WA9302-SP 960302SHIMEK, JACOBS & FINKLEA
CONSULTING ENGINEERS
8333 Douglas Avenue, #820
Dallas, Texas 75225
(214) 361-7900
ROSS L. JACOBS, P.E.
RONALD V. CONWAY, P.E.
JOHN W. BIRKHOFF, P.E.
JOE R. CARTER, P.E.
GARY C. HENDRICKS, P.E.
C. L. SHIMEK, P.E.
I. C. FINKLEA, P.E.
JAMES E. LAUGHLIN, P.E.
March 2, 1996
Mr. Larry Davis
Construction Inspector
City of Coppell
P.O. Box 478
Coppell, Texas 75019-4409
Re: Village Parkway Ground Storage Reservoir No. 2
Dear Mr. Davis:
We are enclosing a copy of the trench safety plan submitted to us by Natgun for the Village Parkway Ground
Storage Reservoir No. 2. The trench safety plan is signed, sealed and dated by a registered professional
engineer in the State of Texas. These copies are for your use during the construction of the Ground Storage
Reservoir. We have retained one copy for our files.
We are available to discuss this project further at your convenience.
Sincerely,
Matt Hickey, E.I.T.
Enclosures
TRENCH SAFETY
SPECIFICATIONS
FOR THE
VILLAGE PARKWAY GROUND
STORAGE RESERVOIR No.2
CITY OF
COPPELL, TEXAS
Prepared for
BARSON UTILITY COMPANY
TREN-TECH COMPANY
2S60 ELECTRONIC LANE #104
DALL4S, TEXAS
214-357-6621
[ have reviewed this Trench Safety. Plan and find that its recommendation and
procedures confore to OSHA guidelines and regulations. ~'ne calc~
herein ~ consistent with generally accepted engineering practice.
REGISTERED PROFESSIONAL ENGINEER
DATE
tl .0 DESIGN ASSUN'IPTIONS ]
1.1
General. These specifications cover the basic requirements for shoring and/or sloping
of excavations for the installation of WATER LINES for the VILLAGE PARKWAY
GROUND STORAGE RESERVOIR No.2 in the CITY of COPPEEk, TEXAS.
1.2
This specification addresses the satiety 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
based on information obtained from the project drawings and specifications.
1.5
In accordance with Revised OSHA (Appendix A to Subpart P effective March 2, 1990),
the Contractor's "Competent Person" will conduct the required Soil Classification
Tests. If soils other than those previously 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
Contractor shall be responsible for selecting the appropriate safety system option shown
in these specifications, depending on trench depth and soil conditions.
1.7
The protection of existing structures and utilities which may be affected by these trench
excavations is beyond the scope of this report (See Sect.4.2)
1.8
The Contractor must identify a "Competent Person' in the Contractor's firm
responsible for performing inspections of the excavations to ensure that expected
subsurface conditions are present. NOTE-This person must be 'Competent" as
described in OSHA 1926.650(b).
1.9
It is the Contractor's responsibility to ensure that all excavation work and site
conditions are within the regulations as established by OSHA. Any property damage or
bodily injury (including death) arising from the use of these specifications, from the
Contractor's negligence in performance of contract work, or from Owner's failure
note exceptions to these specifications shall .remain the sole responsibility and liability
of the contractor.
2.0 DEFINITIONS'
2.1
2.2
2.3
2.4
All definitions of section 1926.653 of Subpart P, Part 1.926, of the Code of
Federal Regulations shall be by reference an integral part of this section.
"Sealing Engineer"- The engineer whose Texas seal is affixed to these
specifications.
"The Contractor"-The contractor responsible to the owner for the excavation
work described herein.
"Competent" as described in OSHA 1926.650(b).
3.0 APPLICABI,FJ CODE AND STANDARDS
3.1
3.1.t
3.1..2
3.1.3
3.1.4
3. l.5
3.1.6
3.1.7
3.1.8
3.2
The Contractor shall perform all shoring work under this contract in accordance
with all applicable codes and standard safety requirements and regulations
including:
OSHA 2207, Construction Industry Standards (Part 1926,
Occupational Safety and Health Standards)
AISC Code ot' Standard Practice.
AISC Specifications of the design, fabrication, and erection of steel buildings
AITC Timber Construction Manual
AWS D 1.. 1 Structural Welding Code
The Uniform Building Code
OSHA 2226
U S Army Corps of Engineers EM 385-1-1
The latest 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 time of bid but later
-. revised shall be acceptable provided such revisions are not required by law.
