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Competent Person Training for Excavations
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GlobeTec CONSTRUCTION
COMPETENT PERSON
TRAINING February 01, 2011
"
o I t
~ ;> < u
What You Will Learn
How to prevent fata I ities.
How to save money~
Identify hazards before ground is
roken. ~oil classification.
- ---.---.~~----,
How to choose a protective system~
What to inspect for.
I,
-
Trench Accident Statistics:
A large % of all excavation fatalities are "would-be" rescuers.
An excavation accident is 15 times more likely to result in death than any other construction accident.
80 % of all deaths occur in < 15ft.
40 % of all deaths occur in < 10ft.
Trench Accident Statistics:
lIver Worker Fatalities Per Yearll
Over Serious Injuries per year - Internal Injuries - Broken Bones - Crushed Legs, Ribs, Ankles - Head Injuries
Multiple Liability Claims - Underground Utilities - Public Injuries I Property Damage
Excavation Mishap yths vvork can be completed and back-filled so fast
that it will not have time to cave-in ..
A rope tied to a worker will help rescuers find them if the trench caves in.1I (it might, but they'll be dead)1I Cave-in victims can be dug out easily with a backhoeOIlIl(true, but the victims are usually
disemboweled or decapitated).
It is possible to out-run a collapsing wall'~
Dirt smells peculiar just before it caves in~ .'
UI
Why do these "accidents" occur? Possible reasons include:
Boss has requested you get down into an unsafe trenchlB You don't want to "rock the boat" or get your boss mad by refusinglE
~ --- -----_ .. __ .. _-------,
It is "wimpy" to be afraid of dirtll This is the 50-called "cowboy-ish" effect. This is closely related to peer pressure to do the job and not worry about the safety aspects.
Not being educated on the hazards of a potential cave-inll
Attempting to save $$ (and time) by not properly sloping or shoring.
.... the Results! I __ mum ----~------- -
Collapse of trench injures worker ficials said.
The $12.9 million renovation of Bernville suffers a broken leg during a school renovation 'project. . From our news staff
A Bernville mansufrered a.bro-ken right leg Tuesday wben a trench collapsed and buried him to his waist during renovations at the PennBernvillet;~ementary Cente in Penn Township:
43, was in satisfac tory condition 'in Lehigh VaHey Hospital. near Allentown, where be was r twn after the collapse about 11 a.m., officials said.
was working with a shov-el in a lo.Coot-
orne leading reasons for trenching accidents:
* Soils heavy from rain * Normally-wet soils d
out, lose the ability to stand on their own
* Proximity to highways, heavy machinery, or back-filled areas
* Lack of safety procedures
* Soft zones * Layered soil * Vibration * Soft pocke * Old utility crossing
trench * Fractured rock
,cavator's Trench Is Not Good Enough An excavation contractor has won a lit-tle leev;ray and yet lost some ground in its efforts to overturn or mitigate safety citations by the Occupational Safety and Health Administration in the U.S. Court of Appeals for the Eight Circuit.
Dakota Underground Inc. was replac-ing a water main in Fargo, N.D., in Au-gust 1997 when an OSHA-compliance officer made an unscheduled inspection. He cited the firm for four violations of the Occupational Safety and Health Act. One was thro"\'.n out by an administrative law judge on review. The three remain-ing citations centered on hazards associ-ated with working in trenches.
Dakota had a crew of four workers and one foreman. OSHA claimed that at least one worker did not have a safe
54 ENR/ FEBRUARY 21, 2000
Appealing before . the " "Elghdl Circuit, Dakota daimed the ladder violation was not willful, that the water violation did not occur and that the three violations should have been "grouped."
The -willfulness of the ladder citation ""'as supported by substantial C'vidence, the appeals court said. Federal regula-tions require that
Rescue Considerations General Guidelines
.Any incident in which a person is trapped, buried or experiencing a medical emergency in a trench or excavation will require the response of the Trench Rescue Team (TRT). -No workers or EMS personnel shall enter an unprotected trench to render patient care or perform disentanglement operations. AU trenches shall be "safe and protected" using approved methods prior to entry by any TRT personnel.
oAIl emergency vehicles shall park at least 100 feet from the collapse site. The only exception shall be the trench rescue trailer which may park no closer than 50 feet.
-All traffic shall be stopped or detoured within 300 feet of the collapse zone. A hazard zone shall be established to control at least 75 feet around the perimeter of the collapse zone. This should be done with fire line tape.
Whatever You Do" .. Don't "Don't go, don't go, don't go in the hole."
