HomeMy WebLinkAboutCity Council Resolutions (R-88-359)-03/21/1988
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RESOLUTION NO.
R-88-359
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WHEREAS, in the 70th regular session of the Texas Legislature,
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House Bill #662, which was incorporated into the
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Session Laws in Chapter 722 was passed; and
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WHEREAS, said Bill requires certain information and
requirements be contained in bid documents and
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contracts for projects in which trench excavation
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will exceed a depth of five (5) feet; and
WHEREAS, the City of Colleyville desires to comply with the
requirements of House Bill #662,
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THEREFORE, BE IT RESOLVED AS FOLLOWS:
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Sec. l:
That the Guidelines for Obtaining Geotechnical
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Engineering Services in Reference to Trench
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Stability, which are attached hereto as Exhibit "A"
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are hereby adopted by the City of Co1leyvil1e.
That the staff and consulting engineer are directed
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Sec. 2:
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to comply with the aforesaid guidelines in the
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bidding and contracting on projects which require
trenching.
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AND IT IS SO RESOLVED.
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4 to 0 on this c:2 /4 day of
, 1988.
9-K- 4rJ! t: /9 f i' ~ s-t.o t) u;tj"
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CITY OF COLLEYVILLE
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~ %/p
D. . Hubbard
Mayor
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City Secretary
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APPROVED AS TO LEGAL FORM:
~7/1vL
R ss T.! Foster
city Attorney
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RESOLUTION R-88-359
EXHIBIT nAn
APRIL 18, 1988
CITY OF COLLEYVILLE
GUIDELINE FOR OBTAINING GEOTECHNICAL ENGINEERING SERVICES
IN REFERENCE TO TRENCH STABILITY
1. General
1.1 This is a guideline for obtaining geotechnical engineering services
on City of Colleyville (City) projects where excavations over five
foot in depth are required.
1.2 This document should be used as a guideline and is not intended
to replace engineering judgment in the development of necessary
servi ces.
1.3 Plans issued for bid are required to include design of slopes or
shoring systems for protection of personnel.
The slopes and shoring system design shall be prepared by a geo-
technical engineering firm and bear the seal and signature of a
professional engineer registered in the State of Texas.
2. Governing Documents
2.1 Occupational Safety and Health Administration (OSHA) Construction
Industry Standards, OSHA Publication 2207-Revised 1983; Part 1926 -
Occupational Safety and Health Standards, Subpart P - Excavations,
Trenching and Shoring.
2.2 Texas State Legislature House Bills 662 and 665 as amended and
dated May, 1987.
3. Qualification and Selection of Geotechnical Engineer
3.1 The civil engineer will assist the City in identifying Geotechnical
Engineers offering the type of services needed in this area and will
advise the City of any factual information known to them that would
be a factor in the selection to be made by the City.
3.2 The selection of the Geotechnical Engineer will be based on the
consultant's experience in the design of excavations and shoring,
and local soil and groundwater conditions, and familiarity with
referenced governing documents.
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3.3 The Geotechnical Engineer shall maintain professional liability
insurance through the design and construction phases of the project
and shall furnish the City a certificate of insurance for same
satisfactory to the City Manager.
4. Scope of Servi ces
4.1 The Civil Engineer will provide plans, specifications, and other
available documents in preliminary form to the Geotechnical Engineer
so that an estimate of services can be provided.
4.2 The Geotechnical Engineer will provide a written proposal to the
City with a copy to the Civil Engineer outlining the scope of ser-
vices and proposed schedule.
4.2.1 The scope of services should include all borings, laboratory
tests, and engineering services necessary to provide recommendations
on safe excavation slopes, dewatering, and shoring design parameters.
The scope of services should also include the preparation of trench
excavation and shoring plans and specifications, review of alternate
trench safety designs and/or trench shield or box designs submitted
by the consturciton contractor, attending the pre-construction con-
ference for the project and on-site trench safety system inspection
and testing during construction.
5. Proposal
5.1 The proposal should, as a minimum, address the following:
5.2 Field Investigation
5.2.1 One boring per 500 linear feet is considered a guideline;
however, additional borings may be required in soft ground, complex
geology, and shallow groundwater, at bore or tunnel locations, or
in unusually deep excavations. Less borings may be required in
shallow excavations and uniform or simple geology.
5.2.2 Borings should be extended a minimum of two feet below depth
of excavation, or two feet into unweathered rock or shale, whichever
is shallower. Deeper borings may be required for soft or unstable
ground, at locations of shallow groundwater, adjacent to existing
structures, or where shoring may be required.
