Load-carrying capacity of ice for timber transport

(1)

Publisher’s version / Version de l'éditeur:

Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n’arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca.

Questions? Contact the NRC Publications Archive team at

PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information.

https://publications-cnrc.canada.ca/fra/droits

L’accès à ce site Web et l’utilisation de son contenu sont assujettis aux conditions présentées dans le site LISEZ CES CONDITIONS ATTENTIVEMENT AVANT D’UTILISER CE SITE WEB.

Technical Translation (National Research Council of Canada), 1960

READ THESE TERMS AND CONDITIONS CAREFULLY BEFORE USING THIS WEBSITE.

https://nrc-publications.canada.ca/eng/copyright

NRC Publications Archive Record / Notice des Archives des publications du CNRC :

https://nrc-publications.canada.ca/eng/view/object/?id=9965d9b4-982b-4749-a0dd-d90cb9da8b1a https://publications-cnrc.canada.ca/fra/voir/objet/?id=9965d9b4-982b-4749-a0dd-d90cb9da8b1a

NRC Publications Archive

Archives des publications du CNRC

For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous.

https://doi.org/10.4224/20358994

Access and use of this website and the material on it are subject to the Terms and Conditions set forth at

Load-carrying capacity of ice for timber transport

Korunov, M. M.; National Research Council of Canada. Division of Building Research

(2)

NRC TT

-

863 Ref

Ser

~ 2 1

NATIONAL

RESEARCH

COUNCIL

~ 2 t 4

1

NRC TT-863 BLDG TECHNICAL TRANSLATION NRC TT- 863

LOAD

-

CARRYING CAPACITY OF ICE FOR

TIMBER TRANSPORT

* ' .--.7," dt.& d:%~ f,, <y !, t: 9 BY M.

M. KORUNOV

FROM LESN-AlA PROM. (11): 18

-

19, 1956

THIS IS THE F I F T Y . SIXTH OF THE SERIES OF TRANSLATIONS PREPARED FOR THE DIVISION OF BUILDING RESEARCH

OTTAWA 1960

(3)

NATIONAL RESEARCH COUNCIL OF CANADA

Technical Translation 863

Title: Load-carrying capacity of ice for timber transport

(0 gruzopodyemnosti ledlanogo pokrova pri

transportlrovke less)

I.sI q t-18.. 8 z i, 7 u 1

Author:

M.M.

Korunov

Reference : Losnala Prom. (11): 18-19, 1956

(4)

PREFACE

Extensive use i s made of frozen l a k e s and r i v e r s f o r t r a n s p o r t a t i o n purposes i n Canada. One of t h e major problems which a r i s e s I n t h e i r use i s t h e p r e d i c t i o n of t h e i r s a f e b e a r i n g c a p a c i t y . I n t h e Division of B u i l d i n g Research of t h e National Research Council, t h e Snow and I c e Section a r e c a r r y i n g o u t i n v e s t i g a t i o n s with t h e purpose of p l a c i n g t h i s p r e d i c t i o n on a firm engineering b a s i s .

I n A p r i l 1958, a conference on t h e b e a r i n g c a p a c i t y of f l o a t i n g I c e s h e e t s was held i n O t t a w a under the sponsorship of t h e Associate Committee on S o i l and Snow Mechanics. The papers presented a t t h i s conference were published i n a

s p e c i a l i s s u e of t h e Transactions of the Engineering I n s t i t u t e , Volume 11, No. 3, September 1958.

Much p r a c t i c a l f i e l d experience has been gained i n

Canada and i n o t h e r c o u n t r i e s on t h e b e a r i n g c a p a c i t y of i c e . One of t h e r e s u l t s of t h e conference i n Ottawa was t h e

i n i t i a t i o n of a survey by the National Research Council i n cooperation with t h e Canadian Pulp and Paper Association, t o take advantage of t h e valuable experience of t h e Pulp and Paper Industry. The r e s u l t s of observations from the f i r s t winter have now been analyzed and a r e proving t o be very s i g n i f i c a n t .