Definition - Trench
OSHA defines a trench as " ... a narrow excavation (in relation to its length) made below the surface of the ground. The depth is greater than the width, but the width of a trench (measured at the bottom) is
~~ ,-" .',( - ". "' h 1 fi 11" not greater t an 5 eet ..... ,-"'~,_ ,;, , :.', ."
I
Definition .. Excavation ------- -I
An excavation is defined as any man-made cavity, trench, or depression in the earth surface formed by earth removal.
ffi Therefore, it can be assumed that aU trenches are excavations, but not all . excavations are trenches.
Soil Pressure / i2:ht
Cubic Foot of Soil = approxil -~,~ _Woad
Cubic Yard of Soil = 27 Cubic Feet or
Volkswagen Beetle =
Typical trench wall collapse involves ..... _ ',~' __ ~~_~ of soil.
Workers in trench exposed to anywhere from :- . ~ u. __ .~_ during a typical
trench cave .... in!
'" t
\ "II-...... ~ D.. .... Q aD ~
"'"\ &.!"i N
,....
rough approximation: Pv=rh, P v 2 Ph
@ 1998, Alan J. Scott
~ 100 lb/ft3
Vejrtieal Soil Pressure = 500 Ib/ft2. horizontal pre s sure .... 250 lb/ft.2 but only on one side ere ating mftability
Is this a safe situation? Notice the huge tension cracks developing in the soil behind the worker. Why is the worker putting themselves into harms way? There is 110 sloping or retaining structure for the soil behind the worker.
SHA Standaras
Designed to protect workers in trenches.
If accurately complied with most fatalities would be eliminated[l Injuries significantly reduced.
Prevention of liability claims and ~ lawsuits involving underground utilities, homeowners, and members of the publicI!
Excavations - Subpart P ---------------------
1926 650 Scope, Application, and Definitions 192611651 Specific Excavation Requiremen 192611652 Requirements for Protective Systems Appendix A Soil Classification Appendix B Sloping and Benching Appendix C Timber Shoring for Trenches Appendix D Aluminum Hydraulic Shoring Appendix E Alternatives to Timber Shori'ng Appendix f Selection of Protective Systems
cope, Application, Definitions _ ____________ _ ____ __ n __ ~
- This subpart applies to all open excavations made in the earth's surface.. Excavations are defined to include trencheslB (Any time soil is removed from the ground.)
Ke}, Definition - Competent person - One who is capable of identifying existing and
predictable hazards in the surroundings, or-working conditions which are unsanitary, hazardous, or dangerous to employees, acndi;who has authorization to take prompt correcti'vE! measures to eliminate them.
I
What Makes you an Excavation Competent Person?
You MUSThave specific training in and be
knowledgeabl~ about: c~ ffi Soil Typing & analysis
ffi The different kinds of protective systems & their proper use
ffi Hazard recogn.i,t'~Q:I1L' ~ When a regi~~f.4 ... ,
P.E. is requiri;d:'::~.: ;::,:,;.' ~ Knowledge ot:~cc
Subpart P
n
U) e o cu o.
g. ~ .5 U) CU -C fa ._
.e e ...., __ ...., fa fa I-
e .e U) ...., U)
CU 8
Potential for Cave-in?
Slope Design Based On Soil Type
Appendices A & B
Tabulated Data
Design By A Registered Professional Engineer
Excavation> 5 Feet?
Excavation> 20 Feet?
Soil Type Detennined? Slope L5H: IV
Shoring Or Shielding
Timber Shoring v Appendices A& C
Hydraulic Shoring Appendices A & D
Shields, Jacks Appendices A & E
n
Specific Requirements
~urface Encumbrances
Underground Installations
Access & Egress vehicular Traffic Falling Loads Mobile equipment
Hazardous Atmospher
Water ccumulation
Adjacent tructures
Loose Rock Inspections Fall Protecti
pecific Requirements
- All which create a hazard to employees removed or supported as necessary to safeguard employees. Examples include trees, rocks, telephone poles, signs, tanks, sidewalks, etc II
pecific Requirements
- Estimate location of all utilities and underground installations prior to opening an excavation. '
- Safe means used when nea ri n9 identified utilities in excavation.
- Underground installations protected, supported or removed as necessary to safeguard employees working in the excavation.
BEFORE CALL YOU DIG!
- Notify facility owners through PA One Call System at least 3, but no more than 10 days prior to start of excavationm;
I!II i!i!!
I I ust request info at least 10 but no more
that 90 working days before final design.s iii
- Required to be a member of PA One Call System !I
I
I-I .....
I ..
u
CALL BEFORE YOU DIG!