5.2.3 Borings should be sampled at strata breaks or at maximum
five-foot intervals. Sampling shall include split barrel samples
in non-cohesive soils and thin-walled tube samples in cohesive soils.
5.2.4 The locations of the borings shall be determined by the
Geotechnical Engineer. Those selected locations shall be staked
and surface elevations determined by the Civil Engineer.
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5.2.5 Groundwater evaluation should be made to include 24-hour
post-drilling observations. Depth to water and caved depths should
be noted on logs.
5.2.6 All borings will be left open following completion of
drilling operations for groundwater level readings. Each hole
is to be securely covered to prevent injury. Following ground-
water readings, each hole shall be backfilled.
5.2.7 If rotary wash methods are used, each borehole will be bailed
to the completion depth so that accurate water data can be obtained.
5.2.8 The consistency of each sample of cohesive soil should be
checked in the field with a pocket penetrometer and recorded on
the log of borings at the respective depth.
5.3 Laboratory Investigation
5.3.1 Moisture content and visual identification should be performed
on every sample, with liquid and plastic limit tests, unconfined com-
pression tests, unit weight, and grain size analysis performed on
representative samples.
5.3.2 Soil samples obtained from the borings shall be maintained
for visual inspection for a minimum time period of up to thirty
days after award of the construction contract.
5.4 Geotechnical Engineering Report Services
It is the responsibility of the Geotechnical Engineer to consider
aspects related to the project that affect the excavation. These
specifications are not intended to replace engineering judgment.
In general, the following minimum items should be included in the
repo rt :
5.4.1 A site plan illustrating the location of each boring, or
station numbers and offset recorded on each boring log.
5.4.2 Log of boring for each hole indicating the station and
offset, surface elevation, soil classificaton and description
of each strata, field penetrometer readings, and groundwater
and caved depths of boreholes at a minimum of 24 hours after
completi on.
5.4.3 Laboratory test results.
5.4.4 Descriptions of the field and laboratory procedures.
5.4.5 General discussions of subsurface conditions and geology
which may affect excavation and construction. Interpretation of
conditions between borings which may affect excavation design
should be clearly identified.
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5.4.6 Recommended safe excavation slopes. For variable conditions,
recommended slopes should be identified by station numbers. Plan of
excavated slope is to be sealed by a professional engineer registered
in the State of Texas.
5.4.7 Any available information that would indicate the possible
need for dewatering should be identified. The effect of dewatering
on adjacent structures and the excavated slope should be analyzed.
An estimate of the quantity of groundwater is not required; however,
relevant information should be provided that will assist bidders in
anticipating the general nature of pumping requirements.
5.4.8 Earth pressure diagrams for design of bracing and shoring
should be included. This section should also include parameters
used to determine loads and estimated affect on adjacent structures.
5.4.9 In lieu of earth pressure diagrams, identification of the OSHA
wood shoring type should be included with the engineered slope plan.
5.4.10 Trench excavation and shoring plans indicating safe slopes
and shoring should specify minimums allowable, and where feasible
should identify various alternatives at each station (i.e., sloped
excavations, use of trench shields, and/or minimum shoring), and
should not unduly restrict the Contractor to one particular method.
5.4.11 The report should clearly identify the City, project name,
project number, and location. Upon completion of the report, five
(5) copies shall be delivered; three (3) to the City and two (2)
to the Civil Engineer.
5.5 Other Geotechnical Engineering Services
Additional responsibilities of the Geotechnical Engineer are listed
as follows:
5.5.1 The Geotechnical Engineer shall review and approve trench
excavation, shoring and/or trench shield or box plans furnished
by the construction contractor as alternates to those prepared by
the Geotechnical Engineer.
5.5.2 The Geotechnical Engineer shall perform daily inspections of
the trench excavations and bracing systems. These inspections will
provide information to the City in determining the construction
contractor's compliance with approved plans and specifications and
in no way are these inspections to be construed as relieving the
contractor of his duties and responsibilities as defined in the
technical specifications. Daily reports shall be submitted weekly
to the City, City Inspector, Civil Engineer and construction con-
tractor.
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6. Appendix Provisions
The attached Appendix provlslons which are made a part of this Guideline
are provided for detailing some of the requirements of this Guideline.
