BLAST RESISTING CONCRETE WALLS K.N .Indiketihewage Thesis submitted to the in partial fulfillment of the requirements for the Degree of Master of Engineering in Structural Engineering Design. Department of Civil Engineering University of Moratuwa Sri Lanka. December, 2008. 93027 ABSTRACT Today people around the world wake up, eat, live and sleep with terrorism. It has become a global menace. As a citizen lives in a country hit by a civil war for over three decades gave me motive and courage to set off this project. The project was basically planned to carry out in two parts, i.e. the literature survey and the experimental investigation. Initially a comprehensive literature survey was carried out to cover the several areas. As terrorism is the main reason to for this project to exist, the literature survey was started off with an insight view of terrorism, its motives, methods and objectives of terrorist organisations. Later the survey was expanded to explosives and weapons frequently used by the terrorists. At the next stage of the literature survey, a review was done on the existing knowledge of blast resisting designs followed by a study on the various structural responses to blast loadings. The literature survey was further extendedto design of blast resisting structures and finally to design of elements to resist blastloadings was also completed. As a measure to increase the resistance to blast loadings, important characteristics of steel fibre and welded meshes were also studied. The experimental investigation of the project was directed to find solutions to two situations, in battle field or terrorist attack. First series of tests of the project were concentrated on close range high explosive detonations. Unfortunately, this part of the project had to be abandoned due to unavailability of TNT explosives in slab form. This brought to the abrupt end to the test series one of the project. The second series of tests were focused more on a military situation, where terrorist fire with RPG 7 at bunkers. After the testing, it was revealed that the designed concrete panel might barely withstand the RPG 7 fire. The reason for this may be the fact that the effects of small steel balls were not considered in the design. Only the amount of explosives and the distance from the centre of the RPG 7 mortar to panel were considered T A B L E O F C O N T E N T S P A G E N O ! ' ' ' I . R A C T K~'\)OWLEDGEMENTS ':~ r O F F I G U R E S < i O f · T A B L E S • 1 ! i \ r l O N S l N T R O D U C T I O N \ . 1 B a c k g r o u n d 1 . 2 O b j e c t i v e s o f t h e S t u d y L l M e t h o d o l o g y L l T E R A T l J R E S U R V E Y 2 . 1 2 . 2 , . , . , . : . . _ 1 2 . 4 2 . 5 ' ) r ~.0 T e r r o r i s m : i t ' s M o t i v e s . M e t h o d s & I m r n e d i a t e R e s u l t s E x p l o s i v e s , W e a p o n s & O t h e r I m p o r t a n t M a t e r i a l s U s e d R e v i e w o f E x i s t i n g K n o w l e d g e f o r B l a s t L o a d E f k c t s S t r u c t u r a l R e s p o n s e t o B l a s t L o a d i n g D e s i g n o f B l a s t R e s i s t i n g S t r u c t u r e s D e s i g n o f E l e m e n t s i n R e i n f o r c e d C o n c r e t e & S t r u c t u r a l S t e e l 2 . 