Structural Engineering & Statics
where the load goes
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Drawing as calculation — page 3

Essays 49 to 50 of 50 on this thread, in the same order.
the centre200 kN80 kNλ = 1.339 · lowest over the hinge position 1.339 at 100% of the rafterthe centre sits 5.5 m above the ridge Equilibrium

The point the mechanism turns about

A collapsing frame is a chain of rigid pieces, and every piece is rotating about some point. Find those points and the whole collapse load reads off two ratios of lengths, with no trigonometry anywhere — and for a pitched roof the point in question is well above the top of the drawing.

 36 × 36210 non-zerosof 1296 entriesbandwidth 13nullity 3before the supports go indense solve 16kbanded 6ka member reaches only its own two nodes Deflection

The matrix that replaced the hand methods

Moment distribution passes moments round a frame until they stop moving. Virtual work computes one deflection at a time. Both are exact and both stop scaling in the low tens of members. What replaced them adds no physics at all — the whole of the invention is the bookkeeping.

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