Slide-4

Experiments

• The initial experiments were conducted in the area of conceptual design of wind bracing in steel skeleton structures of tall buildings.
  
• Experiments were conducted for a symmetrical three-bay structural system of a 16-story tall building.

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A small space with only four nominal attributes was used:

A1. Static Character of Joints (3 values)

A2. No. of Bays Occupied by Bracing (3 values)

A3. No. of Vertical Trusses (4 values)

A4. No. of Horizontal Trusses (4 values)

The total number of points in the representation space is 144. It may be insufficient to produce truly novel concepts, but sufficient for the initial experiments.

1. Do not generate braced frames wider than 1 bay, i.e.

constraint C1 = (A1=3, A2=2), and constraint C2 = (A1=3, A2=3)

2. Do not generate bracings with more than one horizontal truss, i.e.

constraint C3 = (A4=3), and constraint C4 = (A4=4)

Generate wind bracings with hinged connections with one vertical truss, i.e.

Requirement R1 = (A1=hinged, A3=2)

Concept generation was conducted 6 times up to the moment when the first feasible combination of attributes and their values was produced:

A1 = mixed

A2 = 2 bays

A3 = no vertical trusses

A3 = 2 horizontal trusses

It represents a bracing in the form of a system of two rigid frames in the outer bays connected by two horizontal trusses.

First concept generation produced an infeasible combination of attributes and their values, although obviously satisfying the imposed constraints. The second generation, however, produced the following feasible combination:

A1 = hinged

A2 = 2 bays

A3 = 2 vertical trusses

A4 = no horizontal trusses

It represents a wind bracing in the form of two vertical trusses in the outer bays.

Concept generation was conducted one time and a feasible combination of attributes and their values was produced:

A1 = hinged

A2 = 2 bays

A3 = 2 vertical trusses

A4 = 2 horizontal trusses

It represents a bracing in the form of a system of two vertical trusses in the outer bays connected by two horizontal trusses.

Concept generation was conducted 1 time, and a feasible combination of attributes and their values was produces:

A1 = hinged

A2 = 2 bays

A3 = 2 vertical trusses

A4 = 2 horizontal trusses

Surprisingly, it is the same bracing as produced in the case of the experiment with the Requirements Satisfaction.