A f u r t h e r source of information Is t h e published theory and o b s e r v a t i o n s of o t h e r c o u n t r i e s . Unfortunately, t h i s information i s u s u a l l y n o t i n English and t h e r e f o r e not

a v a i l a b l e t o most Canadian engineers. Whenever a s i g n i f i c a n t paper i s found, arrangements a r e made f o r i t s t r a n s l a t i o n and p u b l i c a t i o n i n t h e National Research Council Technical

T r a n s l a t i o n Series. This p r e s e n t paper has been t r a n s l a t e d from t h e Russian and d e a l s with t h e c a l c u l a t i o n of the s a f e b e a r i n g c a p a c i t y of i c e f o r timber t r a n s p o r t . The D i v i s i o n of Building Research wishes t o express i t s a p p r e c i a t i o n t o Mrs. M. Howson of t h e T r a n s l a t i o n s S e c t i o n of t h e National Research Council L i b r a r y f o r t h e t r a n s l a t i o n of t h i s paper. Ottawa

February 1960

R.F. Legget

(5)

LOAD-CARRYING CAPACITY OF ICE FOR TIMRER TRANSPORT

An important problem confronting the timber industry, as well as other branches of the national economy, is the determination of the load-carrying capacity of an ice cover, to ensure safe transport across rivers anCl lakes. The following formula, recommended by us, gives the required ice thickness "h" in centimetres or the permissible load P in tons, for safe traffic conditions for single vehicles crossing the ice (for temperatures below zero):

h2 tons (metric)

h = cm or P =

-

₁₀₀

On the basis of experience during the times when caterpillar actors crossed the ice over the river Kama, I.V. Alpatskli* ted that the above formula gave a considerable margin of safety nce, even with a minimum ice thickness in the navigation channel

h = 27 cm, the crossing could Be successfully accomplished. r was the ice destroyed even when the tractor caught a telephone re and got stuck in the middle of the navigation channel itself. he ice showed slight cracks within a radius of 10

-

15 metres.

Great difficulty arises in calculating the safe ice cover hickness for the movement of a vehicle train, althougb several alculation methods do exist. For instance we have Prof.

ernshtein's method. llBut'l, writes I.V. Alpatskii

,

"this calculation method is a complicated one, and we assume that it will be quite adequate to take as the ice thickness necessary to ensure safe train movement the thickness derived from

M.M.

Korunov8s formula multiplied by a factor of 2 or 3." However, we cannot accept such a simplified solution to the problem.

I.V. Alpatskii. Opyt Ustroistva Ledianykh Pereprav (Experience on the organization of ice crossings) in Sbornik Ratsiomliza- torskikh Predlozhenii i Obmena Opytom na Predprilatiiakh Lesnoi Promyshlennosti. Molotov, 1948.

(6)

safety when it comes to the passaee of Isolated vehicles, whereas

Prof. Rernshteinls

and other calculation methods seem too compli-

cated for estimating vehicle train traffic, then more reliable

and simpler calculation methods for these purposes must he formed;

such will be the endeavour of this article.

We must explain here that it Is by no means the purpose of

is article to tackle the possiblllty of reinforcing ice crossing8

y means of an additional layer of ice frozen onto the surface, nor

e possibility of creating any kind of superstructure. On the

sis of data issued by the Physical-Technical Institute, as well

s ice tests conducted by the Ice Commission of the Academy of

ciences

U . S . S . R . *

we propose to use the correction coefflclents

isted below in the formula for calculating the load-carrying

pacity of fresh-water ice of varied composition when the tem-

erature of the ambient air varies between -7O to -lO°C and lower

able

I).

After applying the correction coefficient, the formula of

ce-loading capacity for single vehicle traffic will be as follows:

khere n

=

the correction coefficient given in Table I.

Let us elucidate by several examples:

Example

1:

For ice type No.

4,

with a correction coefficient

II =

1 and the thinnest ice thickness being h

= 30

cm, the calculat-

~d bearing capacity is:

h2

p = - =

302 = 9

tons.

lO0n

100.1 Example

2:

For one person of weight P

= 100

kg

= 0.1

tons and

!

J P.P.

Kobeko,

N.

I. Shishkin,

F.1

.

Mare1 and N.S. Ivanova. The

!

breakthrough and loading capacity of ice. Zhur. Tekh. Fiz.

:

14 (3):

1946.

9

5

.j

(7)

i c e of type No. 3 the minlmum s a f e thickness i s : h = l 0 F n = 10~0.1 * 1.4 = 3.7

=

4 cm.

The minimum thickness permissible f o r Ice type No. 4 t o ensure safe vehicle t r a f f i c i s shown i n Table 11.

The minimum i c e thickness admissible f o r o t h e r types of i c e w l l l vary more o r l e s s , depending on the value of the correction coef f i c i e n t

.

The load-carrying capacity of an i c e cover consisting of vari- ous types of i c e w l l l vary greatly since tho ultimate strength of the i c e , a s shown i n Table I, w i l l change from 5 t o 38 kg/cm2, o r from 50 t o 380 t / m P .

