Manual for Engineering

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Engineering Manual

Revision Date: November 23, 2007

RESOURCE TENURES & ENGINEERING BRANCH

Ministry ofForests and Range


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Ministry of Forests and Range ENGINEERING MANUAL 2006

Table of Contents

Table of Contents......................................................................................................................... 5-1

5. Design and Construction of Bridges and Major Culverts................................................... 5-15.1 Introduction................................................................................................................ 5-1

5.2 Policy ......................................................................................................................... 5-1

5.3 Mandatory Practices................................................................................................... 5-15.4 Design Requirements for Bridges and Major Culverts.............................................. 5-2

5.4.1 Design Responsibility and Considerations .................................................... 5-2

5.4.2 Typical General Arrangement Design Approach .......................................... 5-3

5.4.3 Design Opening ........................................................................................... 5-105.5 Types of Bridge Structures ...................................................................................... 5-10

5.5.1 Bridge Superstructures................................................................................. 5-10

5.5.2 Bridge Substructures.................................................................................... 5-12

5.6 Types of Major Culvert Structures .......................................................................... 5-135.7 Site Data and Survey Requirements for Bridges and Major Culverts ..................... 5-14

5.8 Design Discharge Criteria........................................................................................ 5-155.8.1 Factors Affecting Runoff ............................................................................. 5-15

5.8.2 Methodologies to Estimate Design Flood Discharge................................... 5-16

5.8.3 Comparing Discharges Using Hydrological Information............................ 5-175.9 Agency Referrals ..................................................................................................... 5-17

5.10 General Arrangement Construction Drawings and Specifications .......................... 5-20

5.10.1 General Bridge Arrangement Drawing Requirements................................. 5-20

5.10.2 Bridge Superstructure Drawing Requirements ............................................ 5-245.10.3 Bridge Substructure Drawing Requirements ............................................... 5-24

5.10.4 Log Bridge Superstructure on Log Crib Drawing Requirements ................ 5-255.10.5 Major Culvert Drawing Requirements......................................................... 5-255.10.6 Portable Bridge Superstructures .................................................................. 5-26

5.11 Major Works Construction Contract........................................................................ 5-26

5.12 Bridge and Major Culvert Materials Acquisition .................................................... 5-275.13 Bridge and Major Culvert Materials Quality and Fabrication................................. 5-28

5.13.1 Assurance of Material Quality..................................................................... 5-28

5.13.2 In-Plant Inspection of Bridge Materials and Fabrication............................. 5-31

5.14 General Conformance and Construction Documentation ........................................ 5-325.15 Resources and Suggestions for Further Reading ..................................................... 5-33

Chapter 5 Design and Construction of Bridges and Major Culverts 5-1


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5. Design and Construct ion of Bridges and Major Culverts

5.1 Introduction

This chapter describes some of the key activities and practices important to

ensuring the successful design and construction of bridges and major culverts onforest roads. The topics covered include:

design requirements and considerations;

types of structures;

site data and survey requirements;

estimating design discharge for streams;

construction drawings and specifications;

construction materials, quality assurance, and fabrication; and

statement of general conformance and construction documentation.

In this chapter:

Bridge means a temporary or permanent structure carrying a road above a

stream or other opening and includes a log stringer structure equal to or

greater than 6 m in span length, or with an abutment height of 4 m or higher.

Major culvert means a stream culvert having a pipe diameter of 2,000 mm or

greater; a pipe arch with a span greater than 2,130 mm; a log stringer structure

with a span 6 m or greater or a log crib height greater than 4 m; or a structure

installed over a stream that has a design discharge of 6 m3/sec or greater.

Portable bridge superstructure is a bridge superstructure that is designed

and fabricated, in accordance with the Forest Service Bridge Design and

Construction Manual, for ease of movement and installation.

The Forest Service Bridge Design and Construction Manual (B.C. Ministry ofForests, 1999) provides further discussion on planning, design, and construction

of forest road bridges.

Note: Log culverts, defined as those with gravel decks, spans less than 6 m and

abutment heights less than 4 m, are covered in Chapter 4: Road Survey and

Design andChapter 6: Road Construction of this manual.

5.2 Policy

All bridges and major culverts on Forest Service Roads must be designed by a

professional engineer and constructed not only to be cost-effective, appropriatefor the site, and safe for users, but also to minimize the impacts on forest and

other resources.

5.3 Mandatory Practices

All ministry bridges and major culverts must be designed by a professional

engineer, and constructed with the involvement of a Coordinating RegisteredProfessional. See5.4.1: Design Responsibility and Considerations

http://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdf


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All ministry bridges must be designed and constructed in conformance with

the Forest Service Bridge Design and Construction Manual.

See5.4.2: Typical General Arrangement Design Approach

All fabricated bridge superstructures must be permanently labelled with

unique identifiers. See5.10.2: Bridge Superstructure Drawing Requirements

All new steel, pre-cast concrete, and treated timber bridge materials acquiredby the ministry must be inspected at the fabrication plant by ministry

Inspectors as a measure of quality assurance.

See5.13.2: In-Plant Inspection of Bridge Materials and Fabrication

After construction of a bridge or major culvert, a professional engineer must

sign and seal a Statement of Construction Conformance and as-built drawings.

See5.14: General Conformance and Construction Documentation

After construction of a bridge or major culvert, a Coordinating Registered

Professional must sign and seal a Crossing Assurance Statement consistent

with the Guidelines for Professional Services in the Forest Sector Crossings.

5.4 Design Requirements for Bridges and Major Culverts5.4.1 Design Responsibi lity and Considerations

Bridge and major culvert designs must be signed and sealed by a professionalengineer.

Designs should clearly identify the professional engineer who is taking overalldesign responsibility. The professional engineer who takes overall responsibility

to ensure that all aspects of the design are appropriately addressed is called theEngineer of Record, and may or may not be the detailed design engineer (e.g.

detailed structural design).

If a log stringer structure requires a gravel road fill depth greater than 2 m, thestringer structure should be designed by or at minimum be reviewed by a

professional engineer.

The design of bridges and major culverts encompasses more than just the design

of structural components. A bridge or major culvert design should consider the

composition and interaction of all the components, as well as their relationshipand impact on not only the users, but also on the road and stream components.

A bridge includes the superstructure, substructure, connections, approach road

fills, and scour protection works. A major culvert includes the culvert materials,

compacted bedding and backfill, embedment materials for embedded culverts,scour protection, and the roadway.

All bridge or major culvert designs should consider:

user safety;

accommodation of pedestrian traffic where required;

site selection, including assessment of stream geomorphology and

geotechnical (global and local) considerations;

http://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/isb/forms/lib/fs138.DOChttp://www.apeg.bc.ca/ppractice/documents/ppguidelines/guidelinesforestcrossings.pdfhttp://www.apeg.bc.ca/ppractice/documents/ppguidelines/guidelinesforestcrossings.pdfhttp://www.for.gov.bc.ca/isb/forms/lib/fs138.DOChttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdf


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environmental integrity;

fish habitat and fish passage;

impact of the proposed structure on the stream during and after construction;

site revegetation requirements;

structure alignment and location (vertical and horizontal) relative to the road

and stream channel; complete structure combination (substructure, superstructure, connections,

and scour protection);

suitability of selected foundations for the specific site;

design flood development;

navigation (Navigable Waters Protection Act), if applicable;

debris potential and passage;

scour protection;

design vehicle configuration for load and alignment;

design traffic frequency;

design service life influence on selection of bridge type and composition;

construction layout, methodology, and timing; and economics.

