*

,,

...,

OThis Paper for Presentation at the

ASCE 1980 ANNUAL CONVENTION AND EXPOSITION

*e-~ lon on Construction of Nuclear Facilities

October 29, 1980Hollywood, Florida

.

.

" BLASTING VIBRATION LIMITS ON FRESHLY PLACED (GREEN) CONCRETE".

By. .

Allen J. Hulshizer, Supervising Structural EngineerUnited Engineers and Constructors Inc.

&Ashok J. Desai, Structural Engineer

United Engineers and Constructors Inc.

!6106 310 & ss

. - _ , . . . . _ -m,- - ., _, - , _ . , . . . . _ - - . _ _ . , _ , . . , . _ . . - . _ , , . - . , . . _ _ . , , . - , . . ...

1,.

.

" BLASTING VIBRATION LIMITS ON FRESHLY PLACED (GREEN) CONCRETE"

1By Allen J. Hulshizer , F. ASCE and Ashok J. Desai , M. ASCE

INTRODUCTION

This paper summarizes the results of an extensive program carriedon for the Seabrook Nuclear Station to increase blast-vibration limitsfor freshly placed concrete (" Green") without detrimental effect on itsstrength properties. In the absence of available data, a test programwas carried out in both the laboratory and field to study a wide rangeof variables to insure the enveloping of various combinations ofvibration characteristics and concrete ages.

Ccnclusions from the program have resulted in significantly raisingpreviously utilized green concrete re-vibration limits while still pro-viding conservative margins with respect to any effect on design re-quirements. These "new" vibration limits allow for more productiveblasting work during concurrent concreting operations providing

,

economies in both cost and schedule.|

BACKGROUND

Due to long and various starting delays, it became necessary to re-schedule excavation and concrete work concurrently in order to recoverschedule losses. Blast vibration specification limits relating togreen concrete, which did not hamper the previously time independentblasting and concreting efforts, became very restrictive and would haveresulted in serious construction delays if necessarily maintained.

,

- *

The original Seabrook specification blast vibration limits forgreen concrete was taken from work done for the Maine Yankee AtomicPower Plant, Wiscasset, Maine (1), herein after referred to as the

j "Weston Report." Apparently, these values have been used for other' nuclear power plants in this country.

Examination of the Weston Report indicated that the parameterssuitable to obtain vibration limits for the initial intended purposesdid not establish conclusive limits and an apparent increase in thesevalues could be substantiated.

DEFINIIIONS

Green concrete, as used within this paper, refers to concretehaving an age within 24 hours after placement.

The term re-vibration or vibration of green concrete utilized with-in this paper refers to the vibrating of consolidated ' concrete duringits early curing stage and does not refer to re-vibrating of freshconcrete to improve its properties.

Supervising Structural Engineer, United Engineers and Constructors Inc,Phila., PA.

2Structural Engineer, United Engineers and Constructors Inc, Phila. , PA.

|

1'

. . . _ . . . _ . _ . __ ., _ _ _ _ . . _ _ - _ _ _ _ . . _ . _ . _ _ _ _ . _ . . _ . - . _ . _ -

. __ _ ._ _ _-- _ _ . _ _ __ _ _ .-._ _ ___ _ _ . _ _ . _ _ . _ ..

!

I |- *

-.

.

I

j REVIEW OF HISTORICAL DATA

! With the knowledge that green concrete vibration limits were notunique to the Seabrook work and that some margin was likely in the4

original Weston Report limits, a literature and industry practice; search was undertaken to find quantitative data that would substantiate

new higher vibration limits.:

i

A survey was made of nuclear plants constructed on rock sites to-

ascertain what blast vibration limits were imposed to insure " safe";

concrete work. A sununary of the values as reported is given in Table 1.Apart from vibration limits imposed to prevent tripping of on site

|operating nuclear plants, wide variations in specified peak particle

:velocities were found. The data used to establish the green concrete

! vibration limits was not available (unless based on the Weston Report)and in all cases the limiting values would have been restrictive to the

i Seabrook construction operation.

In addition to industry and literature searches, organization suchas the American Concrete Institute, Portland Cement Association, Bureauof Reclaimation, blasting powder companies, cement and concrete com-

| panies and other sources even remotely related to the problem were con-tacted. An index of more salient related publications is provided in

,

the Compendium.',

Much of the experimental work and studies found were associatedwith consolidation during concrete placement and other information onre-vibrating green concrete required various degrees of extrapolationto obtain useful parameters. It was, therefore, determined that test-

ing work should be undertaken to obtain factual information specifical-'ly identified with raising green concrete re-vibration limits.

Of general note is that the normally cited blast damage criteria,

limits of 2 inches /sec. and lower appears to be established basicallyto protect masonry and plastered structures sud to avoid public and

! legal struggles and does not directly reiste itself to construction|

efforts removed from the public which involve engineered structuresi built of reinforced concrete. (See Compendium, Reference 1, Chapter 7,

Paragraph 7-3, pgs. 7-5 to 7-10.)

SEABROOK TEST PROGRAM!

The Seabrook testing program was developed to evaluate what effectblast induced vibrations on green concrete would have on structuralproperties of concrete with the goal of obtaining the critical damagelimits. Concrete properties deemed most significant to structuralperformance and durability were that of compressive, shear and rein-forcing bond strength. Since reinforcer'. concrete is basically designed ,

as a " cracked section", no effort was made to test or evaluate plain,

concrete flexural performance.

