Introduction to Bridge Design and

Construction 1

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Bridge Engineering 101 Part 2 -Planning and Design

Questa Engineering Corporation

Sydney Temple, P.E.

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Introduction Today’s Talk:

General Design Steps Planning to Construction

Bridge foundation types

Environmental Review & Permits

Construction

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Multi-Discipline Approach

Structural Engineering

Geotechnical Engineering

Civil Engineering

Planning and Permitting

Geomorphology

Hydraulic Engineering

Biologic Evaluations

Geologic Evaluations

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Basic Design Steps

Investigate the site

Survey, Geotech, Hydrology, Biology

Opportunities and constraints

Determine bridge type and location

40% Design

Permitting

Final foundation and superstructure design

Construction drawings

Construction

Construction management

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Site Survey Data

Site Survey General topography for 100 feet upstream/downstream min.

Channel slopes Long profile at 350 feet upstream and downstream

Existing structure data Slope, shape, dimensions, top of roadway, top of culvert, apron

slopes and wing wall geometries

Make sure bridge approach roads are surveyed including edge of pavement, roadway crowns, super elevations

Map utilities and nearby structures

Introduction to Bridge Design and

Construction 2

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Site Analysis

Site analysis:

Geotechnical Considerations

Hydrologic/Hydraulic Studies

Geomorphic Considerations

Biologic issues

Bridge Layout

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Geotechnical Investigations

Regional geologic and seismic conditions

Local Soil conditions

Local Geologic hazards

Subsurface exploration

Design recommendations

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Subsurface Investigations

Exploratory holes; 10 - 100+ feet

Soil samples are collected for analytical testing

Perform Standard Penetration Test (SPT) sampling for strength characteristics (I.e. Blow Counts/ft)

Determines groundwater levels

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Types of Drilling

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Geotechnical Reports

Summarize geological hazards

Local site conditions

Provide recommendations for foundation design

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Introduction to Bridge Design and

Construction 3

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H & H Investigations

Hydrology data

Regional source – Flood Control Agencies

Site specific modeling

Hydraulics analysis

Governmental sources; Caltrans, FEMA, and County Flood Control Agencies

Complete site specific analysis

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Project Site

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Design Water Surface Elevations

Hydraulic Design Criteria and Freeboard

Vary by Jurisdiction

50-year with 2 ft of freeboard

100-year with at least 1 ft freeboard

Levees – three feet of freeboard

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Geomorphic Analysis

Vertical & Lateral creek movement

Sediment transport

Bankfull channel

Low-Flow (scour line) channel

Introduction to Bridge Design and

Construction 4

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Determining Vertical and Lateral Creek Movement

Historic profile analysis

Existing condition long profile analysis

Historic air photo examination

Historic topographic map analysis

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Lateral movement

Longitudinal Profile Analysis

70

80

90

100

110

120

130

140

150

-1+50 3+50 8+50 13+50 18+50 23+50 28+50 33+50

River Station (ft)

Flo

w L

ine

Ele

va

tio

n (

ft)

Reach 3Reach 2Reach 1

Mitigated Knickpoint (armored)

Un-mitigated Knickpoint

Dri

sco

ll R

oad

Pal

m A

ven

ue

SF Aqueduct,

concrete

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Fall 2003 March 2005

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Introduction to Bridge Design and

Construction 5

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Biological Reconnaissance

Special-Status Species

Existing Habitat ID and Mapping

OHW/Wetland Delineation

CNDDB Search

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Bridge Layout – Structure Positioning

Right of Way

Alternative alignments

Approaches

ADA Requirements

Traffic/Roadway design issues

Utilities

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Roadway Design Issues

Alignments

Approach elevations

Vertical curves- approach slopes

Will you need embankments or other retaining structures?

Introduction to Bridge Design and

Construction 6

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Bridge Widths

Typical trail - 10 feet width

Major trail - 12 foot width lanes plus 2 feet of railing/curb

Single lane = 18 feet, 14 feet between railings/curbs

Two Lane = 28 feet, 24 feet between railings/curbs

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Bridge Design and Impacts

Goal: shortest bridge with the least amount of impact

Design Criteria

Passes design flows with freeborad

50-year with 2 ft of freeboard

100-year with at least 1 ft freeboard

No increase in flood threat

Minimizes scour and deposition

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Planning Level Bridge Costs

Pedestrian Bridge construction costs in northern California $125-$140 per square feet (sf) for cast in place concrete, $115-$150 per sf for prefabricated bridges. $1,500 per lineal foot

Traffic Rated Bridges Two Lane light to medium traffic

$350-500 sf

Major arterial structures $600-$750 sf

Introduction to Bridge Design and

Construction 7

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Project Concept

CEQA

Certification

Flood Control

Public Safety

Permits

Environmental

Permits

Implementation

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Project Permit Documents

Site Map Water of the USCOE Jurisdictional Area Project Description Detailed Alternatives examined/project justification 40% design drawings

Project Analysis Technical analysis or separate back up design

memorandum (H&H, Geotech, etc.)