5.4.2 Typical General Arrangement Design Approach

Bridge and major culvert designs and construction approaches for forest roads inBritish Columbia have evolved into industry standards. Typical details and

arrangements are described in the Forest Service Bridge Design and Construction

Manual and in guidelines and requirements for ministry bridges. The mostcommon components have been structurally pre-engineered and are well known

by bridge engineers, fabricators, erectors, and owners.

Practitioners in bridge and major culvert design for forest roads should bethoroughly familiar with:

the Forest Service Bridge Design and Construction Manual;

CAN/CSA S6-00, Canadian Highway Bridge Design Code;

Navigable Waters Protection Act;

other associated bridge standards (for welding, fabrication, etc.); and

the Engineering Equipment and Services (EES) Directory.

Forest Service Bridge Design and Construction Manual

The Forest Service Bridge Design and Construction Manual drawings include

standards that contain ministry-approved component configurations and details.Detailed designs for various components, such as concrete decks, slab girders, andvarious footing arrangements, are also provided in the manual.

As well, the manual lists proprietary bridge components (consisting of conceptual

drawings with minimal details) that have been approved by the ministry.Proponents wishing to have proprietary systems accepted by the ministry must

show proof that their components will meet the stringent requirements laid out in

http://laws.justice.gc.ca/en/N-22/index.htmlhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.csa.ca/products/construction/Default.asp?articleID=4422&language=englishhttp://laws.justice.gc.ca/en/N-22/index.htmlhttp://www.for.gov.bc.ca/hth/engineering/EES-Consultants.htmhttp://www.for.gov.bc.ca/hth/engineering/FRBDC.htmhttp://www.for.gov.bc.ca/hth/engineering/FRBDC.htmhttp://www.for.gov.bc.ca/hth/engineering/EES-Consultants.htmhttp://laws.justice.gc.ca/en/N-22/index.htmlhttp://www.csa.ca/products/construction/Default.asp?articleID=4422&language=englishhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://laws.justice.gc.ca/en/N-22/index.html


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the manual for structural integrity, durability, and other relevant aspects

pertaining to the products usage.

Note: It is the responsibility of the proponent to prove out their product, not theministry.

Deviation from the requirements of the Forest Service Bridge Design and

Construction Manual and the associated standard drawings is not recommended.

Where an unproven system or product is implemented, it is being done so withoutministry approvals. Products or systems that are not currently approved, but for

which it appears efficiencies might be gained by their acceptance, should bebrought to the attention of Resource Tenures and Engineering Branch for

evaluation. If the branch determines that products or systems provide efficiencies

and meet stringent performance requirements, those components will beincorporated into the Forest Service Bridge Design and Construction Manual as

acceptable ministry standards.

The Resource Tenures and Engineering Branch web page provides links to theForest Service Bridge Design and Construction Manual and other pertinent bridge

and major culvert information and documentation. Additional design guidelines

can also be found posted on this site. During the transition from CAN/CSA S6-88,

Design of Highway Bridges to CAN S6-00, Canadian Highway Bridge DesignCode, interim design guidelines are provided on the Bridges and Major Culverts

website to supplement the Forest Service Bridge Design and ConstructionManual.

Typical Design and Implementation Process

The typical bridge or major culvert design and implementation process is as

follows:

The requirement for a bridge or major culvert structure is determined.

A professional engineer is engaged to develop the most efficient crossing

configuration design.

The performance requirements for the crossing (which should includeinformation that captures the relevant design considerations listed in 5.4.1:

Design Responsibility and Considerations) are conveyed to the engineer.

The design engineer evaluates the options for the crossing given the available

information.

The engineer conducts a site visit and makes note of the physical site

parameters, including observations on design flood hydrology, foundation

evaluation, vertical and horizontal alignment and crossing locationopportunities, and construction limitations (such as equipment and materials

access).

The designer makes recommendations for the development of a site plan.

Generally, for all but the most simple crossings, a detailed site plan is

recommended. The site plan, described in more detail in 5.7: Site Data and SurveyRequirements for Bridges and Major Culverts is the detailed crossing design.

http://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://gww.for.gov.bc.ca/hth/engineering/manuals.htmhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.for.gov.bc.ca/hth/engineering/Bridges_And_Major_Culverts.htmhttp://www.for.gov.bc.ca/hth/engineering/Bridges_And_Major_Culverts.htmhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/Bridges_And_Major_Culverts.htmhttp://www.for.gov.bc.ca/hth/engineering/Bridges_And_Major_Culverts.htmhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://gww.for.gov.bc.ca/hth/engineering/manuals.htmhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdf


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Figure 5-1: Sample General Arrangement Drawing: Site PlanControl Traverse


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Figure 5-2: Sample General Arrangement PlanDesign Criteria


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Figure 5-3: Sample General Arrangement Drawing: Foundation Details



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Figure 5-4: Sample General Arrangement Drawing: Abutment Assembly Details



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Detailed Structural Design

For all but the most complex structures, detailed structural design is not usually

completed in the development of general arrangement designs. For the typical,

simply supported forest road bridge structures, detailed structural design of thesuperstructure components is most effectively completed by bridge material

fabricators or it may already have been completed according to ministrystandard designs within the Forest Service Bridge Design and Construction

Manual.

Where detailed bridge component structural design is required, the fabricatorsprofessional engineer would design the most cost-effective and efficient structures

based on material availability and fabrication process. Where a detailed design

has been produced by others, the fabricator may encounter fabricationinefficiencies.

Detailed structural design of superstructure components, by designers producing

general arrangements for typical simply supported bridges, is not recommended.

5.4.3 Design Opening

The Forest Planning and Practices Regulation (Sec. 74 (1)) defines the peak flow

return period (design flood) requirements for bridges and major culverts basedon the anticipated life of the structures. Bridges to be in place for a relatively short

life pose reduced risks (compared with bridges expected to have longer life), and

thus reduced design flood concerns can be considered subject to the criteriadescribed in the Forest Planning and Practices Regulation (Sec. 74 (2) (3)).

In addition to design flood passage, allowances must be made for anticipated

debris. For bridges, freeboard above the design highwater needs to beincorporated to allow for passage of floating debris. In the case of major culverts,

accommodation for debris (floating or submerged) also needs to be considered in

the design process. Where floating debris is minimal and regular maintenance isanticipated, debris catchers/traps may be suitable. Where significant volume or

size of floating or other debris is anticipated, a culvert may not be an option, and abridge will be necessary to allow high water and debris to pass.

5.5 Types of Bridge Structures

5.5.1 Bridge Superstructures

The approved ministry superstructure configurations are identified in the Forest

Service Bridge Design and Construction Manual. As noted previously, use of

non-approved systems is not recommended.

The approved systems provide for numerous construction options including:

timber decks on steel;

precast concrete slabs;

non-composite concrete decks on steel girders;

http://www.for.gov.bc.ca/tasb/legsregs/frpa/frparegs/forplanprac/fppr.htm#section74http://www.for.gov.bc.ca/tasb/legsregs/frpa/frparegs/forplanprac/fppr.htm#section74http://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/tasb/legsregs/frpa/frparegs/forplanprac/fppr.htm#section74http://www.for.gov.bc.ca/tasb/legsregs/frpa/frparegs/forplanprac/fppr.htm#section74


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composite concrete decks on steel girders;

Compo-Girders; and

steel-free decks (precast concrete arch panel composite deck).

