regulations and standards for rock blast

7/26/2019 Regulations and Standards for rock blast

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Regulations and Standards

Vibration standards come in two varieties: those dealing with human comfortand those dealing with cosmetic or structural damage to buildings. In both

instances, the magnitude of vibration is expressed in terms of Peak ParticleVelocity (PPV and millimetres per second (mm!s.

"uidance relevant to acceptable vibration at the foundation of buildings iscontained within #$ %&' ()**&: +valuation and measurement for vibration in

buildings Part : "uide to damage levels from ground-borne vibration. his

states that that there should typically be no cosmetic damage if transientvibration does not exceed )mm!s at low fre/uencies rising to 0mm!s at )12

and 0mm!s at 3012 and above. hese guidelines relate to relatively modernbuildings and are normally be reduced to 04 or less for more critical buildings.

5ritical buildings include premises with machinery that is highly sensitive to

vibration or historic buildings that may be in poor repair, including residentialproperties.

he "erman standard 6I73)0 provides limits below which it is very unlikelythat there will be any cosmetic damage to buildings. 8or structures that are of

great intrinsic value and are particularly sensitive to vibration, transient vibrationshould not exceed &mm!s at low fre/uencies. 9llowable levels increase to 'mm!s

at 012 and )0mm!s at )0012 and above.

In Ireland, the 7ational oads 9uthority (79 have issued "uidelines for thereatment of 7oise and Vibration in 7ational oad $chemes and have indicated

( able -79 "uidancetypically deemed acceptable vibration levels in order tominimise the risk of building damage during road construction as shown below:.

In practice, construction vibration limits may be found in planning permissionconditions for large pro;ects which are likely to generate potentially significant

vibration, limits are usually set which are below the thresholds of structural andcosmetic damage in order to limit nuisance. In addition +P9 IPP5


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vibration is also a useful document in vibration assessment. #ritish $tandard>3%, )**, "uide to evaluation of human exposure to vibration in buildings

()12 to '0 12 and #ritish $tandard ': Part &, )**%, 7oise and vibrationcontrol on construction sites, Part &.5ode of practice applicable to surface coal

extraction by opencast methods are also applicable in this respect.

sumber: http:!!www.consultnet.ie!environmental40vibration.htm

sumber: http://www.edumine.com/xtoolkit/xmlicon/PPVThresholds.htm


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Vibration Standard Criteria

The blasting seismograph vibration monitortranslates its raw observations into a number

of different measures of the speed of ground vibration. The one most accepted in the fieldis the peak particle velocity (PPV). This, as the name implies, is a measurement ofmaximum ground particle movement speed, specified in the U.S. in inches/second. Thisquantity is measured in all three perpendicular axes of the seismograph's geophones, asthe magnet!in!coil detecting devices within the seismograph transducer head are called.

""# is a vectorquantity $i.e. it has both a valueand an associated direction%. The peakvector sum$"#S% is usually also quoted& it is simply the square root of the sum of thesquares of the ""# values in all three vector directions measured by the seismograph. "#Sis a scalarquantity, i.e. one with only a value, which is always larger than the individual""# vector values. Scientific studies have shown the PPV correlates best with damagepotential of all the tested characterizations of ground movement$e.g. acceleration,displacement, or strain%. #irtually all the standards are quoted in ""# values, not "#S orother measures of movement, although the acceptable values of ""# differ with thestandard used and with the frequency of the vibration components.

The three axes of measurement, the longitudinal$sometimes referred to as radial, thevector connecting the orientation arrow on the seismograph transducer and source ofvibration%, transverse$the vector in the same plane as, but perpendicular to, thelongitudinal% and vertical$up and down% vectors, are always measured and reportedseparately. ne reason for this is that they have different degrees of importance incausing damage. Structures are built to withstand vertical forces. (or that reason,vibrations along the vertical vector are usually of lesser importance in causing damage,

though not always benign. #ibrations in both the longitudinal and transverse vectors havethe potential for causingshearin the home structure, which is a ma)or contributortodamage effects. *hen in shear, various parts of the house move at different speeds oreven in different directions, which can cause cosmetic crac+ing or even structuraldamage. #ibration standards generally do not ta+e into account directly these differencesin damage potential between vibration components, simply specifying the same limits forall three axes of measurement.

Understanding Vibration Standards
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#ibration standards, li+e the S standard and US- 0123 recommendations at right,are set forth, usually by governmental agencies or professional groups, to provideguidance to those who might be expected to cause vibration in their wor+ and want toavoid causing damage. 4ll scientific studies have limitations, including those of vibrationdamage and standards based on them. *ithin their scientific limitations, such standardscan be invaluable in helping to avoid unnecessary damage by telling contractors andothers when their efforts should be of concern. They also suggest when and how vibrationcan be reduced to avoid damage.