COLOR CODE fORMAAKING
UNDERGROUND UnUTV 'l..i"~v'
COMMUNICATfON CATV
WATER
SEWER
TEMPORARY SURVEY MARKINGS PROPOSED EXCAVATION
ALLOTM.R A~ 1~ ... aa2ii232 NEW dERSEY ONE CALL
TYPICAL CODES FORMARKOUT
Ga$,a~SfMm, ~~4Jr Ga~~1s
WHITE.
~ &tawmn
I u~ Potential Liability Costs
,
l.npper Trunk Lines: Lost revenue can run aDDroximately $2S,Ouu per minute.
I-iber Optic Lines: Lost revenue can run as much as
,000 to $100,Ouu per inutell
Pioneer Press, Saturday, December 12, 1998 Tide - St. Cloud gas main explosion kills four
Specific Requirements
Underground installations protected, supported or removed as necessary to safeguard employees working in the excavation.
Overhead Line CI rance
For lines rated 50 kVtl or below, minimum clearance between the lines and any part of the equipment or loa shall be 20 feetll
For lines rated over 50 kVllt 20 feet plus 4 inches for each 10 kVII over 50 kV.
A person shall be designated to observe clearance when operator's view is obstructed.
H'.I> ...... ~ltaBe.L"",D DlimI1D . ~ .. .:.,e :mJM rOlWer
-]
s cific ts equlrem
- Structural ramps designed by competent personm
-- Ramps and runways of uniform thickness and connected to prevent movementll
- Ramps cleated to prevent slipping on top. - Cleats used to connect runway members,
attached to bottom.
Stairway, ladder, or ramp provided in a'll. excavations over 4 feet deep, no more than 25 feet of lateral travel ..
Specific Reauirements
arning vests worn by all employees exposed to traffic~
- No employees allowed under loads lifted by digging or lifting equipment, or near vehicles being loaded.
- Barricades, stop logs, or signals used when mobile equipment operated near edge of excavation ..
Specific equlrements
- Test excavations over 4 feet deep if located where problems could reasonably be expected .. (Oxy .. < 191150/0 or > 230/0 )
- Provide adequate ventilation"
- Control flammables 20% of lEL) - Emergency rescue equipment available~
- Deep and confined excavations entered 11'1 0 full-body harness and lifeline, attended>at all timesli
Hazardous tmos s
+ THE PHILADELPHIA INQUIRER . 9/11/02 www.philly.com Suburbs C 15
er INQ~E=~~~'TER. . .11.lltJ~n~~W:~I~~'~= ~~~;!!:O~~~t~,r::~s=
A Philadelphia man who, was 'rum'consCibus with oxygen until . unidentified firefighter. They sealing the foundation of anew firefighters were able to haul and several other emergency home in central Bucks County the men out of, the .+by-8-foot workers underwent decontami.-died' yesterday when fumes ditcb with harnesses. nation as a precaution, hospital from a . waterproofing com- The victims'names were not spokeswoman Karen McCurdy 'pound overcame him. ' released. said.
. The 36-~arold victim may Theaccid.entoccurred . Rub--R-Wall, composed of hy-have been using the substance around noon along Creek Road drocarbon polymers and sol-without proper ventilation, New in New Britain, where the foun- vents, is only hazardous in liq-Britain Township Police Chief. dation of a single-family home uidform, McCurdy saieJ .. "Once Robert Scafidi said. Federal oe- had been recently poured. ;;m~ it hardens, it is ba.sitally in~rt."
~;::e~=~_ ~~~S~ said.
New Britain Police Officers ShaWn Knight and Robert
A compliance officer for the Occupational Safety and Health Administration was at the scene investigating, said George Tom-chick, regional OSHA director in Allentown .
~cUUs at Rubber Polymner Corp., of Akron, Ohio, which makes Rub-R-Wall, were not available for comment. The workers' employer, Dale Wa1ter-proofing Systems . of Doyles-toWn, did not return a. callse!ek-ing comment.
Contact LNry King at 215-345-0446 or [email protected].
--
J
5vecific Requirements
- No work in excavations with accumulated water unless adequately protected by water removal, special support or shield systems, or harness and lifeline ..
-- Water removal equipment monitored by competent person.
-- Natural flows prevented from enteringll
pecific Requirements
- Protected with shoring, bracing, or underpinning.
- May require PE design.
- Sidewalks, pavement, not undermined unless supported to protect employees from collapse.
-------,------------------_ .. _--------,
Specific Requirements --_.- ---- .. -... --... -.. ------1
- Scale to remove loose material~
- Barricades to stop falling materials ..