The following general rules of thumb can be used to help guide estimating orevaluating concept designs for typical single-lane, simply supported, single-span

bridges:

Cost efficiencies for in-place bridges, by superstructure span types:

For spans 12 m or less, concrete slab structures are typically most economical.

For spans between 12 and 18 m, non-composite concrete decks on steel

girders are most economical.

For spans greater than 18 m, composite concrete decks on steel girders are

generally most economical.

Selection considerations, by superstructure material options:

a) Precast concrete slabs:

are extremely heavy and required appropriate equipment to launch andplace (although there are options to reduce piece weights);

are expensive to freight because of their weight;

have advantages for use as widenings for corners: much more cost-efficient than concrete on steel for short spans;

involve two main options for shear connectors between slabs: grouted connections: they are structurally continuous; they are labour-

intensive and time-consuming to install; grout requires time to set, and

installation should not be done in cold temperatures

welded connections: they require installation by a certified welder;they allow the bridge to be put into service immediately; their

installation is not limited by temperature; the welds can be cut and the

bridge moved elsewhere (though this should not be done more thanonce)

allow for thinner profiles, which may be an advantage to minimize

approach height and still meet the 100 year peak flow (Q100)requirements;

if 7 m or shorter, do not require connections between slabs but have more

steel, making heavier individual components; and

are relatively heavy structures, impacting foundation requirements.

b) Non-composite concrete decks on steel: require deeper girders than slabs or composite decks on steel (below);

require less grout work and are not as structurally critical as compositeconcrete decks on steel;

are not as conducive as composite concrete decks on steel to flaring of

decks at bridge ends, because the superstructure cannot transfer loadsbetween deck panels; and

can be set up to allow for bolted deck connections to allow for bridge

removal and use elsewhere.



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c) Composite concrete decks on steel:

require shallower girders than non-composite concrete decks;

require grout work that is labour-intensive, time-consuming, and

significantly more extensive than for non-composite concrete deck;

are not easy to dismantle; and

are more conducive than non-composite concrete decks to flaring of decksat bridge ends, because of the ability of the superstructure to transfer loads

through the deck panel connections.

With flared concrete decks at bridge ends, structural design is more complex.Designers typically use the precast ballast wall to support the end deck panel.

Grouting between the ballast wall and end deck panels is required as a means of

providing full contact to obtain full bearing of the deck on the ballast wall.

Note: A composite concrete deck saves on materials (such as steel girder

dimensions), compared with a non-composite concrete deck, but

installation of the composite superstructure is more expensive because of

the need for extensive grout work in the field.

d) Timber deck on steel girder superstructures:

are very common though for permanent applications, concrete deck

structures are more economical in the long term because the decks have a

longer expected life;

timber decks are available in treated and untreated systems; treated

systems are cost comparable to concrete; treated wood decks, particularly

those treated with Creosote, can be controversial among certainstakeholders and regulatory agencies because of the pollution potential;

timber decks are lighter than concrete and thus generally, when compared

to non-composite concrete systems require smaller girders; timber decks can be modularized for easy removal and re-installation; and

timber deck on steel girder systems are available with skid plates and more

robust girder systems for portable/temporary installations.

e) All steel portable superstructures:

are very expensive relative to other types of superstructures;

are not recommended for typical permanent installations;

are good for high frequency of reuse; are very portable and easy to install;and

require deck coatings, which is a high maintenance item, to provide for

trackability, and are high maintenance.

5.5.2 Bridge Substructures

Several types of substructures are available to support bridge superstructures. The

options for a particular site should be based on the type of superstructure,operational requirements, and specific-site conditions. The substructure types

range from simple log sills to driven piles.



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The Forest Service Bridge Design and Construction Manual presents numerous

permanent bridge substructures standards. The standard design drawings in themanual typically consist of precast concrete spreadfootings and are suitable where

adequate soil bearing can be obtained. The standard drawings also provide for Tfootings, suited to concrete slab girder superstructures requiring shallow

abutments; and steel pipe columns on precast footing standards, suited to steelgirder superstructures and concrete slab superstructure requiring higher

abutments.

The Forest Service Bridge Design and Construction Manual should be consulted

for the standards on cap and bearing details for pile foundations.

The following substructures are not captured in standard design drawings in the

Forest Service Bridge Design and Construction Manual:

log cribs (suited to temporary usage);

concrete lock block abutments (typically limited to three blocks high); and

steel binwalls (numerous steel binwalls exist, but few new ones are beinginstalled).

5.6 Types of Major Culvert Structures

Log, concrete, steel, and aluminum culverts are all types which can be classifiedas major culverts according to the criteria noted in 5.1: Introduction. Log stringer

structures have been discussed previously (5.4.1: Design Responsibility and

Considerations) and are not further discussed in this section.

Culverts are often preferred structures in suitable situations. Their advantagesover bridges may include:

economics culverts are generally cheaper than bridges for typical sizes used;

reduced maintenance when installed correctly; and

greater flexibility in terms of alignment options culverts are suited to siteswith horizontal and vertical curves; they can be fit to suit the road alignment

and approaches so as to minimize impacts; and they enable maintenance of

road widths and provide extra road width (widenings) more readily than

bridges.

Steel and aluminum culverts are typically soil-metal structures. The soil and themetal work together to provide the structural integrity to support loads on the

structure. The metal without the soil is insufficient to support the design loads andwould collapse. Typical designs require soil to be compacted in lifts immediately

adjacent to and in contact with the culvert bottom and sides, to combine with the

metal to support the design loads. Uncompacted fill is not sufficiently dense tocombine with the metal to support the design loads.

For most soil-metal culvert installations, the metal is galvanized steel. Somealuminum culverts exist, but they are less common than galvanized steel. For agiven installation, aluminum culverts are generally thicker but lighter than

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galvanized steel. However, the aluminum culverts tend to be more easily damaged

during installation.

Culverts come in a variety of shapes and sizes. The selection of appropriate sizeand shape should be a function of the design parameters.

5.7 Site Data and Survey Requirements for Bridges and MajorCulverts

The engineer assuming design responsibility for a bridge or major culvert requires

site-specific information for the proposed crossing. For very simple sites, thedesigner can personally obtain the required information through on-site

measurements and sketches, but it is usually more efficient to have a survey crewobtain this information.

A detailed site survey (see Forest Service Bridge Design and Construction

Manual Appendix E Bridge and Major Culvert Site Plan Specifications) is

recommended for the majority of bridges and major culvert projects. The surveyinformation is used to produce site plan and profile drawings for planning,

evaluating, and developing the crossing design. The designer should determinethe type and extent of site survey to be completed, including the quality of site

information to be collected.