Biologic Reconnaissance

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Project Description

Project Justification Site plan

Project channel bed profiles

Project cross section views

Habitat enhancement features

Limits of work, Mobilization

Area of impact

USCOE, riparian area, vegetated area

Determination of cut and fill quantities

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CEQA Review

Categorical Exemption

Initial Study Preparation

Mitigated Negative Declaration

EIR/EIS

Lead Agency

City, County or Special District

State for some grant funded projects

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Environmental Permits

U.S. Army Corps of Engineers 404 Permit

Endangered Species Act Consultation

California Department of Fish & Game Streambed Alteration Agreement

Regional Water Quality Control Board

Water Quality Certification & General Stormwater Construction Permit

Coastal Development Permit

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USCOE Permits

Reviews application and notifies National Marine Fisheries Service (NMFS) and/or US Fish and Wildlife Service (USFWS)

May ask for formal or informal consultation

May require preparation of a Biologic Opinion (BO) and/authorization for take

NMFS will review Fish passage analysis

Introduction to Bridge Design and

Construction 8

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Streambed Alteration Agreements

CDFG staff review

Must have CEQA completed to issue

Includes impacts to riparian areas

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Coastal Development Permit

Usually processed through the County

May require architectural review

May require separate monitoring protocols

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Permit Timeline

6 month is likely minimum

1 year is not out of the question

NMFS and USFWS have 135 days

CDFG - 30 days

Coastal Development Permit – 6 months+

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Design Breakdown

Foundation design

Bridge deck design

Channel Design if needed

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AASHTO & Caltrans

American Association of State Highway and Transportation Officials

National Association which establishes and promotes highway construction and safety standards.

California Department of Transportation

Manages State Highway System

Issues permits for encroachment into state owned highways and properties

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Typical Light-Duty Bridge Crossing Profile

80

0+00 0+40 0+80 1+20 1+60 2+00 2+40 2+80

94.4

94.3

94.1

93.5

93.1

90.7

89.7

86.0

82.9

81.2

83.9

86.5

92.5

96.0

97.0

98.0

98.8

99.7

100

.2

100

.2

100

.2

100

.2

100

.2

99.2

98.2

97.2

90

100

94.4

95.3

96.2

97.1

96.8

96.7

2+91

80

90

100

Introduction to Bridge Design and

Construction 9

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Required Load Capacity and Anticipated Uses

Public Trails -

Pedestrian/Bicycle/Equestrian/Disabled Users

Light-Duty – Typically Residential

Automobiles/Light Trucks

Highway Traffic – Heavy Trucks HS20-25 loads

(AASHTO Load Standards)

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Bridge Foundation Considerations

Required Load Capacity and Anticipated Uses

Site Conditions & Geotechnical Investigations

Foundation Types Spread Footings

Driven Piles

Drilled Cast-In-Place Piers

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Foundation Types - Spread Footings

Relatively shallow reinforced concrete mats to distribute bridge loads over wide area of supporting soils.

Advantages

Typically least expensive option

Minimal equipment mobilization requirements

Disadvantages

– Not suitable over soft or liquefiable soils

– Minimal resistance to undermining or slope instability

– Moderate to heavy site disruptions

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Typical Spread Footing Bridge Foundation

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Foundation Types - Driven Piles

Tubular and Sheet Steel, Reinforced Concrete or Composite Piles driven into soils using a dropped weight or piston hammer, applied typically in marine settings.

Advantages Minimal site disruption

Provides support over soft or variable subgrade conditions

Applied in areas prone to flooding or with very soft soils

Disadvantages Requires mobilization of large equipment and materials

Requires minimum embedment depth into soil

Introduction to Bridge Design and

Construction 10

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Reinforced Concrete Piles Being Installed in a Marine Environment

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Foundation Types - Drilled Cast-In-Place Piers

Drilled holes filled with cast-in-place reinforced concrete piers.

Advantages Typically provides greatest resistance to vertical and lateral

loads

Provides excellent resistance to scour

Used in steep and/or unstable slope areas

Disadvantages Typically highest cost

Difficult to apply in areas of shallow ground water or loose soils

Moderate site disruptions

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Drilled Pier Foundation Design for Timber Framed Bridge

#4 BAR

#4 BARS

FOR STEM WALL

1'

3'-4"

14'-8"

#4 HOOPS @12" O.C.

4 #5

3" COVER3' COVER

58" X 12" ANCHOR

BOLT @ 48" O.C.

12"

#4 HOOPS @12" O.C.

4 #5

9 #5

7 #4

8"

12"

1'

5'-8"

10'-0"

12"

8"

3" COVER

3" COVER

2'-4"

7 #4

12"

12"

12"

12"

14'-8"

3'-8"

10'-0"

#5 #4

C'

B

3" COVER3" COVER

#4 HOOPS @12" O.C.

4 #5

#4 HOOPS @12" O.C.

4 #5

3' MIN.

12"

12"

7 #4

B

PLANSECTION B-B'

SECTION C-C'

SECTION A-A'

C

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Photo of Drilled Cast-In-Place Pier Installation

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Public Safety Permits

County/ City Building Permits

Structural & Roadway Design Review

Floodplain Management

Caltrans

Primarily concerned with impacts to their facilities and safety

Maintenance responsibility

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Construction 11

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County/City Review

Reviews detail plans and calculations

Roadway design

Structural design

Geotechnical design

Flood control

Construction Drawings

Plan set

Site Plan and layout

Foundation plans

Superstructure plans

Road or trail plans

Erosion Control

Ancillary structures

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Construction Specifications

Bidding instructions

Work hours

Contracting requirements

Construction and material specifications

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Picture of ferrasci improvements

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Construction Factors

Site and Channel Access

Work Conditions

Biological monitoring

Restricted Seasons

Mobilization and Staging Areas

Materials Storage Areas

Dewatering

Limits of Work

Introduction to Bridge Design and

Construction 12

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Construction Sequence

Water control

Foundation construction Drilling

Concrete forming

Grading

Installation or construction

Approach construction

Erosion control

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Contact Info

Sydney Temple

Questa Engineering Corp.

Stemple@questaec.com

(510) 236-6114 ext 220

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