Because of the strong demand to have information related to actualconditions, one phase of the program was conducted in the field utiliz-ing explosive blasting under controlled, monitored conditions. The i

other phase involved laboratory work which economically allowed for amore extensive and more contro?. led and monitored testing program but

, one which could be easily correlated with the field work and which could'

also be used to evaluate the effects of other than blast type vibrations(i.e.: more regular patterns). Since it is generally recognized that

d.'

t-T. -eeme -epgg--gm.-e..-e>gy-.+y.vm---wgyn yy,e-g<ay. g.. ,.m9gggp+y,_gg-g, gg,99 m,94q.3wgy,w,y y-- yp gr y''y=eMe -p- v yy311'yMT t'T'T TTM"9'"'-4'' PM-W'e'NMW*NWT' PW 7 v "-V'9"4--TM*-f"4"*'''

.;

.

tha first 24 hours of etnersta sse time will raprec nt tha most criti-cal period, the program limited its study to concrete vibrated atvarious intervals within 24 hours after concrete placement.

The entire test program was carried out under fully implementedQuality Assurance procedures.

The following is a summary of the number of control and test sam-pies utilized:

Cylinder BondCompression Shear & Bond Pull Out

Test Beam Test Test Cores

Field 120 140 255 31

92_,Laboratory 258 -

Total 378 140 347 31

FIELD TEST PROGRAM

Essentially the fiell test program was comprised of casting varioustypes of concrete specimens and subjecting them, at specified concreteages, to blast vibrations of differing magnitudes which were measuredand recorded. Control (un-vibrated) specimens were cast from the sameconcrete batches. Field work was carried out in areas remote to heavyconstruction traffic and basically free from other blast induced vi-brations so that the test vibrations introduced and monitored representclean data free from background distortions. After the appropriate 7or 25 day period had elaps ed, the vibrated and control specimens wereload tested and results evaluated.

The field test program was divided into three areas, namely:

1. Cylinder Test2. Beam Test3. Wall Test

Field Cylinder Test Program

This program consisted of casting standard 6x12 inch cylinders,|

subjecting them to blast vibrations (except for controls), curing thecylinders in accordance with ASTM C31 and then performing the standard:

| ASTM C39 compressive load test. Reinforced concrete test pads wereconstructed on 20 foot (6.1 m) centers. Pads were founded on and an-chored to rock by means of resin type rock anchors. Pads were equippedwith hold down bolts and apparatus to hold four concrete mold cylindersfirmly in place during the blast. Provisions were also made to boltdowr. a monitoring transducer on each pad and read reniotely at a centralstation. (See Photograph No.1).

|

| A set of four cylinders were cast and rigidly f oxed to the test pad.At the appropriate time the blast was detonated and the vibrations re-'

corded for each of the four pads. The cylinders were then protected! and cured in place for 24 hours after which they were removed (along| with the remotely cast control cylinders), cured in the testing labora-

tory and compressive load tested after the 7 and 28 day curing time(two 7 day and two 28 day tests from each pad).

3

Il

- - - - - - . - - . . _ - - - - . - . . - . . _ _ _ - _ . ,- .__. ._,__

--. - - -- - . -_ .-- -- .- . .. .-. . ..

.

|*

The effect of blast vibrations on tha cylindars wcs evaluttsd by ;

normalizing the change in vibrated cylinder strengths by representing |

them as a percentage of increase or decrease in strength from that ofthe control cylinders and plotting the variation with respect to the

i experienced peak particle velocity. Comparatae plots of 7 and 28 daycylinder compressive tests are shown in Figures 1 and 2 respectively.i

|As can be noted from the normalized test results plotted on Figures

1 and 2, no specific trend in the change of cylinder compressive.

strengths can be established since the relative variation in compres-| sive strength increases and/or decreases randomly for any given age or i

curing or magnitude of induced vibration. A further comparison of cor- |

|responding 7 and 28 day relative compressive test for a specific;

vibration level-concrete age datum point (i.e.: cylinders subjected tothe same blast vibrations) illustrates the fluctuating-oscillatingchanges in the concrete cylinder strengths for identically vibrated

|cylinders. The effect of differential curing time (7 days vs. 28 days)is considered to be of little consequences since no specific or generalchange in test values can be associated with the observed test results.(i.e.: Longer cure time did not apparently produce greater strengthcylinders due to autogeneous healing which would offset any detrimentalcracking effects produced by the induced vibrations. See Reference 3).

.

!

With respect to the magnitude of tha incrasae or decrease in cylin-der strengths it must be noted that the variations actually lie in arelatively tight band where 967. of the relative test values fall withina plus or minus 67. variation and 98% fall within a plus or minus 77.variation. This range of variation is considered to be within anacceptable level of variation that occurs in cylinder testing.I

:.'