Information to be collected and noted on a site plan/profile (Forest Service Bridge

Design and Construction Manual Sec. 1.3.2) typically includes:

contours to 0.5 m interval accuracy (may vary depending on complexity of thesite);

the riparian class for streams or lake classification; the apparent high-water elevation of the stream, based on visible evidence of

recent flooding;

a description of the composition and size of stream bed materials;

a description of streambank materials and stream stability;

cross-sections and a profile of the stream: one cross-section should be alongthe proposed road centreline and extend beyond the stream channel width,

normally to at least 50 m on each side;

horizontal and vertical location of reference points established during the sitesurvey, which can be used to establish (and re-establish) the structure location

during construction;

the stream flow velocity and direction, if the flow may influence the size orlayout of the structure;

a description of the soil profiles and foundation soil conditions, based on soil

explorations appropriate to the level of risk;

presence (or absence) of bedrock, and depth to bedrock;

a description of any evidence of stream debris or slope instability that could

affect the crossing, based on upstream observations;

any existing improvements or resource values in the vicinity that mayinfluence the size or layout of the structure;

http://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/Bridge%20Manual-Web%20version%20Aug%2002-Rev.June07.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/Bridge%20Manual-Web%20version%20Aug%2002-Rev.June07.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/Bridge%20Manual-Web%20version%20Aug%2002-Rev.June07.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/Bridge%20Manual-Web%20version%20Aug%2002-Rev.June07.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdf


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location and dimensions of any existing structure, including edge of roadway,

abutment, superstructure, stream, edge of clearing information, profile ofexisting road to the limits of the survey, and location, general description, and

extent of vegetation;

the locations and dimensions of any upstream structures, and a note about

whether there is any evidence of damage or disturbance from any sources(erosion, debris damage, etc.);

potential sources of rip rap, endfill material;

any other pertinent information: Is the site currently accessible by road? Arethere road or bridge restrictions on load length or weight? If so, how can these

be overcome? If test drilling seems likely, how much work is required to get a

drilling truck (usually not all-wheel drive) to the site?

if equipment fording or temporary bridge crossings will be necessary for

construction, information about possible ford and temporary bridge crossing

locations and other considerations such as depth of stream at that point,

bottom material, and access gradients; and

the date of the survey and name of the surveyor.

If a fish stream is involved, the Fish-stream Crossing GuidebookChapter 3 should

be consulted for additional site information requirements.

5.8 Design Discharge Criteria

The design discharge for streams should be determined for a particular recurrenceinterval. Establishing a return period provides a benchmark of the relative risk to

be attached to any particular design.

See Forest Planning and Practices Regulation Sec. 74 (1)

5.8.1 Factors Affecting Runoff

The runoff effect of a stream depends on many factors, most of which are not

readily available or easy to calculate, such as:

rainfall (e.g., occurrence of cloudbursts; hourly and daily maxima);

snowpack depth and distribution, and snowmelt;

contributory watershed area, shape, and slope;

topography and aspect;

ground cover;

soil and subsoil composition;

weather conditions; harvesting and road or other upslope development or disturbance;

drainage pattern (stream order, branchiness; lakes and swamps); and

stream channel shape, length, cross-section, slope, and roughness.

Because topography, soil, and climate combine in infinite variety, drainage forspecific sites should be designed individually from available data for each site. In

addition, the designer should consult those who have long experience in

http://www.for.gov.bc.ca/tasb/legsregs/fpc/FPCGUIDE/FishStreamCrossing/FSCGdBk.pdfhttp://www.for.gov.bc.ca/tasb/legsregs/frpa/frparegs/forplanprac/fppr.htm#section74http://www.for.gov.bc.ca/tasb/legsregs/frpa/frparegs/forplanprac/fppr.htm#section74http://www.for.gov.bc.ca/tasb/legsregs/fpc/FPCGUIDE/FishStreamCrossing/FSCGdBk.pdf


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maintaining drainage structures in the area, as well as observing evidence of local

activity/events.

5.8.2 Methodologies to Estimate Design Flood Discharge

There are too many analytical and empirical methods for estimating stream

discharge to be discussed at any length in this manual. Professional engineers,who in the course of carrying out their professional functions as designers of abridge or a major culvert, are ultimately responsible for establishing the design

discharge for a structure. Those estimating stream discharges should be familiar

with methods used and their limitations, or consult those with training andexperience in stream discharge determination. Those methodologies commonly

used involve:

working from available evidence of flood flows in the stream in question;

gathering evidence of flood flows in other streams, relating these to theirdrainage basin characteristics, and then, from the characteristics of the basin

under consideration, estimating a flood flow; and relating meteorological data to stream basin characteristics and estimating

flood flow through empirical methods.

The necessary data for these methodologies can be obtained from several sources:

Site Information

Site-specific data at, and adjacent to, the proposed crossing can be used toestimate the maximum flow. Records of culverts and bridges within the vicinity

that have successfully withstood known flood events can provide usefulinformation in the estimation of flood flows.

Stream Basin Characteristics

Stream basin characteristics such as length, slope, order, roughness, vegetative

characteristics, and elevation band, combined with meteorological data, can beused in empirical approaches to determine design flood flows.

Data on Other Streams

Studies done on other streams in the vicinity, with similar characteristics, can

provide information on relationships and comparative values.

Hydrometric Records

The Water Survey of Canada publishes Surface Water Data (annual reports of

readings on hydrometric stations throughout the province), as well as HistoricalStream Flow Summaries in which mean values and annual peaks are tabulated.

These stream flow records can be used to project design flood flows fromtheoretical analysis.



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5.8.3 Comparing Discharges Using Hydrological Information

Determining design flood discharge usually involves applying several different

methods and then using judgement to select an appropriate design value. In allstream flood discharge determinations, it is prudent to compare the proposed

opening size with historically problem-free existing stream crossings serving

similar drainages in the same area.

The designer should compare the flood discharge estimates derived from the site

information with other data and theoretical derivations. The final selection of

design discharge and resulting bridge opening or major culvert size should then bebased on the designers judgement (taking into account these comparisons),

together with consideration of debris potential, ice jams, and any other localfactors that might influence the structure opening.

5.9 Agency Referrals

Once the site plan and preliminary design are completed, the Ministry

Representative responsible for the project must decide if applications for permits

to construct a crossing need to be made with relevant agencies such as the B.C.Ministry of Environment (MoE), Fisheries and Oceans Canada (DFO), and

Transport Canada (Navigable Waters Protection Division).

B.C. Ministry of Environment is concerned with protecting water, land and air

quality, managing flood and erosion control, and protecting the population andhabitat of animals and resident fish species. The ministry administers various Acts

that might be relevant to bridge or major culvert construction.

Fisheries and Oceans Canada is the lead federal government department

responsible for protecting anadromous fish species and their habitat byadministering the Fisheries Actand Regulations. Timing and methods of

construction might be stipulated by either DFO or MoE agencies.

DFO Pacific Region has provided some commentary for small clear span bridges:Pacific Region Operational Statement - Small Clear-Span Bridges.

Transport Canada,Navigable Waters Protection Division, administers theNavigable Waters Protection Act. Its mandate includes protection of the public

right of navigation in tidal waters. According to the division, approvals arerequired for every crossing. However, it is the ministrys practice to only refer

and apply for crossings where the type and size of the structure or the nature ofthe stream have a potential for navigation problems.

Once it is established that a waterway is indeed navigable, then in general thereare two main types of documents that may be issued for a work:

formal approval; and

a Work Assessment letter.

http://www.gov.bc.ca/bvprd/bc/channel.do?action=ministry&channelID=-8395&navId=NAV_ID_provincehttp://www.pac.dfo-mpo.gc.ca/pages/default_e.htmhttp://www.tc.gc.ca/pacific/marine/nwpd/menu.htmhttp://www-heb.pac.dfo-mpo.gc.ca/decisionsupport/os/os-clear_span_e.htmhttp://www.tc.gc.ca/pacific/marine/nwpd/menu.htmhttp://www.tc.gc.ca/pacific/marine/nwpd/menu.htmhttp://www-heb.pac.dfo-mpo.gc.ca/decisionsupport/os/os-clear_span_e.htmhttp://www.tc.gc.ca/pacific/marine/nwpd/menu.htmhttp://www.pac.dfo-mpo.gc.ca/pages/default_e.htmhttp://www.gov.bc.ca/bvprd/bc/channel.do?action=ministry&channelID=-8395&navId=NAV_ID_province


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The formal approval process is followed when the work is considered to

potentially have a significant impact on navigation, or when the work isspecifically named within the Act. Works named within the Act are bridge, boom,

dam, and causeway. Work Assessment letters can be issued in the case where thework is considered not to have a significant impact on navigation.