- Spoil pile and other materials kept back 2 feet from edge of excavation, orwlth retaining devices!!
pecific Requirements
inspections made by competent person. Document!
- Inspections required after rainstorm or other hazards.
- Anytime conditions change.
- Employees removed until hazard corrected II
INSPECTING FOR?
lIossible cave-ins
Protection system failures
Hazardous atmosphere
Falling objecc Any other
hazards
ecific Requirements
- Walkways or bridges provided over excavations. (6 feet) Standard guardrails are requiredli
- Wells, pits, shafts must be barricaded, covered, or backfilledll
- (From Subpart M-Fall Protection) Guardrails systems, fences or barricades required when excavation is not readily visible due to plant growth or other visual barrier.
Soil Classification Reauired When:
Slope of excavation greater than 1 1/2: 1 or 34 aegrees.
Benching is used in the excavationl! Timber Shoring is used. Aluminum Hydraulic Shorina is used. Alternatives to Timber Shorina are used.
If you assume worst case scenario -C Soil - No Classification Require
=:J
Apuendix A - Soil Classification ==:J
Unconfined Compressive Strength ... Load per unit area at which a soil will fail in compressionml Determined by laboratory testing or estimated by use of a pocket penetrometer, thumb penetration, and other tes.~11
Basis of Soil Classification - Classification based on at least m I and at least analysis, conducted by a competent person using tests described in Appendix A, Sec:tion\(d) ... Acceptable visual and manual tests~
ndix A .. Soil Classification
us III ............
Stable Rock ... natural solid mineral matter that can be excavated with vertical sides and remain intactll
Type A - cohesive soil with unconfined compressive strength of 1115 tons per square footlJ - Never type A if:
Fissured or previously disturbed. Subject to vibration from traffic, pile driving, etc. Part of a sloped, layered system where laye"l'"s di>p
into excavation on a slope of 4H:1V or greaterll Subject to other factors making it unstablea
Appendix - Soil Classification Type B .. cohesive soil with unconfined compressive strength greater than 0115 tsf but less than 195 tsf~ - ...... ranular soils and crushed rockBi - Previously disturbed soils, except those classified
as type C - Soil that meets compressive strength for Type
Soil but is fissured or subject to vibration.
Type C ... cohesive soils with unconfined compressive strength of 0 .. 5 tsf or lessB -- .. -ranular soils including gravel and sandlm -- Submerged soils or soils where water is freely. .-seeping ..
- Submerged rock that is not stablell
ppendix A - Soil Classification
CL.
SOLID ROCK
CL. -A
CLASS-B
CLASS-C
COMPRESSIVE STRENGlH
A NO VIBRATION,
> 1.5 TSF FISSURES OR LAYE
> 0.5 but < 1.5 TSF ".
~
I ...
HOW TO TELL
VISUAL GRAIN SIZE CLUMPING TENSION CRACKS LAYERING WATER VIBRATION
MANUAL PLASTICITY TEST DRY STRENGTH
TEST THUMB
PENETRATION DRYING TEST
" .
PEN ETROM Et:I!"R>':;~',. : ~-: .C~ ,,,, ':f-. ':/
"-
Appendix A - Soil Classification 1:-1
Visual Tests - Excavation site in general, adjacent soil, sides of open
excavation, samples of soil taken from excavated material. - Particle size indicates cohesive or granular soil. - Soil that clumps is cohesive, granular soils break up. - Cracked sides of excavation and spalling of materials off
excavation wall indicates fissured soil. - Look for existing utilities and other structures which indicate
previously disturbed soils. - Observe layered systems and estimate slope. (4H:1Vl,,," .... - Look for surface water, water seeping from excavatid"~~ahii"'
location of level of water table. - Look for sources of vibration - traffiC, pile driving~"~~,
boring etc.
endi oil Classification anual -.-ests
- - - I
I
- Dry Strength ... Crumbles with minor pressure if it is granular soila If broken with great difficulty it is unfissured soilll
e I i - Drying Test
Cracking indicates fissured soil Difficulty breaking indicates cohesive soil Easily pulverized indicates granular soil
I
PLASTICITY TEST
ROLLA "WORM"- 2" x 1/8"
IFITDOES NOTI NON-COHESIVE I
WORK TYPE B OR C
IF IT WORKS COHESIVE A, B, or C,
ppendix A - Soil Classification
Plasticitv (or ribbon test) i
" I .,
- The cylinder is then placed across the palm of the hand and squeezed between the thumb and index finger until it is approximately 1/8 inch thick.
