Earthquake competition Workshop on analytical model

Analytical Model by using Computer Software Error / Deviation from real behaviors comes from: Imperfection of Idealization Data Accuracy

Minimum Data Input for Structural Analysis Geometry Material Section Restraint Load

1. Geometry 1 bay x 1 bay (15 cm x 15cm) 9 stories (@5 cm)

1. Geometry (define grids)

1. Geometry (define grids)

1. Geometry (draw frames) Draw Quick Draw Frame

2. Material (define) DefineMaterialAdd New Material Static & Dynamic

3. Section (define) Define  Section Properties Frame Section Add New Property  “Concrete” Rectangular

3. Section (assign) View  Set Display Option  View by Color of

3. Section (assign) Select all  Assign  Frame  Frame Section  “5mm”

4. Restraint (assign) Select “Foundation” Joints  Assign  Joint  Restraint

5. Static Load Draw “Platforms”  Steel, 5cm x 15cm x 3mm “Extrude”

5. Static Load (apply loads) 10 kN in x-direction on each platform centroid Define  Load Pattern  Add Live Load

5. Static Load (apply loads) Select each platform centroid Apply Frame Point “Live” Load in x direction

Run Analysis (F5) Display  Show Deformed Shape  Live Load See U1 (x direction of a point)

Should Be Noted: With the same material, restraint, and load: More “U1”  More Deflection  Less Stiffness  Weaker Structure “Modify” Geometry & Section (see Competition rules)  to get “minimal” U1  make your Structure stronger Aside of geometry & section design, each team may have variations of : joint strength, precision of construction (eccentric load !!!)

Static versus Dynamic Loads In reality, the deflection = U1 (static) x Dynamic Magnification Factor

5b. Dynamic Load Define  Function  Time History  Sine Adjust the input

5b. Dynamic Load Delete the previous static load Select all platform  Assign gravity Live Load

5b. Dynamic Load Define Mass Source  From Loads

5b. Dynamic Load Define  Load Cases  Add New

Run Analysis (F5) View “U1” @1 sec, @2sec, etc. & Envelope

Again: “Modify” Geometry & Section (see Competition rules)  to get “minimal” U1  make your Structure stronger Important (dynamic analysis): Stiffer structure  does not automatically show less U1 (Resonance Effect  See video) If the natural frequency of structure is far from that of the ground motion  no resonance effect, all logics are the same as static analysis