Formal approvals issued by the Navigable Waters Protection Division require thatthe work be subjected to an Environmental Assessment in accordance with the

Canadian Environmental Assessment Act. See Ministry Guidelines for Navigable

Waters approval submissions.

Use and Role of Environmental Monitors

Environmental monitors are only required as described by the Fish-streamCrossing Guidebookand only when specified by the environmental agencies on a

site specific project basis. To avoid the potential for or perception of conflict ofinterest, an Environmental Monitor, when required, must be retained by the

ministry rather than the works contractor.

An Environmental Monitor may be retained to monitor site activities for

conformance with construction contract work plans that incorporate measures to

protect forest resources in accordance with legislative requirements or duringactive development operations in sensitive habitats and ecosystems.Environmental Monitors may be warranted where road or bridge construction

occurs in critical or important fish habitats, or where instream work is approved

outside of the fisheries timing window. The requirement for an Environmental

Monitor may be a condition of project approval and construction contract workrequirements. However, utilization of Environmental Monitors should only be

implemented when warranted.

Appropriate qualifications for Environmental Monitors can be found on theEngineering Equipment and Services (EES) Directory under two categories:

i) Professional Environmental Monitoring (RPBio); and

ii) Technical Environmental Monitoring

Where an Environmental Monitor may be warranted, their scope of duties may

include:

1. liaise with ministry staff or other regulatory agencies;

2. observe, record, and photograph the baseline site conditions before workcommences and identify any significant (material adverse) changes in site

conditions during and after work;3. attend the pre-work meeting and other project meetings as necessary, and

provide assistance to the Licensee/Permittee/Contractor or ministry to assessconformance with the construction contract work plans, contract conditions,

and BCTS EMS requirements (e.g., EFPs; Hazardous Materials Spill

Preparedness Responsibilities and Spill Action Steps; Landslide and Major

http://laws.justice.gc.ca/en/C-15.2/174391.htmlhttp://gww.for.gov.bc.ca/hth/engineering/documents/policies_procedures/mld/June%202004%20Navigable%20Waters%20Submission%20Guidelines2.pdfhttp://gww.for.gov.bc.ca/hth/engineering/documents/policies_procedures/mld/June%202004%20Navigable%20Waters%20Submission%20Guidelines2.pdfhttp://www.for.gov.bc.ca/tasb/legsregs/fpc/FPCGUIDE/FishStreamCrossing/FSCGdBk.pdfhttp://www.for.gov.bc.ca/tasb/legsregs/fpc/FPCGUIDE/FishStreamCrossing/FSCGdBk.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/systems/ees/P20-Professional%20Environmental%20Monitoring.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/systems/ees/T08-Technical%20Environmental%20Monitoring.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/systems/ees/T08-Technical%20Environmental%20Monitoring.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/systems/ees/T08-Technical%20Environmental%20Monitoring.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/systems/ees/P20-Professional%20Environmental%20Monitoring.pdfhttp://www.for.gov.bc.ca/tasb/legsregs/fpc/FPCGUIDE/FishStreamCrossing/FSCGdBk.pdfhttp://www.for.gov.bc.ca/tasb/legsregs/fpc/FPCGUIDE/FishStreamCrossing/FSCGdBk.pdfhttp://gww.for.gov.bc.ca/hth/engineering/documents/policies_procedures/mld/June%202004%20Navigable%20Waters%20Submission%20Guidelines2.pdfhttp://gww.for.gov.bc.ca/hth/engineering/documents/policies_procedures/mld/June%202004%20Navigable%20Waters%20Submission%20Guidelines2.pdfhttp://laws.justice.gc.ca/en/C-15.2/174391.html


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Erosion Event Response and Erosion Action Steps; and EMS documentation

requirements);4. conduct on-site field visits either continuously or periodically to observe

active operations; the timing and duration of field visits will depend on thetype and complexity of the work, and on the sensitivity of the site and forest

resource values at risk of damage or loss;5. during field visits, evaluate the adequacy of erosion and sediment control

techniques, including work procedures for instream work, construction anddiversions on watercourses, and observe, record, and photograph siteconditions and work procedures;

6. provide practical and appropriate options to protect or minimize harmful

effects to fish and fish habitat if changes to the work occur due to unforeseen

circumstances;7. modify or stop operations if the following occurs:

a. site activities do not conform with approved construction contract work

plans and contract conditions;

b. work activities lead to harmful levels of sediment entering a stream;

c. work activities may harmfully alter, disrupt, or destroy fish or fish habitat

or other forest resources;

d. unforeseen circumstances related to the work cause or may causeenvironmental problems.

8. assist the Licensee/Permittee/Contractor or ministry with documentation

requirements;

9. if applicable, confirm that the completed work activities meet the

requirements of the fisheries agency that grants a variance on the timing

window and/or approval for the planned works;10. provide a brief written report to the ministry (and other agencies if requested)

preferably within two weeks (but not later than four [4] weeks) after

completion of the project that includes the following information:

a. Background information;

b. Summary of Licensee/Permittee/Contractors work procedures and

environmental protection strategies;

c. Description of pre-works activities, works activities, and post-works

activities;

d. Conclusions; ande. Appendices, including copies of stop work orders (if any) and photographs

(with time and date) of all important phases of the work showing site

conditions before, during and after the work.



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5.10 General Arrangement Construction Drawings and Specifications

General arrangement drawings are the outcome of the design process and showthe location, composition, and arrangement of the proposed structure in relation to

the specific crossing. Such drawings are needed to:

describe the structure to other stakeholders, agencies, and other parties, asnecessary;

allow the estimating, contract tendering, and costing of materials, installation,and associated site work; and

provide direction to the builder and reduce the need for ongoing direction

from the designer during the actual field construction.

Note: Site plan and profile drawings are design aids from which a proposeddesign is developed. They are not general arrangement drawings or design

drawings.

General arrangement drawings should be signed and sealed by the professionalengineer who is taking responsibility for the design.

A set of construction drawings consists of the general arrangement drawingssupplemented with detailed superstructure and substructure drawings and other

fabrication, material, and construction specifications. Shop drawings are preparedby material fabricators to detail, and in many cases complete the structural design

of bridge structure components. These drawings will form part of the construction

drawing set and should be retained as part of the as-built documentation. Thecomplete construction drawing set should provide comprehensive details on the

location, composition, arrangement, design parameters, and fabrication, materials,

and construction specifications for the specific proposed structure. Thedevelopment of construction drawings is an integral part of the construction

process and is intended to be completed before on-site construction begins.

The general arrangement drawings and fabricator shop drawings should becompared for consistency.

Typical scales for bridge and major culvert design and construction drawings are

1:200, 1:100, and 1:50. The construction drawings should clearly show all

construction details and enable installation in general conformance with thedesign intent. Where appropriate, a smaller scale should be used for greater detail.

