Week  6:  

Case  Study  -­‐  Structural  Concept  

Name:  Wenjie  Cai  

Case  Study:  The  Queens  College  Members:  Stephen  Kai-­‐Hang  Yuen,  Scott  Andrew  Braithwaite,  Kosta  Archimandritis  

1. Description/Classification  of  Structural  Systems    a) Foundation  &  Footings  

Footing   is   the   first  step  of  construction,  which   is   the  supporting   layer  of  the   structure   of   the   building.   Every   building   needs   foundation   and  footings.   Their   functions   are   to   transfer   loads   (both   dead   loads   &   live  loads)  to  the  ground  and  to  resist  frost.  In  the  construction  drawings,  the  footings  include  piles/piers,  concrete  slab  and  existing  slab  in  place.      

b) Primary  Structure  (Horizontal  and  Vertical)  The  primary  structural  system  is  defined  by  CASE  in  the  National  Practice  Guidelines   for   the   Structural   Engineer   of   Record   as   "the   completed  combination  of  elements  which  serve  to  support  the  building  self  weight,  the  applicable  live  loads,  which  are  based  on  the  occupancy  and  use  of  the  spaces,  and  the  environmental  loads,  such  as  wind,  seismic  and  thermal."  In  the  Queens  College,  the  primary  structure  includes  the  precast  concrete  panels.  

       c) Secondary  Structure  

It  is  defined  as  "elements  that  are  structurally  significant  for  the  function  they   serve   but   do   not   contribute   to   the   strength   and   stability   of   the  primary  structure".  For  example,  the  secondary  galvanized  steel  beam.    

2. Graphic  Structural  Diagrams  a) Foundations  &  Footings  

 This  graph  shows  the  location  of  the  piers  of  the  footings.  

b) Primary  Structure  (Horizontal  &  Vertical)  

 This  is  the  pre-­‐cast  concrete  panel  of  the  primary  structure.  

c) Secondary  Structure  

 This  is  the  steel  beam  for  the  secondary  structure.  

 3. Identification,  description  and  location  of  structural  materials    

a) Precast  Concrete  Panel  Pre-­‐cast   panel   are   mainly   used   as   walls   or   footings   and   structure  materials  for  the  primary  structure  in  the  Queens  College  case.  

 b) Steel  

Steel   is   being   used   for   beam   that   supports   the   building   as   secondary  structure.  It  is  used  for  different  structural  systems  in  this  case  as  well,  for  example,  roofing  system  &  wall  system.  

 c) Timber  

Timber  in  this  case  is  mostly  used  as  rafters  of  roof  system.  

 d) Bricks  

Clay  bricks  are  used  in  this  case  as  walls  or  anchor.  

 

4. Identify  3  Structural  Joints    a) Footing  Pre-­‐cast  Panel  Joint  

 In  this  case,  bolts  are  used  for  connecting  the  cast  in  plate  together  so  that  the  pre-­‐cast  concrete  panels  are  fixed.    

b) Steel  beam  to  pre-­‐cast  concrete  panel  joint  

 This  is  the  joint  of  the  steel  beam  and  pre-­‐cast  concrete  panel.    

c) Pre-­‐cast  Concrete  Panel  Joint  

 

5. Identify  and  explain  the  use  of  different  structural  fixings    a) Weld  

A  weld  is  a  joint  where  two  or  more  pieces  of  materials  have  been  welded  together.  Two  or  more  pieces  join  together  by  melting  and  fusing.  The  base  materials  are  melted  and  added  to  the  filler  materials.  This  will  become  a  strong  joint  once  it  cools  down.  It  is  mostly  being  used  for  joining  metals  together,  for  example  the  structural  steel  members.  In  the  construction  of  the  Queens  College,  continuous  fillet  weld  is  used  in  the  steel  beam  to  pre-­‐cast  concrete  panel  joint  and  also  the  pre-­‐cast  concrete  panel  joint.  

   

b) Concrete  Concrete  is  made  by  mixing  cement,  water,  aggregates  and  admixtures.  Concrete  is  strong  in  compression  but  has  lower  tensile  strength  so  it  also  needs  steel  reinforcement.  It  can  be  formed  in  almost  any  shape  and  widely  used  in  constructing,  such  as  wall  and  floor  systems  as  it  can  withstand  natural  disasters.  In  this  project,  pre-­‐cast  concrete  panels  are  used  for  the  primary  structure.  

 

c) Bolt  Bolts  are  metal  pins  or  rods  that  usually  having  a  head  at  one  end.  It  designed  to  be  inserted  through  holes  in  assembled  parts  and  secured  by  a  mating  nut.  Bolts  provide  strong  bonds  so  that  the  constructions  do  not  break  under  pressure.  In  this  project,  bolts  are  used  in  the  footing  pre-­‐cast  concrete  panel  joint  and  also  the  steel  beam  to  pre-­‐cast  concrete  panel  joint.  

 d) Screw  

Screws  and  bolts  are  both  externally  threaded  headed  fastener.  The  difference  between  screws  and  bolts  is  that  bolt  is  used  in  conjunction  with  a  nut;  and  screws  are  tightened  by  applying  torque  to  the  head.    

 

e) Nail  A  nail  is  a  slim,  pin-­‐shaped  fastener.  It  has  a  point  on  one  end  and  a  head  on  the  other.  Using  nails  is  an  effective  way  of  fixing  or  joining  pieces  of  softwood.  They  are  usually  driven  into  the  material  by  a  hammer.  It  holds  the  materials  together  and  resists  forces  perpendicular  to  them.  

 

6. Sustainability  and  Environmental  Analysis  a) Carbon  Footprint  

‘  The  amount  of  carbon  dioxide  or  other  carbon  compounds  emitted  into  the   atmosphere   by   the   activities   of   and   individual,   company,   country.’  (Dictionary.com   2013)   If   the   building   emit   large   amount   of   carbon  compounds,   it  has  negative   impacts  on  the  environment.  This  concept   is  linked   to   the   distance   of   the  materials   being   transferred.   If  most   of   the  materials   were   from   places   that   are   far   away   from   the   construction,   it  would  be  unsustainable.      

b) Embodied  Energy  "The  quantity  of  energy  required  by  all  of  the  activities  associated  with  a  production   process,   including   the   relative   proportions   consumed   in   all  activities  upstream  to  the  acquisition  of  natural  resources  and  the  share  of  energy  used  in  making  equipment  and  in  other  supporting  functions  i.e.  direct  energy  plus  indirect  energy."  (Treloar,  1994).  This  is  also  related  to  the  materials   as  well.   It   is   not   only   depends   on   the   distance   transfer,   it  also  depends  on  the  energy  needed  to  construct  the  building.      

c) Recyclability  Recyclability   is   the   ability   of   an   item   to   be   reused.   In   construction,   this  means  the  ability  of  the  structural  materials  to  be  recycled.  If  the  building  is   recyclable,   it  means   that   it   is  more   sustainable   that   it  does  not  waste  the  resources.    

7. Economics  Implications  of  decision        

http://www.recampus.com/documents/book15_c01.pdf  http://www.structuremag.org/article.aspx?articleID=321  http://dictionary.com/