I
ciaYI! - The longer the ribbon the more clay, the shorter the ribbon
the more silt (or sand) contentm
==:J
TR T .------:------~~----~---~~--------- .. -.-
SOIL CRUMBLES ON
ITS OWN
HARD TO BREAK INTO
CLUM
IT IS G ULAR TYPEBORC
UNFISSURED TYPE A
LARGE CLUMPS ARE BETTE
'-
-
Appendix A - Soil Classification [--=:==1
Dry Strength Test - Dry soil that crumbles freely or with
moderate pressure into individual grains is granular.
- Dry soil that falls into clumps that subsequently break into smaller clumps (and the smaller clumps can be broken only with difficulty) is probably clay in combination with gravel, sand, or silt.
- If the soil breaks into clumps that do not, ---break into smaller clumps (and the soil (2~A;~~' be broken only with difficulty), the soil.i~t~S'" considered unfissured unless there is vi:$uar::,~:" indication of fissuring.
Appendi .. Soil Classification ------- -------J
trength Test (cont.) Drying a sample of soil that is approximately one inch thick and six inches in diameter until it is thoroughly dry. If the sample develops cracks as it dries, significant fissures are indicatedll Samples that dry without cracking are to be broken by hand. If considerable force is necessary to break a sample, the soil has significant cohesive material content.. The soil can be classified as an unfi;ssured cohesive material and the unconfined com'presslve . strength should be determinedll
Appendix A - Soil Classification . . n__ .,
Strenath Test (cont.) If a sample breaks easily by hand, it is either a fissured cohesive material or a granular materialll To distinguish between the two, pulverize the dried clumps of the sample by hand or by stepping on them .. If the clumps do not pulverize easily, the material is cohesive with fissuresfi If they pulverize easily into very small fragments, the material is
granular~
THUMB PENETRATI ~
(UNCONFINED COMPRESSIVE STRENGTH)
PAST THE TYPE C KNUCKIJE < 0.5 TSF
-
TO THE TYPEB UCKIJE > 0.5 & < 1.5 TSF
JUST AN DENT I TYPE A > 1.5 TSF
ppendix A - Soil Classification
Thumb Penetration Test ..
I i II i
/IU
- If the thumb makes an indentation in the soil only with great effort, the soil is probably Type ArA
III!
- - TE: This is a very subjective test and has a large degree of inaccuracYIi
I '" I
DRYING TEST 1-
DRY A 1" x 6" DIAMETER SAMPLE
CRACKS AS IT DRIE
HARD TO BREAK
EASY TO BREAK
FISSURES TYPEB ORC
UNFISSURE COHESIVE TYPE A
COHESIVE WITH~~ FISSURES OR GRANULAR
TYPEBORC
Two Widely Used Field Tests
Pocket Penetrometer "" Measures the unconfined compressive strength. Note: These instruments have an error rate of +30%.
Shearvane (or Torvane) -Measures the cohesion. They consist of vanes that are pressed into a level section of undisturbed soil, and the torsional knob is slowly turned until soil failure occurs. These measurements need to be multiplied by 2 to give unconfined compressive strength. Careful attention is needed in
U".UH~ the dial measurement.
Requirements for Protective stems
Employees in excavations must be protected from cave-ins by an adequate protective system except when:
- Excavation made entirely in stable rock~ - Excavation less than 5 feet deep and
examination by competent person indicates no potential for cave-insli
Protective systems designed to resist, with:gut . failure, all potential loads applied to or transmitted to the systemll Excess loadsmiay . include spoil piles, equipment, vehicular traffic, cranes, etc.
____ J
Requirements for Protective Systems
., Manufactured materials used per manufacturer's recommendationsil
Materials and equipment used for system free from damage or defects.
1Jamaged equipment inspected by competent person or registered professional engineere
Members of support systems secured together to prevent sliding, falling, kick outs, or other failuresl5
Removed from bottom of excavation firstlm Backfilling progresses with removal of
members.
~
Protective Systems
~nil Classification SloDina & Benchina ( Timber Shoring ( Aluminum Shorina ( Alternatives Systems ( ~elect the System (
- Selection of Protective Sv~tprn~
---......,. -1 ~~AA ... IIIOJ' ....
Common sense approach to selecting the proper protective system for working in any excavationa; Only for excavations 20 feet or less in depths; If over 20 feet deep, be designed by a registered professional engineer. Makes the excavation standard easy to follow and use.
Should be the first step taken when planning,a-n excavation.
Excavation> 5 Feet?
