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Research on vibration criteria from the viewpoint of people living in
high-rise buildings. Part 1. Various responses of humans to motion
Goto, T.; National Research Council of Canada. Division of Building
Research
CANADA I IVSTITUTE
FOR SClElVTlFlC AND TECHNICAL
I N FORMATION
INSTITUT CANADIEN
DE L'INFORMATION SCiENTlFlQUE
ET TECHNIQUE
NRCI
C N R TT-
1881 TECHNICAL TRANSLATION TRADUCTION TECHNIQUERESEARCH ON VIBRATION CRITERIA FROM
THE
VIEWPOINT
OF PEOPLE LIVING IN HIGH-RISE BUILDINGS
(PART
1) VARIOUS RESPONSES
OF
HUMANS TO MOTION
NIPPON KENCHIKU GAKKAI ROMBUN HOKOKU-SHU.
237 (1 1): 1 0 9
-
1 18, 1975T R A N S L A T E D BY
/
T R A D U C T I O N D EALICE TSAl
THIS IS THE TWO HUNDRED AND TWENTY-SIXTH I N THE SERIES OF TRANSLATIONS PREPARED FOR THE DIVISION OF BUILDING RESEARCH
TRADUCTION N U M ~ R O 226 DE LA S ~ R I E P R ~ P A R ~ E POUR LA DIVISION DES RECHERCHES EN BATIMENT
OTTAWA
National Research
Conseil national
PREFACE
A s p e c i a l problem f o r i n h a b i t a n t s of t a l l b u i l d i n g s i s
t h e p e r c e p t i o n of motion induced by e x t e r n a l f o r c e s , such a s wind and e a r t h q u a k e . To e n s u r e t h a t t a l l b u i l d i n g s w i l l b e c o m f o r t a b l y h a b i t a b l e , l i m i t s t o b u i l d i n g v i b r a t i o n a r e r e q u i r e d , b u t as y e t t h e r e h a s been l i t t l e i n f o r m a t i o n p u b l i s h e d on which t o b a s e d e s i g n c r i t e r i a .
T h i s paper by T a k e s h i Goto summarizes e x t e n s i v e
J a p a n e s e s t u d i e s on human r e s p o n s e t o h o r i z o n t a l s i n u s o i d a l motion w i t h p e r i o d s of
1
-
1 0 s e c o n d s and a m p l i t u d e s of 1-
50 cm. The r e s u l t s a r e i n t e r p r e t e d i n b i o m e c h a n i s t i c t e r m s a s a b a s i s f o r e s t a b l i s h i n g h a b i t a b i l i t y c r i t e r i a .
The D i v i s i o n of B u i l d i n g Research i s p l e a s e d t o make t h i s r e s e a r c h i n f o r m a t i o n a v a i l a b l e t o o t h e r Canadian r e s e a r c h workers t h r o u g h t h e T e c h n i c a l T r a n s l a t i o n s e r i e s of t h e N a t i o n a l R e s e a r c h C o u n c i l . The c o n t r i b u t i o n of t h e t r a n s l a t o r , D r . A l i c e T s a i ,
i s
g r a t e f u l l y acknowledged, a s i s t h a t of W.A. D a l g l i e s h of t h i s D i v i s i o n , who checked t h e t r a n s l a t i o n . Ottawa September 1976 C . B . crawford D i r e c t o r D i v i s i o n of B u i l d i n g R e s e a r c hAuthor /Aut e u r :
~ e f erence/RGfGrence:
NATIONAL RESEARCH COUNCIL OF CANADA CONSEIL NATIONAL DE RECHERCHES DU CANADA
TECHNICAL TRANSLATION
1881
TRADUCTION TECHNIQUE
R e s e a r c h on v i b r a t i o n c r i t e r i a from t h e v i e w p o i n t of p e o p l e l i v i n g i n h i g h - r i s e b u i l d i n g s . ( P a r t 1 ) V a r i o u s r e s p o n s e s of humans t o motion
Nippon Kenchiku Gakkai Rombun Hokoku-shu ( T r a n s a c t i o n s of t h e A r c h i t e c t u r a l I n s t i t u t e of J a p a n ) , 237 (11) : 109-118, 1975 T r a n s l a t o r / T r a d u c t e u r : A l i c e T s a i Canada I n s t i t u t e f o r I n s t i t u t c a n a d i e n d e S c i e n t i f i c and T e c h n i c a l
1'
i n f o r m a t i o n s c i e n t i f i q u e e t I n f orma t i o n t e c h n i q u e Ottawa, Canada K I A OS2RESEARCH ON VIBRATION CRITERIA FROM THE VIEWPOINT OF PEOPLE LIVING I N HIGH-RISE BUILDINGS
(PART 1 ) VARIOUS RESPONSES OF HUMANS TO VIBRATION
1. I n t r o d u c t i o n
H i g h - r i s e b u i l d i n g s a r e f l e x i b l e s t r u c t u r e s . T h e r e f o r e , n a t u r a l f o r c e s , s u c h a s e a r t h q u a k e and wind, i n t r o d u c e t h e new problem of b u i l d i n g v i b r a t i o n , which may have v a r i o u s e f f e c t s on l i v i n g c o n d i t i o n s f o r o c c u p a n t s .
I n a s t u d y of t h e s a f e t y and v a r i o u s v i b r a t i o n s of h i g h - r i s e b u i l d i n g s , h a b i t a b i l i t y must b e c o n s i d e r e d f i r s t , and demands o u r u r g e n t i n v e s t i g a t i o n . I n o r d e r t o s t u d y t h e fundamental c r i t e r i a , t h e p h y s i o l o g i c a l r e s p o n s e of o c c u p a n t s t o t h e p h y s i c a l s t i m u l i of v i b r a t i o n must b e u n d e r s t o o d . I n o t h e r words, t h i s c a n b e a c h i e v e d from t h e b i o m e c h a n i s t i c p o i n t of view.
I n view of t h e above, t h e end o b j e c t i v e of t h i s s t u d y d e a l i n g w i t h t h e s a f e t y and comfort of h i g h - r i s e b u i l d i n g s v i b r a t i n g under t h e a c t i o n of e x t e r n a l n a t u r a l f o r c e s i s t o p r o p o s e h a b i t a b i l i t y c r i t e r i a . The s t u d y c o n s i s t s of t h e f o l l o w i n g two p a r t s :
1 ) V a r i o u s human r e s p o n s e s t o v i b r a t i o n .
2) E f f e c t of e x t e r n a l n a t u r a l f o r c e s on v i b r a t i o n of b u i l d i n g s and o c c u p a n t s . However, t h i s paper r e p o r t s o n l y on P a r t 1. The remainder w i l l be r e p o r t e d i n t h e n e x t p a p e r .
2. Method and O b j e c t i v e s
The p e r i o d of v i b r a t i o n of low s o l i d b u i l d i n g s i s u s u a l l y l e s s t h a n 1 s e c , and t h e s i n g l e a m p l i t u d e ( d i s p l a c e m e n t ) i s a t most w i t h i n a r a n g e of s e v e r a l mm.