Field Beam Test Program

Reinforced beams measuring 4 x 8 inches and three feet (0.91 m)! long were selected in order to utilize a standard cylinder testing

machine and flexural beam testing apparatus. A typical beam was de-signed and reinforced with one No. 6 bar. To precipitate a reinforcingbond failure it was necessary to minimize the embedded length to 4

|| inches so as not to fail the 4 x 8 inch concrete section in shear. Em-

bedment length was controlled by installing plastic sleeves over the|

center portion of the reinforcing. (Photograph No. 2),

|

The besa specimens were cast, vibrated and cured in similar fashionto that of the cylinders utilizing the same test pada (See photographNo. 3). Two beams were cast rr. each pad. Two test sets of two beams

| each were made for each cancrete age-vibration level datum point to beevaluated. One set was arranged so that the be.uns'long axes werealigned parallel to the direction to which the blast vibrations wereoriginating and the other arranged with the beams' ions axes perpen-dicular to the originating vibration direction. This approach was takento be sure that there was no variation in results occurring from phenon-enon relating to the difference between the blast wave propagationtransverse to or along the axis of the beam. All beams were load

: tested 7 days after casting. Standard compressive cylinders were madeto determine cylinder strength for analytical purposes.

!

Beams were tested per ASTM C293, center point loading. Due to the

,

plastic sleeve the loading produced an early flexural crack in the beam!

center which did not effect its ultimate load capacity. As loading wascontinued, the beam would ultimately fail by:

i

4|L.- - - - - .. - . - - . . - - - - . - - - _ . - - . _ - - -

. . _. _ . _ _ ._ _ - _ . - . _ _ _ _ _ . __

|, !

j. *

1 Bond failure of ths 4 inch (102 nun) rsbre anchsregs withcutsplitting or shearing of the beam and sometimes followed by a

Ishear failure. l

I

2 Bond failure in the anchorage zone resulting in splitting offconcrete adjacent to the anchorage, usually followed' imediate-ly by a shear failure of the beam. (Photograph 2)

The " Ultimate" load was recorded as the peak load capacity of the| member (which occurred just prior to failure).

Since the mode of failure and the corresponding failure load varied,it was not possible to make a direct comparison between vibrated and un-vibrated (control) beams as was done with the bla.c vibrated cylinders.

i An alternate means of evaluation was derived by calculating the safetyfactor between the " ultimate design capacity" and that of the " actualultimate test capacity". The ultimate beam design capacity was deter-

i mined from ACI 318-77 provisions considering unconfined bond anchoragevalues and actual cylinder test values of the same age and materialutilized in the beam.

A summary of the test values is given in Table 2.

No signs or features were visible in the vibrated or unvibratedsamples tested that could be related in any way to a less than soundconcrete product.

| Field Wall Test Program

! The final stage in the field tasting program was to " simulate atypical" concrete section and subject it to blasting and study thei

effects.

|Five walls were constructed, four test walls were subjected to

blasting and one' control kept free of vibrations. Each wall was made;

up of two - 2 feet. (0.61 m) wide by 8 foot high by 8 foot (2.44 m) long:

walls arranged as a cruciform to introduce longitudinal and trans-verse blast wave effects. Walls were typically reinforced throughoutwith #6 rebars at 12 inches (305 num) on centers, each way.

i

Bond test dowels,,#8 rebars, were placed into the walls at varyinglocations and depths. Plastic sleeves were used over the bars to con-trol the test zone location and provide a 10 inch (254 set) embedmontlength for pull testing of bond values (See photograph No. 6).

Four-hour and fourteen-hour green concrete ages were chosen as suf-ficient to represent the varying spectrum of concrete set time enarac-teristics.

Each of the walls to be vibrated were instrumented at the foundatimslevel and on the top of the wall at the intersection. The two closestwalls to the blast also had a transducer located at the mid-height in-tersection. The higher transducers provided information relative toamplifications through the wall system.'

Twenty eight days after casting the walls, pulling of the #8 testEachdowels commenced, utilizing a 30 ton (27,210 kg) hollow ram jack.bar was 1saded until it began to pull out. The bond failure load wasdetermined to be the load at which continued pumping initially did notresult in' an increase in load. At this point, verification of movement,

,

5

_ _. .. . _ . _ _ _ . _ _ _ . . . . _ . . _ . . . _ _ _ , _ . _ . . . _ . . . . . _ . _ . _ . _ _ . _ , .

I

.

.

\-

unu -p-- - *

i n * o.v .. u m.e.m .e.i.,e, . 1I

>7 ,','[ g - c , .' .:sa ycJa. .taaef cond4WC'Oe ldt1 * .1,s

.,,

6~cm .c. e. one==<=,e um n.co . .o.n,

ii.u i . .u| |,e e., . . . ....

[ ' . , , gg ., .v..- m .c mc. _ . . . ...i., . . . . . . .. ,e

_,

. . , ._._ . . . . .. ..

,h.?/ *.i"'m .*act=' e , .: .,,, , , , , , ,

u .' . .::,in in su iui* , -,..

"'"'. :. i. ..n> Photograph 1

a n ==ce i.i <. se re FIELD CYLINDER TEST PAD.et-r oor ou e.m

,,,, ,

aio s ie es i n i=*

t.n ese. - .v.m s o,e c s r e,Ik:L.no esma, s. I Gaseet le fe. inne of sies.nesa6 I Laeme esees.s 01 eseet ip ese,-y .- _

t : pe,eene + m. be 0.3 et.ee.n ite .em,13 none j;i.i - - - . - e e. .

If b.ane =anones. se O eiese .ftoe F. seti.i -..e.-.~e.e. -. . . ..en.s .- . _. ",f 6 5 :m. samune..as i.em sses si.e Memas a

ONE .sCsi. s.am . T*\

. gjff' '\

$dh Wh: -O.'

)$g-a.e3gk%* E%?g$- ~ m e. -< s . e.:.?d'4

w m.a.cu.|s ,.n, .s.cos{-

ascmc

,;,,, n= =.rctsnsi r ,vawn = ac=we .crum,cuc ;==a .c t , cue ..c , , , i i .as -.