#ibration standards are usually plotted graphically similarly to the S standard and US- 0123 study compliance plots at right5, using log $logarithmic or non!linear% scales inboth the hori6ontal and vertical directions. The vibration intensity $velocity in in/sec% ison the vertical scale and the vibration frequency is on the hori6ontal scale. "lotting them

linearly $i.e. with equal spacing between units on the scales% will change the shape of the

S -lasting Standard

US- 0123 Safe -lasting 7evels


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dividing line separating allowable from non!allowable vibrations dramatically, but willnot change the standard itself.

Using Vibration Standards

-ecause not all vibrations felt by people are damaging to structures, vibration standardsattempt to separate those vibration intensities and frequencies which are potentiallydamaging to structures from those which may be concerning to people, but pose relativelylittle damage probability. t is important to understand that standards are properly usedto udge the probability of a single ground vibration of a given size! duration andfre"uency composition causing damage to a collection of houses of similar construction(see below)! rather than the probability of multiple vibrations causing damage to onehouse#0This differentiation is especially important in cases of construction vibration,where vibration is usually neither single nor short!lived.

ne way of stating what the these diagrams really mean scientifically is8 (or agiven single blasting$caused vibration!lasting less than a few seconds, with frequency

components and intensities which fall below the dividing line defining the standard, 91: ofessentially intact houses on firm foundations, two stories or less in height, having thedimensions of typical residences, will not be damaged by that vibration. That might be amouthful, but that's what the standard and the data really say, at least within the confinesof the US- 0123 study which underlies both the standard plots at right. %f any of theassumptions or conditions which are behind a ground vibration standard are not met ina given situation! then any use of that standard is potentially both unwarranted andmisleading in that situation.

Standards and Statistics

-ecause the acceptable vibration levels set in such standards are based on statisticalanalyses of damage probabilities, assuming ;aussian bell!shaped data distributions li+e theone shown at left! not all vibrations which are deemed &allowable& (e#g# below the linesin the center of the standard compliance plots above') in a given setting and standardwill be non$damaging to all houses#Similarly, not all vibrations deemed non!allowable$those above the central lines at right above% will alwayscause visible damage. Thus, themere fact that a given vibration is of an intensity within the allowable regime cannot beta+en as proofthat a vibration of an allowable ""# did not or will not cause damage. %tis scientifically inaccurate and misleading to say that it is &impossible& for a vibration ofa given size to cause damage to homes! even if it is within a given standard# ur CVDGPropage, Statistics and #ibration


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re"uency ependent amage Potential

4s described on our page, #ibration =2=, ground vibrations are usually complex ones madeup of multiple overlapping and interacting frequency components. Thefrequencycomponentsof the vibrations are important determinants of the damage potential. t is

well +nown and understood that structures have natural vibration frequencies, calledresonances, a little li+e those of a tuning for+. Such resonant vibrations are more feltthan heard, due to their low frequencies. 4t the home's resonant frequency, any repeatedvibrations, li+e those caused by construction, are added to one another. The vibration inthe house grows, rather than dying away in a few seconds. Thus, even small componentsof a vibration which occur at the resonant frequency are potentially dangerous to thehome, if they continue sufficiently long. Such resonant phenomena also bring into play so!called fatigue issues.

(or this reason, most ground vibration standards ta+e into account the frequencydependence of the vibration damage potential, setting more rigorous standards at lowerfrequencies nearer the home resonance frequencies than at higher ones. -ecause of the

self!reinforcing nature of vibrations with components at the resonantfrequencies, continuous vibrations associated with construction are more worrisomethan the relatively infre"uent! short duration ones caused by blasting. (or morediscussion of resonance and fatigueeffects, see ourpage esonance/(atigue.

*lasting$+elated Standards andStudies

-y far the most commonly

used blastingvibration standard inthe U.S. is the U. S. -ureau ofines, ffice of Surface ining$S% standard,, shown above. twas developed in the early =902'sto address shortcomings of earlier,less stringent standards suggestedby S. The -S. standardis basedlargely on a highly respected studydone by the U#S# *ureau of .ines!+eport of %nvestigations /012(US*. +% /012)and studies

referenced therein. 4s with mostother standards, the S explicitly recogni6es a frequency dependence of damagepotential, with lower frequencies +nown to be more prone to causing damage. any stateand (ederal agencies use this standard for blasting!related vibrations. 4n example of aconstruction vibrationcompliance plotshowing the 0123 limits and the S standard isshown at right. t is worth noting that the vibration depicted there caused additionalvideotaped damage in a home already damaged by construction, even though all thepoints are within the &allowable& regime under the line for this blasting standard.

ifferences *etween US*. +% /012 Safe *lasting 3evels and the -S. Standard

>ote that, in the frequency regime below ?2 @6, two limits are defined in the US*. +%/012 study! on which the -S. standard is based at 1#20 in4sec PPV for &.odern homes!
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rywall interiors& and one at 1#0 in4sec PPV for &-lder homes! plaster on wood lath .The S standard does not explicitly recogni6e the Safe -lasting 7evels of 2.1 in/sec ""#suggested in 0123 for lder homes, plaster on wood lath construction for interior wallsat frequencies below ?2 @65. nstead, it adopts the 0123 recommendation of 2.31 in/secfor odern homes,


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vibration standards must be used for construction and blasting!based vibration standardsfor blasting.Use of inappropriate vibration standards is one of the most commonmistakes made when vibration standards are cited.