5.10.1 General Bridge Arrangement Drawing Requirements

General arrangement drawings should clearly depict the proposed components

and configuration of the bridge or major culvert in relation to the forest road,stream, and streambanks. These drawings may also be used during the agency

referral process. Further details can be found in the Forest Service Bridge Design

and Construction Manual.

http://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdf


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Recommended contents for bridge and major culvert general arrangement

drawings include:

site location key map;

designers name (and seal);

name of the stream, road, and station (km) and adequate information to detail

the location of the structure;

design vehicle configuration for load and alignment;

design code references, specifically those from the most recent version of the

CAN/CSA S6-00 Canadian Highway Bridge Design Code and the CanadianFoundation Engineering Manual;

expected life of the structure in place (temporary or permanent);

design high-water elevation for bridges and design discharge;

clearances between the design high-water level and soffit (low point of

underside of superstructure) of bridges;

details of debris passage or management strategies, if required;

road approaches and grades, including width requirements (e.g., allowance forvehicle side tracking) and side slopes, to a sufficient distance back from the

bridge to show potential problems, or to the end of the first cut or fill;

dimensioning and labelling of component parts (to be confirmed with the shopdrawings);

connections for component elements;

drawings scales;

relevant site plan and profile data (for suggested contents, see 5.7: Site Data

and Survey Requirements for Bridges and Major Culverts; sample general

arrangement drawings are shown following in Figure 5.5 and Figure 5.6);

location (vertical and horizontal) of proposed structure relative to field

reference points;

deck elevations at bridge ends;

possible ford or temporary bridge crossing locations;

road and bridge or culvert signs;

approach barriers, if required;

rip rap extents;

limit of construction for contract purposes;

pecial provisions related to the unique nature of the site and crossing,

including specific instructions to bidders related to process or results, asappropriate;

special instructions relating to material erection, installation standards,

requirements, or methods as deemed necessary; and

references to specific design drawings or design aids used.

http://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.library.for.gov.bc.ca/ipac20/ipac.jsp?session=1142YS772470N.89342&menu=search&aspect=basic_search&npp=10&ipp=20&profile=mof&ri=1&source=142.36.141.139%40%21forest&index=.GW&term=Canadian+Foundation+Engineering+Manual&x=8&y=12&aspect=basic_searchhttp://www.library.for.gov.bc.ca/ipac20/ipac.jsp?session=1142YS772470N.89342&menu=search&aspect=basic_search&npp=10&ipp=20&profile=mof&ri=1&source=142.36.141.139%40%21forest&index=.GW&term=Canadian+Foundation+Engineering+Manual&x=8&y=12&aspect=basic_searchhttp://www.library.for.gov.bc.ca/ipac20/ipac.jsp?session=1142YS772470N.89342&menu=search&aspect=basic_search&npp=10&ipp=20&profile=mof&ri=1&source=142.36.141.139%40%21forest&index=.GW&term=Canadian+Foundation+Engineering+Manual&x=8&y=12&aspect=basic_searchhttp://www.library.for.gov.bc.ca/ipac20/ipac.jsp?session=1142YS772470N.89342&menu=search&aspect=basic_search&npp=10&ipp=20&profile=mof&ri=1&source=142.36.141.139%40%21forest&index=.GW&term=Canadian+Foundation+Engineering+Manual&x=8&y=12&aspect=basic_searchhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=English


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Figure 5-5: Sample of General Arrangement and layout (simple creek

crossing)



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Figure 5-6: Sample of General Arrangement and layout (complex creek

crossing)



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5.10.2 Bridge Superstructure Drawing Requirements

In addition to the general drawing requirements, the following elements should be

detailed on bridge superstructure drawings:

design code references, specifically those from the latest version of the

CAN/CSA S6-00 Canadian Highway Bridge Design Code and the CanadianFoundation Engineering Manual.

materials specifications and CSA references, including but not limited to:

steel grades, impact category, finish;

timber species, grades, preservative treatment;

concrete strength, slump, and air entrainment;

bearing materials and connections;

superstructure elements, configuration, and connections;

dimensions and sizes of components;

girder or stringer arrangements and connections;

span lengths;

bridge and road width;

curb and rail configuration, connections, and component elements;

bridge label with structure number, date of manufacture, and load rating;

and

field fabrication details.

5.10.3 Bridge Substructure Drawing Requirements

The following information on foundation requirements should be detailed on the

bridge substructure drawings:

abutment elements, configuration, and connections;

dimensions and sizes of components;

critical elevations of substructure components;

scour protection: dimensions, composition, extent of placement, design slope,

design highwater, and other considerations;

piers;

location and sizes of piles or posts;

pile-driving specifications, minimum expected pile penetrations, set criteria,and required service level capacities;

field welding requirements;

bracing and sheathing configurations; and

foundation requirements, material types and depth, and compaction level.

The above requirements also apply to portable bridge superstructures.

http://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=Englishhttp://www.library.for.gov.bc.ca/ipac20/ipac.jsp?session=1142YS772470N.89342&menu=search&aspect=basic_search&npp=10&ipp=20&profile=mof&ri=1&source=142.36.141.139%40%21forest&index=.GW&term=Canadian+Foundation+Engineering+Manual&x=8&y=12&aspect=basic_searchhttp://www.library.for.gov.bc.ca/ipac20/ipac.jsp?session=1142YS772470N.89342&menu=search&aspect=basic_search&npp=10&ipp=20&profile=mof&ri=1&source=142.36.141.139%40%21forest&index=.GW&term=Canadian+Foundation+Engineering+Manual&x=8&y=12&aspect=basic_searchhttp://www.library.for.gov.bc.ca/ipac20/ipac.jsp?session=1142YS772470N.89342&menu=search&aspect=basic_search&npp=10&ipp=20&profile=mof&ri=1&source=142.36.141.139%40%21forest&index=.GW&term=Canadian+Foundation+Engineering+Manual&x=8&y=12&aspect=basic_searchhttp://www.library.for.gov.bc.ca/ipac20/ipac.jsp?session=1142YS772470N.89342&menu=search&aspect=basic_search&npp=10&ipp=20&profile=mof&ri=1&source=142.36.141.139%40%21forest&index=.GW&term=Canadian+Foundation+Engineering+Manual&x=8&y=12&aspect=basic_searchhttp://www.csagroup.org/news/newsletters/perspectives/default.asp?articleID=5257&searchType=allWords&searchWordList=CAN%2FCSA+S6&language=English


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5.10.4 Log Bridge Superstructure on Log Crib Drawing Requirements

Since log stringer and crib materials are variable in nature and finished

dimensions are not uniform, log bridge drawings will be somewhat schematic.Drawings should address layout, required component sizing, and connection

details.

The following should be indicated on the log bridge superstructure and log cribdrawings:

schematic layout indicating width and span;

reference source for stringer and needle beam sizing;

minimum stringer, curb, and needle beam dimensions;

stringer, curb, needle beam, and crib logs specifications, including species,quality characteristics of acceptable logs, and seasoning;

stringer-to-cap bearing details, including shim types and stringer and cap-

bearing width and surface preparation;

dap details at log connections; needle beam locations and connection details, if applicable;

space to add stringer, curb, and needle beam sizes as part of the as-built

record;

deck layout, indicating tie sizes and spacing, plank thickness, and

connections;

other materials specifications, including sawn timber, hardware, and shims;

excavated depth relative to scour line for mudsill or bottom bearing log;

general layout and arrangement of front, wing wall, deadman, and tiebacklogs, and their connections to each other and to the bearing log or cap;

description of crib fill material;

layout and description of in-stream protection, if applicable; and rip rap protection layout and specifications (as required).

