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IABSE  Working  Group  Forensic  Structural  Engineering    

Pre-­‐Conference  Short  Course    

Forensic  Structural  Engineering  Causes  of  Failures  &  Investigations  

Geneva,  September  22,  2015  

Course  Chairmen:  Fabrizio  Palmisano  &  Karel  Terwel      

 Synopsis  

“Engineering  investigation  of  the  causes  of  structural  failures  of  buildings,  bridges,  and  other  constructed  facilities,  as  well  as  rendering  opinions  as  to  the  cause(s)  of  the  failures  and  giving  testimony  in  judicial  proceedings,  is  a  field  of  professional  practice  of  its  own,  often  referred  to  as  forensic  structural  engineering”  (R.T.  Ratay,  2010).  This  short  course  is  one  of  the  activities  of  the  IABSE  Working  Group  ‘Forensic  Structural  Engineering’.  The  ultimate  objective  of  the  WG  is  to  mitigate  structural  failures  and  improve  forensic  engineering  practices.  To  these  ends  the  activities  of  the  WG  include  seminars,  workshops,  short  courses,  presentation  and  publication  of  papers  for  the  purpose  of  increasing  the  awareness  and  working  knowledge  of  students  and  practicing  engineers  of  the  causes,  prevention  and  consequences  of  failures,  for  the  ultimate  goal  of  ensuring  the  safety  and  reliability  of  structures.  The  WG  organized  sessions  on  forensic  structural  engineering  at  the  IABSE  Madrid  2014  symposium  which  were  well  attended,  demonstrating  that  there  is  much  interest  in  the  practice  of  forensic  structural  engineering.  The  short  course  is  aimed  at  structural  engineers  who  want  to  acquire  a  working  knowledge  of  forensic  structural  engineering,  practicing  forensic  engineers  who  want  to  learn  from  and  share  with  other  practitioners,  and  university  students  who  wish  to  gain  an  advanced  understanding  of  forensic  structural  engineering  to  underpin  future  research/career  interests.          

Objectives  Provide  structural  engineers  with  an  insight  to  the  state-­‐of-­‐the-­‐art  practice  of  forensic  investigation  of  structural  failures,  and  into  lessons  learned  from  failures  to  understand  and  mitigate  design  errors  and  construction  defects.        

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Schedule    

• 9:00  –  9:30  Registration  and  coffee    

• 9:30  –  10:00  Robert  T.  Ratay  1)  An  Overview  of  Forensic  Structural  Engineering    

• 10:00  –  11:00  Karel  Terwel  2)  Causes  of  structural  failures  and  underlying  factors  Ø Goal:  give  an  overview  of  characteristics  of  failures  and  causes.  Ø Based  on  study  of  741  Dutch  cases  with  comparison  of  international  studies.  Ø Characteristics  of  failures:  types  of  structures,  types  of  structural  elements,  types  of  damage,  fatalities,  

loads  during  failures,  elements  involved,  used  materials,  main  causes  (design/construction  errors,  etc.),  phase  of  discovery.  

Ø Comparison  of  international  cases:  studies  of  e.g.  Schneider  Matousek,  Fruehwald,  Hadipriono.    Ø Selected  information  from  the  WG’s  recent  survey  of  forensic  engineering  practices  in  IABSE  member  

countries:  some  countries  suffer  more  from  extreme  weather  and  earthquakes  -­‐>  relative  influence  of  human  errors  is  smaller.  

Ø Underlying  factors:  human  errors?  It  appears  that  organizational  factors  such  as  safety  culture,  allocation  of  responsibilities,  risk  management,  control,  communication  and  collaboration,  and  knowledge  infrastructure  are  determining.  

 • 11:00  –  11:15  

Coffee  break    

• 11:15  –  12:15  Huibert  Borsje  &  Karel  Terwel  3)  Cases  of  failures/collapses  Highlighting  some  important  types  of  failures:  Ø Detailing  concrete  (balconies  Maastricht).  Ø Facades  (Façade  residential  building  Amsterdam).  Ø Temporary  structures  during  construction  (temporary  support  for  floor  of  B-­‐tower).  Ø Unexpected  behaviour  of  materials  (incorrect  stainless  steel  in  swimming  pools,  alkali-­‐silica  reaction,  

Nickel  Sulphide  inclusions  in  glass)    

• 12:15  –  13:30  Lunch    

• 13:30  –  14:30  John  F.  Duntemann  4)  The  forensic  investigation  process  Ø First  steps  after  a  failure.  

o Field  observation.  o Search  for  survivors/victims.  o Assurance  of  public  safety.  o Temporary  stabilization,  repair.  