When loads a r e transported by t r a c t o r - o r truck-hauled t r a i n s of two-runner o r one-runner sleighs o r wheeled t r a i l e r s , the

t r a f f i c s a f e t y c a l c u l a t i o n should be based i n the f i r s t Instance on the weight o f the t r a i n and the minimum ice-cover thickness.

The specif i c load of a t r a i n on the i c e 1 s given by the formula :

9 =

9

t/running metre,

where :

q = s p e c i f i c load I n t/runnlng metre,

Q = weight of loaded t r a i l e r t r a i n i n tons, P = weight of hauling vehicle i n tons,

8 = length of t r a i n i n metres.

Since we know the smallest thickness of the i c e cover h

i n

(8)

and the s p e c i f i c load permissible w i l l be:

-

2 0 _perm.h2

qg

-

t/runnlng metre

where :

E = the modulus of e l a s t i c i t y of the i c e averaging

E = 900,000 t / m a ;

0

perm. = the permissible working s t r e s s of the Ice.*

Therefore q, > q confirms t h a t t h e Ice Is s a f e f o r t r a f f i c . The maximum i c e d e f l e c t i o n Is

and the a i s t a n c e between the p a r a l l e l tracks and t r a i n s moving one a f t e r the other

Example 3: The length 4 _of _a_{t r a i n of single-runner sleighs}

s 50 metres; the gross weight Q

+

P = 100 t. The thinnest p a r t o f , he Ice cover h = 70 cm. Type of Ice: 4th type; Oult. = 2 5 kg/cma.

I c u l a t e the s a f e t y f a c t o r , and f and L f o r t h i s t r a i n . We 'find the value f o r the s p e c i f i c load:

= = 2 _{t/running metre.}

q = 4 50

The calculated maximum working s t r e s s of the i c e according t o

{*

The permissible working s t r e s s of the i c e has been accepted by

u s a s equalling operm 9

.

= 12.5 kg/cm2. 4 > i 5

(9)

formula ( 3 ) is

- a 4 E h j ,

-

= t,ml#

Omax. 2h2 2 0.7'

or =: 11 kg/cme.

By

comparing the value of calculated stress with the value of ultimate strength we find the factor of safety

n,:

The maximum displacement of the ice

The shortest distance between parallel tracks and tractor trains moving one behind the other will be:

According to formula (4) we find the permissible working load 'perm. = 125 t/m2:

2 0

perm. ha

9 r = = ₃125 _17.9

'

Ow7' = 2.28 t/running metre.

Consequently, in this particular case q, > q and it will be safe to move the train of weight:

Q + p = q , e

e

= 2.28 50 = 114 tons.

In order to ensure traffic safety we must not limit ourselves to the calculation of the minimum ice thickness or the magnitude of the load alone.

It

is essential also to make observations con-

(10)

tinuously of the c o n d i t i o n and a c t u a l t h i c k n e s s of t h e i c e cover. During thaws and i n s p r i n g , such observations should be c a r r i e d o u t a t l e a s t every 24 hours w i t h i n a 10

-

16 metre r a d i u s from t h e a x i s of t h e route.

The i c e cannot stand a s l a r g e a s t a t i c a s a dynamic l o a d , and one must t h e r e f o r e n o t make long h a l t s with a t r a n s p o r t convoy.

Due t o the a c t i o n o f a moving load with t h e accompanying i c e d e f l e c t i o n , a wave develops under the i c e . The speed of v e h i c l e s o r t r a i n s vload must be l e s s than t h a t o f the wave under t h e

Ice vwave:

where :

g

-

a c c e l e r a t i o n due t o g r a v i t y = 9.81 m/seo2,

H

-

depth o f water i n

m.

D r y f i s s u r e s i n t h e i c e t h a t widen i n t h e d i r e c t i o n of the s u r f a c e should be f r o z e n over by pouring water i n t o them, and

open c r a c k s should be bridged over b y s u f f l e i e n t l y s t r o n g planking. Snowdrifts on t h e i c e cause it t o melt from underneath. It I s t h e r e f o r e recommended t h a t t h e snow be c l e a r e d from a s t r i p 20 metres wide. Snow f e n c e s should be e r e c t e d so a s . t o prevent d r l f t s from p i l i n g up n e a r e r than 30 m from t h e c e n t r e of t h e road. I n s p r i n g , with t h e beginning of t h e thaw, f r e s h snow should be spread on t h e road.