On t h e o t h e r hand, f o r h i g h - r i s e b u i l d i n g s t h e p e r i o d f o r h o r i z o n t a l v i b r a t i o n caused by s t r o n g e a r t h q u a k e and wind i s 1
-
8 s e c ( f i r s t n a t u r a l p e r i o d ) and t h e a m p l i t u d e may r e a c h s e v e r a l t e n s of cm (Note 1 ) . These v i b r a t i o n a l c h a r a c t e r i s t i c s b e i n g d i f f e r e n t,
t h e measurement of r e s p o n s e i n t e r m s of p e r c e p t i b i l i t y andp e r c e p t i o n t h r e s h o l d i s g e n e r a l l y u s e d a s t h e c r i t e r i o n f o r t h e v i b r a t i o n of t a l l b u i l d i n g s . However, when t h e v i b r a t i o n i s v e r y s t r o n g , t h e h o r i z o n t a l v i b r a t i o n of h i g h - r i s e b u i l d i n g s n o t o n l y c a u s e s s t i m u l a t i o n of t h e s e n s e s , b u t a l s o i n h i b i t s t h e a c t i v i t y and movement of p e o p l e . F u r t h e r m o r e , p r o l o n g e d v i b r a t i o n e v e n w i t h i n t h e n o n p e r c e p t i b l e r a n g e may sometimes c a u s e symptoms o f
s e a s i c k n e s s .
The c o n d i t i o n s f o r t h e v i b r a t i o n of h i g h - r i s e b u i l d i n g s i n t h i s s t u d y a r e t h a t t h e p e r i o d i s 1
-
1 0 s e c and t h e s i n g l e a m p l i t u d e i s 1-
50 cm, a s s u m i n g h o r i z o n t a l s i n e wave m o t i o n . E x p e r i m e n t s w e r e c a r r i e d o u t t o s t u d y t h e d e g r e e of i n f l u e n c e on o c c u p a n t s by t h e a p p l i c a t i o n pf p s y c h o l o g i c a l , p h y s i o l o g i c a l , k i n e s i o l o g i c a l and e n g i n e e r i n g methods. A v i b r a t i o n s i m u l a t o r i s u s e d a s showni n P h o t o 1. The e x p e r i m e n t a l i t e m s a r e shown i n T a b l e I. The r e s u l t s h a v e b e e n r e p o r t e d a t c o n f e r e n c e s o f t h e J a p a n e s e A r c h i t e c t u r a l S o c i e t y (1-7)
A f t e r b r i e f l y o u t l i n i n g t h e e x p e r i m e n t a l c o n d i t i o n s a n d m e t h o d s of t h i s
r e s e a r c h , t h e f i r s t p a r t of t h i s p a p e r c o r r e l a t e s t h e r e s u l t s of m a j o r e x p e r i m e n t s and e x p l a i n s them from t h e b i o m e c h a n i s t i c p o i n t of v i e w . The second p a r t t h e n i n v e s t i g a t e s h a b i t a b i l i t y limits f o r t h e v i b r a t i o n of b u i l d i n g s b a s e d on r e s u l t s of t h e f i r s t p a r t . 3 . B i o m e c h a n i s t i c R e s p o n s e t o V i b r a t i o n 1) C o m ~ l e x human s e n s o r v r e s D o n s e t o v i b r a t i o n The human s e n s o r y r e s p o n s e t o v i b r a t i o n v a r i e s p r o f o u n d l y w i t h d i f f e r e n t i n d i v i d u a l s .
F i g u r e 1 shows t h e a v e r a g e m a l e and f e m a l e p e r c e p t i o n c u r v e s which e x p r e s s t h e r e l a t i o n s h i p between t h e p e r i o d of f l o o r v i b r a t i o n c a u s e d by t h e s i m u l a t o r a n d t h e maximum a m p l i t u d e ( a b b r e v i a t e d a s a m p l i t u d e below)
.
P e r c e p t i b i l i t y ( I ) i s i n t h e r a n g e where t h e v i b r a t i o n i s c o m p l e t e l y i m p e r c e p t i b l e . (11) ( i ) i s t h e r a n g e where t h e v i b r a t i o n i s b e g i n n i n g t o b e p e r c e p t i b l e , and (11) ( i i ) i s t h e*
r a n g e where t h e v i b r a t i o n i s s t r o n g l y p e r c e p t i b l e . ( 1 1 ) i s t h e r a n g e where t h e*
ran slat or's
n o t e : T h i s i s a n e r r o r . A c c o r d i n g t o F i g u r e 1, t h i s r a n g e s h o u l d b e ( 1 1 1 ) .v i b r a t i o n becomes u n b e a r a b l e . T h e r e f o r e , t h e b o u n d a r i e s of p e r c e p t i b i l i t i e s ( I ) and (11) a s w e l l a s (11) and (111) a r e d e s i g n a t e d a s p e r c e p t i o n t h r e s h o l d (Note 2) and t o l e r a n c e t h r e s h o l d (Note 3 ) , r e s p e c t i v e l y . I n g e n e r a l , t h e c u r v e f o r f e m a l e s i s below t h e c u r v e f o r males. I n o t h e r words, f e m a l e s a r e more s e n s i t i v e t o v i b r a t i o n t h a n m a l e s . F u r t h e r m o r e , r e s u l t s o b t a i n e d from d i f f e r e n t a g e g r o u p s , p o s t u r e s and v i b r a t i o n a l d i r e c t i o n s a r e compared, a s summarized i n T a b l e 11. The t a b l e i n d i c a t e s a c o n s i s t e n t t r e n d t h a t t h e f e m a l e i s more s e n s i t i v e t h a n t h e m a l e , c h i l d r e n a r e more s e n s i t i v e t h a n a d u l t s , and p e o p l e i n s t a n d i n g p o s i t i o n s a r e more s e n s i t i v e t h a n t h o s e i n s i t t i n g p o s i t i o n s t o s h o r t - p e r i o d v i b r a t i o n o r v e h i c l e v i b r a t i o n (8-10), However, i f a p e r s o n t a k i n g p a r t i n t h e experiment i s s i t t i n g i n a c h a i r w i t h a back s u p p o r t , t h i s s i t t i n g p o s i t i o n
*
w i l l b e more s e n s i t i v e t h a n t h e s t a n d i n g p o s i t i o n . The p e r c e p t i o n t h r e s h o l d and t o l e r a n c e t h r e s h o l d f o r a l l i t e m s i n T a b l e I1 a r e shown i n t h e same g r a p h , F i g u r e 2 , a s d o t t e d l i n e s . I t should be noted t h a t , f o r example, when t h e p e r i o d i s 1 0 s e c , a l t h o u g h i n some c a s e s when t h e a m p l i t u d ei s 5 cm ( p o i n t M), t h e v i b r a t i o n i s p e r c e p t i b l e , i n o t h e r c a s e s t h e a m p l i t u d e
