Concrete Boom Pump Reach and Setup Radius

ScopeA boom pump's advertised reach is a vertical number and a horizontal number that cannot both be achieved at once, and what a crew needs on a site visit is whether the boom reaches the far corner from the only place the truck can set up. That is a triangle. Treating the envelope as a circle of the boom's total reach gives the horizontal distance available at a working height as the square root of the reach squared less the height squared, and the amount lost to elevation is the number that surprises people reading a spec sheet: a boom advertised at 110 ft gives about 100 ft at 45 ft up. THE CIRCLE IS A SCREEN AND THE MANUFACTURER'S REACH DIAGRAM IS THE TRUTH. A multi-section boom's envelope is not a circle: it has dead zones close in and near the mast, and its reach at a given height depends on which unfolding configuration is used. The circle is good enough to answer whether a pour is plausible from a given setup and much faster than pulling the chart, and it is not good enough to commit to. THE TWO CONSTRAINTS THAT DECIDE A SETUP ARE ALMOST NEVER REACH. Outrigger ground bearing is the first: boom pump outrigger loads are concentrated and large, and one outrigger set over a utility vault, a basement wall, or soft backfill is how a pump goes over. The bearing pressure is reported here so the size of the problem is visible, and sizing the cribbing or mats against an allowable bearing from a geotechnical source is a separate calculation. Power line clearance is the second and it is absolute. A boom is a long conductor swinging near overhead lines, and OSHA excludes concrete pumps from the crane rule (1926.1400(c)(1)), so the clearance comes from ASME B30.27, the pump manufacturer and the utility rather than Subpart CC; a setup that reaches beautifully and puts the boom inside the clearance envelope is not a setup, whatever the reach diagram permits. This does not evaluate boom capacity, the weight of line and concrete in the boom, wind limits on boom operation, or machine stability, all of which are manufacturer limits, and it does not size outrigger mats or address line pressure. The pump manufacturer's reach and load charts, OSHA, and the contractor's competent person govern.

Formula or tablehorizontal reach at a height = sqrt(total reach squared - height squared), the circle approximation; outrigger bearing pressure = load / pad area; power line margin = measured distance - the required clearance.

Source and editionThe reach geometry approximation by name, with the manufacturer's reach diagram and ASME B30.27 named as governing (OSHA 1926.1400(c)(1) excludes concrete pumps from the crane subpart). A multi-section boom's real envelope is a published reach diagram with configuration-dependent limits and dead zones, not a circle. Sizing outrigger mats against an allowable bearing needs a geotechnical source and is a separate calculation. The pump manufacturer's reach and load charts, OSHA, and the contractor's competent person govern.

Free accessOne square root on two numbers off a spec sheet; no reach diagram is reproduced.

What governsEstimate. AHJ and licensed professional govern.

API field namesboom_reach_ft, required_distance_ft, required_height_ft, boom_centre_offset_ft, outrigger_load_lb, outrigger_pad_area_ft2, power_line_distance_ft, required_line_clearance_ft, reach_at_height_ft, reach_lost_to_height_ft, reach_margin_ft, max_height_at_distance_ft, outrigger_pressure_psf, power_line_margin_ft

• A circle, not the reach diagram real envelopes have dead zones and configuration-dependent limitsthe manufacturer's reach diagram
• Mats are not sized here that needs the actual outrigger loads and an allowable bearinga geotechnical assessment
• Power line clearance is absolute it governs the setup independently of reachASME B30.27, the pump manufacturer and the utility