5.10.5 Major Culvert Drawing Requirements

Drawings and notes for major culverts should portray and describe the following:

site plan, see 5.7: Site Data and Survey Requirements for Bridges and MajorCulverts;

location of the culvert, such as a key map;

design vehicle load;

fill height, depth of cover, and maximum and minimum cover requirements;

design slopes of fill and rip rap; culvert invert elevations at the inlet and outlet;

culvert specifications and dimensions: opening dimensions, length,

corrugation profile, gauge, material type, and inlet bevel specifications;

site preparation requirements;

embedment requirements, including a description of the substrate and any

rock used to anchor the bed material in the pipe;

foundation details;

backfill and installation specifications;



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installation camber;

culvert gradient;

seepage barrier details if required;

special attachments or modifications;

inlet requirements (rip rap layout, stilling basin, etc.);

outlet requirements (rip rap layout, stilling basin, backwater weir for fishpassage);

rip rap specifications, including dimensions and configuration;

design high-water elevation and design discharge, inlet or outlet control;

connection details for pipe sections; and

any existing improvements and resource values in the vicinity of the culvert

that would influence or be influenced by the structure.

Any of the above requirements can be combined. For example, drawings for a log

stringer bridge on timber piles can include the details from 5.10.4: Log BridgeSuperstructure on Log Crib Drawing Requirements, plus those from 5.10.3:

Bridge Substructure Drawing Requirements.

Any additional requirements for a fish stream culvert should be included, asspecified in the Fish-stream Crossing Guidebook.

5.10.6 Portable Bridge Superstructures

Where portable bridge superstructures or other structural components are used,

the components must have been designed or structurally analyzed by a

professional engineer. The design or analysis should demonstrate adequacy forthe intended use. Once the components have been reviewed and approved by a

professional engineer, the components may be reused at new sites without specific

professional engineer review of the superstructure, provided that: a Qualified Inspectorhas inspected the bridge at the new site before any use

and does not detect any damage or deterioration of the structure;

see Chapter 7.7.1: Types of Inspections

the design loads to be carried are equal to or lower than the original design

loads for the superstructure; and

the bridge is suitable and has been specifically designed for the new site, andthe superstructure has been fabricated and constructed in compliance with the

appropriate legislation.

Whoever carries out a design must sign and seal the design drawings and

specifications and take responsibility for the design.

5.11 Major Works Construction Contract

Chapter 2: Administration and Management of Contracts and Agreements and the

Contract Management Manual provide details on such matters as:

responsibilities;

construction contract including schedules, tendering, general conditions,

special provisions);

http://www.for.gov.bc.ca/tasb/legsregs/fpc/FPCGUIDE/FishStreamCrossing/FSCGdBk.pdfhttp://www.for.gov.bc.ca/hth/engineering/documents/systems/ees/T07-Technical%20Bridge%20&%20Major%20Culvert%20Cond%20Insp.pdfhttp://gww.for.gov.bc.ca/hfm/pub&guides/cmp/conadm/manual/Table_of_Contents.htm#P457_15567http://gww.for.gov.bc.ca/hfm/pub&guides/cmp/conadm/manual/Table_of_Contents.htm#P457_15567http://www.for.gov.bc.ca/hth/engineering/documents/systems/ees/T07-Technical%20Bridge%20&%20Major%20Culvert%20Cond%20Insp.pdfhttp://www.for.gov.bc.ca/tasb/legsregs/fpc/FPCGUIDE/FishStreamCrossing/FSCGdBk.pdf


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pre-work meeting (including timing of construction, adherence to drawings

and standards, and review layout);

construction monitoring/inspections/records; and

construction assurance/quality assurance (including materials test results).

5.12 Bridge and Major Culvert Materials Acquis itionMaterials for ministry bridges and major culvert projects are acquired in two

ways:

through requisition for materials via the Purchasing Commission and BC Bid;and

through works contract which include supply and installation of bridges and

major culverts.

In either case, all rules of government public tendering apply, and specifications

and standards for bridge and culvert materials should be identical.

Standard templates for acquiring bridge materials have been developed for useand are available on the Resource Tenures and Engineering Branch Bridges and

Major Culverts website.

The ministrys standard bridge material requisition templates are intended to beused primarily by ministry field engineers and/or the professional engineer taking

responsibility for a bridge structure design or installation. Bridge material

requisitions must be consistent with the design. It is recommended that theregional field engineer be consulted when a bridge material requisition is being

developed for a specific project.

The language in the requisition templates should also be incorporated intoministry contracts where bridge material supply is included in the contractedworks. The design and quality assurance requirements for bridge material supply

under direct requisition or through a design, supply, and construct contract areidentical.

Bridge material requisitions should limit the design requirements to specific

structural design. The required components for a structure should be fully

determined, by the design engineer, by the time materials are being acquired. Forexample, for slab girder bridges, the general arrangement design should specify

whether the girders are connected, whether the connections are field-grouted or

welded shear connectors, and how, in detail, the girders connect to the abutments.

Requisitions should be specific to the bridge materials being ordered and makereference to the applicable specifications and standard drawings in the Forest

Service Bridge Design and Construction Manual. Only in the odd instance where

bridge materials have had a unique design completed should other drawings beincluded in the bridge material specifications. In such cases, the attached

drawings should be limited to the detail necessary for the bridge material

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single pour (must not have any cold joints); and

a finish free of honeycombing.

For higher risk structures, those that consist of multiple levels of lock blocks, or

those with significant bearing pressures, quality requirements of precast concreteblocks should be more rigorous and specified by the engineer taking

responsibility for the design.

Structural Steel

Structural steel for permanent and portable bridges must comply with CSAStandard CAN3-G40.21-M Structural Quality Steels. Primary tension members

of welded structures must be of type AT, grade 350 or better.

Weathering steel, type 350 AT, shall not be used for permanent bridges in marineor coastal areas or in areas where there is potential for road de-icing salts to come

in contact with the bridge. Alternatively, galvanized or painted steel must be

specified.

Steel fabrication must be completed by firms certified by the Canadian Welding

Bureau (CWB)to Div 1 or 2. A list of CWD companies can be found on-line atthe Canadian Welding Bureauwebsite.

Timber

Timber used for bridge construction must be graded in accordance with the

standard grading rules of the Canadian Lumber Standards Administrative Board.Timber must be grade-stamped, with the exception of unfinished or rough timber

(in which case grading certificate may be requested), or local log stringers.

Structural timbers must be Douglas-fir/larch #2 grade or better, except timbercurbs maybe any species #2 grade or better. Note that the structure strength and

other characteristics, such as durability, make Douglas-fir/larch a superior product

to other species.

Culvert Materials

Culvert

Corrugated steel culverts must be manufactured in accordance with CAN/CSA 3-G401 standard, Corrugated Steel Pipe Products. Steel culverts fabricated from

steel sheets must meet all requirements of ASTM A444, Standard Specificationsfor Zinc Coated (Galvanized) Iron and Steel Sheets for Culverts andUnderdrains. All hardware must conform to applicable standards (that is, rivets

must be galvanized, and bolts and nuts must be Grade C, galvanized, meeting the

requirements of ASTM standard A563.

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Culvert Bedding and Backfill

The following is a brief discussion of culvert bedding and backfill requirements.