c a n b e i n c r e a s e d 5 t i m e s ( ~ o i n t N , a b o u t 25 cm) b e f o r e i t b e g i n s t o b e p e r c e p t i b l e . The p e r c e p t i b i l i t y t o v i b r a t i o n v a r i e s g r e a t l y d u e t o d i f f e r e n c e s i n p h y s i c a l
c o n d i t i o n from one i n d i v i d u a l t o a n o t h e r . On t h e o t h e r hand, t h e p e r c e p t i b i l i t y of t h e same i n d i v i d u a l may a l s o v a r y from time t o t i m e d u e t o v a r i a t i o n i n h i s o r h e r p h y s i c a l and m e n t a l s t a t e s . I t i s v e r y d i f f i c u l t t o d e t e r m i n e t h e p e r c e p t i o n t h r e s h o l d and t o l e r a n c e t h r e s h o l d f o r a n a c t u a l b u i l d i n g v i b r a t i o n from e x p e r i m e n t a l r e s u l t s . T h i s i s b e c a u s e t h e v i b r a t i o n g e n e r a t e d i s n o t n e c e s s a r i l y s i m i l a r t o t h e a c t u a l v i b r a t i o n of b u i l d i n g s . Meanwhile, p e o p l e t a k i n g p a r t i n t h e experiment a r e n o t i f i e d of t h e c o n t e n t of t h e experiment beforehand. I n t h i s c a s e , p e o p l e a l r e a d y become v e r y a t t e n t i v e a s soon a s t h e v i b r a t i o n s t a r t s . The p e r c e p t i o n t h r e s h o l d i n F i g u r e 2 i s c o n s i d e r e d t o b e more s e n s i t i v e t h a n t h a t o b t a i n e d from t h e a c t u a l b u i l d i n g v i b r a t i o n w i t h o u t warning. On t h e o t h e r hand, t h e t o l e r a n c e t h r e s h o l d i s accompanied by v i s u a l and a u d i t o r y s t i m u l i due t o t h e movement of household o b j e c t s . One f e e l s r a t h e r s a f e d u r i n g t h e experiment and i s n o t h o r r i f i e d a s i n t h e s i t u a t i o n of a c t u a l b u i l d i n g v i b r a t i o n . The e x p e r t m e n t a l
*
e ran slat or's
n o t e : T h i s s t a t e m e n t d i s a g r e e s w i t h t h e r e s u l t s shown i n T a b l e I1 which i n d i c a t e s t h a t t h e s t a n d i n g p o s i t i o n i s more s e n s i t i v e t o v i b r a t i o n t h a n t h e s i t t i n g p o s i t i o n .r e s u l t s should p e r h a p s b e c o n s i d e r e d t o be on t h e u n c o n s e r v a t i v e s i d e . Due t o t h e d i v e r s i t y of c o n d i t i o n s , i t i s v e r y d i f f i c u l t t o make a judgement. For example, should t h e s i t t i n g c r i t e r i o n o r t h e s t a n d i n g c r i t e r i o n b e u s e d ? Many i t e m s l i k e t h i s should b e i n v e s t i g a t e d . Under t h e s e c i r c u m s t a n c e s i t was d e c i d e d t o b a s e t h e p e r c e p t i o n t h r e s h o l d and t o l e r a n c e t h r e s h o l d on t h e a v e r a g e v a l u e s of a l l t h e fundamental c r i t e r i a . The f i n a l p e r c e p t i o n t h r e s h o l d and t o l e r a n c e t h r e s h o l d a r e shown a s t h e s o l i d l i n e s i n F i g u r e 2 (-0-) .
2) P e r c e p t i o n zone i n which people a r e s e n s i t i v e t o v i b r a t i o n
The a v e r a g e p e r c e p t i o n t h r e s h o l d and a v e r a g e t o l e r a n c e t h r e s h o l d a r e shown i n F i g u r e 2. The f l o o r v i b r a t i o n of a house i s e x p r e s s e d by t h e a n p l i t u d e ( A ) . The maximum a c c e l e r a t i o n
(a
which w i l l b e c a l l e d simply a c c e l e r a t i o n ) may b ee x p r e s s e d i n t h e f o l l o w i n g e q u a t i o n i f t h e v i b r a t i o n i s a s i n e wave,
Where T i s t h e p e r i o d . The a v e r a g e p e r c e p t i o n t h r e s h o l d and a v e r a g e t o l e r a n c e t h r e s h o l d d e r i v e d from t h i s a r e shown i n F i g u r e 3 (*).
Human p e r c e p t i o n t o v i b r a t i o n of l o n g d u r a t i o n i s known t o v a r y w i t h a c c e l e r a t i o n . I n t h e a c c e l e r a t i o n p e r c e p t i o n zone, i t i s s e n s i t i v e t o t h e magnitude of t h e p e r i o d . For example, t h e l e f t - h a n d s i d e of p o i n t E , which i s
on t h e t o l e r a n c e t h r e s h o l d l i n e w i t h
a
p e r i o d of 5 s e c and a c c e l e r a t i o n of 65g a l , i s i n t h e p e r c e p t i b i l i t y (111) zone when t h e a c c e l e r a t i o n i s k e p t c o n s t a n t . However, t h e r i g h t - h a n d s i d e of p o i n t E i s i n t h e p e r c e p t i b i l i t y (11) zone. The
same t r e n d i s a l s o observed f o r t h e p e r c e p t i o n t h r e s h o l d . The t o l e r a n c e
t h r e s h o l d c a l c u l a t e d by D r . I s h i m o t o (11) i s shown i n F i g u r e 4 . A s shown i n t h e f i g u r e , t h e c u r v e becomes convex upward when t h e p e r i o d i s below 0 . 3 s e c . T h i s
i s t h e a r e a where t h e p e r c e p t i b i l i t y i s s e n s i t i v e t o changes of t h e p e r i o d . I n o t h e r words, when t h e a c c e l e r a t i o n i s k e p t c o n s t a n t a t 1 . 0 g a l , t h e v i b r a t i o n i s i m p e r c e p t i b l e a t p o i n t A , w h i l e t h e v i b r a t i o n i s p e r c e p t i b l e a t p o i n t B.
F u r t h e r m o r e , t h e h o r i z o n t a l s t r a i g h t l i n e s ( s c r e e n t o n e ) i n F i g u r e 3 r e p r e s e n t t h e r a n k i n g s ( l e v e l s ) . D r . Chang i n v e s t i g a t e d e x p e r i m e n t a l r e s u l t s
of many r e s e a r c h e r s who s t u d i e d v i b r a t i o n s w i t h p e r i o d s l e s s t h a c 1 . 0 s e c and proposed t h a t v i b r a t i o n s w i t h p e r i o d s lower t h a n 1 . 0 s e c a r e s u i t a b l e f o r
(12) r a n k i n g d e t e r m i n a t i o n
.
