Concrete Placing Boom

Overview

A concrete placing boom is the distribution arm of a high-rise concrete pour. A ground-level pump pushes concrete up a vertical line, and this boom takes it from the top of that line and flies it out over the deck so a single operator can place concrete anywhere within a wide circle without moving hoses by hand. It is a distinct machine from a truck-mounted concrete pump: the boom stands on the structure, has no engine of its own driving the concrete, and is fed by a separate stationary pump. On tall buildings it climbs itself up floor by floor as the structure rises.

The machine stands on a Mast and Base. A Slewing System system rotates the Boom Arm around that mast, the Delivery Pipeline carries concrete out to the tip, the Hydraulic Power Unit move everything, and the operator works it all through the Control System system.

Mast, base, and climbing

The Mast and Base raises the boom above the working deck. Its Mast Tube is a steel column, and how it is anchored depends on the job. A standing boom uses a Cross Base spread base with Outrigger legs, while a tall building ties the mast to finished slabs with Tie Collar collars. For the tallest pours the mast carries a Climbing Frame: hydraulic Climbing Jack rams push the mast up Climbing Rail guides against Climbing Shoe brackets cast into the wall, so the boom raises itself one floor at a time without a crane.

The boom arm

The Boom Arm is a folding arm of several Boom Section segments joined by Knuckle joints. Each Boom Cylinder unfolds and positions one section, so the operator can extend the arm straight out, drape it down into a deep wall, or tuck it back to clear an obstacle. All the joints turn on hardened Pin Set pins and bushings, and at the very tip a flexible End Hose lets the placer aim the falling concrete exactly into the form. The folding design matters because it lets a long reach pack into a small footprint for climbing and transport.

Slewing

The Slewing System system rotates the whole arm so the tip can reach any point in a circle. It centers on a large geared Slew Ring ring on top of the mast. A Slew Motor drives a Slew Gearbox whose pinion meshes with the ring, turning the boom slowly and with enough torque to swing the loaded arm and hold position against the reaction of flowing concrete. Powered slew through nearly a full turn means the operator rarely has to reposition the mast during a pour.

The concrete pipeline

The Delivery Pipeline carries the concrete itself. It starts with a Riser Pipe pipe fed by the ground pump, then runs out along the boom through Delivery Pipe sections joined by Pipe Clamp couplings. The pipe is hardened steel, because pumped concrete is abrasive and would quickly wear out ordinary pipe, and it is sized to match the pump output. At each moving joint a Swivel Joint carries the concrete across the rotation, and Pipe Elbow bends route the line around the knuckles. The whole line is built to be opened and cleaned out at the end of every pour before the concrete sets inside it.

Hydraulics and control

The Hydraulic Power Unit move the boom. A Drive Motor drives a Hydraulic Pump that supplies the Valve Block, a set of proportional valves that meter oil so the arm moves smoothly rather than jerking, with oil held in the Hydraulic Reservoir and cleaned by Hydraulic Filter elements. The operator runs all of it from the Control System system using a Radio Remote belt pack whose Remote Joystick sticks send commands to the Boom Controller. That controller reads Angle Sensor units on each joint so it knows the boom geometry, drives the valves to follow the operator, and keeps the arm inside its safe working envelope. Working by radio lets the operator stand right at the form, watch the concrete land, and steer the tip with both hands.

Use on site

Placing booms are standard on high-rise and large-deck concrete work, where they pour floor slabs, columns, and core walls floor after floor. The workflow is a ground pump feeding the riser, the boom flying concrete to wherever the crew is finishing, and the self-climbing mast moving the boom up as each floor is cast. Compared with running flexible hose by hand, the boom places concrete faster, with fewer workers, and reaches spots no hose can, which is why almost every tall concrete building is built with one. The limits are that it needs a separate pump, it must be cleaned out promptly to avoid a blocked line, and its reach is fixed by the arm length, so the mast is positioned to cover as much of each deck as possible before it has to climb or be relocated.