WA9801-SP 9905171.0 DESIGN ASSUMPTIONS
1.1 General. These specifications cover the basic requirements for shoring and/or sloping of
excavations for installation of Water Line for the SH 121 Project, Coppell, Texas.
1.2 This specification addresses the safety of workers in a trench excavation
and does not, in any way relieve the Contractor of his responsibility and
liability to ensure the safety of the project and workers.
1.3 It is not the intent of these specifications to specify every detail and procedure of the
trenching/shoring operations; nevertheless, they shall conform to the high standards of
engineering and of safe trench excavation.
1.4 The personnel protection systems shown in these specifications have been designed
1.5 The personnel protection systems shown in these specifications have been designed
bssed on an assumed subsurface of Type A & B Soils. In accordance with Revised
OSHA (effective March 2,1990), prior to be~nnin8 consmsction, The conlnctor's
"Competent Person' will conduct the required Soil Classification Tests. If soils other
than those identified are found, this specification will be revised. During construction,
the contractor's "Competent Person" will monitor the soil classification as required by
OSHA 1926.
1.6 Conusotor shall be responsible for selecting appropriate safety system option shown in
these specifications depending on trench depth and soil conditions.
1.7 The protection of existing stoictares and utilities which may be affected by these trench
excavations is beyond the scope of this report.
1.8 The Contractor must identify a "Competent Person" in the Contractors firm responsible
for performing inspections of the excavations to ensure that expected subsurface
conditions are present. If conditions in the field vary from the expected conditions, the
design engineer shall be contacted, for possible design modifications prior to personnel
entering the excavation. Note -This person must be "Competent" as described in OSHA
1926.650 (b).
1.9 It is the Contractors responsibility to ensure that all excavation work and site conditions
are within the regulations as established by O.S.H.A. Any property damage or bodily
injury (includinS deslh) arising from the use of these specifications, from Contractor's
negligence in performance of contract work, or from Owners failure to note exceptions
to these specifications shall remain the sole responsibility and liability of the contracto
2.0 DEFINITIONS 2.1 All definitiolls of section 1926.653 of Sublxtn P, Part 1926, of the Code of
Federal Rogulations shah be by reference an integral part of this section.
2.2 "Sealing Engineer" - The engineer whose Texas seal is affixed to these
specifications.
23 "The Contractor" - The contractor responsible to the owner for the
excavation work described herein.
2.4 "Competent" as described in OSHA 1926.650 (b).
3.0 APPHCABLE CODES AND STANDARDS
3.1 The Contractor shall perform all shoring work under this contract in
accordance with all applicable codes and standard safety requirements
and regulations including:
3.1.10SHA 2207, Construction Indusuy Standards(Izn 1926
Occupational Safety and Health Standards)
3.1.2 AISC Code of Standard Practice
3.1.3 AISC Specification of the design, fabrication, and
erection of steel buildings.
3.1.4 AITC Timber Construetion Manual
3.1.5 AWS D 1.1 SUuctuml Welding Code
3.1.6 The Uniform Building Code
3.1.70SHA 2226
3.2 The lalest edition (including supplements and revisions) of the above
publications in effect or promulgated at the time of the bid shall apply.
Equipment fabricated to codes and standards in effect at tim of bid but later
revised shall be acceptable provided such revisions are not required by law.
4.0 SHORING/SLOPING REQUIREMENTS
4.1 Description. This section covers the technical requirements of the
trenching/shoring work.
4.2 Existing Structures. Where existing buildings, other utilities, streets,
highways, or other structures are in close proximity to the trench, or my
otherwise be affected by the proposed trenching operation, the Contractor
shall provide adequate protection by the use of sheeting and shoring to
protect the structure, street, or highway from possible damage. In the case of
utilities, the Contractor may elect to remove the utility provided that the
removal and subsequent replacement meets with the approval of the
engineer, the utih'ty owner, or whoever has jurisdiction of the structure. In all
cases, it shall be the responsibility of the Contractor to protect public and private
property and any person or persons who might, as a result of the Contractors
work be injured.