3) Human p e r c e p t i b i l i t y t o v i b r a t i o n c o n t r o l l e d by head a c c e l e r a t i o n
The s e n s i n g of v i b r a t i o n s of l o n g p e r i o d and l a r g e a m p l i t u d e i s d e t e r m i n e d by t h e head a c c e l e r a t i o n which r e s u l t s from t h e s t r o n g f l o o r ( o r l e g ) v i b r a t i o n .
The a n a l o g o u s r e s u l t s c a n t h e n b e d e r i v e d . The p e r c e p t i b i l i t i e s ( I ) , ( 1 1 ) - i , ( 1 1 ) - i i and (111) were s t u d i e d by measuring t h e a c c e l e r a t i o n s of h e a d s of p e o p l e t a k i n g p a r t i n t h e experiment. The r e s u l t s o b t a i n e d a r e p l o t t e d i n t h e g r a p h a s shown i n F i g u r e 5 . The same p e r c e p t i b i l i t i e s caused by t h e a c c e l e r a t i o n of h e a d s a r e d i s t r i b u t e d i n a l m o s t t h e same a c c e l e r a t i o n z o n e s .
The human p e r c e p t i o n t o t h e a c c e l e r a t i o n of h i s body i s s e n s e d by t h e
v e s t i b u l e i n t h e i n n e r e a r ( F i g u r e 6) and t h i s i s r e l a t e d t o t h e movement of t h e head. V a r i o u s body s e n s e s a r e c h a r a c t e r i z e d a s shown i n F i g u r e 7 . The term w i t h a d o t i n t h e f r o n t i n d i c a t e s t h a t i t i s r e l a t e d t o a s e n s i n g of v i b r a t i o n . I n a d d i t i o n t o s k i n , v i s u a l and a u d i t o r y s e n s e s , p e o p l e c a n a l s o p e r c e i v e l i n e a r v i b r a t i o n by t h e v e s t i b u l e of t h e i n n e r e a r , e s p e c i a l l y t h e u t r i c u l u s . The u t r i c u l u s i s shown i n F i g u r e 6. T h e r e a r e h a i r c e l l s on t h e t i p
of n e r v e f i b r e s . These h a i r s p r o t r u d e from lymphs. T h e r e a r e c a l c a r e o u s s m a l l p a r t i c l e s ( o t o l i t h ) which a r e e n c l o s e d i n membrane (13y14) a t t h e t i p s . The
movement of t h e head, which i n d u c e s t h e movement of t h e s e p a r t i c l e s , t h u s c o n t r o l s t h e s e n s i n g of v i b r a t i o n (Note 4 ) .
From t h e e n g i n e e r i n g p o i n t of v i e w , t h i s i s e q u i v a l e n t t o a n i n v e r s e
pendulum i n a l i q u i d . T h i s phenomenon i s a l s o similar t o t h e s t r u c t u r a l r e s p o n s e of a o n e - s t o r e y b u i l d i n g t o v i s c o u s damping ( F i g u r e 8 ) . The f o l l o w i n g e x p r e s s i o n ( 2 ) d e s c r i b e s t h e e q u a t i o n of motion of t h i s system ( F i g u r e 8 ) . The d i s p l a c e m e n t
(15) and a c c e l e r a t i o n may be d e r i v e d
.
S i n c e t h e v i s c o s i t y c o n s t a n t of lymph i n t h e u t r i c u l u s ( c ) , t h e e l a s t i c i t y c o n s t a n t (k) of h a i r c e l l s and t h e mass of o t o l i t h (m) a r e known, t h e c o r r e s p o n d i n g movement of o t o l i t h which i s caused by movement of t h e head may b e c a l c u l a t e d .
The human s e n s a t i o n of v i b r a t i o n may b e understood s c i e n t i f i c a l l y t h r o u g h t h i s biomechanism.
I n a d d i t i o n t o t h o s e d e s c r i b e d above, t h e s k i n s e n s e i s t h e major s e n s e o r g a n which p e r c e i v e s v i b r a t i o n of s h o r t p e r i o d and s m a l l a m p l i t u d e . V i b r a t i o n of l o n g p e r i o d and l a r g e a m p l i t u d e may g r e a t l y u p s e t t h e body b a l a n c e . T h e r e f o r e , o t h e r s e n s e o r g a n s such a s m u s c l e s , t e n d o n s and j o i n t s a r e a l s o i n v o l v e d i n t h e p e r c e p t i o n of v i b r a t i o n .
4 )
P e o p l e a r e s e n s i t i v e t o t h e s e n s a t i o n of v i b r a t i o nThe a v e r a g e p e r c e p t i o n t h r e s h o l d and t o l e r a n c e t h r e s h o l d a r e proposed above ( F i g u r e 3 ) . O b j e c t s which b e g i n t o move a t t h i s boundary a r e compared.
F o r t y - f i v e g e n e r a l househoid k i t c h e n , d i n i n g room and l i v i n g room o b j e c t s , such a s d i n n e r w a r e , cooking u t e n s i l s , cooking a p p l i a n c e s , f u r n i t u r e , e t c . a r e s e l e c t e d a s shown i n T a b l e 111. T h e i r movement d u r i n g v i b r a t i o n i s a n a l y z e d . T h e a n a l y s i s of motion i s based on t h r e e s t a g e s , i . e . , t h e boundary where o b j e c t s b e g i n t o s h a k e , t h e boundary where o b j e c t s b e g i n t o r a t t l e , and t h e boundary where o b j e c t s b e g i n t o t o p p l e .
The p h y s i c a l phenomenon f o r t h e movement of household o b j e c t s i s compared w i t h t h e p e r c e p t i o n of body r e s p o n s e a s shown i n F i g u r e 9. The p e r c e p t i o n t h r e s h o l d i s below t h e f i r s t l i m i t of movement of household o b j e c t s , i. e . , when t h e o b j e c t s s t a r t t o shake. P e o p l e c a n d e t e c t t h e v i b r a t i o n even b e f o r e t h e household o b j e c t s s t a r t t o shake.
S i m i l a r l y , i n a n a c t u a l e a r t h q u a k e , p e o p l e s u b c o n s c i o u s l y n o t i c e t h e v i b r a t i o n and t h e n a s k anybody who happens t o b e around f o r c o n f i r m a t i o n , o r o b s e r v e t h e movement of household o b j e c t s . From t h i s i n f o r m a t i o n , p e o p l e g r a d u a l l y c o n f i r m t h e i r p e r c e p t i o n .
P e o p l e a r e s e n s i t i v e t o v i b r a t i o n . B e f o r e household o b j e c t s s t a r t t o move, p e o p l e c a n a l r e a d y p e r c e i v e t h e v i b r a t i o n . T h i s a g r e e s w i t h t h e h y p o t h e s i s i n S e c t i o n 3 ) t h a t people c a n p e r c e i v e v i b r a t i o n even i f t h e v i s u a l , a u d i t o r y and s k i n s e n s e s a r e e l i m i n a t e d .
