Week 2 Constructing Logbook! Catherine Waters 699173!!

Critical collapse point:!The middle of the bridge wasn’t the critical collapse point as I expected. !!It was halfway between the table and the point of applied stress where the collapse occurred.

Applied Stress

3

2

1

I think it occurred here because this would be around about where the compression (applied by Darcy in the centre of the bridge) stopped and the tensions came into play (the origin of the tension would be the table where the ends of the bridge are roughly secured)… so the most stress on the bridge (where it ended up breaking) would be at this point where compression becomes tension.

References !1, 2, 3 - Gorse, C. A., Johnston, D., & Pritchard, M. (Hons), PhD. (2012). A dictionary of construction, surveying, and civil engineering [electronic resource] / by Christopher Gorse, David Johnston, Martin Pritchard. Oxford : Oxford University Press, 2012.!!4 - Jfccivilengineer.com, (2014). Columns. [online] Available at: http://www.jfccivilengineer.com/columns.htm [Accessed 21 Aug. 2014].!!5 - Engineering-dictionary.org, (2014). BRACING meaning | NCRS Construction Dictionary. [online] Available at: http://www.engineering-dictionary.org/NCRS-Construction-Dictionary/BRACING [Accessed 16 Aug. 2014].!

Key Terms !!Frame - a load-bearing structure made up of columns, beams, and connections.1!!Tension - the stress that must be exceeded to cause tensile fracture.2!!Span - the horizontal distance between two supports.3!!Column - a vertical member designed to transmit a compressive load.4 !!Bracing - ties and rods used for supporting and strengthening carious parts of a building. Used for lateral stability for columns and beams.5!

The critical collapse point occurred at one of these joints; where 2 of the 300mm lengths had been glued together and then attempted to be reinforced by a smaller segment of

balsa wood.

Our aim was to secure the two outer lengths of balsa with diagonal strips to form triangular spaces to that loads could be supported if placed onto one of the outer lengths. When we put the bridge up between the tables it has flat instead of upright so that the triangular structures had no effect on supporting the load.

Aspiration

Reality

Week 2 Constructing Logbook! Catherine Waters 699173