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Ser
ra]-N2t_t2 no. 62 e . 2 BT,WNATIONAL RESEARCH COUNCIL CANADA
DIVISION OF BUTLDING RESEARCiI
BUIf,DIIqG $I $OBEHER$ CASADA
BY
R . FN TEGGET A N D H" B. DICI(ENS
A i ; ' 1 . L ' ' r ' I I D
TECITNTCAL PAPER NO. 62 OF THE
DTVTSION OF BUTLDING RESEARCH
F'IR$T EDITTO}I
OTTAWA MARCH T959
Nonthenn Resberch Statlon of the
BUILDING IN NORTITERN CANADA
PREFACE
The Dlvlslon of Butldlng Research of the Natlonal R e s e a n e h C o u n c l l , l n c a n r y i n g o u t l t s a s s l g n e d t a s k o f pr:ovldlng a researoh se:lvlce for the eonstnuctl,on industny of Canada in lts broadest sense, ts eoncent::atlng upolt t h o s e a s p e e t s o f b u l l " d l n g r o s e a n c h w h l c h a r e p e c u l l a r t o Canadao The many problems surnoundlng the whol"e questloa
sf butldlng ln nonthern Canada ls one euch sphere of s p e c i a l i n t e r e s t "
Thls has been r:eoognlsed f,rom the etart of the D i v i e l o n t s w o r k " I n d l c a t i v e o f t h e D i r r i s l o n t s L n t e r e s t l n t h e N o r t h l s t h e e x i s t e n c e o f i t s N o n t h e r . n R e s e a r c h S t a t l o n a t N o r m a n W e L l e , o f f l c l a l l y o p e n e d b y t h e P r e s L d . e n t o f t h e Council- ln 1956r followlng a more modest start at the sarne locatlon nlth bonrowed bulldlngs in 1952" Further reeog-nltion of the lmpontance of nonbhenn bulldlng stud.les was
the organlzation, wlthln the Divlslon, of tlre Northenn Bulldlng Sectlon ln L957" Thls brought togethen sevenaL phastss of tt.s Northenn work lnbo one l-ntegnated unit"
Mp* II. Bo Dickensr Jolnt authsn of bFtls nepor"t, is the Eead of thls Sectlon" IIe and hls colleagues are fnequentl-y asked fon genenal lnformatlon about the speeiaL c h a r a e t e n l s t i c s o f n o r t h e r n b u l l d t n g o T h l s p a p e r h a s therefore been prepared as a flnst attgmpt on the pant of t h e D l v l s t o n t o b r l n g t o g e t h e n w l t h l n t w o c o v e r s a s t a t e -ment of the prlnclpal slgniflcant facts affeotlng building
in northe::n Ganada" She authors are csnsclous of the fact that thene must be many omlsslons" but they look forwand to future ::evlslons of this doeument after tt has been put Lnto u.se lgl rrhlch errsrs and omlsslons ean be c o r r e e t e d "
.Accordingl-y" the authors would weLcome crltlcal eornments upon the contents of thls document and suggestlons for addltlonal lnformatl.on whleh ean usefully be lncluded i n f u t u r e ' e d j - t i o n s " E v e n t u a l l y , t h e D i v l s l e n w 1 1 1 b e
prepar5.ng a eomplete manual on bul"Idlng in northe:rn Canada, t o w h l c h t h i s g e n e r a l s t a t e m e n t , w i l l p n o v i d e a g u i d e " T h l s maJor work cannot be contemplated for some tlme yets so
that lt ls hoped that thls more modest document w111 serve usefully ln the interim"
O t t a w a ,
I M a r c h L 9 5 9 ,
R o F o l r e g g e t
PART ONE PART fWO PART TEREE PART FOTIR PART FI\M PARE SIX TABIE OF CONTENTS TNTRODUCTION r . D]STII{GU]SIIING FEATURES O '
TIIE CLI},IATE OF NORTI{ERN CANADA . . BUILDING ON OR BELOW GROUND:
PERUAFROST AND ITS EFFECTS . . . . D l s t n l b u t i . o n o f P e r m a f r o s t E f f e c t s of Penmafrost S o m e C o n g t n u c t l o n P r o b l e r n s : Bulldlng Foundatlons
4 . 2
l+"
3
l+. l+
a a i t a a a a o a r a t a t Q P a g e 1l+
2 l + . 5 S o m e C o n e t r . u c t l o n P r o b l e m s : Waten Supply b " 6 S o m e C o n s t n u c t L o a P n o b l e m s ; S e w a g e D l s p o s a l b . 7 $ o m e Constnuctlon Pnoblems: Roads and Runn'raysBUILDING SUPERSTRUCTURES : S P E C T A T N O R T H E R N R E Q U I R E M E N T S . I O . T ' ' '
7
T
7
10 L2 T7 1 923
2l+
2I+
25
27
27
2 8
2 9
3 o
5 . 2
5 . 3
5.1+
5 . 5
5 . 6
5 , 7
5 . 8
5 , 9
Strengt'h and Rlgidtty B e s L s t a n c e t o I { e a t F l o w
Reslstanee to Water Vapour Flow R e s L s t a n c e t o A l n F l o w a n d
tlquld Water Movement R e s l s t a n c e t o F l n e Heatlng Pr"tlf abrtc atlon N e w Matenlals L O G I S T I C S A N D E C O N O M I C S O C O ! . O 6 " . 2 A e c e s s 6 . 2 ( a ) A 1 n T r a v e L 6.2 (b) Manlne Tnanspont 6 . 2 ( c ) R a l I T n a n s p o n t 6 . 2 ( d ) M a c k e n z l e R l v e r R o u t e 6 . 2 ( e ) H l g h w a y F a c l l l t t e s 6 " 3 E c o n o m l e s 6 . 3 ( a ) C o s t o f F r o l g h t 6 , 3 ( b ) U s e o f t o c a L M a t e n l a l s 6 " 3 ( c ) U s e o f L l g h t M a t e n l a l s 6 . 3 ( d ) P n e f a b n l e a t l o n 6 . 3 ( e ) R e l a t L v e C o s t s . o o , 3 2
3 2
3 6
TABIE 0F CONTENTS (continued) Page P A R T S I X ( C o n t r d ) 5" l+ Remotenes s 38 6 . L ( a ) R u g g e d D e s l g n 6 . 1 + ( b ) E a s e o f R e p a l : : 6 . 1 + ( c ) S t a n d a n d " t z a t i o n 6 . 5 ( d ) F k e P r o e a u t i o n s P A R T S E V E N C O N C L U S I O N . . . . . . . C C C I + O
APPENDIX A Some Publlcatlons of the Divtsion of Bulldlng R e s e a : r c h , N a t L o n a l R e s e a r c h C o u n c i l , r e 3 - a t i n g
t o t h e N o r t h
APPENDIX B Some neferenees on the subject of northern br.rlldlng
PART ONE
INTRODUCTION
Bulldlng in northenn Canada 1n recent years has b e c o m e a n o s t l m p o r t a n t p a r t o f c o n s t r u c t i o n a a t l v l t y 1 n t h l s e o u n t n y . D e s p l t o l t s l l m l t e d v o l u m e , l t s s t r a t e g i c l o c a t l o n and d.efence lmplleat1ons glve northern butldlng a slngulanly lmpontant place ln the natlonal eeonomy"
The North of Canada ls an lIl*deflned regl"on but, however" rovlewed, lt can be soen to embrace at least half of the land area of the countny" Thls one fact ln ltself lends slgniflcance to no::thern bulldlng. The cannylng out of
unusualLy lrnpontant and extensive natLonal defenee lnstalla-tl-ons ln nonthern Canada, ofton Jointly wlth the Untted States of Arnerlca, has glven Canadian onglneens and cont::aetors new experionce and has resulted tn new bulLdlng achlevements. Although defence stll-l domlnates the nonthenn eonstructlon
s c e n e , e l v l l I " a n b u l l d l n g l s a l s o d , e v e l o p l n g : r a p l d l y " F n o m b o t h p o l n t s o f v l s w , t h e r e f o r e , l n f o n m a t l o n r e g a r d l n g b u l l d l n g ln the North ls of current lmpontance" Thls paper 1s &rr attempt to brlng together brlef statements negardlng the maln features r^rhieh dlstlngulsh bulldlng ln the North from that ln other parts of Canad.a"
At the outset lt may be noted that northern buildlng ls a nelatlvely recent development ln the hlstony of Canada, wlth the exeeptlon of the Lnterestlng developments ln tbe
Yukon Ternltory" In this part of the Northwost there has been qulte extenslve bullding so that in furthen references heneln to the l{or"th the Yukon may sonxetlmes constltute an unspeclfled exceptlon. Unt11 the 1920t s the only pu1ldlng in the North worth mentionlng was thdt caruled out by the Hud.son Bay
Cor[pany and other tnaders, the varlous mLssj-ons and tlre Royal C a n a d l a n M o u n t e d P o l t c e . W h e n l t 1 s r . e a l i z e d t h a t I l t t l e n o r e than l0 years aga t'here were pnactlcally no maJor bulldlngs aE all ln northern Canada, 1t r"r111 be appreelated that northern bullding 1g lndeed a very necent development.