B V ' , r Potential for Cave-in? I Excavation> 20 Feet? f I t, J I 11
r I~~" I ' "t"
Yes ~ I '-', I + ~ "! 4-, " I Soil Type Detennined? .,,' f: .. Slope "0 ~. 1.5H: IV =
I ~fcs I 1 I ,j, I I Vertical Sides ~ 1iv I ' I Yes Solid Rock? I Shoring Or Shielding Sloping , I I: f" 1 Nfl f; ... , ','" ---~ l I
Slope Design Based .. Timber,Slloring v
On Soil Type AppendicesA & c Appendices A & B
--. Hydraulic Shoring Tabulated Data
Appendices A & D '". ___ -~-,-. -~-.'P'""
'...,
... 4- Shields, Jacks Appendices A & E
Design By A Registered -",.
Professional Engineer ... .... - -------------------- .
Tabulated Dat ~----~----~~------------------~--~--~------~~--~.~
Identification of parameters that affected the selecti
Identification of the limits of use of the data
Explanatory informatio
(Sloping & Benching Options) Design of sloping and benching systems in accordance with 1 of 4 options below:
_____ - - Sloped 11/2 horizontal to 1 vertical (34 degrees)
----- .. Determination of slopes using appendices A & B
I n - Designs using other tabulated data Kept in written form at site during
construction Specifies all parameters and limi
~~- Design by a registered professional !II
engineer
dix - Sloping and Benching
Refer to Appendix B illustrations for allowable slopes and benches for Types A, 8, land C soilsm
Benches allowed only in Types A and Type B Cohesive soils.
Support or shield systems can be used in conjunction with slopingll - Slope above support or shield must begin 18
inches below the top of the support or shield system.
Layered soils can be sloped separately for e~:. type of soil, unless less stable soil is on t_ bottom layerll If less stable on bottom -centire . slope must meet less stable soil sloping
ill
requlremen'l.~~
=:=J
aximum Allowable Slopes
Stable Rock Vertical 90
Type A Soil 3/4 : 1 53
Type B Soil 1 : 1 45
Type C Soil 1.5 : 1 34
Sloping Requirements for Layered Soils
Slope Required For Each Soil Layer --"------------------,."."---'"-,.,"'---,-,--"' ,,-""'""" ----,--,--,,----- -------------- --------- -_. ---- ---- ---, , ""' -'--~--"-------,,-,-_.,".,,_.,--,---"----., ------ - --.'----"---
ayered Soil Type Type A Layer Type B Layer Type C Layer B over A C over A C overB
1------------
A over B ~-,-,-"'-".,-,.--.. ---,,-,.,.
A over C 1---------- ---------------- -------
B over C
. . ... _ ... -" -._" .----- _ .... _------,--,. ------- --------"._----,--.. ---
3/4:1 1:1 ----------- -- ---~------ ,-- ,--_. -----------------" .. _,.-------"'------ ---_.,""-"""--,.,,--
3/4:1
1:1 1-1/2: 1
1:1 .. _----_. -,.,.,------------".
1:1
1-1/2:1
1-1/2: 1 1-1/2: 1
o en
c
c o
.....
.........,
CO > CO U >< CD (J.) CD a. 0..0 0-_ CJ) en CD
......
0.. E
(f)
.......
x ro E ro
..c ......., ......
~ o (J)
c c o
.......,
ro > CO t) >< (l) "O'+-~ 0 u Q.) c c.. Q.) 0 caU5
Soil Slo lng
riPE ,{" SOIL Simple Bench El:(:,,,,,'.ation
'" T' /l ~ ./ '\,. " -\. I
20' M~xjm'Jm "....L. ~ ,L11 I ';\U/ 314
L 4' r,,'l~x"
TYPE .0. SOI!_ d d f shlelde suPPort~d .~ !c ...... ei porUc.n VeIticallY:51 e
1." ~ s: -.port or r."ifi~d.....?1 , ~ijl' Syr.!~m LJ ~- 3/4 20' M~ximlJm '- I.. I
liS" Mi~"
,r-
riPE ,{" SOIL Un:;:IJpport.ed '.'ert.ically sided !O\';!?f ~II::.rtion
r ... hximum 12 Feet. in depth
~1
L ~~ 112 M~x"
TYPE A SOIL Simple Slope -- Short. Term
1\ I 12' ~,Ibximum \\ / A I ,I .LJl \,--_1 1.'2
Benchin
TYPE ,{" SOIL UnsupportE>d 'Jertic:ally sided 10'.1er portion
Mal:imlJm :3 Feet in depth
: : LJ1 .
8' f\1:."Jxim IJrn 314
, E {"SOIL " T r'P 'h E .. .-:.a"f'
o (/)
c c o
......