5) Symptoms of s e a s i c k n e s s v a r y g r e a t l y w i t h d i f f e r e n t i n d i v i d u a l s I n t h e p e r c e p t i b l e v i b r a t i o n a l r a n g e , p e r s o n s who have n e v e r e x p e r i e n c e d v e h i c l e s i c k n e s s b e f o r e do n o t u s u a l l y r e a c t t o v i b r a t i o n s of l o n g p e r i o d w i t h s e a s i c k n e s s symptoms. I n t h e i m p e r c e p t i b l e v i b r a t i o n a l r a n g e , nobody r e a c t s t o i t w i t h s e a s i c k n e s s symptoms r e g a r d l e s s of o n e ' s p r e v i o u s v e h i c l e s i c k n e s s e x p e r i e n c e . F i g u r e 1 0 shows t h e symptoms p e o p l e e x p e r i e n c e d d u r i n g v i b r a t i o n s w i t h a
p e r i o d of 6 s e c and a m p l i t u d e s of 20 cm (Exp. 1 ) a s w e l l a s 37.5 cm (Exp. 2)
r e s p e c t i v e l y . P e o p l e w i t h p r e v i o u s v e h i c l e s i c k n e s s e x p e r i e n c e e x h i b i t s e a s i c k n e s s symptoms 1 0
-
20 min a f t e r v i b r a t i o n s t a r t s . The symptoms a r e i n c r e a s i n g l y worsened w i t h prolonged v i b r a t i o n . However, t h o s e p e o p l e w i t h o u t p r e v i o u s v e h i c l e s e a s i c k n e s s e x p e r i e n c e e x h i b i t s l i g h t symptoms of s e a s i c k n e s s m o m e n t a r i l y , b u t soon r e c o v e r . No s e a s i c k n e s s symptoms were o b s e r v e d .A s f a r a s symptoms of s e a s i c k n e s s a r e c o n c e r n e d , some p e o p l e a r e e a s i l y a f f l i c t e d w i t h i t but some p e o p l e a r e n o t . It a l l depends on t h e i n d i v i d u a l . For t h o s e p e o p l e w i t h s e v e r e s e a s i c k n e s s symptoms, t h e blood p r e s s u r e , b r e a t h i n g and h e a r t b e a t become o b v i o u s l y abnormal.
P h y s i o l o g i c a l c h a n g e s a r e c a u s e d . A s d i s c u s s e d p r e v i o u s l y , t h e v e s t i b u l a r o r g a n i s e x c i t e d . The e f f e c t of s t r o n g e x c i t e m e n t i s t r a n s m i t t e d n o t o n l y t o t h e s p i n a l n e r v o u s system b u t a l s o t o t h e autonomic n e r v o u s system, t h e r e b y i n d u c i n g r e f l e x i o n , e s p e c i a l l y t h e s o - c a l l e d r e f l e x i o n phenomenon t h r o u g h t h e vagus n e r v e . T h e r e f o r e , i t was p r e v i o u s l y proposed (16) t h a t f o r t h e p r e v e n t i o n of s e a s i c k n e s s , t h e o t o l i t h c o u l d b e d i s s o l v e d t o e r a d i c a t e t h e p e r c e p t i o n of v e s t i b u l a r s t i m u l i . T h i s may b e i n t e r p r e t e d from t h e e n g i n e e r i n g p o i n t of view a s s e t t i n g t h e mass of F i g u r e 8 t o z e r o , i . e . , m = 0. T h i s means t h a t t h e motion e q u a t i o n c a n n o t b e e s t a b l i s h e d .
F i g u r e 11 shows t h e r e s u l t s of e x p e r i m e n t s i n v e s t i g a t i n g whether t h e v i b r a t i o n i n t h e v i c i n i t y of t h e p e r c e p t i o n t h r e s h o l d c a u s e s symptoms of
s e a s i c k n e s s . The r e l a t i o n s h i p between p e r i o d and a m p l i t u d e i s p r e s e n t e d . The b l a c k d o t s i n t h e f i g u r e i n d i c a t e t h e e x p e r i m e n t a l p o i n t s . The s u r r o u n d i n g c i r c l e s r e p r e s e n t t h e number of p e o p l e who t o o k p a r t i n t h e e x p e r i m e n t . The l a r g e b l a c k d o t s i n d i c a t e t h a t p e r s o n s who t o o k p a r t i n t h e e x p e r i m e n t e x h i b i t e d o b v i o u s s e a s i c k n e s s symptoms and l e f t t h e h o u s e i n t h e m i d d l e of t h e e x p e r i m e n t .
The s i g n + r e p r e s e n t s t h o s e p e r s o n s who seemed t o d e v e l o p s e a s i c k n e s s symptoms b u t remained i n t h e h o u s e u n t i l t h e end of t h e e x p e r i m e n t . ( 2 h o u r s ) . The open c i r c l e ( 0 ) i n d i c a t e s t h a t n o t h i n g a b n o r m a l was o b s e r v e d . Based on t h i s , t h e c u r v e f o r t h e b o u n d a r y of s e a s i c k n e s s symptoms c a u s e d by v i b r a t i o n i s shown a s t h e t h i n l i n e c u r v e i n t h e f i g u r e (-
+
-). The c u r v e i s s i c a a t e d a b o v e t h e p e r c e p t i o n t h r e s h o l d (--0-- i n t h e f i g u r e ) . T h e r e f o r e , o n e p e r c e i v e s v i b r a t i o n b e f o r e e x h i b i t i n g s e a s i c k n e s s symptoms. 6 ) A b i l ~ t y t o work i s r e l a t e d s i m p l y t o f l o o r ( t a b l e ) a c c e l e r a t i o n , w h e r e a s a b i l i t y t o move i s r e l a t e d i n a complex way t o f l o o r a c c e l e r a t i o n .A b i l i t y t o work i s t e s t e d by t r a c i n g a s i m p l e d i a g r a m , a s shown i n F i g u r e 1 2 . Walking a b i l i t y was t e s t e d by w a l k i n g on a f l a t s u r f a c e and c l i m b i n g u p and down s ~ a i r s . F i g u r e 1 3 shows t h e e x p e r i m e n t a l r e s u l t s of w a l k i n g o n a f l a t s u r f a c e . The t r a l l s of b o t h head and f e e t a r e shown i n t h e f i g u r e . Based o n t h e r e s u l t s of t h e t r a c i n g t e s t , t h e a b i l i t y t o work i s judged by t h r e e a r b i t r a r y d e g r e e s of d i f f i c u l t y : w i t h o u t d e v i a t i o n f r o m normal s t a t e ( d e g r e e of d i f f i c u l t y [ I ] ) ;
p a r t r a l l y d e v i a t e d f r o m t h e b a s e l i n e ( d e g r e e of d i f f i c u l t y [ I I ] ) ; I o b v i o u s l y d e v i a t e d from t h e b a s e l i n e ( d e g r e e of d i f f i c u l t y [ 1 1 1 ] ) ( c f . F i g u r e 1 2 ) . The