The openlng of the Hudson Bay Rallway ln 1929 and the correspondlng development of the port of Chunchlllr was perhaps the flnet raaJon move ln nonthern development"
Furthen to thg west, ln the Sackenzle Valleyr the dnllllng of the Dlseovery o11 well at Horman trr/el}s 1n 1920 was an lndlca-t i . o n o f g n e a lndlca-t a c lndlca-t l v l lndlca-t y y e t b o c o m e " T h e d l s e o v e n y o f r a d l o -a c t t v e o r e o n G r e a t F o a r L a k e l n 1 9 3 0 u f o l l o w i n g t h e d i s c o v e r y o f g o l d d e p o s l t s o n G r e a t S l a v e L a k e a n d a t L a k e A t h a b a s e a u a l J - c o m b l n e d t o l n t n o d u c e m J - n l n g a n d l t s a s s o c l a t e d a c t l v l t l e e
into the North"
I t l s p e r h a p s m o r e t h a n a c o l n c l d e n e e t h a t t h e f i r s t aeroplano flew lnto the Mackenzle Va11ey 1n 1921 and that the
- 1
f l n s t c h a n g e f n o r n s t e a m n a v l g a t t o n t o d l e s e l t u g b o a t s o n t h e H a c k e n z l e R l v e r s y s t e m t o o k p l a c e a s r e e e n t l y a s 1 9 3 8 o E v e n
fn 1939, however, the only negular alr servlces lnto the l(orth 'were belng provlded by small skl- and float-equlpped planes
slnce there wene still no permanent landlng strlps an;rwhere 1n the North"
ft was the lmperatlve of wan whl-ch eausod lmmense ehanges ln thls slmple scene. Ehe constructlon of the Alaska Hlghway tn order to llnk the United States brLth Alaskau and
t h e a s s o e l a t e d e o n s t n u c t l o n o f p e r m a n e n t a i n f i e l d s f o r t h e N o r t h w e s t S t a g l n g R o u t e , e o n s t l t u t e d t h o f l r s t m a J o r " n e w
development ln nonthenn tnanspontatlon faeilltles" Then came the Canol proJeet lnvolvlng the dnllIlng of further o11 wells and other developrnents at Norman WeL1s and the almost lnered-Lble bulldtng of, bro o1l plpellnss from the Mackenzle Valley across the mountaLns and lnto the Yukon fer"nltoryo
Prlor to thls thene riras, however, a slgnlficant
etant of AnctLc meteorological actlvlty lnvolving the plannlng and bulldlng of the flve Jolnt Arctle Weathen Statlonso One of these, Bt Alert, stlll remalns as the most northorn known settLenent qf any klnd. Although the Jolnt Weather $tatlons are not extenslve, they have lnvolved eonstructlon operatlons whleh were truly of a ploneerlng chanacten"
More necent relaing developments have contlnu.ed the e x t e n s l v e a c t l v l t y w h l c b s t a r t e d w l t h t h e E l d o n a d o M l n e a n d th.e gold mlnes on Great Slave Lalce. The nlckel mlne at Ranktn Inlet on Hudson Bay ls now ln pnoductlon, and there ls in
pnospect the development of a sttll larger base metal rnlnlng p r o J e c t a t P l n e Polnt on Great 51ave Laken Correspondlngly, actlvlty ls now gnowlng ln the search fon o11, not only tn the Mackenzle Lowlands but even as far north as the Arctlc A r c h i p e l a g o , A l l t h e s e p n o J e c t s p o l n t t h e w a y t o a s t o a d y but continuod gnowth 1n bulldlng aotlvlty ln the North"
An r:rrusuaJ- pnoJect has developed from the declslon made by the Goverrunent of Canada i"n L954 to move the town of AkLevlk to a new slte so that lt eould be eqpandedu pnovlded with a proper alrf,1e1d and made lnto a community worthy of
l t s p o s l t i o n a s t h e l e a d l n g C a n a d l a n s e t t l e m e n t o f t h e N o r t h l + o e t " A s a t l s f a c t o r y n e w s l t e w a s f o u n d . t o t h e e a s t
s L d e o f t h e g n e a t M a c k e n z l e D e l t a " F l r s t k n o w p a s ' r E a s t Threen (the rrame glven to 1t dr:-nlng the sur.vey fon the new slte) the new town ls now known offlclally as fnuvlk,
Bulldtng actlvlty l"s belng earrlsd on each sumr$er and thls new nonthenn town w111 eome lnto fuIl use wlthln tho next year or two"
0 n t h e o t h e n s l d e o f t h e A r c t l c a n a p t l v e s t a n t has been made at developlng Froblsher Bay lnto a complete
- 3
northenn eommunLty, ln vlew of lts suddenly-galned imponte.nce a s a vltal polnt on Anctle tnans-Atlantlc a f u " routes,
unfontunalely far too much publlclty has been glven to pre-llmlnany ldeas regardlng the posslble d.eveLopnnent of frbblshero !-lsgountlng all such populan mlsconceptlona, the fact nemaLns that Fnoblshen-Bay |9_eotns to beeome an funportant coamunlty and wlll calL for stlil funtben effonts, nol only ln the deslgn of speclal nonth.ern buildlngs but 1n the exeeution of what wlLl be a maJon eonstnuotlon operatlon in the sor:tb."
It wouLd be lnappnoprlate to make more than passlng n e f e r e n e e tn thts paper to the extenslve defence eonstluetloi openatlons wh.leh were lnvolved Ln the construetlon of the DEW Llne and the eorrespondlng Mid-canada Llneo These dld
lnvolvo qulte the most extenslve buildlng oporatlon yet eannled out ln the North. The suscessfur completlon or the Lwo rlnes showed what eould be done when defence necessltated such
pnojects. The fact that they w€rre ca::nled out wLthout negard to nonrnaL eeononlc eonsldenatlons does not mahe all the
expe:lence galned dlreetly applieabre to elvlllan buildtng in the.I{orth, but the supenlative eonstnuctlon achlevoment rdpre-sente_d_by t!r9 ecnpretlon of the DEW Line ln partleular" or1 sohedule, wtl1 long remaln a continutng challenge and i
densnstratlon of wb.at englnee:rs and contractons ean do ln the Nonth when necesslty eaIls. rt ls agalnst such a background. t h a t the speclar eheractenlstlcs o f n o n t h e r n bulxdlng wril now be revlewed.
l +
-PART TWO
D]STINGUISHING FEATURES
The factons tbat dlstlngulsh northern bulldlng fnom bulLdlng elsewhero ln Canada are the ellmate, the unusual t e r n a l n a n d t h e n e l a t l v e l s o l a t l o n o f m o s t b u l l d l n g s l t e s . C l l m a t e , whlch trlll b e t n e a t e d i n m o n e d e t a l l l n P a n t E l t e e , ls not mueh more severe that condltlons experlenced ln othen c o l d a r e a s o f C a n a d a , s u c h a s t h e P n a l n l e P r o v l n e e s . I t
dlffers malnly ln the dur.atLon of cold weatbe:r rather than ln the extnemes of temperatu:re. TFtrs the technl-cal pnoblems a r i s l n g d l n e c t l y fnorn cllmate are not slgnlfleantly d l f f e n e n t f n o m t h o s e e n c o u n t e r e d l n m o n e s o u t h e r n n e g l o n s , N e v e : l t h e l e s s ,
the cllmate does have several lmportant lmp11cat1ons to
bulldlng 1n the Nonth" fhe long wlnter perlods and hours of d a r k n e s s m e a n a v e r y s h o r t c o n s t r u e t l o n s e a s o n . f h l s s e a s o n t e n d s t o b e r e s t r i e t e d s t 1 l } funthen by the penlods of broak-up and fneeze-broak-up durlng whlch many areas are compJ,etely cut
off fnom each othen because of dlffleulty of movementn An tmpontant featune of the ternaln of nonthern G a n a d . a l s t h e p r e s e n c e o f p e r m a f n o s t 1 n m o s t n o n t h e n n a r e a s , T h t s l e a d s t o m a n y o f t h e t e c h n l c a L p n o b l e m s a s s o c l a t e d w l t h nonthern bulldlng. Much of the north has a shallow top c o v e n l n g o f o r g a n l c m a t e r l a l e a l l e d n r u s k e g . T h l s l s a f l b n o u s m a t e r l a l c a p a b l e o f h o l d l n g v a s t q u a n t l t l e s o f m o l s t u r e " I t s low bearlng porrer creates many dlfflcultles
o f t r a f f l c a b l l l t y a n d of constructlon"
T h e g r e a t d i s t a n e e s , c o m b l n e d w l t h t h e l l m l t e d transpontatlon faclllties ln the Nonth, exe::t an lmportant lnfluence on the oconomLcs of northern bulldlng" The rela-t l v e l s o l a rela-t l o n o f m o s t s l t e s w h e r e c o n s t r u e t l o n m u s t b e c a n n l e d o u t , w l t h l t s a t t e n d a n t p r o b l e m s o f l a c k o f l o e a l } y avallable manpower. and materl-ale rneans that pnactlcal"ly all laboun and materlal requlrements must be met by bnlnglng ln f r o m t h e o u t s l d e a t e x t n e m e l y h l g h c o s t . S l m l l a r l y , m a l n -tenance and repl-acement of damaged on lost pa::ts eneate
fr:rthen dlfflcultles. Thls one aspect alone demands that the e q u l p m e n t o f b u L l d l n g s h a v e r & s 1 t s p r i r n e f e a t u r e s , s l m p l t c l t y o f d e s l g n a n d n e l i a b i l l t y l n o p e r a t l o n . T h e s e s e v e r : a l f a c t o r s J o l n t l y L n t n o d u c e s e n l o u s e c o n o n i c a n d l o g l s t l e c o n s i d e r a t l o n s ln the carnylng out of any eonstruetlon pnoject ln the north t h a t w l t l b e d i s c u s s e d l n eneaten detall ln Part S1x.