.......,
CO > CO U ><
OJ aa-..c 0 o (J) c ~ Q.) ~ ..c CD
.........
c.. ........ .......,
::J ~
il lopin B nchin r-. ------.- ---------------
20' .
TliFIE B ~:;IJIL r\l1ultiple Bench E:~(:.:.lm'.:tt.icl
[F-ermitted in (:ohesi1m1e s~)il clnly]
.'" .. -
:j :.: I IT. IJ ITI
"."
mtf'l f""
. '
rLJ.I' 0" .. . . ' .' . ,,/ 1 . 1
41 rlll~:I:)
r .... PEBsOIL Sin':lIJ? BJ?nch E:-:c-a'.'-ation
141 'I A '" s".-J"'. TYPE 8 SOIL
Supported of shielded Verticall~ sided lower portion
J'm .
T .... ' [Permifted in cohesive sClil onl~] ~ ............ // ....... .,/ , /
..., -' .. ,. " / ",I) ,,- :Jxlm'Jm ...... ..' /]
-r~" r---~ / ''\-. SIlPPOit or :::t.i
Excavation in layered soil The layer of soil is sloped at 1- _, while the layer of soil is sloped at ___ . "'_
Excavation in layered soil where Tvpe A soil tO~$c ' Type C soil. Both theTvee A and Type C soils lfr the excavation must be sloped at 1-112: 1.
(Shoring & Shielding Options)
Design of support systems, shield systems, and other protective systems using 1 of 4 options below:
, __ , ___ - Designs using appendices A, C, and D ~~- Designs using manufacturers
tabulated data __ -,~ ~ - Designs using other tabulated data ~~_- Design by a registered professional,
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engineer
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E}(C4 ~4 TIO,,'" & TRE1VCHING DECISIONFLOfV CHART (Appendix F) Excavation> 5 Feet?
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Applies when timber shoring is used in trenches less than 20 feet deepil Proper soil classification must be determined first~ Tables are provided for different scenarios: - Tables for each soil tvpem - Depth of trench given in intervalsmm - Horizontal and vertical spacing requiremen
given for cross braces, wales, and uprigh~~iI - Based on depth and width of trench. - Gives strength requirements for timbers,usedJn
system~ - Provides required dimensions for timbers
be usedll
~
TIMBER SHORING I
TIMBER SHORING MUST BE PROPERLY DESIGNED USING TABLE DATA (APPENDICES A, C, OR OTHER TABLE DATA),'''OR A PROFESSIONAL ENGINEER
TABLE DATA (NOT FROM APPENDICES A OR C) OR PE SPECS. MUST BE KEPT ON SITE
MANUFACTURED SHORING MUST FOLLOW ,-~--;}'- '.'.-'
MFG. SPECIFICATION
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Timber shoring in a trench approximately:
13 feet deep and 5 feet wide. " Type B soil.
Using OSHA specs described in Appendix C: Table C-1.2
6 x 6 oak cross braces 6 feet horizontally 5 feet vertically
8 x 8 wales 5 feet vertically
2 x 6 uprights It 2 feet horizontally
- Aluminum Hydraulic Shorini! for Trenches
-~
Applies when aluminum hydraulic shoring is used in trenches less than 2 feet deep_
., le'roper soil classification must be completed.
Provides tables for various soil types: -- -ased on soil type, depth, and width
f trenchll -- -rovides required horizontal an
vertical spacing. -- -rovides minimum diameters for
hydraulic cylindersli
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Vertical aluminum hydraulic shoring (w/plywood):
" 18 feet deep, 13 feet wide Type B soil 3 inch cylinders
Appendix D, Table 0-1.2 The vertical shores and 3 inch diameter cylinders are placed 5.5 feet o.c. horizontally and 4 feet D.C. vertically.
Plywood (not structural) is used behind the shores only to prevent local raveling between shores.
Exercise 3
luminum Hydraulic Shorin Waler System
(Typical) 13 Feet Deep ~ Feet Wide TYDe B Soil 2" Cvlinders availabl
----1
A horizontal aluminum hydraulic waler system
-13 feet deep 6 feet wide Type B soil 2 inch cylinders
Appendix 0, Table 0-1.3
Cylinders are spaced at 6 feet o.c. horizontally.
Wales are spaced 4 feet o.c. vertically (3 rows required) 3" x 12" solid' timber sheeting is used. Spaced 2' o.c.