5he Swiss Standards

4nother set of ground vibration standardsthat is widely cited worldwide is theSwiss standards $S> 5?2 B=Ca%. Thereare actually three separate &Swissstandards&6 one for blasting! a morerigorous one for pile driving and a stillmore rigorous one for machines andtraffic. The last of these is the one whichis most applicable to road constructionand use, as well as most other forms ofconstruction. 4s with many other

standards, acceptable levels of vibrationin each of these standards are frequencydependent, with less vibration toleratedat frequencies below 52 @6 $@ert6, cyclesper second% and still less below B2 @6.The Swiss standards are not commonlyused,per se%in the U.S., although they are widely cited and influential in ground vibrationdiscussions and research. The Swiss S> 5?2 B=Ca compliance plot at right shows the samevibration in the SD/US- 0123 plot above, caused by dropping a large chun+ $about=/C ton% of concrete on the ground about 5 feet from the seismograph. t can be seen thatthe vibration is above several building type limits of the Swiss standard and of the relatedU. S. (ederal Transit 4dministration standard, discussed )ust below.

Construction and 5raffic Standards

The most relevant U.S. standard in a situation where the state or municipality has no,limited, or inapplicable construction vibration standards is the ederal 5ransit7dministration (57) standard. The ederal 5ransit 7dministration8s Noise andVibration Manual$shown at left% is one of the most widely cited sources for vibrationstandards for road construction and traffic in the U.S. t is well worth reading in detail, asit has a great deal of summary information on vibration, noise and other constructionimpacts, beyond the vibration standard itself. t defines a standard for vibration intransportation!related construction situations, which is quite different from, and

considerably more restrictive than, the S blasting standard. 4t the ris+ of some over!simplification, the (T4 standard can best be characteri6ed as using the four structuralcategories and limits defined in the Swiss machines and traffic standard $quoted fromAhapter =C of the (T4 standard9below%8
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*T+ Vibration ,imits

Building Category PPV

(in/sec)

I. Reinforced-concrete, steel or timber (noplaster) 0.5

II. Engineered concrete and masonry (no

plaster)0.3

III. Non-engineered timber and masonry

buildings0.

I!. "uildings e#tremely susceptible to $ibration

damage0.%

4 typical modern, wood!framed home with drywall$sheetroc+, gypsumboard% interiors and essentially no

prior damage would be considered a Alass building. 4 home significantly damaged by

construction or any historic home should probably be considered as a Alass # structure.*hile this assignment of damaged homes to Alass # might be disputed by some, myexperience is that a road construction vibration of 2.=01 ""# caused specific andtraceable $i.e. videotaped% additional damage to a home previously damaged byconstruction. 4 comparison of these (T4 vibration limits with the vibratory compactorvibration plot above shows that the compaction operation e:ceeded one or more of the57 standards over ,11 times in about an ,/ minute periodin front of a single home.

The (T4 standard differs slightly from the Swiss one in that it applies the high frequency""# limit in the Swiss standard at all frequencies. Thus, this standard is more lenient thanthe Swiss, particularly at the lowest frequencies of most concern for resonant interactionswith the home, but far more confining on construction vibration than the S blastingstandard. Eou can find lin+s to download copies of all these standards on our orenformationpage.

.unicipal! State and ederal Vibration Standards

ndividual state and (ederal government agencies have set various standards foracceptable vibrations in various settings. 4lthough they tend to be derived from oridentical to one or more of the basic standards discussed here, one should survey his ownstate's ew exico, where reside, theonly road construction vibration standard adopted by the >ew exico


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vibration standard is based on the U#S# -S. standard for blasting is to look for "uotedlimits of 1#20 or 1#0 in4sec. f these numbers are quoted, there is a high li+elihood thatthe standard is derived from the S or US- blasting standards. f your city has suchmunicipal standards based on blasting, you should be prepared to challenge theirappropriateness in a construction setting not involving blasting, should that become an

issue.

Vibration Standards S $4merican >ational Standards nstitute%standard, 4>S SC.?3!=992 $a U.S. counterpart of S ?055%, and a draft 4ST $4merican

Society for Testing and aterials% standard, 4ST *I33B=. n the U.S., acceptable pea+particle velocities are quoted in inches per second $in/sec%, while most other worldwidestandards are quoted in metric $S $Systeme nternationale%, IS $eter IilogramSecond%% units of millimeters per second $mm/sec%.

regulations and standards for rock blast

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