Gulf Bearing-SP 950421 TRENCH SAFETY
SPECIFICATIONS
FOR
GULF UNITED INDUSTRIES
ADDITION
CITY OF
COPPELL, TEXAS
Prepared for
SUPERIOR UTILTIES, INC.
TREN-TECH COMPANY
2560 ELECTRONIC LANE #104
DALLAS, TEXAS
214-357-6621
I have reviewed tlds Trmch Safety Plan and find Ilmt its recommendaliom and
procedures conform to OSHA guidelines and regulaekms. The calculations
here~n a~ consistent with gmerally accepted ~oln~ing Iwactice.
REGISTERED PROFESSIONAL ENGINEER
DAT~
]1 ,
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
General. These specifications cover the basic requirements for shoring and/or sloping
of excavations for the installation of STORM DRAINAGE, SANITARY SEWER
LINES, and WATERLINES for GULF INDUSTRIES ADDITION in the CITY of
COPPELL, TEXAS.
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.
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.
The personell protection systems shown in these specifications have been designed
based on information obtained from the project drawings and specifications.
In accordance with Revised OSHA (Appendix A to Subpart P effective March 2,1990),
the Contractor's MCompetent PersonM 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.
Contractor shall be responsible for selecting the appropriate safety system option shown
in these specifications, depending on trench depth and soil conditions.
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)
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).
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 to
note exceptions to these specifications shall remain the sole responsibility and liability
of the contractor.
2.1
All definitions of section 1926.653 of Subpart P, Part 1926, of the Code of
Federal Regulations shall be by reference an integral part of this section.
2.2 "Sealing Engineer"- The engineer whose Texas seal is affixed to these
specifications.
2.3
2.4
"The Contractor"-The contractor responsible to the owner for the excavation
work described herein.
~Competent" as described in OSHA 1926.650(b).
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
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 of 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
4.1
Description.
This section covers the technical requirements of the trenching/shoring work.
4.2
4.3
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.
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 are observed
which may effect the safety of the trench project. Note-This person must be
"Competent" as described in OSHA 1926.650(b).
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 the project.
4.5.
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.
4.5.3
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.
4.5.4 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.
4.5.5
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 design.
4.5.6
4.5.7
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.
4.5.8 The Contractor shall provide a positive means of ensuring that hydrostatic pressure
does not build up behind the shoring or shields.
4.5.9 If a condition requiring the use of a different method of shoring is encountered, this
specification will be revised.
4.5.10 Remove shoring units from bottom to top as backfilling proceeds.
4.5.11 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 No person shall be exposed to the lower portion of the trench after shoring has been
removed.
4.5.13 Additional shoring of larger sizes may be installed.
4.5.14 Ladders 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.
4.5.15 When two(2) trenches intersect, both trenches must be protected to a distance of not
less that the depth of the deepest trench.
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
SANITARY SEWER LINES
STORM DRAINAGE
AND
WATERLINES
STORM SEWER LINE
LOCATION MAX. DEPTH OPTION
0+00 10.5 I, II
0+00 TO 4+85.6 10.5 I, II
4+85.6 TO 7+55.4 9.5 I, II
7+55.4 TO 7+72.7 7.0 I, II
7+72.7 TO 10+70.8 7.0 I, II
LINE 'A-I' 8.5 I, II, III
LINE "A-la' 5.5 I, II, III
LINE "A-lb 5.5 I, II, III
NOTES
CONN TO EXIST 72 ~
INSTALL 42" RCP
INSTALL 36' RCP
INSTALL 27" RCP
INSTALL 24' RCP
INSTALL 18' RCP
INSTALL 18' RCP
INSTALL 18' RCP
STORM SEWER LINE
LOCATION MAX. DEPTH OPTION
0+00 7.0 I, II
0+00 TO 1+63 8.0 I, II
1+63 TO 3+50.5 7.5 I, II
NOTES
CONN TO EXIST 66'
INSTALL 30' RCP
INSTALL 24" RCP
SANITARY SEWER LINE
LOCATION MAX. DEPTH OPTION
0+00 11.5 I, II
0+00 TO 0+57 10.0 I, II, III
0+57 9.5 I, II
0+57 TO 2+86 9.0 I, II, III
NOTES
CONST MANHOLE
INSTALL 8" S.S.