Excavation> 5 Feet? I
, 1 I l .. ,
Potential for I Excavation> 20 Feet? i' J"O." !". Cave-in? ~ I H : fi c. . ....... [
I No I I No I Yes r + -l Slo~e I I Soil Type Determined? No 1.5H. IV . T
""""" ,o} $iL- .. ",'T_ __ ''cw'",;". ______ ""'~$ _. ~ I Yes I ~, ~ I Vertical Sides ~. ,. IV Solid Rock? I I cs
I Shoring Or Shielding ; Sloping I .. l .. LNo H ". _ ... '{., ... -4." . ".L ... .-.. ~ ... -.~ ...... " ,
Slope Design Based L Timber Shoring On Soil Type Appendices A & C
..
Appendices A & B 4 Hydraulic Shoring __ .. ,T_. __ ~_ , '","',"., ___ ,~ ___ , " . - ~ . =~"
Appendices A & D 1 Tabulated Data ,
; ...
Shields, Jacks --....
"'_" ,-_,_ .... ,. .r, Appendices A & E
Design By A Registered Professional Engineer 1_
L.. __ ~_~._~~~ __ ~~ .. __ ~_" _______ __
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TRENCH SHIELDS .I/tJ!!Jjj[eTREN~:~':Ji~~:::r::r;TU~ER'S
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C~W8~J MAXIMUMDEPTH TABLe $56PS~ SHIELD CAPACITY MODEL-NO. SOIL riPlt EFP: IotAXfMlllotDl!l'Tll(l'T)
9~~ SERIAL NO.
J 0$/07{9a OATEsHIPPt:b
A B
C
C
"~.POR.USE"T~TEDpA'rAt 1~:orhk.T""'~lIMbMn~'lI'Ia~protec.. ,--~-li!I~.to'OblnplfWllh_OSHA:"""2I CfR~f_.~f"; .
25 45
60
80
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019117 Glt.woIdMttcNnt &~ ~
H.I 39';1d
42' 25' 20'
16'
1-'--'1i~ MAX SPREADER LENGTH
S" SCH80 SPREADER SlZg
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3~~~ .. ~"" ..... beWOh~lOW1d cordIIi'on. TrM:hatfddhbiKId"~1itIbt1Dddtliilafor..nr
da~lV':~'.iut."haci~""'Jat~"ma!ie ar~~oI.~~OT~'tM T.~DitaJl.vvtfuntI~"'fh.de"~.b)'.fCl~d pt'olesslonil'......,.. .
4.,Yh6U.otGM&'TIWdt~""'be~.~,llIiIbfil~1ed ddiI_lIIII!~ofb!OStfA~,Mtti:ft.IStftIdIlQ .. GItIer 1h"'~or:~mayabtll.~~:aMC.-*,~" eav""ii.:iIrUcIUt&~;~~~"'ilcW!Wnolr\fQyoreven .... :'OME.,..not\Ie ...... ror1liMkfuNg.lflflW~~
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TRENCH BOXES MUST BE USED ACCORDING TO THE MANUFACTURER'S SPECIFICATIONS, OR A PROFESSIONAL ENGINEER
SPECIFICATIONS MUST BE KEPT ON SITE
Requirements for Protective Systems
Excavation not permitted to mor than 2 feet bel bottom of members of a suppo systelB.R
Extend at least>I'8(~f aDove top of.cut~
~
Requirements for Protective Systems -------- J
Shield systems not overloaded beyond design criteria.
Must be maintained.
Requirements for Protective Systems ~
~hielas installed t not permit movement in the event of sudden lateral loaas.
Requirements for Protective Systems .=:J
'--------------'--'--------'-------'-----'-_.
Employees protected when entering or exiting shieldll
Employees not permitted inside shields when being installed, removed, or moved v~ttiall.YII
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AGoo ExamDle of an r ngln c 1, .n~;_-n crPl ~ ~ UII:VI..I.II.EiCI IUII: ~
ffi Conventional sloping wouldn't work because of adjacent buildings & road that had to remai'l1 ~ Existing utilities were located and supported' ~ PeE. shoring plan followed exactly
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n Excellent amDle of all eets o:f .~
ffi Good example of shoring flagging ffi Good guardrail system around upper perimeter ffi Good impalement protection at lower grade
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amples of Barrier Protection
~ Barricades or equivalent around excavati.onsc .... to keep employees from falling in
ffi Similar measures to be taken to keep vehicles or equipment from going into excavation
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A good bottom-line philosophy on excavation safety: E --c-. - l
It is very risky to cut corners on excavation safety. One accident and there will be law suits, fines, penalties (possible prison time) not to mention personal grief and trauma of losing a co-worker or getting one seriously injured.
One accident can put you out of business. For the long-term financial and emotional health of your business and co-workers, it is best to follow safety regulations.
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SKMBT_C35112030819260Di4701203081736Di4701203081756