'au . u l s? . =u l s? Photograph 2jan g FIELD BEAM SPECIMEN. .s en in i. n l in ' au I 23

" ' on j :. l .o. .AFTER LOAD TESI. j .. .

i st un us .. ! in en ! = i e i. g,, ,

. - | su .ut u. | . o. .

.. o ll ion en I so . . . go.i .a .*

. . . . I i .i e n l au on .

ag,w . . wwdI-> > - su i r. i.n l in om ' u. a i. yyi , ,

t --q1. .i ... ... i ,,, a ,, . c

,-

i. , j . .. . .i .. . .

u,|. . ,

.

eru i.

, 3 .,| j os o i. so u. . y e

m . -

==|ni j ia n, * -

in o o. 23 e i. = ' aansai J.;. . . ; , , , . ,a , , , .n .

,

en l ia .. a .; i e. 2n .= .! iu'

s- ., , , .m.va . .. ! . . . ., .. .

1 ..- ~. i.

> ez -

,d , - ~ ' .vien.no i.u . I su . air e ' E r,x, , , , , . , ,

3 m""5^""'''"'

cc,,.e. . . j i rr- = . -:

-

5.5m

i A,fs-"

cocaat ano . visa.no e..eas en se..s 1,

Photograph 3FIELD BEAM TEST PAD

P00R ORIGML.6

.-. _._. ._. _ - . _ _ _ _. _ . . . _ . . _ . . _ . _ _ _ _ . . _ . _ _ _ - _ . _ . _ _ _ _ . - - - _

. ___ . . - . , _ . - - - _ _ _ -. _ - _ _ _ _ _ _ _. -.

;

e

4 4

was mada by mensuring ths "new" isngth of tha extendid bar. Esssn-tially, the 10 inch embedment of the #8 bar was sufficient to develop a

i stress level in the average bar of 66,667 ksi (459.3 M Pa). In a fewcases, the bars broke at a small notch put in the bar to facilitatejacking prior to breaking the bond.

3

Results of the pull-out values were very close and no significantdifference can be observed between the vibrated and unvibrated values.

| A comparison was made between the ACI 318-77 confined anchorage values(for "other" bars) and the " actual" bond failure loads. A summary of

;

i these and other values are given in Table 3. Note, that the averageunconfined bond safety factor from the beam test (Table 2) and the con-fined bond safety factor from the wall test are reasonably ci,s,e, con-firming a considerable margin of safety for bond values without any'

consideration for " top bar" allowances.

After completing the bond test, 4 inch (101.6 aun) dia. cores weretaken from each of the walls. Visual examination indicated no signs offlaws or deterioration. Cores were load tested asi gave results com-patible with what would be expected from the loaa testing of cores.

Finally, one of the walls was blasted loose from the rock and pushed<

out of the way by bu11 dozing (See photograph No. 7). Examination ofthis wall externally and within the core holes did not reveal any blastinduced cracking which would have been exaggerated by the extremehardling.

,

LABORATORY TEST PROGRAM

Essentially, the laboratory phase of the testing program was com-prised of, casting cylinders and bond pull-out specimens and subjecting

,

them, at specified concrete ages, to various fixed frequencies andi ,

velocities by means of a shaker. table. All specimens were well moni-tored and vibration characteristics respectively recorded. Control(un-vibrated) specimens were cast from the same concrete batches. Afterthe appropriate 7 or 28 day period had elapsed, the vibrated and controlspecimens were load tested and results evaluated.

All testing work, except for load testing of the specimens, wascarried out by The Franklin Institute Rer,earch Laboratories, utilizingthe General Electric Company Space Center facilities at Valley Forge,Pennsylvania.

Nominal curing time from specimen casting to vibration of 3, 6, 12and 24 hours was used.

The velocities and frequencies (and associated accelerations) givenin the following Table were utilized. Test frequencies were chosenfrom the predominate frequencies associated with maximum velocities ob-served from the site blast monitoring records. (Table on next page.)

Vibrations were induced such that the profile of vibration had arise and fall' time of 0.5 I 0.3 seconds and remained at the peak 1&elfor 5.0 t 0.5 seconds. The specimens were subjected to excitation ir. '

one horizontal axis through the base. Vibration profiles were recordedfor each of the three perpendicular axes.

A C150 shaker manufactured by M.B. Electronics, a Division ofTextron' Electronics, Inc. ,was used to energize the shaker table.

7

.

.ped 3 PARTCLE VELOCITYIN INCHES /SEC. MECSUREDAT THE CYLINOER

-- 14 0

e

0yINDICATES NOMINAL TIMEAT WMCM CYLINDERS WERE,SUBJECTED TO BLAST VIBRATIONS

--10 0

/j' .

..

pP''* .Ng /* 80

g:A' .

:<f , ,,k,.

0

-

i ..s* ..

\ \*N s. ..

*N

" * " " ' " .#,

% *? e-o- ,

h. V, , ,,. . .

40 -40 -40 -20 0 +2 0 40 40 40

% VARIATION IN C(MAPRESSivE STRENGTM WITH RESPECT TO UNvi8AATED CC*dTROL CYtlNDER

FIGURE 1

RELATIVE CHANGE IN COMPRESSIVE STRENGTHOF CONCRETE CYLINDERS VIBRATED BY BLASTING . CURED T DAYS ,

PEAM PARTICLE VELOCITV|N INCHES /SEC. MEASURED*

AT THE CyLINOER-- 14 0

e,* .

