by Jaime R. Rico

In the design of a structure, it’s very important to achieve rigidity and stability DESIGN STRUCTURE RIGIDITYSTABILITY we must achieve

RIGIDITY A structure is rigid if it maintains its shape when a force is acting on it RIGID NON/RIGID

STABILITY A structure is stable if it doesn´t fall down or fall over when a force is acting on it STABLE UNSTABLE

STUDYING RIGIDITY All polygons distort, excepto uno. Which one?

TRIANGULATION GUSSET PLATES To achieve rigidity we use triangulation and gusset plates

DESIGN STRUCTURE RIGIDITYSTABILITY we need by means of TRIANGULATIONGUSSETS WIDER BASE LOWER C.o.G. by means of

TRIANGULATION

GUSSET PLATES Are metal * plates used to strengthen a joint

Exercise #1 Indicate if these structures are rigid (R) or non-rigid (NR) R R NR

Exercise #2 Add bars to these structures in order to make them rigid

STABILITY

A structure is stable if it doesn’t topple over easily Two methods are used to give stability: Wider Base Lower Centre of Gravity

BASE, wider o narrower? Which structure is the most stable? Why? CONCLUSION: The wider the base area of a structure, the more stable the structure

Wider Base

Centre of gravity (C.o.G.) If the proyection of C.o.G. is outside the base, the structure topples over

If C.o.G. goes up when we tilt the piece, then it’s stable

If C.o.G. goes down when we tilt the piece, then it’s unstable

Wider Base + Lower C.o.G.

DESIGNING STRUCTURES RIGIDITYSTABILITY we must achieve by means of TRIANGULATIONGUSSETS WIDER BASE LOWER C.o.G. by means of

THAT’S ALL FOLKS!