4
4.0 SHORING/SLOPING REQUIREMENTS Cont'd.
4.3 General Trenching and Shoring Requirements. The contractor shall be solely
responsible for trench safety provisions meeting the applicable requirements of
the United States DetmrUnent of Labor Occupational Safety and Health
Administration including subpart P, Part 1926 of the Code of Federal
Regulations. All trenching operations and procedure shall also conform to the
requirements listed in this specification.
4.3.1 The requirements of sections 1926.50 and 1926.651 of Subpart P, Part
1926, ofthe Code of Federal Regulations shall be by reference an integral
part of this section.
4.4 Requirements Prior to Excavation Activities.
4.4.1 Known underground installations are shown on the site plans. It is the
Contnctoes responsroility to verify exact locations in the field.
4.4.2 Before any individual enmts an excavation, the excavation
will be irapeered by a "Competent Person" to ensure that
trench excavation has been performed according to this
specification and O.S.H.A. requirements and to ensure that
no anomalies ire observed which my effect the safety of
the trench or project Note -This person must be
"Competent" as described in OSHA 1926.65(1>).
4.5 Requirements During Excavation Activities.
4.5.1 During excavation, the exact location of existing underground
installations shall be determined by the Contractor, and when uncovered,
proper precautions and supports shall be provided so as not to cause a
hazard to the workmen or project.
4.5.2 Daily inspections of the excavations shall be made by the Contractor's
"Competent Person". If there is evidence of possible cave-ins or slides, all
work in the excavation shall cease until the necessary precautions have
been mken to ensure the safety of the wotkmen and the trench.
Note -This person must be "Competent" as described in
OSHA 1926.650 (b).
4.5.3 Excavations shall be inspected aria every rainstorm or other hazard-
increasing occurrence to ensure the safety of the workmen and the trench.
5
4.0 SHORING/SLOPING REQIREMENTS Cont'd.
4.5.4 Excavated material shall be stockpiled a distance away from the trench, so as not
to affect the trench stability. The contractor's construction means and methods
will determine the distance. As a minimum to protect the work-men from falling
debris, the toe of the stockpiled soil shall be no closer than two (2) feet from the
edge of the excavation.
4.5.5 All precautions must be made to prevent surface water from entering the trench
excavation Adequate drainage must be provided in the area adjacent to the
excavation.
4.5.Operation of heavy equipment adjacent to the edge of the trench may cause
instability. The Contractor is responsible for the means and methods of
excavation, and therefore, for loads imposed on the trench excavation and shoring
4.5.7 The Contractor must take precautions to protect the face of the excavation from
exposure to freezing.
4.5.8 Water shall not be permitted to stand in tlie bottom ofthe trench and suction
pumps of adequate capacity shall be installed to ensure that such standing water
is removed.
4.5.9 The Contractor shall provide a positive means of ensuring that hydrostatic
pressure does not build up behind the shoring or shields.
4.5.10 If a condition requiting the use of a different method of shoring is encotmtered,
this specification will be revised.
4,5.11 Remove shoring units from bottom to top as backfilling proceeds.
4.5.12 When backfill is within five (5) feet of the top of the trench, all shoring may be
retnoved, unless the trench conditions indicate a hazard.
4.5.13 No person shall be exposed to the lower portion of the trench after shoring has
been removed.
4.5.14 Additional shoring or larger sizes my be installed.
4.5.15 Ladden or other adequate means of exit must be provided and located so as to
require no more than 25 feet of lateral travel.
6
4.0 SHORING/SLOPING REQUIREMENTS
4.5.16 When two trenches intersect, both trenches must be protected to a distance
of not less than the depth of the deepest trench.
