Place a 70-tonne ceiling beam

Choose a scene. Each jump selects the action, time and camera together. Gold is the stone; translucent equipment marks a proposed mechanism.

Drag to orbit · Shift-drag to pan · Scroll to zoom. Camera buttons keep the same time.

The whole build remains the subject

The animation will follow quarrying, delivery, apparatus assembly, repeated lifting and reset, heavy-beam placement, the upper courses, completion of the faces and equipment recovery. The paper supplies the starting mechanisms. Each physical obstacle gets a visible flag and an alternative where one can be made plausible.

The external route uses an unfinished face with a prepared track, an extra edge guide and a supported rope lead from the head. These are engineering additions. It does not assume that a finished stepped stone face is already a working slide.

What this sequence assumes

The 4:1 rope relation is continuous: every metre the load rises requires four metres of counterweight travel. A smooth start and stop keep the estimated inertial correction below the selected 2% force tolerance. Eight separate 70 mm control ropes brake the counterweight. Each has three turns around a supplied belay post at assumed friction μ = 0.3, kept separate from the low-friction guides. Force labels include a conservative allowance for control-rope weight, drag and an extra guide bend. Post anchorage, wear and controlled release still need checks, so this equipment remains ghosted.

Separate 40 mm return ropes include conservative weight and floor-drag bounds. Ballast return uses separate loaded and empty stair lanes, a 0.2 m/s speed limit and 24-second pickup spacing. Walking eases into and out of each leg. Packages weigh up to 10 kg (98 N of load per carrier). The final package retains the exact remainder. Two separate crews remain present at the upper and lower waiting areas. Detailed loading access and traffic remain proposed.

The heavy load is held while the counterweight is disconnected and reset. The added holding candidate uses 32 five-degree wedges, selected wood friction of 0.12 on both sliding faces and four people per setting lever. Two pairs grip crossbars at 1.6 m and 2.4 m from the pivot, at 80% assumed efficiency. Wood bearing and lever bending are checked against the existing cedar proxies. Rope compression, higher wedge friction, grips, full rope routing, anchors and release behavior remain unresolved. After the final ascent it transfers to the proposed receiving sequence.

Receiving the heavy stone

The added route moves the upright carrier along a supplied slipway, raises the stone 0.35 m clear, turns it using four independently controlled end-rope bundles, sets it onto two timber support sledges, pulls them over the chamber, then uses a second fixed rope set to lift the beam clear, withdraw the sledges and lower it onto the selected chamber bearings. The carrier stays in the turning bay. All receiving equipment is ghosted. Rig attachment, rope separation, load handoffs, sledge-frame joints, guide anchorage, foundations and equipment recovery remain open.

The oversized human-power trial supplies 48,384 people in four separate ground areas, each 86.4 × 235.2 m, with 1.2 m rope lanes and 1.4 m standing pitch. Each rope has 168 people. Five staggered grip groups keep at least 134 pulling while the others regrip, giving 79.8% effective participation. The force allocation bounds running and starting friction, including a selected static coefficient of 0.9. During insertion and withdrawal of the support sledges, the end ropes are held and crews pull separate haul ropes. The loaded guide heads stay fixed. Detailed holding and regripping hardware remain proposed. This is a possibility screen, not a historical labor estimate.

With selected rope-guide friction μ = 0.1 and a three-π wrap bound, peak allocated effort is 138 N/person. The rope calculation reserves 8,500 N per circuit for hanging weight and supported-rope drag. Segmented guide beams with 0.7 m net diameter, supported every metre, and the selected stone section pass reduced material screens. The timber calculation assumes those short support spans; the ghosted masonry carrying them still needs a structural design. The timber-frame trial also checks post compression and buckling, top-platform bending and shear, material mass and base-haul overturning. Read the force, rope and material checks and their sources and unresolved details.

Plausibility checks

Friction sensitivity

Low rope-guide friction is an assumption requiring a matched test. The paper proposes polished, lubricated guides, but identifies no measured coefficient for this loaded rope and guide. No particular oil is qualified here.

Calculation, assumptions and source hashes · Reduced-model checks · Friction source register · Stone and timber sources

Repeated-cycle inventory and continuity checks

Scheuring’s proposal · Modern indicative flax-rope proxy · Ayrinhac’s worker-traction analysis