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Construction Workshop  Report   Date:  5th  May  2014   Location:  Level  1,  757  Swanston  Street   Aim:   Use  two  pine  timbers  and  two  pieces  of   plywood  to  construct  and  test  a   bridge-­‐like  structure  to  support  the   maximum  load  from  above.     Materials  and  tools  used:   • Two  pine  timber  bars   • Two  pieces  of  plywood   • Several  steel  and  iron  nails   • Hammer   • Hand  saw   • Cutting  pad   • Pencils  and  rulers  with  right  angle  

2 columns  were  designed  in  two   places  where  the  3  spanning   distances  remained  the  same.    

3 or  more  steel  nails  per  joints  

Design  of  structure:     Idea  of  design:   Considering  about  what  our  group  had:  2   pine  timber  bars  and  2  pieces  of  plywood,   our  group  decided  to  construct  an  I-­‐shape   structure,  which  required  two  pines  bars   and  only  one  piece  of  plywood.     The  above  is  the  sketch  of  what  we  were   going  to  design,  we  expected  our  structure   contains  the  following  special  aspects.     • Diagonal  bracing  on  both  sides   increased  the  integrality  of  structure.  

Description and  Explanations:     • 3  spans  only  reach  300mm  each     We  expect  this  design  had  the   advantage  of  evenly  transferring  load   along  the  way  through  columns  and   base,  so  that  no  scenario  such  as   collapsing  on  one  side  would  occur     • Columns  are  made  of  the  same   material  of  upper  beam  and  base  at   the  bottom,  which  is  pinewood.     Choosing  identical  materials  rather   than  different  ones  would  minimize   the  property  difference,  such  as   strength  or  ability  of  stretching  and   compressing.     • Bracings  are  only  placed  between  two   columns  in  the  middle.     This  is  one  lazy  design,  because  we  

expect the  load  to  act  in  the  middle  of   this  structure.     At  least  3  steel  nails  were  used  in   each  joint.  

Considering  that  what  we  were  doing   was  just  a  simple  structure,  we   thought  the  rigid  joints  would  be  the   most  stable  and  suitable  joints  for   those  connections.  As  a  result,  we   added  many  nails  in  to  resist  their   vertical,  horizontal  movement  as  well   as  rotating  forces.     •

One  consideration  of  this  design  was   aestheticism;  the  other  consideration   was  to  minimize  the  tension  of   plywood  before  testing.     Actual  testing:  

Shapes of  diagonal  bracings  were  not   rectangle,  but  the  shape  matched  the   columns  and  upper  beam.  

Our  structural  was  relatively  shorter  

compared with  the  structures  made  by   other  groups,  so  we  added  few  timber   bricks  to  support  the  edges  of  it.     From  0kg  to  100kg:   Nearly  nothing  happens,  it  is  easy  to  add   loads  on  the  structure,  and  only  tiny  noise   between  nails  and  timber  was  heard.     From  100kg  to  200kg:   Adding  loads  were  going  to  be  harder,   noise  made  by  fiction  became  relatively   louder.  Unfortunately,  the  reading   suddenly  dropped  because  one  nail  did   not  be  pushed  in  deeply  enough.  After   resolving  the  problem,  tiny  noise  of   cracking  could  be  heard  when  more  loads   were  added.     From  200kg  to  300kg:   Noise  of  cracking  became  louder,  upper   beam  and  base  began  to  bend  and   undergone  compression.  At  the  same  time,   the  diagonal  bracing  (plywood)  started  to   stretch  and  undergone  tension.  

From  300kg  to  400kg:   Noise  of  cracking  became  very  loud,   beams  were  bending  in  a  large  scale,  while   plywood  was  stretched  and  seemed  to   reach  the  maximum  stretching  point.     From  300kg  to  489kg:   Noise  not  only  from  pinewood,  but  also   plywood  became  even  louder  than   previous  conditions.  Nails  seemed  to  be   pulled  out,  upper  beams  started  to  fail  and   few  cracks  could  be  observed.     Finally,  the  structure  undergone  the   maximum  deflection  and  be  broken  from   the  middle.     Maximum  depth:  410mm   Maximum  load:  489kg            

Conclusions  and  evaluations:     The  structure  was  able  to  support  up  to   489kg  of  load,  which  is  impressive,  but   there  were  also  some  weakness  and   disadvantages  associated  with  the   structure.  

Nails should  be  put  in  in  a  correct   way.  For  example,  nails  should  go  to   the  structure  vertically,  not  with  any   other  angles.   Follow  the  instructions  to  make  a   longer  structure.

Be more  efficient  with  the  given   materials  and  time.  During  the   working  process,  our  group  only  used   one  piece  of  plywood,  which  is  a  kind   of  wasting.    

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