4.6 Shoring Alternatives for this Work
4.6.1Trenches more than 5 feet deep shah be shored, laid back to a
stable slope, or some other equivalent means of lxotecflon shall
be provided where employees my be exposed to moving ground or cave-
ins. Trenches less than 5 feet in depth shall also be effectively protected
when examination of ground indicates hazardous ground movement may
be expected. The contractor will have options for providing such
4.6.2 Lateral Earth Pressure
P= a uniformly distributed lateral soil pressure, in lbs./ft:2
We= Effective Soil Weight, pcf
H= depth of excavation from top of supported bank to bottom of
excavation, in feet.
Hq= Equivalent Height of Surcharge, ft.
P~ We*(H+Hq)
(Reference OSHA Rules and Regulations-Part 1926 of 29 CFR as
amended by the Federal Reg/ster Volume 54, Number 209, dated
October31,1989.)
4.6.3 Option I The contractor can use Slope as shown in the Option I
section of this specification.
See Drawing 1 and General Notes-Slope
4.6.4 Option II The contractor can use Trench Shield as shown in the
Option II sectiun of this specification
See Drawing 2 and General Notes-Shields
4.6.5 Option IIa FOR BORE/EXiT PITS The contractor can use Trench Shield
as shown in the Option IIa section of this specification
See Drawing 3 and General Notes-Shields
4.6.60ption lIl The contractor can use Trench Shores as shown in the
Option III section of this specification
See Drawing 4 and General Notes-Trench Shores
GENERAL NOTES-Slope
1.) A maximum allowable slopc of l.0 (horizontal) to 1.0 (vertical) may be used during
trench excavation in soil materials in lieu of trench shoring systems. Soil materials that could be
sloped to this configuration include clay and sandy clay. This temporary slope configuration
represents the steepest incline for short-term conditions (a time period less than 72 hours) that is
acceptable given probable but subjective influences from rainfall and normal equipment
vibrations. However, if during excavation or construction of this project there is any indication
of general or local instability, slopes shall be cut back to a slope which is at least 0.25
(horizontal) to 1.0 (vertical) flatter than the specified slopes outlined previously, i.e., this
translates to a total slope of 1.25 (horizontal) to 1.0 (vertical). This flattening of the slopes may
be required due to the deterioration of the shear strength with time or due to trench flooding,
instability induced from excessive adjacent vibrations (resulting from equipment operation),
excessive adjacent surcharge loads due to equipment or stockpiled excavated materials,
shrickage cracks due to drying
2. ) Additional flattening of slopes is required when any of the following conditions are
1.) Slopes in soft loose soils or fill materials shall be flattened to 2:1
2. ) If an existing parallel utility line is located within a horizontal distance
equal to the depth of the new utility excavation, all slopes shall be
flattened an additional 0.5:1.
]. ) Contractors "Competent Persoc" shall monitor the excavation to evaluate subsurface
conditions and determine soft type and condition. When contractors "Competent Person" cannot
assure that the slope is suitable for safe use, a qualified soils engineer shall be consulted
GENERAL NOTES-Trench Shields
1.) A Trench Shield is a structure that normally will not prevent a cave-in, but is able to
withstand th forces imposed on it by a cave-in and thereby protect workers within the
structure~. Trench Shields are also referred to as "Trench Boxes". These general notes also
are applicable to Manhole Shields.
2. ) A "Pre-manufactured Shield" is a product designed, constructed and marketed to the
construction industry as a method of protecting personnel while working in trenches
subject to cave-ins.
3. ) A "Shop-built Shield" is defined herein as a shield built by a contractor or his agent for
their own use as a personnel protection device and is not available commercially as a
product to the construction industry.
GENERAL NOTES-Trench Shields com'd.
4.) Acceptable Shield Systems:
Pre-manufactured shields are commercially available and may be used provided that the
shields are selected and used in accordance with the manufacturer's specifications,
recommendations and limitations. Deviations from manufacturer's specificAtions,
recommendations and limitations will not be allowed without the manufacturers specific
written approval. This specific written approval of deviations must be kept at the jobsite
along with the manufacturers specifications and recommendations for use and other
immwtional use literature for the specific shield.