Ø Assessment.  o Questioning.  o Existing  documents.  o Inspections.  o Testing.  o Re-­‐calculations.  o Structural  performance.  o Reporting.  

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 • 14:30  –  15:30  

Fabrizio  Palmisano  5)  Investigation  of  failures  in  concrete  and  masonry  structures  +  specific  cases  Participants  will  be  interactively  involved  in  the  lecture.  Two  different  cases  will  be  discussed:  the  collapse  of  Giotto  Avenue  building  in  Foggia  (concrete  structure)  and  the  partial  collapse  of  ‘Palazzo  Edilizia’  in  Salerno  (masonry  structure).  The  application  of  the  methodology  described  in  the  previous  lecture  will  be  step-­‐by-­‐step  analysed  with  reference  to  the  case  studies.  The  case  studies  will  focus  mainly  on  the  following  issues:  Ø Giotto  Avenue  building  collapse:  material  defects,  conceptual  and  detailing  design  deficiencies,  linear  

and  probabilistic  analyses.  Ø Partial  collapse  of  ‘Palazzo  Edilizia’:  surveys,  testing,  linear  and  nonlinear  analyses,  hidden  structural  

defects.    

• 15:30  –  16:00  Tea  break    

• 16:00  –  16:45  Huibert  Borsje  7)  Investigation  of  failures  in  steel  structures  +  specific  case  In  July  2011,  during  construction  work,  the  roof  of  the  football  stadium  Grolsch  Veste  in  the  Netherlands  partially  collapsed.  As  a  result  of  this  accident,  two  workers  were  killed  and  nine  injured,  some  of  them  critically.  After  this  accident  an  investigation  was  started  to  determine  the  technical  cause(s)  of  the  collapse.  This  investigation  was  set-­‐up  as  described  in  the  previous  lecture  about  the  forensic  investigation  process.  The  participants  will  be  guided  along  the  steps  of  the  process  the  investigators  have  taken  to  solve  the  problem.      

• 16:45  –  17:00  Huibert  Borsje  6)  WYSIATI  –  What  you  see  is  all  there  is  Most  of  us  go  through  life  assuming  (and  sometimes  insisting)  that  we  see  ‘everything’  and  that  we  are  right  about  our  observations.  This  short  lecture  will  show  the  participants  that  we  often  don’t  see  everything  we  have  to  see  and  sometimes  even  see  non-­‐existing  things.  It  will  be  explained  why  it  is  so  difficult  to  separate  observation  and  interpretation.    

• 17:00  Fabrizio  Palmisano  &  Karel  Terwel  7)  Closing  

           