6.1 Appendix IAI - Sample "Trench Excavations and Shoring Plan". The
format and content of the Trench Excavations and Shoring Plan may
be presented in a different manner based on the engineering judge-
ment of the Geotechnical Engineer if it otherwise meets the require-
ments set forth in this Guideline.
6.2 Appendix IBI - Sample "Trench Shoring - Minimum Requirements".
6.3 Appendix ICI - Sample "Bid Proposal" for Trench Safety Systems.
This or similar language shall be used by the Civil Engineer in
preparation of the bid proposal of the construction project bidding
documents.
6.4 Appendix 101 - Draft "Technical Specifications Section , Trench
Excavations and Shoring". The Geotechnical Engineer willllJse this
draft to develop the specifications for the project. The Geotechnical
Engineer will add his geotechnical report and his trench excavations
and shoring plan to complete the specification. The completed specifi-
cation will then be inserted into the bidding documents by the Civil
Engineer.
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APPENDIX IC'
SAMPLE BID PROPOSAL
UNIT TOT AL.
ITEM QTY . IUN IT DESCRI PTION PRICE PRICE
IlL. S. Trench Safety System in
accordance with Spec.
Section __ for the price
of Dollars
and Cents L. S. $ $
APPENDIX 101
SE cn ON
ORA FT
TECHNICAL SPECIFICATIONS
, TRENCH EXCAVATIONS AND SHORING
1: GENERAL
1.1 This section covers excavation and supporting systems for trenches
to protect the safety of workers. This specification shall govern
for construction of all types of trenches except where the require-
ments are explicitly revised or superseded by another section.
Additional requirements as set forth by federal (OSHA Safety and
Health Standards, 29 CFR 1926/1987), state and local government
regulations will be applicable and must be followed. These
specifications were developed in general conformance with the
Occupational Safety and Health Administration (OSHA) standards
as contained in Subpart P, Part 1926, Title 29 of the Code of
Federal Regulations (29 CFR 1926).
1.2 Designs shown in the Trench Excavations and Shoring Plan included
herein are based on anticipated geologic conditions along the
pipeline and the results of the borings performed by the Owner's
Geotechnical Engineer. Copies of the specific Logs of Borings and
Geotechnical Report are also included herein. The Contractor shall
review the information and familiarize on-site personnel with con-
ditions as shown on the logs. Subsurface conditions between
locations shown on the logs will vary and it is the Contractor's
responsibility to detect varying conditions which may be hazardous
and take appropriate action.
2: APPLICABILITY
These specifications apply to any trench which is over five (5) feet
in depth or trenches that are less than five feet in depth located in
areas where unstable soil conditions are present. (Ref. OSHA, Safety
and Health Regulations, Part 1926, Subpart P, Paragraph 1926.652, Sub-
paragraph (a). "Unstable" soil condi tions refers to soil s which will
slough or move under load or vibration). These specifications also
apply to shored trenches less than 15 feet in width.
3: CONTRACTOR'S RESPONSIBILITY
3.1 These specifications address the safety of workers in a trench
excavation and it, in no way, relieves the Contractor of his
responsibility and liability to insure the safety of the project
and its workers.
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3.2 The Contractor must identify a person in the Contractor's firm
responsible for performing ~ai1Y inspections of the trench excava-
tions to assure conditions ave not changed that may make the
trench excavation or bracing less safe.
3.3 The Contractor shall implement for its employees, sub-contractors,
agents and representatives a safety program for any trench safety
system utilized in this construction project.
3.4 These specifications and trench safety system relate solely to
safety of workers and do not protect or address the structural
integrity of any adjacent or nearby structures. In accordance
with the general conditions contained in the contract documents,
it is the contractor's sole responsibility to develop and imple-
ment a system necessary to protect and prevent changes, injury,
or loss to other property at the site or adjacent thereto in-
cluding trees, shrubs, lawns, walks, pavements, roadways,
structures, utilities and underground facilities.
4: TRENCH DESIGN
4.1 The Contractor is to perform the trench excavations, including
sloping of side walls, to the limits shown on the Trench Excava-
tion and Shoring plans. The trench design is in general confor-
mance with OSHA trench safety standards and does not relieve
the Contractor of its responsibility to use any construction
means, methods, techniques and procedures necessary to insure
the safety of its workers.
4.2 All trenches over five (5) feet deep shall be sloped, shored,
sheeted, braced or otherwise supported. Trenches less than five
(5) feet in depth located in areas of hazardous ground movement,
shall be effectively protected. If soil conditions warrant in
deeper excavations, the sides of the trench above a 5-foot level
may be sloped to preclude collapse. In trenches wider than six
(6) feet, a minimum bench four (4) feet wide shall be provided
on both sides of the excavation at the toe of the sloped portion.