7 I n t r o d u c t i o n t o t h e D e s i g n o f R e i n f o r c e d C o n c r e t e E l e m e n t s t o R e s i s t B l a s t L o a d i n g 2 . 8 I m p o r t a n t C h a r a c t e r i s t i c s o f S t e e l F i b r e R e i n f o r c e m e n t - I l l - v V I I V I I I X X I 0 1 0 2 0 3 0 4 0 5 0 6 1 1 2 4 2 g . , . . . , . ) . ) 5 1 6 1 7 0 ~ll z [! 60! 901 66 96 (6 9L tL SNOISi !LJNO:) SNOISS!L)SlCJ 1? S.U: lSTH ;"U!J ~)d~ .I;JpUn S[;iiJBd l!B,\\ J() ilU!1SZl.J spBOllSntH :'l;\[SO[dX] lfX!f 1 J;)pun St.JUHd UBi\'\ JO ~1U!lS0 L UOi1Jrlp0JlUj SNOU.VDUS:1ANI. 1\lJNJv\i!(EldXJ uo~pnpo.r~ur SD~-ilG\iCn J,SV"JH ~H-LL .LSls::nl OJ T-INVd TlVi\\ JO NDJS:In 1Y?I1U:YnU.S ;y~~ A C K N O \ V L E D G E M E N T S ! w o u l d 1 i k , : 1 < 1 t h a n k t h e f o l l o w i n g i n s t i t u t i o n s a n d p e r s o n n e l f e n · l h c :~upport r e r H k n . : d t o : n c i n c o m p k : t i n g thi~~ p r o j e c t a f t e r a l o n g s t r u g g l e . • T h e Vic~.: C h a n c e l l o r o f U n i v e r s i t y o f M o r a t u v v a . D e a n . F a c u l t : c v o f F n g i n c c r i n g . ! l e a d o f D e p a r t m e n t C i v i l E n g i n e e r i n g . A c a d e m i c S t a f r o f D e p a r t m e n t o f C i v i l l ' n g i n , : e r i n g f i x a l l o w i n g m e t o c o m p l e t e t h i s J ] W j c c L " " P r o j e c t S u p e r v i s o r , P r o f . S I ' . 1 A N a n a y a k k a r a f o r h i s g u i d a n c e . . c n c o u r a g e J n c n L a n d s p e n d i n g h i s \ ' a l u J b l c t i m e t o d i r e c t l h i s p r o j e c t t o a HH'n~ m e a n i n g f u l c m n p l e t i o n . " ' ·rhl~ P r o j t : d C o o r d i n a t o r . D r . ( M r s ) P n : m i n i H e t t i a r a c h c h i f o r h e r u n t i r i n g e f f o r t s w m a k . . : thi~~ p r o j e c t a r e a l i t y a n d P r o f M T R J a y a s i n g h e f o r hi~ t i m e l y a d v i c e . • T ! w c o l h . : a g u c s o f M E n g i n S t r u c t u r a l E n g i n e e r i n g g r o u r f o r t h e i r s h a r e o f t~ncnuragemenl. • ' f h c C o l o n e l C o m m a n d a n t a n d o t h e r o n i c c r s o f t h e o f C o r p s o f E n g i n e e r S c r v i c \ ' : s • B r i g a d i e r K D A P c r : : r < 1 & 1 \ ! l a j o r G e n e r a ! 1 \ . 1 \ V R d e Z o y s a f o r t h e i r g u i d a n c e a n d a p p r e c i a t i n g m y q u e s t f o r k n u w l c d g c . < > f v 1 y f r i e n d s a n d r e l a t i v e s f o r t h e i r " v o n l . . ; 1 ) f e n c o u r a g e m e n t . • F i m d l y h l n 1 y p a r e n t s i l ; r s p e n d i n g t h l · i r m a j o r s h a r e n f l i f e t o b r i n g ml~ u p a n d e d u c a t i n g m e . • i v i r . S u g a t h Arnt~rosekcru a n d m y s t a f f f o r h e l p i n g ' " i r h 1 h c p r o j e c t n~port K i ' i l N l H K E T H I E \ V A G E . \·J~-~jctt' C c • r p s o f F n g i n e c r S·~rvices A r n 1 ' C a n ! o n n K · n t n , l " ' ' i " ( " 1 . , -~ ~ J . h b _ n . . H • . Dcc~..·mher. 2001~. V B - - · F i g 2 . 1 F i g 2 . 2 F i g 2 . 3 F i g 2 . 4 F i o - , . . : : b • • • . } F i g 2 . 6 F i g 2 . 7 F i n ! 1 J b ~.0 F i g 2 . 9 F i g 2 . 9 a F i g 2 . { ) b F i g 2 . 