Simplified precast concrete system with rapid assembly formwork

A hybrid precast and cast-in-place concrete building system comprising:

• an upper precast column and a lower precast column, each comprising:
• a column portion;
• one or more upwardly-protruding rebar;
• a bottom-mounted metal connection plate with penetrations;
• and
• a precast slab comprising:
• a horizontal slab;
• a column foot protruding from a top of the horizontal slab;
• one or more foot risers protruding from a top of the column foot, thus creating space for the later placement of rebar;
• each of the one of more foot risers surrounding a riser penetration;
• whereby, during assembly the precast slab is placed on top of the lower precast column, the upwardly-protruding rebar of the lower precast column passing through the riser penetrations, and through the bottom-mounted metal connection plate of the upper precast column, after which concrete is poured on top of the precast slab, thereby creating a hybrid precast and cast-in-place structure.

A method of erecting a multi-story structure, the method comprising the steps of:

• excavating a building site to create an excavated surface;
• placing one or more base members against the excavated surface, each base member comprised of:
• a horizontal slab;
• a vertical column extended from the horizontal slab;
• placing a precast column atop each vertical column of each of the one or more base members, each precast column comprising:
• a column portion;
• and
• one or more upwardly-protruding rebar;
• placing a precast slab atop each precast column, each precast slab comprising:
• a horizontal slab;
• a column foot protruding from a top of the horizontal slab;
• one or more foot risers protruding from a top of the column foot;
• placing a precast spanning member, the precast spanning member resting atop the horizontal slabs of two or more precast slabs, each spanning member comprised of:
• a perimeter wall;
• a multiplicity of individual cavities;
• one or more formwork support rods affixed to a base of the precast spanning member;
• hanging a rotating formwork panel from one formwork support rods of the spanning member, each rotating formwork panel comprised of:
• a solid panel;
• fixed hooks adapted to rotate around the formwork support rods of the spanning member;
• slideable hooks to affix to formwork support rods after rotation of the panel into place;
• lifting the rotating formwork panel into a horizontal position;
• sliding the slideable hooks of the rotating formwork panel into an adjacent formwork support rod;
• pouring concrete on top of the rotating formwork panels, thereby filling the spaces between the precast slabs and precast spanning member;
• pouring concrete into the multiplicity of individual cavities of the precast spanning member, thereby filling the individual cavities;
• repeating the steps of “placing a precast column” through “pouring concrete into the multiplicity of individual cavities” each time completing a floor of the multi-story structure, stopping when the multi-story structure is the desired number of floors.