As soon as t h e snow begins t o m e l t , t h e s t r e n g t h of t h e i c e w i l l be considerably reduced, and i t s load-carrying c a p a c i t y must be c o r r e c t e d b y i n t r o d u c i n g t h e c o e f f i c i e n t K i n t o the c a l c u l a t i o n s . Then :

h = 1 0 m f o r s i n g l e v e h i c l e s

-

2 a ~ e r m .

K~

(11)

when A = t h e number of days from t h e time water appears on tlrd s u r f a c e of the i c e .

When v e h i c l e s coming from o p p o s i t e d i r e c t i o n s meet, o r wlr~en v e h i c l e s o v e r t a k e each o t h e r , t h e i n t e r f e r e n c e (mutual r e l n f o r c o t n ~ n t o r weakening) of t h e waves forming under t h e i c e may r e s u l t i n t h e f a i l u r e of t h e Ice. Therefore, t h e o v e r t a k i n g o r meeting of

e h l c l e s on t h e same r o u t e i s forbidden.

I n conclusion i t should be pointed o u t t h a t i f t h e l e n g t h 4 the t r a l n o r of a t r a i l e r on wheels, i s s m a l l e r than s i x times e width b of t h e s l e i g h t r a c k s , and t h e i c e thicknesses h

t l s f l e s [ 4 < 6 ( h + h ) ] , one should use formula (1) f o r c a l c u l a t i n g e p e r m i s s i b l e load-carrying c a p a c i t y f o r s i n g l e vehicles. I n a l l

h e r i n s t a n c e s t h e t r a f f i c s a f e t y c a l c u l a t i o n s f o r automotlve a i n s (convoys) should follow t h e formulae ( 2 )

-

(7).

F x a m ~ l e 4: An automotive t r a i n t r a v e l s over i c e of type No. 4 ; e t r a i n c o n s i s t s o f one ZIS-151 t r a c t o r and t h r e e single-runner

S-6 a u x i l l n r y s l e i g h s . The l e n g t h of t h e t r a i n 4 = 30 m , t h e o s s welght Q

+

P = 30 t. The minlmum t h i c k n e s s o f t h e i c e h =

4 m. The width of t h e s l e i g h t r a c k s b = 2.8 m. The average p t h of t h e r i v e r

H

= 3m. The problem i s t o determine by which

thod c a l c u l a t i o n s should be made t o a s c e r t a i n t h e load-carrying p a c i t y of t h e I c e and whether i t would be s a f e t o move a t r a i n

t h i s welght a c r o s s t h e ice.

Since 4 = 30 > 6 ( 2 . 8

+

0.4) t h e following c a l c u l a t i o n fs made o r t h e t r a i n movement.

The a c t u a l s p e c i f i c load:

=

2

= 1 t/running metre.

9 = ₃₀

The maxlmun standard working load of t h e i c e i s :

0

-

a 4 E h =

= 110e6 t,m2,

(12)

-10-

The permissible s p e c i f i c load w i l l be:

-

2Benn. h

-

_* ₁₂₅ _0a4' _{= 1.2} _{t/running metre,}

"'

3 11

The s a f e t y f a c t o r :

The minimum distance between automotive t r a i n s and p a r a l l e l routes :

The maximum d e f l e c t i o n of the i c e cover:

The maximum vehicle speed:

These a r e the c a l c u l a t i o n methods which we recommend f o r the transport of timber and o t h e r f r e i g h t across t h e i c e cover.

(13)

Table

I

Crystalline-transparent ice with full, vertical tubes of a

considerable diameter

.

No.

1

Crystalline-transparent ice with vertical tubes ~f short length and small diameter

Bending load of the ice

at break break kg /an2

Type of ice

Granular slud e ice consisting of ice floes

7

floating anchor

ice)

Ice solidified from the lower layers, transparent, laminated

Correction coef f i- clent

n

I

Ice crystalline-transparent without impurities but wlth

(14)

T a b l e I1 Vehicle t y p e s Weight I n

tons

Minimum per- m i s s i b l e Ice t h i c k n e s s i n cm 23 2 5 2 5 28 32 37 36 24 24 38 39 Trucks ( w i t h l o a d ) : GAZ-51... ZIS-21A... ZIS-50...+...-... ZIS-150... ZIS-151... MAZ-200... T r a c t o r s : S-80...*... KG-12... DT-54... 3-80 w i t h a 2-drum winch.. S-80 w l t h a 3-drum winch.. 5.20 6.20 6.10 7.90 10.08 13.50 13.00 5.80 5.40 14.30 14.60