-5
PART THREE
THE CLIT{ATE OF NORTiTERN CANADA
There are probably morae mlseoneeptlons about the weather of nonthern Canada than about any other aspect of northern wo:rk. It is, f on example, populanly lmaglned that the snowfall ln the North ls heavy. Over most of the
N o r t h w e s t Tenrltonles lb is actually nathen 1lght - about the sarne as over the Pralrle Provlnees and very much Less than over most of eastenn Canada. The far northern lslands get less than 20 lnehes of snow each year, about tLre sarae as the southern pant of Vancouver Island. fn actual fact, much of no::thern Canada ean be descnlbed as the equlvalont of a d e s e r t since its annudl total preclpltatlon l s L e s s t h a n
l - 0 l n c h e s p e r y e a r " I t 1s the wlnd whleh creates the lmpres-slon of much snow, slnce the stnong wlnds df tne North do c r e a t o snow dnlftlng t h a t leads to lndlvldual d e p o s l t s of snow of eurprlslng depth whenever obstnuetlons lnte:rfere wlth the fnee flor^r of the wlnd.
Another popu3.ar mlseonceptlon ls that the cllmate of the Nonth i-s very much colden than anywhere el-se ln Canada" Thls ls not the case. Temperatr.ures ln the North are somewhat lowen than those experlenced elsewhe:re ln Oanada, but thene a r e many occaslons when tompenatures ln the clties o f w e s t e r n Ganada, ln the wlnten, are not far dlfferent from those 1n the North. Taklng long-term average flgures, the temperature r e g l m e 1 n the western half of the Maekenzie Dlstrict 1 n
January ls about the same as ln northern Hanltoba and only s l l g h t 1 y colder than at Wlnnipeg (Flgune 1). T h e n e c o r . d mLnlmum ternpenatures in Canada hoilil6iffi1tt1e varlatlon w l t h latltude. O v e r most of the l{orth, temperatures lower
than 60 below Bero have been observed and, as ES.ggts_,! l n d l c a t e s , s l m i l a n temperatunes have been reach-ed by a few s t a t l o n s ln 0ntanlo and Quobec. Reeord tempenatupes ln the Yukon are somewhat lowen. Thege two eharts suggest th^at the
low annual mean temperatures ln the Nonth shown ln Flgure 3 ars the resuLt of the perslstence of the cold r^ieath6?-ffi8-er t h a n lts severlty.
The perslstent cold throughout the long wlnter ls emphasized by the chert ln Flgure l+, showing the mean ar.rnual d e g r e e days below 65oF" These@nes s e r v e a s a n lndlcatlon o f tbe relatlve f u e l r e q u l r e m e n t s for one wlnter. O n t h i s b a s l s , the fuel consumptlon for the Mackenzle Valley w111 be ab.out twlce that for the Lower Lakes and Upper. St. Lawrence r e g l o n s . C o r r e s p o n d l n g l y , a n lndtcatlon o f t h e s h o r t n e s s o f the surmller ls glven by the average l-ength of the fnost fnee season shown 1n Flgure 5. Tho most nemankable features ane
- 6
the short season ln nonthenn Quebec and the relatlvely longer season around Gneat slave Lake. The extenslon of the 60 day s e a s o n down the Mackenzle Rlver to Aklavik ls also notewortLsr. rn the far northenn lsrands, thene may seldom be mone than a week ln the year wlthout some frost.
Anothen lmportant aspect of the nonthern wl_nten l f t ! " l o n g p e r l o d o f d a n k n € s s o F l g u r e 5 i n d L c a t e s t h a t , l n t h e f a n n o n t h e n n 1 s 1 a n d s , t h e n e a F f f i o n f 1 v e m o n t h s w h e n
the sun is never above the honlzon for more than flve houtrs" Thls perlod of very short days ls about th::ee months at
Aklavlk and dlmlnlshes to lebs than a month in the Gneat S l a v e Lake area"
Just as the eomblnatton of wlnd and low tempera-tu::es raLses certaln problems fon northenn bulldlng, so the comblnatlon of the long dunatlon of the northenn wfnter and l t s eontlnuous dankness raLses dlffteurtles o f llvlng 1 n the North and. senlously rest::lete the perlod durlng whtctl constnuctLon ean be canrLed on, conrespond.lngly, irre row annual mean aln tenpenatures of the Nonth are-r'erated to the tempenature of the ground, and so to tbe wldespread exlstence-of pg-qqqfqost - the name glven to the stite of the gnound wh6i-ffi-Iffierennlalty fiozen.
7
PART FOUR
BUILDING 0N 0R BELOI'{ GROUNDf PERMAFROST AND ITS EFFECTS The presenee of penmafrost ln the l{onth ls a maJon teehnlcal eonslderatlon ln any englneenlng pnoject, but many mLsconeeptlons about 1t have been-bulrt u[ in irte publler s mlnd by over-enthuslastlc reportlng. The ellmate of the Nonth 1s such that a portlon of the gnound nemalns frozen
throughout the yearn sorae surfaee thawlng does bake place dependlng on the locallty and the lnsulating effect oi trre rnggs co\rer, but below thls the gnound nemalns fnozen du:ring all months of the year, fhts perennlally fnozen grou.nd, ts-known a,s permafrost" The materlals ln thle f:'ozen gnound v a r y " T h g , y l n c l u d e bedrock, gnavel, sand, sllt, c l a y and muskeg" Thus permafrost ls not the name of a new matenlal but of the frozen equlvalent of materlals found ln warmer c l l m a t e s .
lf"z Dlstnlbutlon of Permafrost
Per"mafrost ls found ln northern Nonth Amerlca and northern Asla, involvlng an area of sever"al nrllllon square mlles, or about one-flfth of the land area of the r.rorrd.
