on rectangular steel tubes, no cavity formwork or bracket is needed in a cavity, and thus an operation of pulling out the cavity formwork is avoided, and high production efficiency is achieved. The rectangular steel tubes can be welded to horizontal steel bars of interior and exterior wythe boards, avoiding the cumbersome working procedure and high cost caused by stud connection while achieving reliable connection and direct force transmission.

Improved tilt-up and precast construction panels and improved methods for creating the same address deficiencies in the current tilt-up and precast construction panels. Improved tilt-up and precast construction panels use less concrete and less steel reinforcement and weigh less than current tilt-up and precast construction panels. Additionally, improved tilt-up and precast construction panels have greater insulative properties (both heat and sound) than do current tilt-up and precast construction panels. Improved tilt-up and precast construction panels require less labor on the construction site, thereby increasing efficiency and profitability of construction crews. Additional advantages of implementations of the invention will become apparent through the following description and by practice of implementations of the invention.

Insulated hollow core concrete forming system provide a forming system which can integrate the advantages of the hollow core design into the Insulated concrete form (ICF) system. The Insulated hollow core form system includes one or more of a Modular formwork unit, composed and formed of insulative material, where the Modular formwork unit utilizes longitudinal void formers that crafts a forming cavity of a hollow core section in between two spaced parallel side panels. The forming cavity is disposed to receive concrete or other hardening materials to form an insulated hollow core wall or an insulated hollow core slab. The system also includes a furring strip assembly positioned between adjacent Modular formwork units to join them together.