Modelling

PhysicalGraphical

MathematicalStatistical

Modelling

• Models represent reality– Crash testing – Dangerous procedures can be simulated

Modelling

• Working out ideas or hypothesis by building physical models

Modelling

• Using computers to generate mathematical, graphical or statistical models

West Point Bridge Designer

Modelling using West Point Bridge Designer

• Work through the tasks on the worksheet

• Use the tables to examine Mathematical modelling– The costing data– The load test data– The members property data

• Load test the bridge using the animated graphical interface and test

Modelling using Excel

• Mathematical data can be hard to understand and read, therefore the information can be graphically represented using Excel– Copy the Cost Calculations Report and

paste into Excel– Edit the data so only items that cost,

remain in the spreadsheet– Create 2 types of charts to represent the

different ‘Types of Costs’– Save and Printout

Physical Modelling

• Making the Warren Thru Truss Bridge

– Using the straws and joints to make and test the bridge

– Using the plastic maccarno to build and test the bridge

• Take photos and record all observations

The Purpose of Modelling

• Advantages– Time saved– Cost of materials

reduced– Computer

simulations cost less e.g. car crash testing

– Judge peoples reaction e.g. aesthetics

– Standardisation

• Disadvantages– Simplicity of models

lead to aspects being overlooked

– Scaled models can be misleading

– Mathematical models only as good as the formulas

– Computer models create delusions of infallibility

Modelling

Warren Thru Truss - Types of Cost

$0.00$20,000.00$40,000.00$60,000.00$80,000.00

$100,000.00$120,000.00

Mat

erial

Cost

(M)

Connec

tion

Cost (

C)

Produc

t Cos

t (P)

Deck C

ost

Excav

ation C

ost

Abutm

ent C

ost

Cost

Dennis H. Mahan Memorial Bridge

Cost Calculations Report (Design Iteration #1)

Designed By: I. M. Bridgemaster

11/7/2007

Type of Cost Cost

Material Cost (M) $102,197.12

Connection Cost (C) $3,300.00

Product Cost (P) $600.00

Deck Cost $20,000.00

Excavation Cost $92,000.00

Abutment Cost $8,000.00

TOTAL COST $226,097.12

Warren Thru Truss - Types of Costs

Material Cost (M)

Connection Cost (C)

Product Cost (P)

Deck Cost

Excavation Cost

Abutment Cost

Modelling

• You can model the Warren Thru Truss bridge using Google Sketchup

• Try modelling the bridge using another material– Wood– Spaghetti

Links

• http://bridgecontest.usma.edu/download.htm

• http://www.cardesignonline.com/