r n canada, penmafnost underlles about one-half of the total land apes. The southern boundar"y of permafrost has not been g 9 c u g 1 l e l y d e t e n m l n e d b u t t t ts belleved to follow noughLy t h e 50th paraIleI, d n o p p L n g south of thls parallel e a s f , oi Font smlth to abou.t the south shone of Hudson Bay and cut-tlng nonth agaln across Labr"ador" rt ls tneorrect to thlnk of the southern boundany of permafnost aa being a well-d e f i n e well-d Llnen rn practLce, areas containlng eontlfluous layers of permafnost w111 glve way to areas whene permafrost ls the maLn constltuent but 1n whlch lslands of thawed. materlal exlstn l{ext to these areas the thawed gnound becomes predomlnant and permafrost exlsts only as lslands o r lenses wlthln the unfrozen materlal. T h e thlckness of permafrost vanles frorn a few lnches ln the mone southerly n e g i o n s to mone than 11000 feet 1n the nonthenn s.r€as, lts t h l c k n e s s lnereasing generaLly bowards the north,
h , 3 E f f e c t s o f Permafnost
T h e e x l e t e n c e o f p e n m a f r o s t l n t h e N o r t h has been known fon a long time but 1t ls only ln comparatlvely recent yeal.s that lt has become an obvlous problem" As 1ong as water ln the summor and snow ln the wlnter pnovided
neees-s-ary transportatlon noutes, and wlth bulldlngs of slmpl_e deslgn, the thawlng of ponmafrost was relatlvely unlmpontanto When, however, frozen g:round had to be eleared. flrst fon
. B
r o a d c o n s t r u c t l o n a n d t h e n f o r t h e b u l l d i n g o f a i r f l e l d s o a n d w h e n h e a t e d b a s e m e n t s w e r e b u l 1 t t h e p e c u l l a n p r o p e r t l e s o f permafrost made thernselves very evldent to englneers"
Tho gnound ln permafrost &reas nonmally separates i t s e l f l n t o t w o l a y e r s , T h e u p p e n l a y e n w h l c h a l t e n n a t e l y
f n e e z e s a n d t h a w e w l t h t h e s e a s o n s 1 e c a l l e d t h e a c t l v o L a y e r " The lowen layen whleh rernalns frozen
contlnuously-fE'Til1fet'-permafrost. The upper sunface of this permafnost layer ls known as the permafnost table and ls lrregular ln shape. It
l s l m p o r t a n t , a n d y e t o f t e n d l f f l e u l t , t o d e t e n m l n e t h e
boundany between these two layers except by carrying out eub-surface lnvestlgatlons ln late suflrmer or early faII when the aotlve zone ls thar*ed to lts maxlmum depth. The depth of the a c t i v e z o n e b e L o w t h e s u r f a c e d e p e n d s o n t h e s o i . l t y p e , l t s m o l s t u r e c o n t e n t , o n t h e l n s u l a t l n g c o v e r o f v e g e t a t l o n o s n o w
or Lce, and upon the movement of ground water as well as on the exposure to wlnd and srno Genenally, lt Ls lower in s a n d . - g n a v e l s o l l s t h a n l n s l l t y , e L a y o r p e a t y s o l l s , o t h e r : f a e t o r s b e i n g e q u a I . T h e a c t l v e z o n e f n e e z e s l n r * l - n t e n a n d thaws ln sumraer; thus foundatlons located in the actlve zone a r o s u b J e c t t o p r o b l e m s s l m l l a r t o t h o s e e n c o u n t e r e d l n t h e wlnter" months ln mone temperate zoneso
P e r m a f r o s t l s v e r y s e n s l t l v e t o t e m p o r a t u n e d l f f e r -e n c -e s . I n u n d i s t u r b e d a r e a s , a c o n d l t l o n o f t e m p e r a t u r e
e q u l l i b r i u m h a s b e e n g e n e r a l l y e s t a b l i s h e d b y n a t u r e b e t w e e n the permafrost and the sunface of the ground whereby the penmafrost neLther bullds up non breaks down during norrnal dalI-y and soasonal temperature vanlatlons" -A,ny ehar:go ln the natu::al lnsulating cover at the ground surfaee sueh as the :"emoval of trees, bnush and moss, or any change ln the normal fLow of ground water w1]1 upset this thermal balance of
nature and start the permafrost thawlng" Ev6n solar heat r e f l e c t L n g f r o m t h e s o u t h s l - d e o f a b u i l d i n g m a y c a u s e t h e p e r m a f r o s t t o r e e e d e o n t h a t s i d e . C o r r e s p o n d l n g l y , t h e
shadow of a butldlng may reduce the so1l temperatrrre on the n o r t h s i d e s u f f l c l e n t l y t o b r - l n g t h e p e r m a f n o s t c l o s e n t o t h e s u r f a c e , B e a t l o s s e s t h r o u g h u n t n s u l a t e d o r p c o r l y insulated floors of bulldlngs also eause thawlng of the u n d e r l y l n g f r o z e n s o 1 1 s "
The lmportance of permaftrost to elvl1 englneerlng c o n s t n u c t L o n l l e s 1 n t h e f a c t t h a t , a l t h o u g h t h e g r o u n d l s s o l l d w h e n f r o z e n a n d p n o v l d e s l n t h a t s t a t o a n e x q e l l e n t
b e a r i n g f o r a s t r u c t u r o , 1 t m a y l o s e l t s s t r e n g t h w h e n t h a w e d to the extent that lt w111. not support even relatlvely llght l o a d s w h l e h a r e l m p o s e d u p o n i t . U n d e n s u c h c l n c u m s t & n e o s , s e t t l e m e n t o f t h e s t r u c t u r e w l I I p n o b a b l y o c c u r a n d , b e c a u s e the thawlng ls ln rnany cases unequal under the anea of the sttr+uct\.l.ne, the reeult ls often dlfferentlal settlement whleh ean ruln bulldings, brldges, dams, noads, rutlw&ys and any o t h e r f a c l l l t l e s p l a c e d 1 n o r o n t h e g n o u n d "
- 9
The extent of thls settlement r^r111 depond. on eeveral
f a c t o n s t h e t y p e o f s o l l a n d t h e o r l g l n a r l c e c o n t e n t b e l n g
the most impontant. Normal-1y, l1ttle or no trouble l"s
eneoun-t e n e d w i eneoun-t h f n o z e n s o l 1 d r o c k o n frozen dny sand and gravel"
!{ost of northern Canada has been glaclated, however" and as a
r e s u l t , m a n y o f t h e s o l l - s t h e r e e n c o u n t e : : e d c o n s l s t o f f l _ n e g n a l n e d m a t e r l a l s s u c h a s c I a y , s 1 } t o n f l n e s a n d , w h l e h h a v o
a h i g h 1 e e c o n t e n t a n d p o o r frost n e s i s t a n t q u a l i t l s s . I n
t h e s e s o l l s , w a t e r l s d . n a w n u p b y c a p l l l a n y a c t l o n d u r l n g
f r e e z l n g a n d l c e l e n e e s w e r e formed, ln some cases sevonal
f e e t t h l c k , T h e v o l u m e o f l c e m a y b e s l x t l m e s t h a t of the
s o t l . T h e l e e a c t s I 1 k e a c e m e n t , b o n d l n g the lndLvldual
p a n t l c l e s s o t h a t t h e n e s u l t 1 s a s o 1 1 h i l t h c o n s l d e r a b l e
s t n e n g t h . w h e n t h a w e d , h o w e v e r , t h e s o l L c a n change to a soft,
llquld-llke slurny wlth }lttle or no supportlng powero
S l t e s e l e e t i o n 1 s t h e n e f o n e a m o s t l.mportant element
l n n o n t h e r n c o n s t r u c t l o n , o n e o f t h e f l n s t o o n s i d e r a t l o n s
belng what ane the soll and. penmafrost condltions ln the area,
S u b s u n f a c e l n v e s t l g a t l o n s l n p e r m a f n o s t n e g l o n s r e q u i r e
s p e c l a l t e e h n l q u e s o f s a m p l l n g f r o z e n s o 1 1 a n d are generalry
m o r e d l f f l c u l t t h a n s l m l l a r l n v e s t l g a t l o n s i n t e m p e r a t e z o n e s " T h e n e l s , t h e n e f o r e , c o n s l d e r a b l e a d v a n t a g e l f t h e l e s s s u i t * a b l " e a r e a s f o n c o n s t n u c t l o n c a n b o e l l m i n a t e d b e f o r e h a n d b y u s l n g a l n p h o t o s a n d t h e teehniques of alr photo lnterpretatlon"
Expenlence in northern areas has alneady ehonn that
o b s e n v a t l o n o f s u n f a c e f e a t u r e s c a n p r o v l d e u s e f u i c l u e s t o
the natune of subsurface eondltlone which may be encountered"
Hummocky tundra, eommonly known as 'lnlggen headstt, indleatee
t h e e x l s t e n c e o f a p e r m a f n o s t t a b l e n e a n t h e s u r f a c e e p o o r
dralnage and a general waterlogged eondltlono A gnor^rth of
birch tneee lndlcates thawed 6ground, elther 1n the perrnafnost
or between the permafrost and th6 seasonally frozen g:round.
s p n u c e t n e e s i n d l c a t e a p e r m a f n o s t t a b l e r e l a t l v e l y i e a r t h e
surfaee of the gnound, and poor dralnage,
0n the other hand, plne and ftr trees lndlcate a
rnrell--dralned gnanular soll, whlch 1n tunn suggests a lowered
p e r m a f r o s t t a b 1 e . s u c h s l t e s a . r e w o n t h y o f e l o s e i n v e s t i
-gat!.on by ground partles and are lndlcatlve of good
conetnuc-t l o n s l conetnuc-t e s " w l l l o r r s g e n e r a l l y t n d l c a t e g n o u n d w a t e r and a
s l t e l l k o r y t o b e t n o u b l e d w l t h s u r f a c e lce duning wlnten
months. Areas eovened by lrr.egular tree gnowth and contalnlng
Lndlvidual tnees tllted at odd angles lndlcate gnound
s u s c e p t l b l e t o s w e l 1 l n g a n d f r o e t m o u n d s . A n e a s d d v o t d o f tnees and shrube and covered by tundra and moss, partleularly
thoee aroas that exhibtt a polygonal ground pattern aro
c h a r . a c t e r l e t l c o f a h i g h p e r m a f r . o s t t a b 1 e .