1 0 F i g 2 . 1 1 Fio'~ 1"~ b ~- ~ F i g 2 . 1 3 F i g 2 . 1 4 F i g 2 . 1 5 F i g 2 . 1 6 F i g 3 . 1 F i g 3 . 2 F i g 3 . 3 F i g ~1.4 F i g 3 . 5 F i g 4 . 1 L I S T O F F I G U R E S T r i n i t r o t o l u e n e - - T N T m o l e c u l a r s h a p e ! \ R P G \ \ C a p o n i n a c t i o n A R P G w e a p o n & a g r e n a d e F u l l s i z e r e p l i c a o f t h e R P G 7 / \ s c h e m a t i c d i a g r a m o f R P G 7 m o r t a r a n d i t s f u n c t i o n s . T h e l a u n c h s e q u e n c e o f R P G 7 m o r t a r _ l a u n c h e r S o m e p h o t o g r a p h s o f R P G 7 i n a c t i o n i n u r b a n c o m b a t A t a i l c o n e s e c t i o n & T - c h a m b e r s e c t i o n g r i p p a n e l m a d e o f A l u m i n i u m m e t a l S i n g l e d e g r e e o f f r e e d o m ( S D O F ) c l a s t i c s t r u c t u r e s u b j e c t e d t u i d e a l i s e d b l a s t p u l s e . Q u a s i S t a t i c l o a d i n g f m p u l s i v c l o a d i n g M e m b e r e n d r o t a t i o n s f o r b e a m s a n d f r a m e s T y p i c a l r e s i s t a n c e - - d e f l e c t i o n c u r v e f o r i l e x u r a l r e s p o n s e o f c o n c r d e e l e m e n t s S c h e m a t i c d i a g r a m o f b e a m r e i n f o r c e m e n t T y p i c a l s t a t i c a n d d y n a m i c s t r e s s - s t r a i n c u r v e s l o r s t e e l " I d e a l i s e d r e s i s t a n c e - d c f 1 e c t i o n f u n c t i o n I d e a l i s a t i o n o f B l a s t L o a d C o e f f i c i e n t f o r m o m e n t o f i n e r t i a o f c r a c k e d s e c t i o n s w i t h t e n s i o n r e i n f o r c e m e n t o n l y T h e T e s t s e t u p d i a g r a m S i d e o n b l a s t w a v e p a r a m e t e r s f o r s p h e r i c a l c h a r g e s o f T N T i n f r e e a i r N o r m a l l y r c t l e c t c d b l a s t v , ; a v e p a r a m e t e r s f o r s p h e r i c a l c h a r g e s o f T N T C o e f f i c i e n t f o r m o m e n t o f i n e r t i a o f c r a c k e d s e c 1 i o n s w i t h c y u a l r d n f o r c e r n c n t o n o p p o s i t e f a c e s S t r u c t u r a l d e t a i l s o f c o n c r e t e t e s t p a n e l s 1 & 2 T h e f i b r e r e i n f o r c e d c o n c r e t e m i x b e f o r e a d d i n g w a t e r . F i g 4 . 2 F i g 4 . 3 F i g 4 . 4 F i g 4 . 5 F i g 4 . 6 F i g 4 . 7 F i g 4 . 8 F i g 4 . 9 F i g 4 . 1 0 F i g 4 . i 1 r i g 4 . 1 2 M i x i n g o f f i b r e r e i n f o r c e d c o n c r e t e C h e c k i n g f o r c o r r e c t h e i g h t s T h e f i n i s h e d p r o d u c t j u s t a f t e r c a s t i n g T h e f r o n t e l e v a t i o n o f t h e F i b r e r e i n f o r c e d c o n c r e t e p a n e l t e s t e d a t t e s t 1 , T h e r e m e l e v a t i o n o f t h e F i b r e r e i n f ( ) r c e d c o n c r e t e p a n e l t e s t e d a t t e s l L c l e a r l y s h o w s t h e r e s i s t a n c e o f t h e p a n e l w h e r e t h e d e b r i s f a l l e n b e s i d e t h e p a n e l . F r o n t e l e v a t i o n o f a f i b r e r e i n f o r c e d c o n c r e t e p~mcl a t s t a g e 2 , w h e r e R P G 7 h a s p e n e t r a t e d t h e p a n e l A v i e w o f t h e r e a r e l e v a t i o n o f f i r s t