Advanced Structural Design - Lecture note 09 P2.pptx

8/13/15Prepared by: Eng. Chamil Duminda MahagamageB.Sc.Eng (Hons), C Eng, ME(S!)1n"erna"ional College o# Business and $echnology6102BEUG- Lecture Note: 09Pre-stresslosses(Cl.5.10, EC2)Lossofpre-stressesisthediere!ce"et#ee!the$%c&i!'forcei!the te!do!%tthepre-stressi!'st%'e%!dtheforce%fter(ossesh%)e occurred*+o,eofthe(ossesoccuri,,edi%te(-#he!theforceis tr%!sferredtotheco!crete.e*'e(%sticshorte!i!'ofthe,e,"er* /ther(ossesoccur#ithti,e.e*'*creepoftheco!crete*0he$%c&i!' force does !ot e1ceed 902 of the ch%r%cteristic stre!'th of the te!do! %!d is 'e!er%((- !ot (ess th%! 352 4c( 5*10*342).E52)* 6! pr%ctice tot%( (ossesofthe$%c&i!'force%re#ithi!ther%!'eof152-702*6f(%r'e (ossesofpre-stressoccurthe!the%d)%!t%'esofpre-stressed co!crete.e*'*!ocr%c&s%tser)ice(o%d.%re(ost*6tistherefore %d)%!t%'eous to ,i!i,i8e the (oss of pre-stress*perce!t(ossofpre-stress9100:4$%c&i!'stress-;!%(stress)/4$%c&i!' stress)8/13/15Prepared by: Eng. Chamil Duminda MahagamageB.Sc.Eng (Hons), C Eng, ME(S!)2n"erna"ional College o# Business and $echnology6102BEUG- Lecture Note: 09 Factors afect to loss of pre-stress%ela&a"ion o# "he s"eel ('(') *)Shrin+age o# "he concre"e('(, *)Creep o# "he concre"e(-('- *)Dra. in during anchorage(/(- *)0ric"ion in "he duc"s and a" anchorage(1(2 *)Elas"ic de#orma"ion o# "he concre"e('('/ *)Note-:6!iti%((-.i!desi'!c%(cu(%tio!s.the(ossofpre-stressis esti,%ted fro, p%st e1perie!ce %!d (%ter. #he! the sectio! sh%pe %!d si8eh%s"ee!deter,i!ed.%,ore%ccur%tec%(cu(%tio!is,%de*< re%so!%"(-%ccur%teesti,%tio!ofthe(ossofpre-stressisre=uired "ec%use it %ects ser)ice (o%d co!ditio!s* %)* >e(%1%tio! of stee( 4c(* 5*10*7. c(* 3*3*2 %!d