12 0 INDICATES NOMINAL TIMEe, AT WHICM CYLINDERS WERE

SUBJECTED TO BLAST vtBRATIONS

%.(j

,7r '". , -.

\ s' |>(*.g .. 0.,|\.

/>

*., %

| x y i

N.N .$' 0'N,. e 'a

(.0 0

:Q- A~. _. f- W~,N.-r, e a t

, . . .

40 -40 -40 -20 0 *20 +4 0 40 +6 0

% VARIATIOrd IN COMPRES$1vE STRENGTH wiTH RESPECT TO UNvl8 RATED CONTROL CYLINOER

_RELATIVE CHANGE IN COMPRESSIVE STRENGTH

OF CONCRETE CYLINDERS VIBRATED BY BLASTING - CUREO 28 DAYS

P00R ORGM4

-

a -

!l

. ,

|-

,

!

IN E C EASI.R O

.. Q AT THE CYUNDER

\'

T C E$ RE# %~

'% s*#TJ,A:?.T.u' "-- ' ' -

%

/ \; 'y-

,

/ N/ 4- N

\,/-- 40 ,

ssy-40

| ||

|/ .N-"

/r

--

/, .Mt' " " '' 20 N-

b. . .

. . .

-12 0 10 0 -40 -40 -A 0 -20 0 20 -40 40 40 10 0 12 0

% vansATION IN CouemEssivE SimENGTH wiTH RESMCT TO UNV10AATED CONTROL CYUNCER

FIGURE 3

of CONCRE E YUNDE v BRA D wi M FRE E Y OF 100 M2 .

CURED 20 QAYS

.

'

' '

-(.

, . . -|

a 3- as n -, .g s.' . ,

fy7:' c .m.

~

i

-

1,.:. . 'g .

?[f M F"-

."

.

y

.i.'i m w& . _

- -

*- i 4. . y '

Photograph 4 Photograph 5CYLINDER FIXTURE FOR VIBRATING INSERTING " GREEN" CONCRETE

GREEN CONCRETE MOLDS INIO CYLINDER FIXTUREMOLDS .IN LABORATORY ON SHAKER TABLE

P00R R G E!.9

. . - - . - _ _ _ _ _ _ . - _ _ _ _ _ __ _

'

,

.

IABORATORY TEST VELOCITIES AND FREQUENCIES(AND ASSOCIATED ACCELERATIONS)

FREQUENCYMAXIMUM PEAK PARTICLE ACCELERATION IN g j

50 hz 0.83 1.66 3.3 6.6 '

13.2-

100 hz 1.66 3.3 6.6 13.2 26.4-

150 hz 2.5 5.0 10.0 20.0 30.0 -

PEAK PARTICLEVELOCITY 1 2 4 8 12 16INCHES /SEC. |

One Inch =25.4 mmThe energy input into the laboratory vibrated specimens is consid-

ered to be comparatively more severe due to the longer period the spec-L=en is subjected to the induced vibration. *

Laborarary Cylinder Test Program

!This program consisted of casting standard 6 X 12 inch (152.4 X

304.8 mm) cylinders and subjecting a group of 4 cylinders at a time tothe selected vibrations by means of a rigid steel fixture fastened tothe shaker table. (See photog.aph Nos. 4 and 5.) Cylind1rs were cast,cured and compressive load tested in accordance with ASTM C31 and C39.Control cylinders (unvibrated) were cast from respective concretebatches.

Af ter the appropriate 7 or 28 day curing time, 2 cylinders from eachgroup were load tested along with control specimens. The effect of vi-bration was evaluated in the same manner as the Field Pro * gram cylindersby normalizing the change in vibrated cylinder strengths by representingthem as a percentage of increase or decrease in strength from that of ,

the control cylinders and plotting the variation with respect to theexperienced peak particle velocity.

A representative plot is shown in Figure 3 and a table of testvalues, irrespective of vibration levels or green concrete age is givenin Table 5

Results of the laboratory cylinder test program were essentially thesame as the field cylinder program. Specifically, no specific trend canbe established in the change of cylinder strength with respect to any ofthe vibration levels introduced for any of the green concrete agestested.

Laboratory Pull-Out Test Program

This program consisted of casting, curing and testing pull-out sam-ples in accordance with ASTM C234(152.4 mm) cubes with a 3 foot

Pull-out specimens were 6 inchtending to the specimen bottom. (0.91 m) long, #6 reinforcing bar ex-

Specimens were cast in specially mademolds, structurally strong enough to permit direct attachment to theshaker table. Specimens were subjected to the same basic age-vibrationlevels as that of the cylinders and tested 7 and 28 days after casting.

10

_ - _ _ - - _ _ - _ _ - _ - - - - - - - - - - - - - - - - --

,

.

Dus to tha nominal 30 inch (762 mm) cxten=4 of tha #6 rainforcingbar, a whipping action was introduced during the shaking operation eventhough the top of the bar was relatively secured to the casting mold.This behavior created an added severity to the reinforcing bar bondingcapability.

Although the ASTM C234 is to evaluate concrete strengths by com-parate bond failures (not necessarily related to ACI 318 design values),the test did confirm information relative to the effect of the inducedvibration on bonding characteristics.