Dnalnage ls a vlta1 facton 1n permafroet a^rsaso
- 1 0
so that all movement of water must be over or just below the gnound sunfaceo Becau,se of thls lack of subsurface dralnaga, t h e n e l s u s u a l l y a n excess of surface waten in northenn areas" I f p n o p e r d r a l n a g e facllltles a r e n o t p r o v l d e d o r t h e n a t u r a l dnalnage ts lmpeded by eonstructlon wonk, thls sunfaee water c a n s e n l o u s l y conrpllcato eonstnuctlon operatlons and ean c n e a t e m a l n t e n a n c e p r o b l e m s by intenslfylng f n o s t a c t l o n ln the aetLve layer 1n wlnten and cauelng thawlng of the
permafnost 1n su$rmerc
h.l+, Some Constructlon Problems: Buildlng Foundatlons
I t is pnefenabLe to locatu bulldlngs on or ln solls that conslst of gravel or eoarse sand because standard con-s t r u e t l o n technlquecon-s are then pocon-scon-slbLe con-slnce the thawing of t h e s e m a t e r l a l s d o e s not usually matter:" If, however, a s t n u c t u r e m u s t b e p l a c e d on s1lt, clay, flrre sand or onganic m a t e r l a l , e v e r y effont should be made to pnesenve tLre frozen
s t a t e f o n t h e llfe s p a n o f t h e b u l I d l n g . S t a t e d s l m p l y , thl-s means that the natural permafnost condltlon should be dls-t u r b e d as ldls-tdls-tdls-t1e a s p o s s l b l e . T h l s nequlnes not enly specl-fle c o n s t n u c t l o n technlques but also strl-ct dlsclpl1ne and eontnol o f t h e e o n g t n u c t l o n crewc
Pnoservatlon of the ther"mal reglme, and thus the permafnost table, may be attempted by elthen ventllatlon on
L n s u l a t L o n " W l t h v e n t l - l a t l o n , a c l , e a r s p a o e d f a t least t w o feet ls pnovlded beneath a weLL-lnsuLated floon so that cold aln can clrculate beneath the butlding and mlnlml-za heat fl"ow to the gnound. Thls nequlres excellent floon insulatlon Ln onder to malntaln comfont condltlons ln the l l v t n g areas above" It ls also wlse to attempt to pneserve the natu:ral lnsulatlng cover by pr"otectlng the moss dr:::lng constnuctton r+lth one to two feet of gnavel or slmllar
m a t e r l a l or by plaelng addltlonal moss over the bulldlng a r e a w h e n t h e j o b ts complete,
W h e n t h e lnsulatlon nrethod ls used, a substanttal t h l c k n e s s of non-frost active matenlal such as gnavel ls placed elther on the gnound surface dlnectly on to repl"ace the actlve zone matenlals" The former 1s nor:maIly conflned t o tempona:ry structures because of the posslblllty o f s e t t l e -ment whlle the latter ls very costly. Gravel mats should extend beyond the llmlts of the bulldlng and be gr:aded to draln surface run-off.
A11 types of foundations ean be used ln the Nonth, pnovldlng they lend themselves to the method adopted. fot^ p n e s e r v l n g the permafrost" P l l e s have boen found to be the most sultable type of found.atton l-n the North" They can be n e a d l l " y u s e d w l t h the ventllatlon m e t h o d t o p n e s e r v e p e r m a -fnost and can support bulldlngs even whene lt ls lmpossi.ble
- 1 1
t o m a l n t a l n t h e p e r m a f r o s t a t l t s o n l g l n a l l e v e l o T h e y a r e p a r t l c u l a n l y w e l l s u l t e d a s f o u n d a t l o n s f o n b u l l d l n g s w l t h
heavy floor Loads or. whene the bulldlng slte ls 1ow-ly5.ng
a n d p o o r l y d r a l n e d ,
I t 1 s e x p e c t e d t h a t p l l e f o u n d a t i o n s w i 1 l b e u s e d m o r e a n d m w e e x t e n s l v e l y l n t h e N o n t h s i n c o n o e x p e n s l v e
e x c a v a t l o n l s n e q u i n e d o P 1 l e s a r e p l a c e d 1 n p e r m a f n o s t b y settlng them ln holes pnevlotsly p:repar"ed by steamlng and a l 1 o w l n g t h e m t o f n e e z e l n p l a e e o F o r d e p t h s u p t o 2 0 f e e t , s t e a m p r e s s u r e s o f a t l e a s t 3 0 p n , s o l . e b u t p r e f e r a b l y
1 0 0 p . s . 1 . , d e l L v e : r e d t h r o u g h a 3 / 4 - 1 n c h o r 1 l n c h s t e a m J e t ( n o u n d steel plpe) are suggested., the plpe belng fonced down a s t h e g r o u n d t h a w s . F o r g r e a t e n d e p t h s , s t e a m p r e s s u r e s of 1 0 0 p " s . l q o r o v e r , w l t h 1 l n c h a n d 2 l n c h s t e a m p l p e s a r e r e q u t n e d . s t e a m l n g p e n e t r a t L o n r a t e s t o p n o d u c e s u f f l c l e n t t h a w f o r a p t l e w 1 1 1 v a r y r a l t h t h e ty?o of fnozen solr belng t h a w e d . P l l e l o c a t l o n s m a y b e d n l I l e d l n s t e a d o f s t e a m e d
but thls technLque tends to be more costly than steamtng and
has been used only rarely in tFre canadlan North, The drtlling
method offers advantage mainly 1n neduclng thermal dlsturbance
of the penmafrost and may be of partlcular value fon pnoJocts
l-n the gouthenn neglons of penmafrost where the temperature
of the frozen ground ls alneady cloee to thaw5.ngo
T h e p 1 L e t n a n s f e n s l t s l o a d t o the permafnost
lrr"gpgrt a comblnatlon of end beanlng and adfneezlng strength" O n thls basls, t h e d e p t h o f t h e p i l e l n t o t h e p e n m a f r o s t
s h o u l d b e s u f f l c i e n t t o k e e p l t w e l l b e r o w t h e t h a w e d ap@a.o T h e n e l s , h o n e v e r , a n o t h e r c o n s l d e r a t l o n l n u s i n g p t l e
foundatlons and thls ls the tendeney for plles to be rlfted
upwards by the fonces developed by the fneezlng of aLl or
p a r t of the actlve layer. T h e s e f o r s e s a r e s l g n l f l e a n t o n l y 1 n f n o s t a c t l v o s o l l s s u e h a s s t l t s a n d . f l n e s a n d s o T o o v e r c o m e t h l s u p l i f t f o r c e , t h e p 1 l e s h o u l d b e s e t i n t o the
permafnost fan onough that the adfneeze or frlctlon fo::ce
p r u s t h e load on the plle ls greater than the upLtft f o r e e .
Uslng a rule of thumb, a plIe ls generaLly placed lnto the
p e n m a f n o s t at a depth equal to at least twice the thlckness o f t h e a c t l v e 1 a y e r . A l t e r n a t l v e l y , t h e p i r e m a y b e a n c h o n e d i n t h e p e r m a f r o s t b y m e a n s o f s h o e s o r c o l l a r s . - o c e a s i o n a l l y ,
the p1}e may be greased or loosely urrapped wlth tarpaper overi
t h a t p a r t o f l t s length sLtuated ln the actlve layer to
p n e v e n t adheslon of the frozen sotl over that sectlono p l l e s
rnay be of wood, precast concrete or metal, though the troro
latten do tnansfer more heat downward tnto the permafrost
l a y e n o
P 1 1 e s a r e e l a s s e d a s b u n l e d foundatlonso O t h e r t S r p e s o f b u r l e d f o u n d a t l o n s a r e c o n e r e t e p l e r s , t l m b e r c r l b s a n d w a I l f o o t i n g s . T o b e s u c c e s s f u l , t h e y s h o u l d b e b u r , l e d d e e p e n o u g h t o n e m a i n b e l o w t h e p e r m a f r " o s t tableo E x e a v a t t o n
- L 2
f o : r t h e s e noay be very dlfflcult. M e t h o d s used may lnclude:-thawing by stnlpplng and exposing to sun, and
rernovlng the thawed materlal at fnequent lntenvals. TLrawlng amounts to a few lnches per day;
t h a w l n g by hydraullc methods, i.e. flooding with waten I
- breaklng wlth exploslves or pneumatlc hanrmerso
surface foundatlons ano generalry used. only fon veny sma1l bulldlngs and for Iow eost o:: temporary constri.ctlon and may conslst of log muds1l1s on tlmber pads. FoI' more per:manent eonstr"uetlon, eonerete slabs or concrete pads on a gr:avel mat have been advoeated but these may requlre neplacing-any frost actlve soll ln the aetlve zorte wltfr L substanttat f,hlekness of coan'se granula:r matenlal.
rn the $ope southenn areas where permafnost oceurs 1 n p a t c h e s , ls lfualted ln extent and is clo-se to nreltlng, 1t m a y be economlcal to remove the penmafrost pnlon to
conJtnuc-tlon, by thawlng, and then to prbceed uslng standard. c o n s t r u c t l o n t e e h n l q u e s .