4.3 Alternative designs equal to or better than the excavation plan
may be utilized. Alternative plans are to be submitted prior to
bid opening and approved by the Owner's Geotechnical Engineer
prior to beginning of trench excavation. Plans are to be designed
and sealed by an Engineer registered in the State of Texas. Plans
must meet accepted engineering requirements and OSHA Standards
and Regulations. Approved alternative excavation plans are to be
available at the contractor's office and the site of the work for
reference. The sole liability for the alternate design rests with
the Contractor and Contractor's Engineer.
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5: INSPECTION
5.1 Owner
5.1.1 Subsurface conditions encountered in the borings must be
reviewed by the Contractor and disucssed with the Owner's
Geotechnical Engineer at the preconstruction meeting, to
be held prior to initial excavation operations. If
conditions arise concerning interpretation of subsur-
face conditions, test excavations may be performed at
the Contractor's expense to familiarize the Contractor
with soil types, stratification and groundwater condi-
tions. A representative of the Owner's Geotechnical
Engineer performing borings will be made available if
requested to discuss materials exposed by excavations.
The Owner's Geotechnical Engineer shall perform daily
inspections of the trench excavations and bracing systems
on those days which require workers to enter trenches
in excess of five (5) feet deep. These inspections are
intended as an information service to the Owner in deter-
mining the Contractor's compliance with the approved
trench excavation and shoring plans and specifications
and in no way are these inspections to be construed as
relieving the Contractor of this duties and responsi-
bi1ites as described in Items 3.2 and 5.2.2 of this
specification.
5.2 Contractor
5.2.1 The Contractor is responsible for familiarizing on-
site personnel with soil conditions shown on the Logs
of Borings.
5.2.2 The designated on-site safety person (as identified in
Section 3.2) must perform daily inspections of the trench
faces and bottom and/or any structural systems utilized
for supporting the trench walls prior to personnel
entering into the excavation. If evidence of possible
cave-ins or slides is apparent, all work in the excavation
shall cease until the necessary precautions have been
taken to safeguard the employees.
6: TRENCH EXCAVATION REQUIREMENTS
6.2 General Requi rements
6.1.1 Walkways, runways, and sidewalks shall be kept clear of
excavated material or other obstructions and no sidewalks
shall be undermined unless shored to carry a minimum
live load of one hundred and twenty-five (125) poundS
per square foot.
3
If planks are used for raised walkways, runways, or
sidewalks, they shall be laid parallel to the length
of the walk and fastened together against displacement.
Planks shall be uniform in thickness and all exposed
ends shall be provided with beveled cleats to prevent
tripping.
Raised walkways, runways and sidewalks shall be provided
with plank steps on strong stringers. Ramps, used in lieu
of steps, shall be provided with cleats to insure a safe
wal king surface.
All employees shall be protected with personal protective
equipment for the protection of the head, eyes, respira-
tory organs, hands, feet and other parts of the body as
set forth in Subpart E, OSHA Part 1926.
6.1.6 Employees exposed to vehicular traffic shall be provided
with and shall be instructed to wear warning vests
marked with or made of reflectorized or high visibility
material.
6.1.2
6.1.3
6.1.4
6.1.5
6.1.7
6.1.8
6.1.9
6.1.10
6.1.11
Employees subjected to hazardous dust, gases, fumes,
mists or atmospheres deficient in oxygen, shall be pro-
tected with approved respiratory protection as set
forth in Subpart D, OSHA Part 1926.
No person shall be pennitted under loads handled by
power shovels, derricks, or hoists. To avoid any
injury from spillage, employees shall be required to
stand away from any vehicle being loaded.
In locations where oxygen deficiency or gaseous condi-
tions are possible, air in the excavation shall be tested.
Controls, as set forth in Subparts D and E, OSHA, Part 1926,
shall be established to assure acceptable atmospheric con-
ditions. When flammable gases are present, adequate
ventilation shall be provided or sources of ignition
shall be eliminated. Attended emergency rescue equip-
ment, such as breathing apparatus, a safety harness
and line, basket stretcher, etc., shall be readily
available where adverse atmospheric conditions may
exist or develop in an excavation.
Where employees or equipment are required or permitted
to cross over excavations, walkways or bridges with
standard guardrails shall be provided.