Shop-built shields may be used, when designed and sealed by a professional
engineer registered in the state of Texas and having a background in the practice of
structural engineering.
6. ) All shields must be free from damage or defects that might impair their proper
function. Shields shall be used and maintained in a manner consistent with the
recommendations of the manufacturer or design engineer. Damaged shields shall be
removed from service until authorized repairs are made.
7. ) Shields shall be installed in a manner which restricts lateral or other hazardous
movement of the shield in the event of the application of sudden lateral loads. Where
trench shields are stacked a mechanism must be available for connecting the shields to
prevent differential movement between the shields when subjected to laterals. Benching
of earth material below the bottom of the shield is allowed to a maximum of 2.0 ft., when
this benched material is of sufficient strength to support the shield.
8. ) Workmen shall not be allowed in shields when shields are being installed, removed or
moved vertically. A ladder or other safe means of entry and exit shall be located such
that workmen are not exposed to a potential cave-in hazard during entry or exit from the
shield.
9. ) Shields shall be used such that excavated soil, rock or other debris can not fall or roll into
the trench shield. In vertical trenches, the shield should rise a minimum of 1 '-6" above
the ground surface. In situation where a slope is constructed above the top of the shield,
the top of the shield should extend a minimum of l '- 6" above the point at which the
slope begins. In addition, the contractor shall be responsible for removal of soil which
may slide into the trench or against the trench shield and for replacing these materials in
accordance with backfill specifications.
9
GENERAL NOTES-Trench Shores
1. ) Aluminum Hydraulic Shores are a product designed and manufactured as an
alternate to timber shoring in order to provide a light weight product capable of being
installed and removed without entering the trench.
2. ) Aluminum Hydraulic Shores shall be designed and manufactured so as to comply with
OSHA regulations and provide strengths of the vertical rail and hydraulic cross-brace
witich are not less than a timber bracing system which would be required under the same
loading condition. The manufacturer must have complete design calculations on all
system components and shall make this information available to the Owner. The
following minimum requirements shall be met by the manufacturers' product:
a. Vertical rails shall have a minimum width of 8 inches and have an
equivalent strength in bending of not less than that of a 3" by 10" No. 2
Douglas Fir timber with its' wide side to the trench wall. The rail must be
capable of having plywood attached to it, if necessary.
b. The hydraulic cross-braces shall be minimum 2-inch I.D. and capable of
sustaining a axial force of not less than 20,000 pounds at al.50 safety
factor at 50% extension.
c. Aluminum oversleeves shall be used in accordance with the
manfacturer's recommendations. Extensiom shall not be used unless
approved in writing by the manufacturer.
d. Hydraulic pumps shall be equipped with calibrated guage having a
minimum operating range of 750-1500 psi,
e. All other accessories and specialty tools shall be furnished and used as
per the manufacturer's recommendations.
3. ) The vertical rails, hydraulic cylinder cross-braces and all other components of the
systems shall be in good, serviceable condition and without damage or defects which
would prohibit proper use. The hydraulic system shall not exhibit leaks or pressure loss
or otherwise indicate the possible loss of system pressure while in use. Damaged
components pr improperly operating equipment shall be removed from service. The
contractors ~Competent Person shall be responsible for making these inspections and
determinations. Alterations to shoring components shall not be allowed unless pertained
in writing by the manufacture's authorized agent.
4.) Plywood, used in conjunction with hydraulic shores, shall meet the following
raluirements:
a. Softwood plywood must be 11/8" minimum thickness, exterior grade
quality, CDX grade or better.
b. Hardwood plywood must be 3/4", minimum thickness, Arctic Birch
plywood. "FinnForm" brand or equal, 14 ply-all hardwood
Plywood which is broken, bent, frayed or otherwise deformed and
unsuitable for its iraended purpose shall be replaced.