r e l a t i o n s h i p between p e r i o d and a c c e l e r a t i o n i s shown i n F i g u r e 1 4 . The d e g r e e s o f d i f f i c u l t y shown a s d o t t e d l i n e s i n t h e f i g u r e a r e c o n t r o l l e d by f l o o r a c c e l - e r a t i o n . A s t o t h e e f f e c t on w a l k i n g a b i l i t y
(Q),
t h e e x p e r i m e n t a l r e s u l t s f o r w a l k i n g on a f l a t s u r f a c e(0)
and t h o s e f o r c l i m b i n g u p a n d down s t a i r s( V )
a r e r a t h e r s i m i i a r . The d e g r e e of d i f f i c u l t y i n a b i l i t y t o w a l k i s c h o s e n , o n t h e s a f e s i d e , b e l a w e a c h c u r v e . S i m i l a r l y , t h e r e l a t i o n s h i p b e t w e e n p e r i o d and a c c e l - e r a t i o n i s shown i n F i g u r e 1 5 . F u r t h e r m o r e , t h e d e g r e e of d i f f i c u l t y i n w a l k i n g up and down s t a i r s and w a l k i n g on a f l a t s u r f a c e i s r a t h e r similar. T h i s may b e e x p l a i n e d a s f o l l o w s : t h e s t a i r c a s e i s 1 2 0 cm w i d e w i t h w a l l s on b o t h s i d e s . T h i s h a s a p s y c h o l o g i c a l e f f e c t o n p e o p l e t a k i n g p a r t i n t h e e x p e r i m e n t b e c a u s e when t h e y a r e o f f b a l a n c e t h e y c a n r e l y on w a l l s o n b o t h s i d e s . D u r i n g t h e e x p e r i m e n t some p e o p l e a c t u a l l y s t r e t c h e d o u t t h e i r h a n d s t o g e t s u p p o r t f r o m t h e w a l l . I n t h e e x p e r i m e n t of w a l k i n g on a f l a t s u r f a c e , t h e r e i s no s i d e w a l l w i t h i n r e a c h . T h i s makes t h e p e r s o n s who t o o k p a r t i n t h e e x p e r i m e n t f e e l u n s t a b l e . T h e s t a i r c a s e w i t h w a l l s o n b o t h s i d e s w i t h i n r e a c h i s a c t u a l l y u s e di n t h e experiment. The d e g r e e of d i f f i c u l t y i n walking i s d e t e r m i n e d a c c o r d i n g t o t h e p r e v i o u s method.
A s shown i n F i g u r e 1 5 , t h e r e s p o n s e i n walking a b i l i t y t o t h e f l o o r a c c e l - e r a t i o n i s complex. The c u r v e s o b t a i n e d t e n d t o b e q u i t e s i m i l a r t o t h e per-
c e p t i o n c u r v e s of S e c t i o n 1 ) . These c u r v e s a r e known t o b e i n f l u e n c e d p e r i o d i c a l l y by t h e p e r i o d . U n l i k e t h e s t a t i c s t a t e , t h i s c o m p l e x i t y may b e due t o t h e a d d i t i v e p e r i o d i c e f f e c t of t h e f l o o r v i b r a t i o n and f o o t - s t e p p i n g . On t h e c o n t r a r y , t h e a b i l i t y t o work a t a d e s k i s a f f e c t e d by f i x e d f a c t o r s . I t i s m a i n l y c o n t r o l l e d by a c c e l e r a t i o n . 4 . I n v e s t i g a t i o n of V i b r a t i o n L i m i t s and H a b i t a b i l i t y T h i s s e c t i o n i n v e s t i g a t e s t h e s i g n i f i c a n t biomechanist i c r e s p o n s e of p e o p l e t o v i b r a t i o n a s a means of e v a l u a t i n g h a b i t a b i l i t y . The e x p e r i m e n t s on i t e m s e n c i r c l e d w i t h o l i s t e d i n T a b l e I were c a r r i e d o u t . The r e l a t i o n s h i p s between p e r i o d and a c c e l e r a t i o n f o r t h e s e e x p e r i m e n t s a r e shown i n t h e same g r a p h , F i g u r e 16. The r a n g e s between t h e s e c u r v e s (and a l s o s t r a i g h t l i n e s ) a r e d e s i g n a t e d f o r c o n v e n i e n c e a s
@
-
@
.
The c o n t e n t f o r each of t h e s e a r e a s w i l l b e de- s c r i b e d a s f o l l o w s .@
: I n t h i s r a n g e , most p e o p l e do n o t p e r c e i v e v i b r a t i o n . The v i b r a t i o n of b u i l d i n g s caused by a n unwarned e a r t h q u a k e o r s t o r m i s even more i m p e r c e p t i b l e .: I n t h i s r a n g e , most p e o p l e a r e aware of t h e s l i g h t v i b r a t i o n , and s t a r t t o t a l k a b o u t i t . The boundary between r a n g e s
@
and@
i s c a l l e d t h e p e r c e p t i o n t h r e s h o l d . To e n s u r e comfort and h a b i t a b i l i t y , t h e v i b r a t i o n should b e w i t h i n t h e weak r a n g e . The l i m i t where comfort i s l o s t depends on t h e per- c e p t i o n of e a c h i n d i v i d u a l . T h e r e f o r e , t h e p e r c e p t i o n t h r e s h o l d i s t h e f i r s t l i m i t f o r t h e i n v e s t i g a t i o n of comfort. These c u r v e s a r e based on p e o p l e ' s f e e l i n g . The i n d e x may b e e s t a b l i s h e d from t h e f o l l o w i n g e q u a t i o n (17) which i s e x p r e s s e d i n t e r m s of a c c e l e r a t i o n(a)
and p e r i o d (T).
I n t h e
@
r a n g e w i t h a c c e l e r a t i o n of 5-
1 0 g a l , t h e w a t e r i n t h e w a t e r t a n k w h i c h was i n s t a l l e d w i t h a p e n d a n t l i g h t b e g a n t o s h a k e g e n t l y . T h i s i s d e t e c t e d v i s u a l l y , b u t t h e v i b r a t i o n i s n o t y e t p e r c e i v e d . T h i s phenomenon h a s b e e n con£ irmed.@
: I n t h i s r a n g e , t h e v i b r a t i o n of t h e s u r r o u n d i n g s i s d i s c e r n i b l e e v e n w i t h o u t h o u s e h o l d o b j e c t s . Everyone c a n f e e l t h e v i b r a t i o n . A b i l i t y t o work a t & d e s k i s s l i g h t l y i n t e r f e r e d w i t h . A b i l i t y t o walk i s e q u i v a l e n t t o t h e c u r v e f o r t h e f i r s t d e g r e e of d i f f i c u l t y , l. e .,
i s n e a r l y n c r m a l . However, p r o l o n g e d v i b r a t i o n c a u s e s s e a s i c k n e s s sympto,ns f o r c e r t a i n p e o p l e . T h i s i s t h e b o u n d a r y f o r a r e a s@
and@
.