Typical culvert installations require compaction to obtain adequate structuralintegrity of the installation because culverts are generally soil-steel structures. The

culvert itself will not support the design load without the soil-steel interaction. Inorder for the soil to work with the steel to support the design load, the culvertmust be adequately bedded and the soil must be appropriately compacted to be

structural. The flexible steel is designed to distribute loads to the bedding andbackfill surrounding it. Soil is most compactable when it is composed of select

granular, free-draining material. The backfill should conform to a specified size

gradation.

The typical backfill compaction required is the minimum Standard Proctor

Density of 95%. To achieve that level of compaction, vibratory equipment isrequired, such as hand tools to work smaller areas (between corrugations);

mechanical compactors such as plate and jumping jack tampers; or rollers andvibrating compactor equipment.

The steps following are recommended practice:

Adequate bedding is required before culverts are installed and backfilled.Where subgrade material is unsuitable, it should be removed and replaced

with select granular, free-draining material compacted to support the culvert.

Backfill should typically be placed in lifts working on both sides of theculvert. Uniform layers, 150300 mm thick, of select granular, free-draining

material should be placed and compacted on each side of the culvert in a

balanced and progressive manner. The fill on both sides should beapproximately balanced or equal at any given point in time to avoid potential

distortion or displacement of the culvert.

obbles and boulders should be removed from the backfill, particularly where

they could contact the culvert. Hand tools should be used to compact the

material immediately adjacent to the culvert within the corrugations. Eachlayer should be fully compacted before the next layer is placed on top.

Compaction should be monitored and compaction testing completed as

specified by the designer. Special monitoring and/or testing equipment may be

specified or warranted.

Backfill work should avoid over-compaction which can also distort the

culvert. Backfill and compaction should continue to above the culvert, as

specified in the design. Minimum culvert cover should be established beforeany equipment loads are applied.

Designs for major culverts should be specific with respect to bedding and

backfill requirements including material and compaction specifications.



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Materials Documentation

All relevant material documentation must be obtained and kept on file, such as

mill test certificates, in-plant test results, field test results, and all reports orcomments made by field or in-plant inspectors.

5.13.2 In-Plant Inspection of Bridge Materials and Fabrication

Forest Service Road bridge components assembled or manufactured off the

construction site (such as steel girders, precast concrete footings, girders, footingsor deck panels) require off-site inspection to provide quality assurance that all

materials and procedures meet applicable codes and standards. The ministry

carries out this measure of quality assurance to ensure that acquired materialsmeet fabrication standards and specifications. The costs associated with

inspection have been demonstrated to be minor in terms of off-setting futureproblems with the fabricated components. The ministry engages a contractor to

provide the in-plant inspection services at the various fabrication plants around

the province. The in-plant quality assurance inspection contract is coordinated by

the Resource Tenures and Engineering Branch.

Note: All bridge materials acquired by the Ministry of Forests and Range,

whether installed by hired equipment, contracts, or licensees, must be

inspected at the fabrication plant by Ministry of Forests and Range

inspectors as a quality assurance measure.

The fabricator producing the bridge materials must provide copies of detailed

shop drawings to the in-plant inspector. The inspectors role is to confirm that thestrength of materials and details of fabrication are consistent with the shop

drawings and applicable specifications, as accepted for the project, standards, and

codes. Where discrepancies occur, the inspector must notify the appropriateRegional Bridge Engineer for input on acceptability or required modifications.

For more detailed information regarding material and fabrication requirements,

refer to the Forest Service Bridge Design and Construction Manual.

Upon completion of in-plant inspection works, the inspector must complete an in-

plant inspection report for each bridge and submit it to the Regional BridgeEngineer.

Structural Field Welding

All structural field welding must be in conformance with CSA Standard W59.Structural welds are connections that contribute to the load-carrying capacity ofthe structure (e.g., bearings to pipes and precast concrete foundations, and welded

shear connectors for precast slab bridges). Steel fabrication must be completed by

firms certified by the Canadian Welding Bureau Certification (CWB) to Division1 or Division 2. A list of CWB certified companies can be found on-line at the

Canadian Welding Bureau website.

http://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdfhttp://www.cwbgroup.org/tal/12850974868375471570.asphttp://www.cwbgroup.org/tal/89639818689327013224.asphttp://www.cwbgroup.org/tal/89639818689327013224.asphttp://www.cwbgroup.org/tal/12850974868375471570.asphttp://www.for.gov.bc.ca/hth/engineering/documents/publications_guidebooks/manuals_standards/bridge_manual.pdf


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Structural Field Grouting

Where structural field grouting is required, such as for composite concrete decks

or shear connections for concrete slabs, the grout should be mixed and placed inaccordance with manufacturers specifications.

Because grout, when mixed properly, is not fluid and cannot be poured, it mustinstead be packed into place. Where too much water is used in the mix, thestrength and quality of the grout is compromised. This can be a serious problem

where the grout is intended to be a structural connection, which is almost always

the case. When too much water is incorporated, the durability of the grout willalso be negatively affected. Grout mixing procedures should be monitored and

adherence to manufacturers specifications strictly enforced.

Additional precautions are required for mixing and placing concrete or grout in

cold weather. Preheating and continued heating for the initial set period for theconcrete or grout may be required to ensure that the setting of concrete or grout is

not affected by cold temperatures, in particular freezing. Compliance with themanufacturers specifications should be ensured.

Where structural field grouting is carried out, samples of the grout should be

collected at various times, at the direction of the engineer taking responsibility for

the structure. The grout samples should be placed in a safe area that isrepresentative of the setting conditions for the grouted works for a minimum of 12

hours. The samples should then be tested, by appropriate testing facilities, at thedirection of the engineer taking responsibility for the structure. Results of the

testing must be considered by the engineer when determining that the structure is

in conformance with the design and that the structure is safe to put into service.

5.14 General Conformance and Construction Documentation

After construction of a bridge, major culvert, or other specialized structure, theengineer taking responsibility for the bridge must sign and seal, as appropriate, a

statement indicating that the entire structure is in general conformance with thedesign drawings and specifications.

The Ministry of Forests and Range Statement of Construction Conformance

(FS 138) is required to be completed and placed in the file.

Documentation of materials used, along with as-built records for the bridge or

major culvert, should be obtained during fabrication and construction. The personresponsible for construction must obtain and retain the following as-built records:

pertinent construction data including, but not limited to, any pile driving

records, hammer type, penetration, set criteria, and any critical dimensions;

fabrication plant inspection reports, including mill test certificates, andconcrete test results;

shop or as-built fabrication drawings;

concrete and grout test results;

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field compaction results;

confirmation of scour protection requirements;

footing base elevation, deck elevation, and alignment location; and

other pertinent fabrication, field, and construction data.

As-built drawings are the approved for construction drawings (which may in

fact be the approved design drawings), marked up to show all significant

variations from the original design. Mark-ups would show as constructed detailsof the records kept by the construction inspector (see the list preceding). The as-

built drawings (see sample) should be signed (and sealed, where applicable) bythe professional engineer in charge of ensuring that the as-constructed structure is

in general conformance with the design. Where the original design has been

modified, these drawings should have been amended accordingly by the designerbefore the as-built notes and details are inserted.

The as-built drawings, materials records, fabrication documentation, and other

field and construction documentation must be retained for the life of the structure.

Copies of all original as-built documentation, including the signed and sealeddrawings,

Documents

Manual for Engineering