Where ramps are used for employees or equipment, they
shall be designed and constructed by qualified persons
in accordance with accepted engineering requirements.
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6.1.12
All ladders used on excavation operations shall be in
accordance with the requirements of Subpart L, OSHA
Part 1926.
6.2 Prior to Trench Excavation
6.2.1
Prior to opening an excavation, effort shall be made to
determine where underground installations, i.e., sewer,
telephone, water, fuel, electric lines, etc., will be
encountered. Utility companies shall be contacted and
advised of proposed work prior to the start of actual
excavation.
Trees, boulders, and other surface encumbrances, located
so as to create a hazard to employees involved in exca-
vation work or in the vicinity thereof at any time during
operations, shall be removed or made safe before excavating
is begun.
6.3 During Excavation
6.2.2
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
6.3.6
All slopes shall be excavated to at least the angles
shown on the excavation plans provided herein.
The excavated slopes shall be flattened when an exca-
vation has water conditions, silty materials, loose
boulders, and areas where erosion, deep frost action,
and slide planes appear.
When the excavation approaches the estimated loaction of
an underground installation, the exact location shall be
determined and when it is uncovered, proper supports
shall be provided for the existing installation.
Daily inspections of excavations shall be made by the
Contractor's designated safety person as identified in
Section 3.2. 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 assure
the safety of the trench.
Excavations shall be inspected after every rainstorm
or other hazard-increasing occurrence to assure the
safety of the trench. Portection against slides and
cave-ins shall be increased as necessary.
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 workers
from falling debris, the toe of the stockpiled soil
shall not be closer than five (5) feet from the top of
the excavation.
5
6.3.7
6.3.8
6.3.9
6.3.10
6.3.11
6.3.12
6.3.13
6.3.14
Excavations below the level of the base of footing of
any foundations or retaining wall shall not be permitted,
unless the wall is underpinned and all other precautions
taken to insure the stability of the adjacent walls
for the protection of employees involved in excavation
work or in the vicinity thereof.
If the stability of adjoining buildings or walls is
endangered by excavations, shoring, bracing, or under-
pinning shall be provided as necessary to insure their
safety. Such shoring, bracing, or underpinning shall
be inspected daily or more often, as conditions warrant,
by the Contractor's designated safety person and the
protection effectively maintained.
Diversion ditches, dikes, or other suitable means shall
be used to prevent surface water from entering an exca-
vation and to provide adequate drainage of the area
adjacent to the excavation. Water shall not be allowed
to accumulate in an excavation.
If it is necessary to place or operate power shovels,
derricks, trucks, materials, or other heavy objects on
a level above and near an excavation, the side of the
excavation shall be sheet-piled, shored, and braced as
necessary to resist the extra pressure due to such
superimposed loads. Shoring designs provided for herein
do not include such surcharge loads.
When mobile equipment is utilized or allowed adjacent
to excavations, substantial stop logs or barricades
shall be installed. If possible, the grade shall be
away from the excavation.
Additional precautions by way of shoring and bracing
shall be taken to prevent slides or cave-ins when ex-
cavations or trenches are made in locations adjacent
to backfilled excavations, or where excavations are
subjected to vibrations from railroad or highway traffic,
the operation of machinery, or any other source.
The Contractor must take precautions to protect the face
of the excvation from exposure to excessive drying, water,
or freezing when excavations are to remain open for more
than two (2) calendar weeks.
If shoring, bracing, underpinning or other means are
used to provide the stability of the excavation walls,
it shall be inspected daily or more often, as conditions
warrant, by the Contractor's safety person designated
in Section 3.2 to insure that the protection is effec-
tively maintained. This includes checking all shim
plates, braces and stringers for tightness.
6
6.3.15
6.3.16
6.3.17
6.3.18
6.3.19
6.3.20
6.3.21
Materials used for sheeting, sheet piling, cribbing,
bracing, shoring, and underpinning shall be in good
serviceable condition, and timbers shall be sound,
free of large or loose knots, and of proper dimensions.
Shoring will be applied by starting from the top of the
trench excavation and working down. All cross beams or
trench jacks will be placed in true horizontal position,
be spaced vertically, and be secured to prevent sliding,
falling, or kickouts.
Backfilling and removal of trench supports shall progress
together from the bottom of the trench. Jacks or braces
shall be released slowly and, in unstable soil, ropes
shall be used to pullout the jacks or braces from above
after employees have cleared the trench.