4 , 5 S o m e Constquctlon probLems: Water $T:pp1y
The problems of water supply ln the North ar:e gr-eatly influenced by two factors -- fermafnost and low temperatlrpe. Readlly avallab1e supprles of water for yean n o u n d use ar€ scarce ln permafrost &reas and the avaLLiUftfty
of water may well govern the locatlon of communitles and detenmine the futune development of a reglon.
Although thene are numerous small lakes and pond.s exlstlng throughout the lsor"th, these a.ne rerattvely shlllow and duning the long wtnter period, most of such waier sources a r e ln a compJ-ete1y frozen state. B o d l e s of waten must be m o r o than B to 10 feet d.eep before they can be expected to p:rovlde some waten throughout the year. Rarely dLes ice e o v e n exceed I feet but the storage space ln a'1ake 1s very much reduced when a thlak lce coven eilsts even though som6
l l q u l d water st111 r"emalns below. The freezlng aet16n tends to coneentnate the mLneral and organie eontent-of the lake 1 n t h e unfnozen water below tbre Lee, and fon thls reason, t-he waten may be undeslrable or unsuJ.tabre for domestic use, Hany northenn lakes would pr"obably not provlde ad.equate
storage for a communlty of more than a few people.
Lakes whlch ane fed by undergnound. spnLngs or4 necelve an appreclable amount of shallow subsurface dnalnage may provlde an adeqr:.ate supply of water, but many lakes are
13
d.eeetvlng ln that they ane pninclpally the result of retarded dnalnage through penmafrost rather than evldence of a large and contlnuous source of water, A thorough study of lake d e p t h s , t e m p e r a t u n e s a n d n e r l a t o d g e o l o g l c a l f e a t u n e s l s o f v l t a l l m p o n t a n c e b e f o r e a w a t e n s o u r c e l s s e l e c t e d "
There are comparatlvely few rlvers ln the Nonth whleh ane l-arge enough to malntaln an appreclable flow
throughout the year. Utlllzatlon of water from ::ivors ln the p e r m a f n o s t n e g l o n l s e o m p l l c a t e d n o t o n l y b y s u c h b o d l e s
f r e e z l n g s o l l d l n s o n r e p l a c e s b u t a l s o b y t h e f o r m a t l o n o f f n a z l I a n d a n c h o r l c e . F r a z 1 1 l c e l s l c e f o r m e d b y t h e fneezLng of turbulent water and lt ::esembles slush. Anchor l c e l s t h e l c e f o r " m e d o n t h e b o t t o m o f r i v e r " s a n d l a k e s ' Clogglng of tntakes wlth trazlL and/or anehon ics can bo c o n t r o l l e d t r l t h s t e a n l l n e s p l a e e d l n t h e l n t a k e s t n u c t u n e ,
T h e u s e o f w e L l s a s a s o u r c e o f w a t e n h a s b e e n v e r y ltmlted ln permafrost areas, although suggestlons have been made that deep well-s tapplng the sub-pelrmafrost water offer e x c e l l - e n t p o s s i b l l l t t e s f o r a y e a r r o u n d w a t e n s u p p l y " A pantleulan advantage of well water ls lts Low burbidity whlclt elLmlnates the need for lange settllng baslns genenally
n e q u l n e d b y t h e h t g h l y t u n b l d s u r f a c e s o u r c e s . O f f s e t t l n g thls 1s the difftculty of locatlng sub-permafnost uraten and. t h e t e n d e n c y f o r s u e h s u p p l l e s t o c o n t a i n o b J e c t l o n a b l e
quantltles of lron and nrangaRese. In addltlon, well dnll1lng through penmafrost and subsequent conetruetlon and" operatlon o f t h e w e l l - p r e s e n t s e n l o u s d l f f l c u l t l e s , p a r t l e u l a r l y l n the far north wher"e the penmafrost may be several hundred f e e t t h l c k .
Ralnfall ts so small th:roughout much of the l{orth t h a t l t l s l m p r a c t l c a l t o n e l y u p o n c l s t e r n s a s a s o u r c e o f water supply" The prlnclpal source of rEater supply for the
typlcal sma1l northern eonrnunlty ls melted lce aqd sl:ow. I e e 1 s c u t f r o m f r e s h w a t e r l a k e s o r r l v e r s l n t h e f a 1 I w h e n l t l s a b o u t 1 0 t o 1 2 l n c h e s t h l c k a n d t h e l c e i s s t o r e d 1 n a p e r m a f n o s t e e l l a r o n a n l c e h o u s e o r s l m p l y s t a c k e d o n t h e g r o u n d a t a c o n v e n i e n t 1 o c a t l o n . S p e e l a l m e l t l n g t a n k s
equipped r.rlth stearn coLls have been pnovlded ln some large b u t l d l n g s , b u t l n t h e m a J o r l t y o f h o m e s , 1 c e t s m e l t e d b y p l a c l n g l b l n a c o n t a l n e r l n t h e h o a t e d h o m e t o b e u s e d
I a t e r a s w a t e n " R e l a t l v e l y h l g h c o s t s o f f u e l a n d t h e l a b o u r neeessary to produce an adequate supply of water by melting ice or snolt make sueh a method lmpract5-ca1 for obtalni-ng lange quantltles of waten such as are requlred to servo an entiro eornmunltyo Duntng the summe:" months, water for
h o u s e h o l d u s e l s u s u a l I - y o b t a l n e d f r o m f r e s h w a t e r l a k e s o r r : l v e r s , b e l n g s l m p l y d l p p e d u p b y a b u c k e t , p o u r e d i n t o a barnel and hauled to tho home.
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-Contrany to popular bol,1ef, the extended perlods of Low temperatune Ln the North do not obvlete the noed for
customary envl:ronmental health contnol measunes" Although the prlnclples of waten tneatment ln penmafrost apeas are e s s e n t l a l l y t h e s a r n 6 as elsevrhene, the physlcal featunes of such tr.eatment must be modif 1ed to sult low temperatur"e con-d l t l o n s . A l l e q u i p m e n t a n d p r o c € s s e s n u s t b e p r o p e r l y
housed, insulated and p:rotected. agalnst these 1ow temperra-tunes. Waterworks bulLdlngs, plplng and other gtnuctunes have t o b e p n o t e c t e d agalnst frost aetlon 1n the actlve layen and ln addltion have to be constr^ucted. so &s not to thaw the perruafnost" Thls imposes pnoblems not onl-y of constnuetlon b u t a l s o o f c o s t o
Aeration, sedlnentatlon, mlxlng of ehemlcals and chemlcal actlon all take pl"aee at a elowen rate ln the North because the nater ls at lower temperatunes than normaL for the rnore temperate zoraeso Often the tomperature of such water may be between 32 and L10oF. Thls lenerally means the't
the tlne of mixLng and aeratlon and. sLmlla:r openatlons should b e ineneased. Ce.pacttles of sedfunentation chambens should be mad.e largen than normally p:rovlded ln the temperate elimates a n d c h e m l c a L s , lf added, should be used ln greaten quantltles, S o m e dlfflcu1tles h a v e b e e n experleneed wlth the use of
cLrlonlna la col"d watcr. At tcmporatures between 32 and l+gotr' a chenlebl actlon takes place, nemovlng the chlonlne firom s o l u t l o n a n d at 32"F thene ls pnactteally no ehlonlne ln s o l . u t l o n . F o r the most effeetive use of chlonine, the wator t o b e t r e a t e d s h o u t d be at a temperature of 50oF.
fhe most eoarmon methods of water dlstnlbutlon ln the Nonth are by sledge and barnel and by tank tru.ck, These methods subJeet the waten to undeskabl-e handltng and
pos-slble eontamlrratlon. It has been reponted that modenate waten servlee by tank tnuck fon a famlly of foun may cost up to
1 5 d o l l . a r s p e r m o n t h ln some areas. W a t e r u s e t s t h e n e f o n e often curtalled below adequate standards of pensonal hygLene and the problem of ffu:e fightlng ls mad,e more sentous.