f i b r e r e i n f o r c e d c o n c r e t e p a n e l a l t e r t e s t e d a g a i n s t t h e R P G 7 m o r t a r f i r e . A n o t h e r v i e w o f t h e r e a r e l e v a t i o n o f f i r s t f i b r e r e i n f o r c e d c o n c r e t e p a n d a f t e r t e s t e d a g a i n s t t h e R P G 7 m o r t a r f i r e . R e a r e l e v a t i o n s o f t h e c o n v e n t i o n a l l y r e i n f o r c e d c o n c r e t e p a n e l a f t e r R P G 7 m o r t a r f i r e . F r o n t e l e v a t i o n s o f t h e s e c o n d f i b r e r e i n f o r c e d c o n c r e t e p a n e l a f t e r R P G 7 m o r t a r f i r e R e a r e l e v a t i o n s o f t h e s e c o n d f i b r e r e i n f o r c e d c o n c r e t e p a n e l a f t e r R P ( } 7 m o r t a r f i r e ' 1 :---d~l~; 2 . 1 'f"J:"d,~ ~.=: 1 ::.~hh.: · 2 . 3 · r J h l t · - 1 - . ! h i \ : . : 1 . 2 f ' d h ) r , . : 4 . 3 ·r~db~c 4.~ L I S T O F T A B L E S D y n a m i c i n c r e < i s e f a c t o r s ( D l F ) ~~~r d e s i g n o f n : i n f n r c e d c o n c r e t e a n d s t r u c t u r a l s t r . . : c l element~. D y n a m i c d e s i g n s t r e s s e s f n r r c i n ! ' o r c . . : d c o n c r e t e ! } . : f n r m a t i o n l i m i t s i ' v l i x p r o p o r t i o n s f o r t l ' S i l I \ 1 i x proportion~; f o r t e s t 2 2 X d a y s C o m p r e s s i v e S t r e n g t h s o f h . ' s t c u b e s . ( \ l r t l p a r i s t . H 1 o f Cornprcs~ivc S t r e n g ! h s L I S T O F N O T A T I O N S : 1 a c c d c r a t l t m 1 \ . J a r e a n f d i a g o n a l b a r s a t t h e s u p p o r t \ V i t h i n a w i d t h b 1 \ , a r e a o f t e n s i o n r c m f o r c e m e n t w i t h i n a w i d t h b a r e a o f c o m p r e s s i o n r e i n f o r c e m e n t w i t h i n a w i d t h h i \ , t 1 l 1 : J I a r e a o f s t i r r u p s i n t e n s i o n w i t h i n a d i s t a n c e s a n d a v v i d t h b h w i d t h o f i k x u r a 1 r n c m b c r J ( i t ; p t h o f b e a m d d i s t a n c e f r o m e x t r e m e c o m p r e s s i o n f i h r e t o c e n t r o i d o f t e n s i o n r e i n f o r c e m e n t , J ' d i s t a n c e f r o r n e x t r e m e c o m p r e s s i o n f i b r e t o c e n t r o i d o f c o m p r e s s i o n d e D l F E E . . r ' . . . --~. F ~· ! r l k U F ( t ) ! ' l e u C.~c 1 ' . l , J · . C t . . r J , ( : \ c , , , _ i \ T l n : i n f o r c c m e n l : d i s t a n c r l ' C t \ \ C c n t h e c e n t r o i d s o f t h e c o m p r e s s i o n a n d t e n s i o n r e i n f ( w c e m e n t d y n a m i c i n c n : ' : l s c f a c t o r m o d u l u s o f e l a s t i c i t y modulu~; o f c l a : ; t i c i t y o f c o n c r e t e m o d u l u s o f e l a s t i c i t y o r r e i n f o r c e m e n t o r s t e e l s e c t i o n c o e f f i c i e n t f o r r n u m e m o f i n e r t i a o f c r a c k e d s e c t i o n s!re~~" d y n a r n i c u l t i m a t e c o m p r e s s i v e s t r e n g t h o f C t m c r e t c a t 2 8 d a y s b l a s t l o a d f r o m i d e a l i z e d t r i a n g u l a r p u l s e s t a t i c u l t i m a t e c o m p r e s s i v e s t r e n g t h o f c o n c r e t e a ! 