Basically, all pull-out specimens failed by splitting of the con-crete block prior to achieving a bond failure. However, the load,developed by the 6 inch (152.4 mm) embedment of the #6 reinfor'cing barwas, again, significantly above the ultimate anchorage load calculatedfrom ACI 318-77 for unconfined bars.

Values, irrespective of the green age or vibration level, are givenin Table 4

Essentially no reduction in concrete strength or bond capacity canbe recognized as a result of the vibrations introduced to the various

-

green concrete ages.

SUMMARY

1. Due to space limitations, detailed discussions of test and evalua-tion work and data, presentation has been greatly shortened. Datahas been summarized in an attempt to provide sufficient overallinformation to. establish the validity of the work.

* .

2. Test work was done for the mogt part with readily available re-sources, and there was no attempt to pursue a full scale researchprogram outside the realms of establishing increased vibrationlevels for green concrete.

| 3. Although the test program was aimed at finding a " critical"I vibration intensity for green concrete, no vibration level was ever

reached that could be associated with ultimate damage to the con-crete tested.

4 Although many specimens of various types were subjected to inputvelocities up to and in the range of 8 to 12 inches per second andsome subjected to velocities aa high as 20 inches per second (l" =25.4 mm), there has been no evidence to indicate that the re-vibrated green concrete tested would not structurally perform inaccordance with its standard 28 day strength design values or wouldotherwise produce a less durable structure.

5. Results of the test were used to re-establish green concrete blastvibration limits as given in Table 6. The values listed are stillconservative with respect to the test program results and even withrespect to some of the " original Table 1" values. Prevision for anincrease in blast vibration levels above the Table 6 values wastreated on a case-by-case basis, but essentially the Table 6 valuesallowed reasonable excavation efforts without schedule difficulties.

6. Bond test results indicate an appare.nt strong conservatism in the .

ACI-318-77 anchorage provisions. This conservatism should be looked

.

11

_ _ , _ _ _ _ _ _ -_ . - _ _ . _ _ . _ _ _ _ _ _ . . _ _ . . . _ _ _ _ _ . _ . _ _ . . _ _ _ _ _ _

. - _ - _ _ _ _ _

.

'

.

ct with respect to eliminating ths 1.4 factor for horizonta?cwalllaps which are currently identified as " top bars." This reductionin horizontal lap length would serve to reduce added congestion in *

heavily reinforced walls apart from any savings in reduced steelrequirements.

CONCLUSIONS'

l. The Seabrook Green Concrete Blast Vibration Limit Program hasprovided valuable data which conclusively supported increasingprevious blasting vibration limits. Based on the observations ofthe Seabrook work, there is strotig confidence to indicate that evenhigher vibration limits can be established if additional test workis performed.

2. If no environmental, public structures, human tolerance or othersafety considerations are involved, considerable margin stillappears to exist in raising blasting vibration limits relative tothe concurrent placement of concrete.

ACKNOWLEDGEMENTS

The Seabrook Station Power Plant is jointly owned by a number ofutilities. Public Service Company of New Hampshire is the major share-holder and agent for the owners. Yankee Atomic Electric Company is theEngineering Supervisor for the Owners.

United Engineers & Constructors Inc. , is the Architect-Engineer andConstruction Manager for the total facility.

!

Field wo,rk was carried on under the supervision and direction of*

United Engineers and Constructors Inc. Field Engineering Department byvarious'on-site contractors.

Stephen A. Alsup serve'd as bir.ec monitoring consultant and advisoryto vibration testing phases. (4)

APPENDIX - DIRECT REFERENCES

1. "In-SITU Dynamic Elastic Moduli of Concrete During Curing Procesafor Maine Yankee Atomic Power Plant, Wiscassett, Maine", WestonGeophysical Research, Inc. , Weston, Mass.

| 2. " Measurements of Vibrations Caused by Construction Equipment andBlasting Report RR172", April 1971 Department of Highways, Ontario,Canada.

,

.

3. Waddell, Joseph J. " Practical Quality Control for Concrete", McGraw-Hill Book Company, 1962, par. 7-8, Autogenous Healing.

4 " Measured Vibration Levels, Blast Shock Testing on Curing Concrete-Final Summary Report," S.A. Alsup & Associates, Inc. , August 12, 1977;

| (Prepared for Public Service Company of New Hampshire.)

COMPENDIUM - Relative Documents on the Effects of Vibration on GreenConcrete

i 1110-2-38001 US Corps of Engineers, Engineering and Design Manual,EM

dated March 1972, " Systematic Drilling and Blasting for Surface Ex-cavations", Chapter 7 - Damage Prediction and Control.

[

~12

I>

. . - _ - - _ . _ . _ _ _ - . _ - . . _ - - _ _ _ _ _ _ _ _ _

-- - __ __ - ..

.

.

.

Bastian, CE, "The Effect of Vibrations on Freshly Poured Concrete."2.

Portland Cement Association, "The Effect of Jarring on Fresh! 3.Concrete."

Consolidation byPopovics, S, "A Review of the Concrete4Vibration," Materiaux Et Constructions, Vol. 6, No. 36,1973,Pgs. 453-463.

Voina, N.I and Mirsu, 0 "Some Aspects Concerning the Influence of5. Vibration (Revibration) and Retarders on Concrete Workability andStrength."

Wiss, John F, " Damage Effects of Pile Driving Vibration," paper6.presented at the 45th Annual Meeting of the Conunittee onConstruction Practices-Structures.