2
4.0 SHORLNG/SLOPLNG [
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 may 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 meet
with the approval of the engineer, the utility 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 Contractor's work, be injured.
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 Department 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 1926.650 and 1926.651 of Subpart P, Part
1926, of the Code of Federal Regulations shall be by reference an
integral part of this section.
4.4.1 Known underground installations are shown on the site plans. It is the Contractor's
responsibility to verify exact locations in the field.
4.4.2
Before any individual enters an excavation, the excavation will be inspected by a
'Competent Person" to ensure that trench excavation has been performed according to
this specification and OSHA requirements and to ensure that no anomalies 'ar~ observed
which may effect the safety of the trench .project. Note-This person must be
"Competent" as described in OSHA 1926.650(b).
3
4.5 REQUIREMENTS DURENG EXCAVATION'
4.5.l
4.5.
4.5.3
4.5.4
4.5.5
4.5.6
4.5.7
4.5.8
4.5.9
4.5.10
4.5.11
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 the project..
Daily inspections of the excavations shall be made by the 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 taken to ensure the safety of the workmen and the
trench. Note-This person must be "Competent" as described in OSHA 1926.650.
Excavations shall be inspected after every rainstorm or other hazard-increasing
occurrence to ensure safety of the workmen and the trench.
Excavated material shall be stockpiled a distance away from the trench, so as not to
affect the trench stability. The Contractor's means and methods will determine the
distance. As a minimum to protect the workmen from falling debris, the toe of the
stockpiled soil shall be no closer than two(2) feet from the edge of the excavation.
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.
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 design.
The Contractor must take precautions to protect the face of the excavation from
exposure to excessive drying, water, or freezing.
Water shall not be permitted to stand in the bottom of the trench and suction pumps of
adequate capacity shall be installed to ensure that such standing water is removed.
The Contractor shall provide a positive means of ensuring that hydrostatic pressure
does not build up behind the shoring or shields.
If a condition requiring the use of a different method of shoring is encountered, this
specification will be revised.
Remove shoring units from bottom to top as backfilling proceeds.
When backfill is within five(5) feet of the top of the trench, all shoring may be
removed, unless the trench conditions indicate a hazard.
4.5.12
4.5.13
4.5.14
4.5.15
No person shall be exposed. to the lower portion of the trench after shoring has been
removed.
Additional shoring of larger sizes may be installed.
kadders or other adequate means of exit must be provided and located so as to require
no more than twenty-five(25) feet of lateral travel.
When two(2) trenches intersect, both trenches must be protected to a distance of not
less that the depth of the deepest trench.
I4.6
REQUIRE~IENTS FOR CONFINED SPACE
4.6.1
4.6.2
4.6.3
4.6.4
4.6.5
Prior to construction the contractor shall identify any areas near the proposed
excavations that could expose workmen to harmful levels of atmospheric
contaminants (i.e. landfills, manholes or materials storage).
During construction, before workmen are allowed in an excavation or existing structure,
the contractor shall test the air quality at these previously identified areas for hazardous
atmospheres in all excavations greater than four (4) feet indepth. Atmospheres
containing less than 19.5 percent oxygen or more than 20 percent concentration of
flammable gas shall be deemed "hazardous" adequate precautions shall be taken.
Retesting of work areas shall be conducted as often as necessary to ensure that the
atmosphere remains safe for workmen.
During construction. emergency rescue equipment shall be readily available where
potentially hazardous conditions are expected to develop.
As a minimum, the contractor shall have on site the following emergency equipment.
Breathing apparatus, a safety harness and line, or a basket stretcher. During
construction in potentially hazardous areas, the required equipment shall be attended.
SECTION 5.0
SITE SPECIFIC EXCAVATIONS
AND
SHORING SPECIFICATIONS
FOR
WATERLINES
6
5. I EXCAVATIONS SPECIFIC TO THIS PROJECT
INLET PIPING
LOCATION MAX. DEPTH OPTION
i +00+ 11.0 I, II
I +00_+ TO 4+64.36'_+ 12.0' I, II
NOTES
CONN TO'EXIST 36'
INSTALL 36" W.L.
OUTLET No. 1 PIPING
LOCATION
t+40.3_+
t +40.3_+ TO 2+03.26
MAX. DEPTH OPTION
10.0 I, II
10.0 I, II
NOTES
CONN TO EXIST 36"
INSTALL 36" W.L.
