Engineering As Design

Transcription

1 Engineering As Design Toni Kotnik Professor of Design of Structures Aalto University Department of Architecture Department of Civil Engineering Rak Seminar in Structural Engineering Stress-Strain Diagram steel concrete wood natural stone 2 1

2 Plasticity Theory irst undamental Theorem of Limit Analysis in a rigid, perfectly plastic continuum, plastic flow cannot occur under loads for which a stable, statically admissible stress field can be found. Plasticity Theory Statics relates external forces with stresses physically compulsory Strength of Material relates stresses with strains matter of modelling Kinematics relates displacements with strains physically compulsory many possible stresses that fulfill equilibrium unique solution of stresses and deformation many possible deformations that fulfill compatibility lower bound solution ultimate load upper bound solution 3 Plasticity Theory irst undamental Theorem of Limit Analysis in a rigid, perfectly plastic continuum, plastic flow cannot occur under loads for which a stable, statically admissible stress field can be found. Plasticity Theory Statics relates external forces with stresses physically compulsory many possible stresses that fulfill equilibrium lower bound solution 4 2

3 Plasticity Theory irst undamental Theorem of Limit Analysis in a rigid, perfectly plastic continuum, plastic flow cannot occur under loads for which a stable, statically admissible stress field can be found. Plasticity Theory Statics relates external forces with stresses physically compulsory many possible stresses that fulfill equilibrium lower bound solution for design purposes it is enough to focus on equilibrium of an insbribed inner force flow 5 compression & tension 6 3

4 equilibrium geometric description the forces add up to zero the line of action of the forces intersect in one point x = 0 = y M = 0 analytic description 7 reciprocal form-force relationship 8 4

5 duality: principal of inversion 9 duality: principal of inversion analysis of structural behaviour of cuppola of St. Peter by Giovanni Poleni,

6 duality: principal of inversion Antoni Gaudi: hanging models of Sagrada amilia, duality: principal of inversion similar pattern of force flow but different structural behaviour! 12 6

7 compression & tension ball-and-spring model of transmission of forces in solid materials - - compression tension 13 compression & tension t t ball-and-spring model of transmission of forces in solid materials - - compression unstable tension stable 14 7

8 compression & tension thick thin similar pattern of force flow but different structural behaviour & different design strategies! compression tension unstable stable 15 Directed Materialization Robert Maillart Salginatobel Bridge Schiers, Switzerland, 1930 Robert Maillart: Salginatobel Bridge, Schiers, Switzerland,

9 Directed Materialization overlay of inner force flow of all possible load conditions in order to define the geometry of the structural element Robert Maillart Salginatobel Bridge Schiers, Switzerland, Directed Materialization Sir Horace Jones Tower Bridge London, UK,

10 Bracing Vladimir Shuhov Arcade, GUM Shopping Center Moscow, Russia, Bracing Richard Brosi & Obrist Bus Station Chur, Switzerland,

11 Bracing 21 Bracing 22 11

12 Bracing Grimshaw Architects Airside Center, Zurich Airport Zurich, Switzerland, Bracing Norman oster Renault Distribution Centre Swindon, UK,

13 Bracing Norman oster Renault Distribution Centre Swindon, UK, design thinking matter spectra of possibilities force flow Engineering is a design discipline! design idea is required to make a decision 26 13

14 design thinking engineering is not a science engineering requires efficiency, economy, and aesthetics engineering is a new type of art Engineering is a design discipline! 27 exercise cantilevering canopy, SUTD East Coast Campus, Singapore 2015 or the cantilevering canopy a very typical technical solution has been conducted based on heavy use of material. The resulting expression is one of heaviness and stability. Base on variation of the inner force flow and material articulation develop four new type of solution for the canopy that express: dynamic equilibrium fluidity levitation feminity or each example draw a section, the inner force flow and give a short description how your solution expresses the attribute. Deadline: at 16:00, upload one pdf for each group at MyCourses 28 14