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Outrigger sweep on a tall core

A concrete core with one outrigger to two perimeter columns: move the outrigger and watch the top drift, against the closed form, over the whole height.

Parameters

40
3.5
m
0.5
× H
9
m
12
m
1
m²
30
kN/m
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Results

Top drift with the outrigger 268.82 mm Reference Smith & Coull = 268.82 mm · difference 7.5 × 10−9 %
Top drift of the core alone 364.18 mm Reference wH⁴/8EI = 364.18 mm · difference 7.8 × 10−9 %
Drift reduction 26.186 %
Column axial force 2,138.5 kN Reference Smith & Coull = 2,138.5 kN · difference 7 × 10−9 %
Outrigger level used (nearest storey) 0.5 × H (20/40)
Best outrigger height (sweep) 0.75 × H

Certified (linear solve)· relative error bound ≤ 2.8 × 10−6

Top drift against outrigger height (mm)

mm0100200300400050100150z (m)

A square concrete box core (E = 30 GPa, walls 0.3 m) is a cantilever under a uniform wind load. One stiff outrigger (I = 2 m⁴) ties it to two perimeter columns, pinned at the ground and at the outrigger, which carry only axial force. Each slider move solves the model once for the chosen level and once for every storey, so the chart is the engine’s own sweep. The top drift and the column force are shown beside the Smith & Coull compatibility solution for one outrigger, with the outrigger’s bending and the columns’ shortening included.

Verified by: Tools: cantilever beam, checked against closed forms

A teaching example, not a design check. SI units: m, kN, MPa. Published by Ergodic Group.