OUTLET No.2 PIPING
LOCATION
1+03.3_+
t +03.3_+ TO 2+22.78
MAX. DEPTH OPTION
9.0 I, II
9.0 I, II
NOTES
CONN TO EXIST 36"
INSTALL 36" W.L.
7
5.2 SHORING CONSIDERATIONS FOR THIS WORK
5.2.1
Trenches more than five(S) deep shall be shored, laid back to a stable slope, or some
other equivalent means of protection shall be provided where employees may be
exposed to moving. ground or cave-ins. Trenches less than. five(5)feet. in depth shall
also be effectively protected when examination of ground indicates hazardous ground
movement ma~' be expected.
The Contractor will have Options I or II for providing such protection.
S .2.2
Lateral Earth Pressure: P = We(H+ Hq)
Hq
Assumed Soil: Boring Logs on Plans -~-
P= a uniformly distributed lateral soil pressure, in lbs./ft2
We= Effective Soil Weight. pcf(Use 45 pcf Type"B" Soil)
H = Depth of excavation from top of supported bank to H
bottom of excavation in feet.
Hq = Equivalent Height of Surcharge. in feet.
Reference OSHA Rules and Regulations-Part 1926 of 29 CFR
as amended by the Federal Register Volume 54. Number 209,
October 31. 1989
I
WE 45
5.2.3
5.2.4
Option I The Contractor can use Slope as shown in the Option [ section of the
specification. Applicable slopes may be obtained by either straight cut or benched
method. Vertical cuts for the benched method shall not exceed four(4) feet. Easement
restrictions may limit the use of this option. Option I is normally not permissible in
paved street areas. See Drawing Option I.
Option II The Contractor may use a Trench Shield as shown in the Option II section
of this specification. Requirements set forth in this Option shall include curricular
trench shield(s) and or manhole boxes. All slopes above trench shield(s) shall conform
to guidelines set forth in Option I, Trench shield(s) used on this project will be
required to carry a minimum "PSF" as specified. Certification of trench shield(s) or
manufacture's "tabulated data" shall be available for verification during construction.
See Drawing Option II.
TRENCH SAFE TY SPECIFICATIONS
OPTION I
spoil ~i~l SLOPE
\
2' Min )t'_ .
_
H/V - REQUIRED SLOPE PER SOIL TYPE
H/V = 3/4 to l
H/V = l to 1
H/V = 1V2 tol
H/V = 2 to l
Stiff clay less than 12 feet in depth (Type 'A')
Stiff clay or weathered limestone (Type 'A' or 'B")
Silty clays or saturated material (Type 'C')
Fill material or loose soil.
NOTES
t. All trenches shall be dewatered as specified in 4.5.7
2. All slopes assume sufficient right-of-way exists.
3. All slopes shall be flattened and additiona ~h foot if an existing parallel utility line is
located within the horizontal distance equal to the depth of the new utility excavation.
4. ',No spoil or equipment shall be permitted nearer than 2 feet from the edge of the excavation.
5. A single 3' 67 vertical bench may be used in 'stiff clay' only.
6. Exposed existing utility lines are to be supported.
9
TRENCH SAFE TY SPECIFICATIONS
OPTION H
TRENCH SHIELD
Spoil Material
2' Min
l' Bench is recommended
Sloped portions of the excavation shall
begin 18" below the top of the trench
shield(s) and conform to guidelines
set forth in Option I.
Trench shield(s) m~' be benched 2 feet
in "stiff clay". -
Requirements and methods stipulated
heroin will apply to "manhole boxes"
and/or "circular shields" that have been
manufactured for personnel protection.
NOTES
1. Trench shields shall be inspected and be flee of structural defects that may impair their proper function.
2. Trench shields shall be used in accordance with the manufacturer's guidelines and recommendations.
3. Trench shields shall be installed so as to prevent any lateral or other haTardOtts movement.
4. Personnel shall not be allowed in the trench shield during its installation or removal from the excavation.
5. When shield(s) axe stacked. the upper shield shall be rated for its physical depth in the trench.
6. Trench shield(s) used on this project shall be rated to withstand anticipated "PSF" (left side of graph) for depth
of cut indicated below. Manufacmre's tabulated data or certification shall be maintained on site.
650 ...............................................................
600 ...............................................................
550 ............................................. i ......' ........
500 .......................................... ~ ....................
· 450 '- - --'-' -' .............~ ....~ ................- ............2 _' ........
400 ................................ ?: __. ........_ ..........
5 Feet 7.5 Feet 10 Feet 12.5 Feet
10