The next stage of r*ater dlstrlbutlon Ls the su$rmer water system where water under pr:essure 1s dlspensed durlng tkre sulnmer months by sunface distntbutlon through a system of plpes lald sn the ground. Dunlng the wlnter months, tLrls s y s t o m Ls dtsmantled, dnaLned, and the plpes l.eft to lle on the gnound"
ln nor"thern ax"eas, vrater plpes eannot be laid bolow frost due to the presenee of permafrost, tilhone yea.r round w a t e n d l s t n i b u t l o n l s d e s f u ' e d , l t l s n e c e s s a r y t o p r o t e c t
a g a l n s t freezing by placing tkre water malns ln heated utllldors o n b y Lnstalllng a r e c l r c u l a t l n g d l s t r l b u t l o n s y s t e m "
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p l p e s are lnstalLed together wLth il,ecessary lnsulatlon to m a l n t a l n threm at satlsfactory t e m p e n a t u r e s o
P l a c e m e n t of water Llnes ln heated utllldons h a s
b e e n u s e d 1n several areas and contlnuous dlstrlbutlon c a n be
m a l n t a l n e d . nelatlvely e a s l l y b y t h l s m e t h o d . U t l l l d o r s a r e ,
however', costly to lnstalL and operrate. Estinrates suggest
t h a t utll-ldor c o n s t r u e t l o n may cost frnom $5O.OO to StO6.OO
p e n f o o t "
U t t l l d o r s m a y be coltstructed of concrete, wood or
m e t a l , some of these belng pnoduced eommenelally ln
pre-f a b r l e a t e d sectlons, H e a t i n g of utllldons m a y be accompllshed by waste heat from the steam and condeneate llnes withln the u t l l l d o r , b y w a r m ain fonced thnough the utllldor, o r b y
h e a t l n g the waten ltself c . ,
U t l l L d o n s may be bullt t o c a n r y several senvlces
lncludlng steam, roater", sewer, conmulll.catlons and powe::, or1
o n l y one or tno senvlces. C e r t a l n hazar"ds exlst whete both
water and sewer are placed ln the sane duct. teakage of
sewage and negatlve heads ln water malns may serS.ously
con-tamlnate a waten supply. To neduce thls dangen, waten plpes
s h o u l d be kept above sewage plpes" D r a J . n a g e constltutes a m a J o n p n o b L e m 1n constructl.on of utllldors. F l o o d l n g of
utllldor by ground water may cotltamLnate the domestl"c waten
supply and nuln the tnsul-atlon. Underground utllldors must
be mad.e watentlght and those above gnound must be bullt so
t h e y can be dnalned.
Ut1l1dors range ln sLze from those large enough to alIol,r maLntenance from lnslde to those no largen than neees-s a : r y to carry the utlllty l l n o s . A c c e s s to the smalle:: ones may be arnanged thnough a removabLe topn Many typee of plpe u t L l l d o r s e a n n o t be readily opened for nepaln"
A r e c l r e u l a t l n g w a t e n s y s t e m consLsts of a
dlstnl-butlon maln, a return maln, cLrculatlon pumps, and a waten
heatlng system" It may be a slngle maln or dual main system,
In a si.ngle maln system, one plpe serves as both dlstnlbutlon and netunn maln and ts looped in one contlnuous llne startlng
and ending at the neolnculatlon pumps. fa a dual maln
s y s t e m , a two plpe system ls used wlth the hlgh and low p r e s s u r e llnes slde by slde. f n d e s l g n l n g the system, dead ends should be elimlnated and the system arranged so that the largest use::s are Loeated at the points of maxlmum dlstance from the water soltrce!
W h e n e v e r p o s s l b l e , the waete heat fnom the enengy
used for dr'lvlng the cinculatlng pumps should be used. fon
pneheatlng. The r*ater may need heatlng only a few degrees
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-f n o e z l n g a t a n y p o L n t l n t h e l L n e " I t l s v e P y d l f f l c u l t t o s t a n t o p e n a t l o n o f a r € e l n c u l a t i n g s y s t e m , h e a t e d o n l y a l i t t l e a b o v e f n e e z l n g , d u r l n g e o l d w e a t h e r . 0 n 1 y smalL sec-tions of the system should be started at a tlme and intenslve pumplng wlth contlnuing waste ls noeessary untll the entlre system has been wa:rmed.
W h l e h e v e r s y s t e m L s s e l e e t e d , t h e q u e s t l o n a n l s e s a s ' t o w h e t h e n t o p l a c e t t r e d l s t n t b u t l o n s y s t e m a b o v e o r b e l o r o r g:eound. fhls must be deolded on the basls of a eareful study of the heat losses lnvoLved, the problerns whlch may arlse and t h e reLatlon between the costs of conetnuction, operation and malntenance" Pnobably the most lmportant factor here ls the c o n d i t l o n o f t h e s o L l l n t h o a r e a a n d t h e d l f f l c u l t l e s w h l e h may arl.se from fnost aetion ln the actlve layen or from
m e l t l n g of the permafnost" O n e cnlterisn s u g g e s t s t b a t u n l e s s the actlve zone and the undenlylng permafrost are ln urell-d r a l n e urell-d non-frost actLve materlal extenurell-ding to eonsiurell-denable d e p t h ( 1 5 feet), a s u n f a c e s y s t e m s h o u l d , b e u s e d .
If these c,ondltlons do not pnohlblt pl"aelng the e e n v l c e s below gnade, then the questlon of constructlon cost p l u s heat loss becomos lmponts.nt. If the systera ls placed above gnade rather than 1n tLre gnoundn r*Lnter temperatures are lower but sunmer tempenatunes are hlgh. If the system ls
p1-aeed ln the gnound, lt may be 1n the permafrost or ln the actlve 1ayer" In the permafrost, lotu ternperatures prevall
throughout the year but at no ttme are they as extreme as whon the ptpe is placed nearer the grour:d. sunface. In the actlvo layer advantage may be taken of the latent heab of fuslon of entrapped water but at thls loeatLon, there ls a danger of floodlng from ground watel:u
Othen Lmpontant factons are the wonk required to excavate fon burled llnes and, if sewers are used., the
n e c e s s l t y of obtalnlng proper grade. W l t h s y s t e m s c o m p 3 . e t e l y a b o v e g r o u n d b h e s e r v l c e s m a y h a v e t o b e r a l s e d c o n s l d e r a b l y a t s o r n e p l a c e s . R o a d e n o s s l n g m u s t b e m a d e o v e r s u c h
u t l l l d o r s b y n e a n s - o f s l o p e d g n a d e s t o b r l d g e s o r b y u s e o f c u L v e r t s . T h e n e l s a l s o t h e d l f f l c u l t y o f o b t a l n l n g g n a v l t y dralnage fnon bulldtngs. When utflldo:rs are used oven fnost a e t l v e s o l I s , l t i s c o m m o n p r a e t l c e to support the utLlldor on plles wlbh a nrlnlmrln afu' space of 2 foet between the utllldor and the ground.
Senvlce connectlong ln a water eupply system are g e n e r a l l y the most vuLnenable to freezlng" T h e s e c a R b e k e p t operatlve 1n nonthenn systems by lnsulatlon, heated utllldons f r o m t h e m a l n t o eaoh bul1-dlng, eLectnlcal reslstance tape e n e n g l z e d t o h e a t t h e s e r v i c e p l p o r o F b y a d u a l p l p e c o n -nectlon to each bulldlng fnom the maln. Wltb a dual- main s y s t e m , t h e d u a l p i p e connectton affonds a positlve means of
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c o n p l e t e reclrculatlon b u t even wtth a slngle maln system, lt e a n b e m a d e effectlve b y u s l n g a special pitot type onlflce at the connectlon between the senvice llne and the maln" l + " 6 S o m e Constructlon Pnoblems: Sews.qe Dlsposal
T h e e f f e c t t v e n o s $ and safety.of most methods of s e w a g e dlsposal ln the t{orth are greatly lmpalred by low t e m p e r a t u r e s , B l o l o g l e a l and chemtcal roduetlon of organlc mater"lal pnocoeds very sIowly in low tempenatures. The usual p r o c e s s e s of deoomposltlon do not appean to occur at aLl
wlthtn the permafnost and onLy very slowly withln the shallow top layons of seasonalS-y thawed gnound. The permafrost pre-vents propen leachlng lnto the soll and nesulttng poor
dnalnage eausss a verltabJ.e cesspool on the sunface of the gnound r,rhore norrnal praettces of dlsposal ln the sol-l are u $ 6 d " Thts actlon is also llkely t o nenden unsafe the use o f s u r f a c e waten supplles.
The use of plt prlvies and septXe tanks as a mearls of sewage dlsposal ls therefore sertousLy cur:ta!.Led ln perma-frost areasr r6sultLng ln many nor"thern eornmunitles havlng t o r e l y on the prlmltlve p a l l system fon dlsposal of human wastes. ?hese wastes ane slmply du:nped on the tundna ln
summer! or plaeed in banrels and put on the neanby lce of
oceans, nlvers or Lakes to be eamled away ln the spnlng thaw. Waste water ls of,ten aLlowed to draln lnto th.e soll anound
each bulldtng but gneat catre must be taken in dischanglng heated llquld wastes near a butldlng because they may thaw the permafrost, causlng ground water to collect and the b u l 1 d l n g t o s e t t l e .
Very ferr water-carrted cornmuntty sewage collectlon s y s t e m s have been fnstalled l n p e r m a f r o s t areas. T h l s ls due 1n pant to the lack of water, but an lmpontant contrlbutony facton ls the problem and expense of eombat5-ng low temperature, frost aetlon, and permafrost, Expenlenee has shoran that
c o l l e c t i n g s e w e r s , 1lke water Llnes, can be kept operatLve in the North only 1f they ane pnotected fnom fneezlng and from dlffenential movement due to fnost actton 1n the actl-ve Layen of solL on to meltJ.ng of the permafnost.