Neville, AM " Properties of Concrete," Fresh Concrete-Revibration,7. 212-213.John Wiley & Sons, New York, pgs.

Larnach, W.J., " Changes In Bond Strength Caused By Revibration of8.Concrete and Vibration of Reinforcement," Magazine of ConcreteResearch, July 1952.

Bergstrom, " Test of Properties of Fresh Concrete," Magazine of Con- '

9.| crete Research, October 1952.'

10. Taylor, W.H. , " concrete Technology in Practice" 2nd Edition Angus &'

Robertson, London, England.,

.

Post Program Documents

11. Krell, William C., "The Effect of Coal Mill Vibratien on FreshConcrete", Concrete International, December 1979, as. 31-34.

i

12. MacInnis, Cameron, Kosteniuk, Paul W. , " Effectiveness of Rivibrationand High-Speed Slurry Mixing for Producing High-Strength Concrete,"ACI Journal, December 1979, Technical Paper Title No. 76-51,pgs. 1255-1265.

13. Akins, Kenneth P. Jr., Dixon, Donald E., " Concrete Structures andConstruction Vibrations," ACI SP 60-10, pgs. 213-247.

j

14. Chae, Yong S. ,'" Design of Excavation Blasts to Prevent Damage,"I

Civil Engineering, April,1978, pgs. 77-79.,

s

i

i

13l

L--- _ . _ . . . . _ _ . __ ,, _ - - _ _ _ _ . . _ . _ . _ _ _ . _ , , _ _

9

'..

4

.

'

| J J *il 'I ,*

.nu r....a c .'.10 au ,,,, m,

..

=

., . .Ai '

$ -mb*

4$= -.co. "-""a',',a "'Ir l'"a= aaax

t808 Loao ACfuavC.tC $' p. gn.o p- h.,3 wa 3

test .se ,,o

; .f --i < nC u.i - Co n

%j r- ac2e'"'

.e 15*' *a 2.'' = F r

ic -it

. 1 w , g ( 4,:un a fo- 'o~s '~:

m-e _ as,-

, 2.!* [__ - a, , ,,,.. . .. .. > > , .. n. 0,, ni O O., on . ,, .

..

.t1 i. io . . , . .. .3 00 in .m ne. . , . ~.'* v A

3 . . . .. 2. , 0 ,. in Om .=, ' Photograph 6 I

FIELD TEST WALL SHOWING= i. O ., - 3,. I ., u. 0 ,0 in 00n nii .

REBARS EXTENDED FOR3 - - .. u .. u. ns em on . FULL-0UT TESTING

avet.G. witeAft0 w.wt3 fo i. 13

CONW|tSIODe f ACTOel - Cset edCM * 25. astuangf fe5CPet Tops. 07 3 saccaasalOped PSe e . . astOPASCAtl

A ;'QMy .* :a .

w t. i. .

*?ecsafGPT ' Elf Am{M LOADS

,,'f3 *'Get 5MCWW W G.tfee CXst't age ce v0AaFON tfvtt ic'-A .~,.. ~Q MCcsersat via Afe0

-.- - , . .

. . - . s .. -W ~ .CCac ? fit a ,,,G, ay,,aa, 'e ,eso Put our g 7

-%^ C" W esO Put mf g

a,,,3,.,-

.

=ecs auss

,

, ,nfy:N a 4 Q-

, , . . . . mn e ir. e3 2

= ,,0 .m . i n> u."

7 2 r2. 750 1225 10 12. 1 5 i.30

Photograph 73

a e isirs in it iun ine

FIELD TEST WALL AFTER, i iui3 rw >> isn. u.,

BEING BLASTED FROM FOUNDATION*, , ium ,0,i is is i.0 in,

CEPs[. tit CftsectB STEEas",fM5 Givlet eN fan $ .

WD0 poscl e .53 . anOGaa.as

I,dhU us< niast v'esatieN emets peetancear-re mf evt.een s ar cus tiep ya cos gratioN,,eenangue grancevegg

##fsMCT'WE OP e C&Cstif .GE of WWarcN tEvit

Ovp

CON _CRlff, AGE, a,y 3,,, , , , , , y,,,,..,,

avtaact avttaG4II STD Df u

nreteeGfee litEt<GFMni >> t far .., .6 ,, 20 .0 0

sesCMS Pte RfC.

| 3 3343 53 9 32 32.S 11. .F

2. 3 .00, . . . >> . ..

7 3 2,.0 .. F 10 7..I 13 3 se EESPfCfivE PLACEntNT GOWf tNeNG ING .aQRt $f BtNGENT3

2. 3 37 7 .l. te 370 103 GaCLMO WliOOTT 99QuittentNTS.

# 3 2.S7 270 .I Nie sFOR 0 S seeCats Pt. 54CO*eo Af i.00 past on .000 peti peons

2. 3 35 3 it. .3 31. i$3. feet Ana&f iDCATOas stSPECfivitt.

P 3 3e .. I3 1710 51 .ONG sesCM e 19.==

.

2. 3 * J.7 22. . 21 3 09 11F W #007*OJOS=.

OA8 Ples. Est0Pa5Catl

P00RDilBML-,

- - --- - - . - -- -- -- - _ . - - - - . - - - .

..

,, ,..

. .

