Up and over

How much main boom and luffer do these picks actually require? Compare one setup with a move if the jib gets excessive.

Your job: configure a crawler to reach the roof picks over the building. Adjust the main boom and luffer, compare working from one side with moving to both sides, and find a combination that clears the roof and reaches the work. With both sides enabled, get the tip to the midpoint from each side. More than one configuration can work.

Elevation

Reference section toward building

Plan

Top view · select a pick

Gold: main boomBlue: luffing jibCross: hook at current radius

Configure the crane

How to try the two-side plan

Try the two-side plan

Start on One side. Adjust the main boom and luffer; watch how long a jib it takes to reach every pick.
Tap Both sides. The same crane now moves to the opposite face for the second setup.
Tap Side A or Side B to adjust that side’s setback. Aim for the dashed midpoint from each side, then check the colored picks.

Active setup setback

Move the crane back from this side of the building. Switch setups to adjust the other position.

Main boom Main boom angle

75° · 83° · 88°

Luffing jib Jib angle

Lower the jib to extend its reach. This exercise checks simplified geometry only.

Slew · active setup 0°

Rotate around the center pin in plan. 0° faces the building. The elevation stays a reference section; the check uses the full reach envelope, not this viewing direction.

Main tip above roof

Reach into building

Picks covered

Midpoint target · 130 ft from each side

Shortest listed jib for midpoint and picks

Adjust the crane, then check your configuration.

Selected pick

Select a pick to inspect its required radius.

A spatial exercise

Loosely based on an LR 1300 crawler. Explore how main boom, luffer, angles and position affect reach over a building. Geometry and crane details are simplified; capacity is not calculated.

Building a real crane plan? Use the manufacturer’s charts for your exact machine and configuration: Liebherr LR 1300 SX ANSI/ASME US data sheet ↗.

Related Field Note: Use 4D to test the erection plan → follows the same idea of adding detail when it changes a planning decision.

What the check means

The fictional building is 160 ft tall and 260 ft deep. With both sides enabled, each setup must reach at least the midpoint. Every pick must be inside at least one enabled setup’s geometric envelope. The model also checks roof-edge clearance and an 8 ft tip-height allowance.

One crane moves between the two setup locations. Slewing turns its drawing in plan but does not change its full reach circle. The elevation remains a section facing into the building, not a clearance calculation for the selected slew direction.

No load charts, rated capacity, hook path, three-dimensional collision checks, rigging, ground bearing or stability are evaluated. The schematic support frame and cables are illustrative.