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Lecturers’  biographical  notes      Huibert  Borsje,  MSc.,  is  a  structural  engineer,  graduated  at  the  Delft  Technical  University  and  now  working  as  a  senior  scientist  at  TNO  the  Netherlands.  From  the  beginning  of  his  career,  over  25  years  ago,  he  is  investigating  damage.  The  first  years  he  was  mainly  focusing  on  damage  analysis  of  concrete  structures,  both  material  related  damage  and  structural  damage.  Later  on  his  work  developed  into  forensic  engineering  of  structural  damage  in  general.  Last  years  he  has  investigated  several  severe  collapses  of  buildings  and  other  structures,  in  order  of  the  Public  Prosecution,  the  Labour  Inspectorate  of  the  Ministry  of  Social  Affairs  and  Employment  and  The  Dutch  Safety  Board.    John  Duntemann,  P.E.,  S.E.,  is  a  Senior  Principal  at  Wiss,  Janney,  Elstner  Associates,  Inc.  in  Northbrook,  Illinois,  USA.  He  is  a  licensed  structural  engineer  primarily  engaged  in  the  assessment  and  rehabilitation  of  existing  structures,  and  specializes  in  the  assessment  of  structural  distress  and  serviceability  problems.  He  is  a  graduate  of  the  University  of  Illinois  at  Urbana-­‐Champaign,  where  he  received  a  Bachelor  of  Science  degree  in  Civil  Engineering  and  a  Master  of  Science  in  Structural  Engineering.  He  is  a  member  of  IABSE  and  serves  on  Working  Group  8  Forensic  Engineering  and  the  Outstanding  Structure  Award  (OStrA)  Committee.  He  is  also  a  member  of  the  American  Society  of  Engineers  (ASCE)  Standard  Committee  for  Minimum  Design  Loads  for  Buildings  and  Other  Structures  (ASCE  7)  and  a  contributing  author  to  the  Forensic  Structural  Engineering  Handbook  published  by  McGraw-­‐Hill.      Fabrizio  Palmisano,  MEng.,  Ph.D.,  P.E.,  is  an  Adjunct  Professor  of  Structural  Mechanics  at  the  Politecnico  di  Bari  and  Director  of  the  Engineering  and  Architecture  Consulting  Company  ‘PPV  Consulting’.  He  was  responsible  for  many  structural  projects  in  Italy  and  in  2005  he  received  the  fib  ‘Diploma  to  Younger  Engineers’  award  in  the  design  and  construction  category.  He  was  involved  in  the  vulnerability  assessment  of  many  buildings  and,  on  behalf  of  the  Public  Prosecutor  Office,  he  investigated  some  of  the  most  important  collapses  occurred  in  Italy  in  the  last  15  years.  In  1998  he  received,  from  the  Italian  Minister  of  the  Interior,  the  'Diploma  of  merit'  with  medal  for  the  service  done  in  the  seismic  vulnerability  assessment  of  buildings  struck  by  the  1997  Umbria-­‐Marche  earthquake.  He  is  author  of  more  than  90  articles  on  structural  engineering,  referee  of  scientific  international  journals  and  member  of  scientific  and  technical  Italian  and  International  Committees.      Robert  T.  Ratay,  Ph.D.,  P.E.,  is  a  structural  engineer  in  private  practice  and  a  Visiting  Professor  at  Columbia  University  in  New  York,  where  he  developed  and  teaches  the  graduate  course  of  Forensic  Structural  Engineering.  His  five  decades  of  practice  encompass  design,  failure  analysis,  and  teaching.  Dr.  Ratay  has  been  an  expert  consultant/witness  on  some  200  cases  of  structural  problems.  He  is  the  editor  of  three  books:  Handbook  of  Temporary  Structures  in  Construction,  3rd  edition,  Forensic  Structural  Engineering,  2nd  edition,  and  Structural  Condition  Assessment;  published  numerous  articles  and  lectured  widely  in  the  US  and  abroad  on  the  subject  of  forensic  structural  engineering.  Dr.  Ratay  is  a  Fellow  of  IABSE,  and  the  founding  Chair  of  its  Working  Group  on  Forensic  Structural  Engineering.          Karel  Terwel  (1975)  studied  Civil  Engineering  at  Delft  University  of  Technology  (DUT)  and  graduated  in  2001.  From  2001  until  2007  he  was  working  as  a  structural  designer/  project  leader  at  Zonneveld  Engineers  on  complex  structural  designs  like  two  office  towers  (height:  146m)  for  the  government  in  The  Hague  (awarded  Dutch  concrete  prize  2013)  and  the  Palace  for  music  in  Utrecht.  Since  2007  he  has  been  a  lecturer  (from  2015:  assistant  professor)  on  structural  design  at  DUT.  In  2013  Terwel  founded  Coenraedt  B.V.  He  is  committed  to  providing  consultancy  in  investigations  of  structural  failures,  second  opinions  and  structural  risk  management.  He  finished  his  PhD  on  influencing  factors  for  structural  safety  in  2014.  He  is  member  of  the  Platform  Structural  Safety  in  the  Netherlands,  of  IABSE’s  WG8  Forensic  Engineering  and  of  the  editorial  advisory  board  of  the  ICE’s  journal  Forensic  Engineering.