10
GENERAL NOTES-Trench Shores cont'd.
5. ) The contracttar shall install .aluminum hydraulic shores in accordsnee with these
specifications and the manufacture's specifications, instructions, recommendations and
limitations. The recommended shore lengths and spscing are shown in these
specifications. The contractor may decrease the spacing to provide additional lateral
support if so required by site observations. The contractor's 'Competent Person~ shall
insure that the workmen installing, removing and working around the shoring have been
adequately trained in the proper procedures for their installation, safe use and removal.
6.) Hydraulic shores shall be installed flush against the trench walls such that the vertical
rails have uniform support. The top hydraulic cylinder must not be located above the
existing ground surface. The hydraulic cylinders shall be pressurized to a normal working
range of?70-1000 psi.
7. ) The contractor may at his discretion utilize shorter rails in order to accommodate those
situations such as backfilling where the trench depth becomes to shallow for use of the
standard 7-foot vertical rail. The shorter aluminum hydraulic shores must meet or
exceed all of the specification requirements herein.
8.) Plywood shall be attached to the vertical rails and used in this manner any time there is
evidence of raveling, sloughing or caving which cannot be adequately shored by skip-
shoring. In particular, plywood backing will be necessary when shoring cross-trenches,
when excavating in previously disturbed soils, and at those locations as indicated in
these specifications.
9. ) The contractor may at his discretion temporarily remove shoring to expedite the
installation of piping provided that workmen are not located in the unshored trench
and provided that the shoring is properly replaced.
10. ) While backfilling the trench, the contractor shall maintain the stability of the trench
walls by adjusting the location of the shores vertically such that workmen can safely
place and compact the backfill materials. Workmen shall not be in a position to be
endangered by adjustment procedure.
11. ) The contractor may remove the hydraulic shores from the trench during backfilling
operations provided the following conditions are met:
Backfilling is performed by mechanical devices which do not require that
workmen be in the trench.
b. The trench walls maintain their shape without sloughing
c. The removal of the hydraulic shores does not endanger adjacent
structures, roadways or utilities.
11
5.0 EXCAVATIONS SPECIFIC TO THIS WORK
Location Max. Depth Options Notes
Water Line
0+00 to 1+00 S.0 [,ii or In ~ 12' Wsl~r Liae
1400 to 6449 7.5 I, lI or lu Iraall 12' Wster Line
6+49 8.0 Iorlla ConstmctBo~Pit
64-82 8.0 I or !~ Constr~ Exit Pit
6+82 to 11+50 K0 I,]I or m ~ 12' Wslet Li~
11+50 8,0 I,II or m lmall 10 LF 8" WL
ImmlISLF6*WL
ll+50to 1~-00 9.0 I,]l or IlI Insall 12" Wstes'Line
19+00 9.0 I,llorm llmsll 10LFS"WL
lnsts!ISLF6"WL
~ Fi~ Hydrm
19+00 to 21+00 10.0 I,II or m Insall 12' Wl~r Line
21+00 to 26+50 10.0 I, II or m Imtsll 12' Wsm' Line
26+50 10.0 I, II or m Itmall 10 LF S" WL
InsUsliSLF6"WL
InsmllFnHydrant
26+50 to 26+80 10.0 I,II or BI Instsll 12' Wsl~r ~
26+80 10.0 Iorlh CommsctBo~Pit
27+20 10.0 I or Ih Commla Exit Pit
27+20 to t1+00 ll.0 I,lI or m Imu~l 12' Water
11+00 8.0 I,ll orlU ~ 10 LF 8" WL
ImtslISLF6*WL