S i n c e m o s t of t h e a b o v e items a r e con- c e n t r a t e d on t h i s c u r v e , i t i s e s t a b l i s h e d a s t h e second l i m i t f o r t h e c o m f o r t i n v e s t i g a t i o n . To b e on t h e s a f e s i d e , t h e l i n i t s h o u l d b e e s t a b l i s h e d below e a c h c u r v e .@
: I n t h i s r a n g e , it i s s t i l l p o s s i b l e t o move a r o u n d , b u r w i t h g r e a t a i i f i c u l t y . I n a d d l t i o n t o t h e d i f f i c u l t y i n movement, t h e o c c u p a n t s f e e l u n s a f e d u e t o v i o l e n t s h a k i n g of t h e b u i l d i n g . The l a s t c o m f o r t l i m i t ( t h e t h i r d ) s h o u l d b e a s s i g n e d below t h i s r a n g e . Beyond t h i s r a n g e , t h e i n v e s t i g a t i o n on h a b i t a b i l i t y s h o u l d b e s w i t c h e d from c o m f o r t t o s a f e t y . T h e r e f o r e , t h e t h i r d c o m f o r t l i m i t i s a l s o t h e f i r s t s a f e t y l i m i t . T h i s i s t h e b a s i s f o r e s t a b l i s h i n g t h e c u r v e of d i f f i c u l t y i n moveiient.Beyond t h e
@
r a n g e of 35 g a l a c c e l e r a t i o n , d e s k work becomes d i f f i c u l t . 'The l i m i t f o r which d e s k work becomes i m p o s s i b l e i s s e t a t 35 g a l . However, i ti s p o i n t l e s s t o s e t t h e working l i m i t when i t a l r e a d y e x c e e d s t h e c o m f o r t l i m i t .
@
: A t 4 0 g a l , h o u s e h o l d o b j e c t s s t a r t a c l e a r l y a u d i b l e r a t t l i n g . I t becomes i n c r e a s i n g l y d i f f i c u l t t o move a r o u n d . I t i s a l m o s t i m p o s s i b l e t o m a i n t a i n b a i a n c e even i f o n e t r i e s t o s t a n d s t i l l . Above 4 0 g a l , o n e h a s t o b e v e r y c a r e f u l t o m a i n t a i n b a l a n c e i n moving a r o u n d . The l o w e r l i m i t of t h i s a r e a i s e s t a b l i s h e d a s t h e second s a f e t y l i a i t . : i n t h i s r a n g e , movement i s p o s s i b l e t o some d e g r e e b u t t h e d e g r e e of p e r c e p t i b i l i t y i s i n t o l e r a b l e .@ :
Movement becomes i m p o s s i b l e . However, t h e p e r c e p r i b i l i t y i s i n t h e " s t r o n g l y p e r c e p t i b l e a r e a " . I n a c t u a l b u i l d i n g v i b r a t i o n , t h e o c c u p a n t s s t a r t t o e s c a p e , f e a r i n g t h a t t h e v i o l e n t v i b r a t i o n may t h r o w them o u t . The a b o v e o b s e r v a t i o n i s conf irmed by two a c c i d e n t s d u r i n g t h e e x p e r i m e n t . I n t h e8
and@
r a n g e s , movement i s s u p p r e s s e d . From t h e a b o v e d i s c ~ s s l o n , t h e t h i r ds a f e t y l i m i t , i n which movement i s p r e v e n t e d , i s e s t a b l i s h e d below t h e lower l i m i t of t h e p r e v i o u s two a r e a s .
@ :
I n t h i s r a n g e , t h e r e s p o n s e t o v i b r a t i o n i s g r e a t e r t h a n t h a t i n@
and@
a r e a s . It i s u n d e r s t a n d a b l e t h a t i t s v i b r a t i o n a l c o n d i t i o n i s a l s o more s e v e r e t h a n that of t h e o t h e r two r a n g e s .@
: I n t h i s r a n g e , household o b j e c t s s t a r t t o t o p p l e . The o c c u p a n t s have t o e s c a p e o r e l s e t h e o b j e c t s may f a l l and h i t them. From t h e v i e w p o i n t of l i v i n g c o n d i t i o n s , t h e a c c e l e r a t i o n caused by t h e b u i l d i n g v i b r a t i o n i n t h i s a r e a i s u n f a v o r a b l e f o r l i v i n g . I n o t h e r words, t h e lower l i m i t of t h i s r a n g e i s t h e f i n a i s a f e t y l i m i t f o r occupancy. It i s a s s i g n e d a s t h e 4 t h s a f e t y l i m i t .5. C o n c l u s i o n
From t h i s v i e w p o i n t of h a b i t a b i l i t y , t h e comfort and s a f e t y l i m i t s f o r v i b r a t i o n of l o n g p e r i o d and l a r g e a m p l i t u d e a r e proposed based on t h e above o b s e r v a t i o n s a s shown i n F i g u r e s 17 and 18. F i g u r e 17 shows t h e r e l a t i o n s h i p between p e r i o d and a c c e l e r a t i o n . F i g u r e 1 8 shows t h e r e l a t i o n s h i p between t h e p e r i o d and a m p l i t u d e ( d i s p l a c e m e n t ) .
I n t h e n e x t p a p e r , t h e limits o b t a i n e d from t h e a c t u a l v i b r a t i o n s of
b u i i d i n g s and t h e a n a l y s i s of r e s p o n s e t o v i b r a t i o n w i l l b e compared. The f i n a l c r i t e r i a c o n c e r n i n g b u i l d i n g v i b r a t i o n s w i l l t h e n b e proposed.
Acknowledgement
The a u t h o r acknowledges t h e c o n s t a n t a d v i c e of P r o f e s s o r M. Yamada, F a c u l t y of E n g i n e e r i n g , Hosei U n i v e r s i t y and t h e d i s c u s s i o n of M r . N. Koshima dho was a g r a d u a t e s t u d e n t working i n t h e same l a b o r a t o r y s i n c e t h i s p r o j e c t was u n d e r t a k e n i n 1967. The a u t h o r would l i k e t o t h a n k a l l t h e g r a d u a t e s t u d e n t s who a s s i s t e d and p a r t i c i p a t e d i n t h i s p r o j e c t i n v a r i o u s ways.
1. The v i b r a t i o n a l c h a r a c t e r i s t i c s of h i g h - r i s e b u i l d i n g s due t o n a t u r a l f o r c e s w i l l b e d i s c u s s e d i n P a r t 2. The e x p l a n a t i o n of d a t a i s t h e r e f o r e o m i t t e d .