CONST MANHOLE
INSTALL 8" S.S.
7
PROJECT WATER!.INES AND APPURTENANCES
The contractor is required to install various water lines and their appurtenances on the project.
No profiles for these various waterlines were provided on the plans but it is doubtful that
excavation depths greater than five feet will be necessary and therefore shoring may not be
required. If excavation depths greater than five feet are encountered or if there is evidence of
raveling or caving for any reason including predisturbed soil conditions, the contractor will be
required to shore or slope the excavation so as to provide a safe workplace. The contractor
may use guidelines set forth in Option I, II or III for these excavations.
8
5.2.1
5.2.2
Trenches more than five(5) 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 may be expected.
The Contractor will have Options I, II or III for providing such protection.
Lateral Earth Pressure: P = We(H+Hq)
Assumed Soil: Clay
P = a unifomaly distributed lateral soil pressure, in lbs./ft2
We = Effective Soil Weight, pcf(Us~ 45 pcf Type'B' Soil)
H = Depth of excavation from top of supported bank to
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
WE 45
5.2.3
5.2.4
5.2.5
Option I The Contractor can use Slope as shown in the Option I 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.
Option III The Contractor can use Trench Shores as shown in the option III Section
of this specification. Shores are to be installed as shown with horizontal spacing
determined by the depth of cut and soil type but shall not exceed 6 feet. See Drawing
Option III. If there is raveling of the trench wall, the contractor shall install plywood
behind the shores as shown on the Option III drawing.
TRENCH SAFETY SPECIFICATIONS
OPTION I
Spoil Material SLOPE
3'6" Single
allowed in stiff clay ~ benched metl~oa o~"slope".
H/V - REQUIRED SLOPE PER SOIL TYPE
H/V = ;A to 1
H/V = ltol
H/V = 1¼ to 1
H/V = 2 to 1
Stiff Clay less than 12' in height (Type 'A")
Stiff Clay greater than 12' in height (Type 'A' or
Silty clays or saturated material (Type
Fill material or loose soil.
NOTES
1. 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 ~A 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' 6' vertical bench may be used in 'stiff clay' only.
6. Exposed existing utility lines are to be supported.
10
TRENCH SA FE TY SPECIFICATIONS
OPTION H
TRENCH SHIELD
Spoil Material
H
1' 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) may be benched 2 feet
in "stiff clay"· -~_
Requirements and methods stipulated
herein 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 free 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 hazardous movement.
4. Personnel shall not be allowed in the trench shield during its installation or removal from the excavation.
5. When shield(s) are 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. Manufacture's tabulated data or certification shall be maintained on site.
600
55O
500
450
400
350
300
5 Feet 7.5 Feet 10 Feet 1 1.5 Feet
11
TRENCH SAFETY SPECIFICATIONS
OPTION III
SHORING
Plywood installed behind
shores to prevent raveling.
NOTES
1. Shores shall be double stacked when trench depths exceed nine (9) feet.
2. Maximum horizontal spacing for double stacked shores shall be five (5) feet.
3. Maximum allowable depth of cut for this Option shall be fourteen (14) feet.
4. AJnminum hydraulic shoring may be used in Type 'A' or 'B' soils only.
5. Maximum horzontal spacing of shores in Type "A" soil shall be 6 f~t.
6. Maximum horizontal spacing of shores in Type 'B' soil shall be 5 feet.
7. The contractor's competent person shall inspect shores and verify that they are in good working order.
8. The hydraulic shores shall have a mlnlmllm working pressure of 750 psi.
9. The contractor shall adhere to the shoring manufacturer's guidelines for use in trench excavations.
10. If there is evidence of raveling or caving the contractor is required to install 11/8' thick plywood or ~A ' thick
14 ply attic white birch (Finnland form).
11. Spoil material will not be allowed nearer than 2' from the edge of thc excavation.
12