11+00 to 1~+90 11.5 1,1I or llI Insmill 2" W~i~r Line
t5+90 10.0 I,II or llI InsUdl 10 LF 8" WL
InstsiiSLF6"WL
Ins~!!IrnHydrm
15+90 to 41+60 10.0 I,iI or m Insall 17 Wli~-Line
41+60 10.0 1,1I or II1 Iraall 10 LF 8' WL
Imud!SLF6"WL
41+60 to 43+80.44 10.0 l, II or rtl Install 12' Wstes' Li~
CASE: H & W Utility Construction
Input File = UNTITLED.APR
Time: 12:02:01 Date: 05-17-1999
Total active pressure = 3741.26
With angle from horizontal = 0.00
Failure surface from horizontal =57.10
Pressure at wall base = 623.54 ~
Pressure at wall base along horizontal
Pressure at wall base along vertical =
coeficient of active pressure Ka = 0.43
***************************~ATA****************************
The Height of Wall (H) = Battered Angle of Wall = 0.00
Friction Angle of Wall = 0 Friction Angle of Soil = 27.00
Soil Unit Weight = 120.00
Section Slope Angle Length Of Slope
No. (deg) S
1 0 48
Distributed Left Point Left Load Right Point Right Load
Load No. X1 Q1 x2 Q2
1 2 14 4 u ~6~44~4~
Depth Is Measured From Ground Surface
**Units**********************************************************
Force -- lp/ft Pressure -- psf Length -- ft
-' ~"~ Notes:
HN = Steepest Nlowable Sideslope
Meede HN= .75:1 Wea~tered Limestone
HN= 1: 1 Natural Clay or Sandy Cley
T5 ref. gefierdNotee(4.8,1) H/V= 1,5:1 Existing Fills
T~morettenS.0feetlnclepltebelbe
.0' Meg. Shored, Lad Beck to. eee dope or ~ome NO SpOil or equipment neraer than 2.0 feet
oter eWkek~ meem of preeekm dd be tO edge of excavation.
to moving around or m. See specification- General Notes Slope for
TreftdteeleeethenSfeetindeplhdwieleobeeffeelvdyWoteeMd
when eemkeon of groegl Indleetes hazmkxe ground movement additional requirements.
may be eeeceed. Slope all sides when protecting, structure,
U.~ yeahal me aeeed w.~ certab ceeekx., wte. manhole or pit excavations.
deldl does cot exceed 1.8 feet,
When" Stable Rock" is encountered, bhe rock
may be excavated with vertical sidewalls and slope
above the rock. The rock must be "STABLE"
as defined in OSHA 1926.
When The Contractors "Competent Person"
Cannot Be Assured Of The Soil Type Or
Suitable Slope, A Qualified Geotechnical
Engineer Shell Be Consulted.
2~,:.__k~ This Deign Assumes Dewatered Soil Conditions
12.0' lax.%~ ~__~~~(~sam, f CLAY Contractor: H & W Utility Constnaction
' . ~ taem:~ Wmr Line
ORBNNW SLOPE Proje~: SH 121
Coppert, Tea
Nee:
Sk)pe mac/not be ale in cerlain Date: 5/11/99
paved m, verily with dry requirements.
Fie No. 99517
12.0' Max. , o. e,,.~ ,,~: <,v~
/ (.75H): (IV)
3.5' .
opuonl
SLOPE Wl UNSUPPORTED BOTTOM SLOPE
U,w, custer. P E ....
NO lJ~ Adinglcm, Texee 7e016
811-4e3-~/9 ~
I II II I I I ii i i iiii i iIi I I I!l~ltl~ef I II II I I I I I I I
Use Chart To Determine Minimum
Allowable Lateral Besring Capacity
Contractor Shell Make Available Manutacturefs
Tabulated Data For Capacity Certification
For All Shields Used On This Project
Trench Shields May Be Stacked As Required
In Stiff Clays Or Rock, The Bottom Of The Shield
May Sit On A Bench Not To Exceed 2~0 Feet
From The Bottom Of The Excavation
Steepest Nlowable Slope Above Shields 1H :I V
Example Shield "Trench Shields" For Additional Requirements
Should "Stable Rock" Be Encountered,
Above The "Stable Rock"
1.5' Min. When The Contractor's "Compeerst Person"
2.0' Min. Cannot Be Assured Of The Soil Type Or
= ExcAvated Suitable Shield, A Qualified Geotechnical
- Material Engineer Shell Be Consulted.