2. The p e r c e p t i o n t h r e s h o l d i s d e f i n e d a s t h e minimum v i b r a t i o n a t which i t i s p e r c e i v e d when t h e i m p e r c e p t i b l e v i b r a t i o n i s g r a d u a l l y i n c r e a s e d . 3 . The t o l e r a n c e t h r e s h o l d i s d e f i n e d a s t h e minimum d i f f e r e n t i a l p o i n t a t which t o l e r a n c e and i n t o l e r a n c e a r e d i s t i n g u i s h e d . 4. D r . S. T a k e s h i t a ' s h e l p f u l a d v i c e i s a p p r e c i a t e d . R e f e r e n c e s
1. Koshima, Goto and Yamzda. E f f e c t of l o n g p e r i o d and h i g h a m p l i t u d e v i b r a t i o n on human b e i n g s . P a r t 1. On t h e s u s q e p t i b i l i t y and body v i b r a t i o n . A b s t r a c t , P r o c e e d i n g s of J a p a n e s e A r c h i t e c t u r a l S o c i e t y , O c t . , 1972.
2 . G o t o , Koshima and Yamada. I b i d . , P a r t 2 . O b s e r v a t i o n on t h e p r o p o s a l of v i b r a t i o n a l b o u n d a r i e s . A b s t r a c t , P r o c e e d i n g s o f J a p a n e s e A r c h i t e c t u r a l
S o c i e t y , Oct.
,
1973.3 . Koshima, Goto a n d Yamada. I b i d . , P a r t 3 . E f f e c t o n g o i n g u p and down s t a i r s . I b i d . , O c t . , 1973.
4 . G c t o , Koshima and Yamada. I b i d . , P a r t 4 . S u p p l e m e n t a l e x p e r i m e n t s on p e r c e p t i b i l i t y . I b i d . , O c t . , 1973.
5 . Koshima, G o t o , Deguchi and Yamada. I b i d . , P a r t 5. E f f e c t o n p h y s i o l o g i c a l c h a n g e s . I b i d . , O c t . , 1974.
6. D e g u c h i , G o t o , Koshima and Yamada. I b i d . , P a r t 6. E f f e c t on t h e d e g r e e of d i f f i c u l t y of w o r k i n g a t a d e s k . I b i d .
,
O c t . , 1974.7. Goto, Koshima, D e g u c h i and Yamada. I b i d . , P a r t 7. E f f e c t on t h e movement of f u r n i t u r e and h o u s e h o l d o b j e c t s , e t c . I b i d . , O c t . , 1 9 7 4 .
8. R . J . S t e f f e n s . Some a s p e c t s of s t r u c t u r a l v i b r a t i o n , v i b r a t i o n i n c i v i l e n g i n e e r i n g . P r o c . of a symposium, o r g a n i z e d by t h e B r i t i s h N a t i o n a l S e c t i o n of t h e IAEE, Ed. by Skipp, B . O . , B u t t e r w o r t h s , 1 9 6 6 .
9. J o h n W . Reed. Human r e s p o n s e t o t a l l b u i l d i n g m o t i o n , wind-induced m o t i o n and human d i s c o m f o r t i n t a l l b u i l d i n g s . M a s s a c h u s e t t s I n s t i t u t e of T e c h n o l o g y , November, 1971. 1 0 . L a u r e n c e R . Young, J a c o b L. Meiry. P e r c e p t i o n of m o t i o n i n t a l l b u i l d i n g s . B i o s y s t e m s I n c .
,
Cambridge, M a s s a c h u s e t t s , J u l y , 1965. 11. I s h i n i o t o and Ohozuka. D e t e r m i n a t i o n of p e r c e p t i v e l i m l t of v i b r a t i o n . R e p o r t s of Tokyo S e i s m i c R e s e a r c h I n s t i t u t e , V o l . 11, K O . 3 , 1933-3.1 2 . Fu-Kuei Chang. Human r e s p o n s e t o m o t i o n s i n t a l l b u i l d i n g s . J o u r n a l of t h e S t r u c t u r a l D i v i s i o n , ASCE, A u g u s t , 1973.
1 3 . H. Katzumoto. New p h y s i o l o g y . F i r s t volume. M e d i c a l C o l l e g e , May, 1964. 1 4 . Kagakunoj i t e n . Iwanami Book Co.
,
Nov., 1964.1 5 . M. D e n z i . A r c h i t e c t u r a l v i b r a t i o n . L e c t u r e s on A r c h i t e c t u r a l S t r u c t u r e , Vol. 1 7 , Colona L t d . , O c t . , 1970.
1 6 . M e d i c a l E n c y c l o p e d i a . Nanzen d o , A p r i l , 1968.
1 7 . K.F.H. M u r r e l l . 1 5 . I V . V i b r a t i o n , Ergonomics, Chapman & H a l l , 1965.
P h o t o 1 V i b r a t i o n s i m u l a t o r
T a b l e I Items of e x p e r i m e n t a l o b j e c t s S t a t i c s t a t e P e r c e p t i b i l i t y ( 1 , 4 ) Symbol r e p r e - s e n t i n g t h e r e s u l t s S t a t e of p e r s o n s i n experiment A n a l y s i n t h e s t a t e of body shaking 913 A c c e l e r a t i o n produced i n v a r i o u s p a r t s of body E f f e c t on a b i l i t y t o work ( 6 ) Experi- ment No. E f f e c t on v i s i o n I t e m s of experiment
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I R e s u l t s of e x p e r i m e n t s on p e r c e p t i b i l i t y It ems compared E x p e r i m e n t a l r e s u l t sD i f f e r e n c e i n p e r c e p t i b i l i t y d u e t o sex Female
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T e l e v i s i o n 26. E l e c t r i c f a n 27. Clock 28. T r a s h c a n 29. Upright a s h t r a y 30. Vase d i a m e t e r of t h e b a s e ; em,kg)
31. Frame 32. E l e c t r i c b u l b 33. D r e s s e r 34. Make-up d r e s s e r 35, Baby d r e s s e r 36. E l e c t r i c s t a n d 37. Hanger 38. Wooden-shoe r a c k 39. S t e p l a d d e r 40. 3-way m i r r o r 41. Sewing-machine s t a n d 42. Empty boxes 43. Locker 44. Hanger f o r h a t 45. Swing f o r babyP o s t u r e : s t a n d i n g V i b r a t i o n d i r e c t i o n : back and f o r t h e i n s e x D i f f e r e n c e P e r i o d , h e r - Fig. 2 Average p e r c e p t i o n t h r e s h o l d and a v e r a g e t o l e r a n c e t h r e s h o l d
0 1 2 : 3 1 ; 0 7 8 9 1 0 P e r i o d is,,. F i g . 3 Comparison on p e r c e p t i b i l i t y o b t a i n e d by o t h e r r e s e a r c h e r s P o s t u r e : s i t t i n g i n c h a i r V i b r a t i o n direction: f r o n t t o back I I I 1 1 P e r i o d ( S ~ C I Fig.
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