. ,

,

'

United States Department of the Interior15

<

_ ) GEOLOGICAL SL*RVEY=-- RESTON, VA. 20092 ,

..,- N . ab!!'j \'

ciTICE oF THE DDLECMR , , .* ' ' *

nff$"'In Reply Refer To: 'n> - July 25, 1980EGS-Mail Stop 106

Dr. Robert E. JacksonChief, Geosciences BranchDivision of EngineeringMail Stop P-314U.S. Nuclear Regulatory CommissionWashington, D.C. 20555

Dear Bob:

Enclosed are comments in response to the August 9, 1979, letter fromMr. Frank Schraeder and to your letters of September 18, 1979, andOctober 18, 1979, requesting that the Survey review material relevantto determining the response of the Limerick Generating Station, Units1 and 2, Docket Nos. 50-352/353, to nearby quarry blasting.

This review was performed by me, and we have no objections to yourmaking this review part of the public record.

Sincerely yours,

_ - ,; = - J

\JamesF.Devine,'

pcting Assistant Directorfor Engineering Geology

Enclosure

:;. -y - ,, g n ~ -nyyg zy;

;LT' -::* + , a__w c ..

DUPLICATE DOCUMENT..i.

Entire document previouslyf

.fi entered into system under:os

ANO T8e EOl/ QC 7d_.hd No. of pages: l/ _

-

pyy:n.gn , g csyy g; _~ , .z.- n. ..ww , - + _ m_ wunn

-

-. .---.

'

pt--

.

/'k's United States Department of the Interior_, ]3..

GEOLOGICAL SLTT!*

_% RESTON. VA. 2:2092,s

omCE oF THE DIREC"0R

In Reply Refer To: August 11, 1980EGS-Mail Stop 106

Dr. Robert E. JacksonChief, Geosciences BranchDivision of EngineeringMail Stop P-314U.S. Nuclear Regulatory CommissionWashington, D.C. 205S5

Dear Bob:

In reviewing my letter of July 25, 1980, to you concerning the LimerickGenerating Station, Units 1 and 2, Docket Nos. 50-352/353, I have dis-covered that an incorrect word was used in describing distances from thefuture blasting and Class 1 structures at the Limerick plant site.

. ne word "manmum" in the second line of the fourth paragraph of the firstpage of review coments should have read " mini =um." This now makes thatsentence consistent with the first sentence of the first paragraph ofpage 2 of my coments.

I apologize for any inconvenience that this =ay have caused you.

Sincerely yours,

n -

k.= ffJames F. DeviaeActing Assisttnt Director

for Engineering Geology

coo)S

i/o

.

8008150 % %-.

. .. ~,

.

>.

.

PHILADELPHIA ELECTRIC COMPANY

rewano s. sausa. Ja. 2301 MARKET STREETv ie ... ..o =,

.. um.. $caua n

PHILADELPHIA. PA.19101suc.c.Ns J. snacL.e.v. xmv. m 6 cou...

CCNALD SLANMEN (2ISI S41-40009u COLPH A. CHILLEMtc.C."'"" ~^ " July 29s 1980T. M . WAMEM ComNELL

Decket No. 50-352 and** u t. 4 u ca s*".".6 eau .".....v.,... 50-353EC.W..A.R D..J,. CO LL.E.N J R..v cou

Mr. l. S dwencer, CliefLicensir.g Branch No. 2Civisicn of Licensing

U.S. Nuclear ~@ter/ &=i ahWashington, D.C. 20555

Subject: Li::exick Generating Sta* Blasting :'## acts

Paferences: 1. Letter, E. J. Bradle/ to R. L. Baer, datedJanuar/ 15, 1980

2. Iatter, E. J. Bradley to R. L. Baer, datedFebruarf 14, 1980

3. Letter, E. J. Bradley to Al Sc :wencer,. datedMay 20, 1980

Cear hr. Schwerr.er:

A.-tached are #ive (5) ccpies of a rescrt titled "Cmparisen of Near-.

Site Cuarry Blast C.aracteristics to the Saieie- Cesicn at Limerick GeneratingStatien". S.is retx:rt was .pted at a :neetirs en rez 18, 1979, byrepresentatives of the NBC.

?.e ccnclusien of the repcrt states that the respense spec ~m develcpedfrmt rec::rds of recer:t cuarry blasts are essentially envelcped at dticalfrequencies Lf the CBE design spec ~m for dtical strrtures.

?.e subnittal of this report c:2rpletes all of the car.it:nents madeby us at the Dececicer 13, 1979 meeting with NBC representatives.

Sincerely, , ,

" % .ni 'V, /

y / G .**. > ,r. . . ,_ -;

\ICGDE J. SPACIH C

,

f

h300ao4o q.

. - . . -. . . . - - . .. ._ ..

:.

.

i

|

|

||

COMPARISG CF NEAR-SITE

CCARRY SIAST CEAFNCS|

T THE SEISMIC CESIG1

ATt

IIMERICK GDIFATDG S~4CNt

DCCCI NCS. 50-352 Ata50-353

July, 1980

t

!

.

DUPLICATE DOCUMENT

Entire document previouslyentered into system under:

%DO% Ot/0o07*

aNo'

No. of pages:x s

. . . _ _ _ . _ . _ . - . . - _ _ _ _ _ _ _ , . _ _ . . _ _ _ . . _ . . _ . _ . _ _ _ - - . - _ _ _ _ . , - - _ _ _ _ - . . . . . _ _ _ _ . _ _ . _ _ _ _ . --

-