Encloslng the sewer ln a heated condutt on utllldor ls pnobably the most posltive way of ensuning trouble-free o p e n a t l o n , but sueh lnstallatlons a r e expensive to construct. S a v l n g s can be achleved lf the plpes can be placed dfu.ectly ln the gnound and the hlgh cost of uttlldor esnstnuction a v o l d e d " T h e f e a s l b t l t t y o f s u c h l n s t a l l a t l o n s w 1 1 1 be govenned to a large extent by the soll and permafnost con-d l t l o n s . R o c k o u t c n o p s , fr.ost actlve so11 and permanently frozen gnound with hlgh lee contents are factons that will
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g r a d e . Wlth alL lnstaLlatlons, a d e q u a t e s u p p o r t s t o m a l n t a l n p r o p e r allgnment of plpes ane essentlal and l-n soLLs subJect to settlement on thawlng, plllng anchored ln the penmafnost may be requlned.
Sewers are somewhat l"ess rnrLnerable to freezLng than wate:r malns, slnce the sewage eontalns warm waste waten fnom heated buildtngs and thus the temperatu:re of the sewage ls genenally higher than that of the water supply" Preeautlons t o p n e s e r v e heat and pnoteet agalnst fneezlng are neventheless l m p o r t a n t wlth sewer lnstallations. P i p e s b e l o w g r a d e s h o u l d be located where ad.vantage can be taken of solan radlatlon and of the insulatlng effects of gnornr and vegetatlve covorc T h e y s h o u l d n o t b e p l a e e d u n d e n t h e t n a v e l l e d e e c t l o n o f r o a d s w h e : : e l l t t l e l n s u l a t l n g c o v e r l s a v a l l a b l e a n d w h e n e t h e y a r e
subject to damage fnom compactLon of soi-l above them"
Perlodlc flushlng of sowers wlth water" can help to reduce the fneezlng problem and to malntain eufficlent velocity of flow t o p n e v e n t d e p o s l t l o n of soltds" B l e e d l n g of steam condensate lnto the sewer is aLso useful. G:ravlty dnalnage of sewag€ is o f t e n d t f f t c u l t , t o a c h l e v e b e e a u s e o f t h e g e n o r a l l y f l a t
terraln of the Nonth and sewage pumptng statlons may be
requlred. these pumps can be used to malntaln contlnuous flora 1n the system and funther a1d ln keeplng the sewer operatlve"
In most nonthern cornrnunltles, flnal dlsposal of sewage ls obtalned slmply by dilublon in large water coursos o r t i - d a l w a t e n s . E h e e u i t a b l l i t y o f t h l s m e t h o d o f d l s p o s a l w111 vary. For lsolated con:rnunities or lnstaLlations on
l a : r g e w a t e n courses, tho practlce may be satlsfacto:ry but whene other wate:: users aro sttuated downstrea:n from the
s e w e r outfall o r t h e w a t e n c o u F s e lnto whlch Bewage ls dls-eharged 1s small and conflned, thene ls dangen of creatlng s e r i o u s health hazards. T l d e i r a t e n lnstallatlons a p p e e r t o o f f e r t h e b e s t m e t h o d of disposal by dllutlon, a l t h o u g h o b J e c t l o n a b l e e o n d l t l o n s ean occur ln areas whene thene is conslder"able depth of tlde and where sewage can thenefo:re accu:nulate on open tlda1 flats dunlng low tide. Streann p o l l u t l o n h e s a l r o a d y p o s e d health problems ln the Nonth,
e v e n w i t h t h e n e l a t l v e l y s m a l l p o p u l a t l o n d e n s i t l e s t h e t e x l s t to-day, A s t h e p o p u l a t l o n l n o n c a s e s , t h e d l s e k r a r g e o f raw gewag€ lnto natunal r*aten coulrses w111 become a mone
slgntflcant health rnattor and the need for tneatnnent faclll-tles mox'e pnonoulleed.
Both prlatary and secondary tneatment of sewage have been attempted in 1ow tealpenatune reglons but there are stlLl m a n y p r o b l e m s to be soLved ln the openatlon of these facill-tles. The faet that the conventlonal sewage tneatment proeesses nequtne a warm envlnonment to functlon properly, c o r n p l l e a t e s t h e d e s l g n and constnuctlon of pLant facllltles located ln permafnost areas and eomblned wlth the expense of p r o v i d l n g the necessary heat, adds greatly to the cost of
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O n e m e t h o d o f s e u a g e t r e a t m e n t r " e e e l v l n g l n e n e a s l n g c o n s l - d e r a t l o n f o r n o r t h e n n l n s t a l l a t i o n s i s t h e p r o c e s s o f s e w a g e l a g o o n l n g . T h l s s y s t e m e o n s l s t s o f d l s c h a r g l n g r a w
sewago into lanp5e shallow lagoons or oxidatlon ponds, &s they
a r e s o m 6 t l m e s c a l I e d , w h e r e a e n o b l c c o n d l t i o n s a r e m a l n t a l n e d a n d . n a t u n a l d e c o m p o s l t l o n t a k e s p l a c e . S e w a g o l a g o o n s p n o
-vide for" blologl-e or secondar.y tneatment of eewage and
e x p e r l e n c e h a s l n d l c * t e d t h a t , i f p n o p e n l y c o n s t r u c t e d , t h o y w l l l p r o v i d e a h l g h d e g r o e o f t r e a t m e n t a p p r o a c h i n g t h a t l n
most of the rnore exponslve treatment plants, Lagoons appear
t o w o r k s a t l s f a e t o r l l y l n c o l d e l l m a t e s , a l t h o u g h l n w l n t e r m o n t h s , t h e e f f e c t l v e n e s s o f t h e L a g o o n l s r e d u c e d . F o r b e s t r e s u l t s , t h e l a g o o n d e p t h s h o u l d n o t e x c e e d 3 E o 5 f e e t , t o e n s u r e a e r o b i c c o n d l t l o n s a n d e l l m l n a t e o d o u r s b u t l n c o l d c l l m a t e s , d e p t h s g n e a t e r t h a n t h l s r m r s t b e p r o v i . d e d t o a l l o w f o r l e e c o v e r w h l c h m a y b e i + f e e t o r m o r e i n t h l c k n e s s , I t m a y b e d e s l r a b l e 1 n s u e h & r e a s t o p r o v l d e s o m e f o n m o f c o n t r o l
that wlll penmlt the lagoon to openato at shallower depths
dunlng the surulr^er.
The maLn advantages of lagoons are that both lnitlal a n d o p e : : a t l n g c o s t s a r e m u c h l e s s t h a n f o n c o n v e n t l o n a l p l a n t s
and the effluent Ls nonmally ln a sufflciently stable
condl-t l o n condl-t h a condl-t n o condl-t n o u b l e s n e s u l condl-t . A n i m p o r t a n t e o n s l d e r a t i o n w l t h l a g o o n s l n p e r m a f n o s t r o g l o n s w o u l d a p p e a r t o b e t h e r e t e n t l o n o f t h e s e w s . g e l n a n e a s o f s o t l s w l t h h l g h l c e c o n t e n t s a n d
where melting of the penmafnost ca,trr cause eettlement " Und.er
such condltlons, the dykes may wash out and allow seepage of
s e w a g e n r a s t e s l n t o t h e s u m o u n d l n g a n e a . I n m a n y n e s p e c t s , s e w a g e l a g o o n s a p p € a r t o o f f e r a n e c o n o m l c a l a n d a e c e p t a b l e
answer to tho pnoblem of sewage tneatment ln the North" It
n e m a l n s t o b e s e e n h o w w e l l t h e y c a n b e a d a p t e d t o n o r t h e r n c ond it lons "
h , 7
Some Constnuction Pr"oblems : Roads and RungggS i t e s e l e c t l o n l s a m o s t l m p o n t a n t e l e m e n t i n n o a d a n d a l n f l e l d c o n s t r u c t l o n 1 n p e r m a f r o s t a r e a s o I n s e l e e t l n g a n o u t e f o r a r o a d , g r e a t a t t e n t l o n s h o u l d b e g l - v e n t o s u c h f a c t o r s & s s u b s o l l c o n d l t l o n s , g r o u n d w a t e r , $ u r f a e e l c i n g ,
surfaee dralnage and snow. Slde h111 cuts should be kept to
a mlnlmum because they may cause seepages 1n wlnter and
c n e a t e a f l o w o f l c e o v e r t h e r o a d . S u b g r a d e s o l l i s p r o b -a b l y t h e m o s t l m p o r t -a n t l t e m " F l n e - g n a i n e d s o l l s s u b J e c t t o i n t e n s l v e f r o s t a c t l o n s h o u l d b e a v o l d e d w h e r e v e r p o s s l b l e .
Caneful study should be glven the effeets which cuts may have
on the thermal reglme, The shortest route for a road may
n o t n e o e s s a n i . l y b e t h e b e s t "
The gneat area nequired for an airfleld makes the
l o c a t l o n o f a s u l t a b l e s l t e a m o r e d i f f l c u l t p r o b l o m " T h e