6" Max. This Design Assumes Dewatered Soil Conditions
Shields May Be ' TrEnCh Shield C, Bpiicity
/ Stacked As Req*d.
12,0' 624 PSF
Shield May Sit
On a 2.0' Bench In Stiff CIe ....
or Rock
Shield Extends From Bottom
Of Excaveion To Surface
C, etlracl~. H & W Utility Construction
Water Line
I~ Excaveed Project SH 121
Material
Datec 5/t7/99 ......
Min. M.W. CUSTER
r Max. Fie No. 99517 63092
12.0' k sruem May Be
Stacked As Req'd.
Option II
Sh~,k~ ;amy Sit Trench Shield
On a 2.0' Bench In Stiff Clay
Slope Above Shield or Rock 2
Use Chart To Determine Minimum
Allowable Lateral Bearing Capacity
Contractor hll Make Available Manufactumr's
Tabulated Data For Capacity Certification
For All Shields Used On This Project
Trench Shields May Be Stacked As Required
In Stiff Clays Or Rock, The Bottom Of The Shield
May Sit On A Bench Not To Exceed 2.0 Feet
From The Bottom Of The Excavation
Steepest Allowable Slope Above Shields 1H :I V
'Trench Shields" For Additional Requirements
ExmTtple Shield Should "Stable Rock" Be Encountered,
PLACE MIN. i. THICK STEEL PLATE The Rock May Be Excavated VVith Near
Vertical Sidewells And The Shield May Sit
BETWEEN SHIELD END AND PIT FACE Above The "Stable Rock"
When The Contractors "Competent Person"
1.5' Min. Cannot Be Assured Of The Soil Type Or
% 2.0' Min. Suitable Shield, A Qualified Geotechnical
d Excavated Engineer Shag Be Consulted.
Material
This Design Assumes Dewetered Soil Conditions
6-M,x. Trench Shield Capsalty
"'~ Shields May Be ........
12,0' MI(. 8tacked As Req'd. MIIX. DeiXh lib1.
12.0' 624
Shield May Sit
On a 2.0' Bench In Stiff Ck .......
or Rock
ShietdE~FromBottom
Of Exc.veuen To Surface
C.,oraacl~. H & W Utility Construction
· F. xaveedPqec~Water Ijne ~ ~ .T~ k~.~ ,
s. 21
Mi,. Date:SlW99 ~,~,::.... 6309~ ../~
Sacked As Req'd.
OpGon Ila
Trench 8hlekl
Shield May 8Jr 3
On a 2.0' Bench In Stiff
' smpe ~x~ve sr.eld o~ Rock No 3
Use Standard Duty Aluminum Hydraulic
Trench Shores as Manufactured by;
Speed-Shore
Tren-Shore
Maximum Horizontal Safe-T-Shore
Spacing 6.0 feet or Equal
Single 8tacked
Maximum Depth= 9,0° See General Notes:
....... Tren~ 8hore~ for aclditjonel requirements
Plywood Backing
ExampleStandard Shore Required,
81ngle Stacked when them is
·
Maximu'm Horizontal
p,cing4.0~et
mum Depth=14.0'
. ""!'~ ~ ~ .... Contracton. H & W Utility CeielucUon
Project:SWH late~ Line
~! ~ Copp¢~l, Texas
..... : Dale:~., "O"'F""~"~"~'~'lll
Fie No./.~**,,,..;,- -,.,,
:. 1!
Exlmplm etlmdard 8bores Opljon III
TRENCH
~ ..... MW: custer PE
Scale
I