If shoring is utilized in trench excavations, installation
will closely follow the excavation work. Trenches will
not be left unsupported for a period longer than two
calendar days.
When employees are required to be in trenches four (4)
feet deep or more, an adequate means of exit, such as
a ladder or steps shall be provided and located so as
to require no more than 25 feet of lateral travel.
Adequate phYsical barrier protection, such as guardrails,
fences, or barricades and warning lights maintained from
sunset to sunup, shall be provided at all locations where
animal or human life may inadvertently enter the trench
excavation.
Portable trench boxes or sliding trench shields may be
used for the protection of personnel in lieu of a shoring
system or sloping. Where such trench boxes or shields
are used, they shall be designed, constructed and main-
tained in a manner which will provide protection equal
to or greater than the sheeting or shoring required for
the trench. The substitution of portable trench boxes
or sliding trench shields shall be contingent upon
approval by the Owner's Geotechnical Engineer.
7: SPECIAL CONSIDERATIONS
7.1 Special precautions shall be taken in sloping or shoring the sides
of excavations adjacent to a previously backfilled excavation or a
fill, particularly when the separation is less than the depth of
the excavation. Particular attention also shall be paid to joints
and seams of material comprising a face and the slope of such seams
and joints.
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7.2 Groundwater shall be adequately controlled to a point such that
no water seepage occurs on the excavation slopes or bottom. The
use of tight sheeting, pumping, drainage, or similar control
measures shall be planned and directed by the Contractor. Con-
sideration shall be given by the Contractor to the existing
mositure balances in surrounding soils and the effects on foun-
dations and structures if it is disturbed.
7.3 In rock excavations, the face and slope of the excavation shall
be inspected by the Contractor's safety person for joints and
seams or other discontinuities that may cause block failures.
Vertical slopes (90 degrees), without bracing or use of trench
box, will not be allowed in any rock material except as shown in
the Trench Excavations and Shoring plan included herein.
8: DEFINITIONS
(Reference: OSHA Safety and Health Regulations, Part 1926, Subpart P,
Paragraph 1926.653)
8.1 IIBraces" - The horizontal members of the shoring systen whose ends
bear against the uprights or stringers.
8.2 "Dewatering Systen" - A mechanical systen which artifici ally
lowers the static groundwater to a level which prevents groundwater
seepage into the excavation. These include; well-points, sumps,
pumping wells, or cut-off walls.
8.3 "Groundwater" - Water that is present in the soil in sufficient
quantities that it will flow and collect at a point. This includes
a natural aquifer water level or perched groundwater on top of an
impervious layer.
8.4 "Lagging" - Horizontal boards supported by the flanges of two H-
piles and are used to separate the natural soil from the excavation.
8.5 "Rock" - A mass of soil particles that cannot be excavated by hand.
This includes any weathered rock that contains soil seams. Shale
is to be considered a rock material.
8.6 IIRunning Soilll - Soils that exhibit a fluid behavior generally
brought about by excess moisture, imbalanced hydrostatic (water)
conditions, or vibration.
8.7 "Sheet Pi1e" - A pile, or sheeting, that may fonn one of a contin-
uous interlocking line, or a row of timber, concrete, or steel pile,
driven in close contact to provide a tight wall to resist the lateral
pressure of water, adjacent earth, or other materials.
8.8 "Sides" - Also referred to as IWa11s", or IIFaces". The vertical
or inclined earth surfaces formed as a result of excavation work.
8
8.9 "Slope" - The angle with the horizontal at which a particular
earth material will stand indefinitely without movement.
8.10 "Stringersll - Also referred to as "Wales". The horizontal members
of a shoring system whose sides bear against the uprights or earth.
8.11 "Trenchll - A narrow excavation made below the surface of the ground.
In general, the depth is greater than the width, but the width is
less than 15 feet. A trench may consist of the void between un-
supported earth and the wall of a structure if the wall is within
15 feet of the unsupported earth.
8.12 "Trench Shield" - A shoring system composed of steel plates and
bracing, welded or bolted together, which support the walls of
a trench from the ground level to the trench bottom and which can
be moved along the trench bottom as work progresses.
8.13 IIUprights" - The vertical members of a shoring system.
9: MEASUREMENT AND PAYMENT
The lump sum amount bid for Proposal !ten IITrench Safety Systen" shall
be the total compensation for furnishing and installing all materials
and equipment, for doing all necessary work and for taking all other
measures required to comply with this Technical Specification, Trench
Excavations and Shoring.
9