2 8 d a y s d y n a m i c d e s i g n s 1 r e s s f o r c o n c r e t e d y n a m i c d e s i g n s t r e s s f o r r e i n f o r c e m e n t o r s t e e l s e c t i o n d y n a m i c u l t i m a t e s t r e s s o f r e i n f o r c e m e n t m s t e e l s e c t i o n d y n a m i c d e s i g n s h e a r s t r e s s f o r s t e e l s e c t i o n d y n a m i c y i e l d s t r e s s o f r e i n f o r c e m e n t o r s t e e l s e c t i o n s t a t i c u l t i m a t e s t r e s s o f r e i n f o r c e r n L : n t s l a 1 i c y i e l d s t r e s s o f r e i n f o r c e m e n t s p a n h e i g h t m o m e n t o f i n c r 1 i a u n i t p o s i t i v e i m p u l s e I - : ' l K K t K i \ 1 m M ~>1n M r r r p p P r m ' \ P r R r , , s B T l d 1 m v c \ - ' d v " \ ' ! ! w ' - { ' y ' " ' m o m e n t o f i n e r t i a o f c r a c k e d c o n c r e t e s e c t i o n o f w i d t h b u n i t p o s i t i v e n o m 1 a l r e f l e c t e d i m p u l s e s t i f f n e s s e q u i v a l e n t e l a s t i c u n i t s t i f f n e s s l o a d - - - m a s s f a c t o r m a s s o f h u m a n s u b j e c t m a s s o f t h e s t r u c t u r e u l t i m a t e n e g a t i v e m o m e n t c a p a c i t y u l t i m a t e n e g a t i v e m o m e n t c a p a c i t y m o d u l a r r a t i o p r e s s u r e l o a d p e a k p r e s s u r e p e a k p o s i t i v e n o r m a l r e f l e c t e d p r e s s u r e r a n g e f r o m c h a r g e c e n t r e u l t i m a t e u n i t r e s i s t a n c e p l a s t i c s e c t i o n m o d u l u s c o e f f i c i e n t a p p l i e d t o t o i l e t l o a d P t o d e t e r m i n e d y n a m i c r e a c t i o n V t i m e n a t u r a l p e r i o d o f v i b r a t i o n o f s t r u c t u r e d u r a t i o n o f i d e a l i z e d b l a s t l o a d t i m e t o r e a c h m a x i m u m d y n a m i c d i s p l a c e m e n t p o s i t i v e p h a s e d u r a t i o n s u p p o r t r e a c t i o n u l t i m a t e s h e a r s t r e s s p e r m i t t e d i n a n u n r e i n f o r c e d c o n c r e t e w e b u l t i m a t e d i r e c t s h e a r c a p a c i t y o f t h e c o n c r e t e o f w i d t h b s h e a r a t t h e s u p p o r t p e r u n i t w i d t h u l t i m a t e s h e a r s t r e s s m a s s o f s p h e r i c a l T N T c h a r g e d i s p l a c e m e n t d e f l e c t i o n x d e p t h l ) f n e u t r a l a x i s b c h n v e x t r e m e c m n p r c s s i o n t i h r c i n a l 1 c x u r a l m c m h e r e q u i v a l e n t c l a s t i c d c i l c c t i o n m a x i m u m t r a n s i c r l t d e t 1 c c t i n n : - : , : . < ' · m a x i m u m d y n a m i c d i s p l a c e m e n t / . s c a k d d i s t a n c e / e L 1 s t i c s e c t i o n m o d u l u s 1 1 . c o c f f i c i e n 1 a p p l i e d t o t o i l e t i n t e r n a l r e s i s t a n c e R t~) d e t e r m i n e d y n a m i c r e a c t i o n V · v . , p a r t i a l s~:!Cty t~lctor f o r m a t e r i a ! : > s i d e - s V \ a y d c f k c t i o n S t r a i n s t r a i n i I s u p p o r l r o t a t i o n a n g l e 1 ' ' c k n s i t y , ~ t e n s i o n n::inr~)rccmcnt r a t i o c n m p r c s s i t m r e i n f o r c e m e n t r : . n i o u d u c t i l i t y r a t i u t · l n a t u r a l c i r c u l a r i ' r c q u e n c y o f v i b r [ _ u i o n