Geotechnical Aspects of the Twin Ports Interchange (TPI) Duluth, … MWGC... · 2019-09-26 ·...

Geotechnical Aspects of theTwin Ports Interchange (TPI)

Duluth, Minnesota

Rich Lamb, P.E.

2019 Midwest Geotechnical Engineering Conference

September 16-19, Columbus, OH

mndot.gov

Sorry, Wisconsin

Project Location

Lake

Superior

Duluth,

Minnesota

Superior,

Wisconsin

Port of Duluth-Superior

1

3

2

Current Interchange

• Known locally as the “Can of Worms”

• 3rd highest crash rate statewide for

interchanges

• 33 aging bridges (built in late ‘60’s),

mainline interstate on land bridge

• 16 bridges weight restricted 7 non-

redundant

• Problem for over-sized and over-weight

traffic coming from port and getting on

Interstate

4

Routes of Diverted OSOW Traffic

5

Current Main Interchange

6

I535

Lake Superior

Historic

Neighborhood

Trestle Bridges (mainline I35 and all ramps)

7

US53

8

Garfield Interchange I535

9

Twin Ports Interchange (TPI) Project Goals

• Enhance safety by eliminating blind merges and

left exits

• Replace aging infrastructure

• Reduce maintenance and closures

• Reduce bridge structure

• Improve freight mobility

• Allow oversize/overweight freight on the Interstate

by reconstruct/rehab substandard bridges

10

Project Overview

• Alternate Deliver Method - Construction

Manager/General Contractor (CMGC)

• Currently nearing 60% design status

• Consultant design for both roadway and bridges

• Construction scheduled for 2020-2022 ($250-

300M)

• Driven Pile Load testing and Column Test

Project (Rigid Inclusions) currently underway

11

Construction Manager/General

Contractor (CMGC)

• Contractor hired at start of design under professional/technical consultant contract

• Contractor responsibilities

• Constructability Reviews

• Maintenance of Traffic, Construction Staging Reviews

• Work will be let in two Work Packages

• Three cost estimates (EE, Contractor, ICE) must be close for Contractor to do work

12

Current Design Layout

• 14 New Bridges, 4 Bridge Rehabs

• ~600,000 sq. ft. of Column

Supported Embankments

• Fill heights up to 38 ft.

• 40% reduction in bridge deck area

• 8,000 L.F. Retaining Walls

• Cast-in-Place Concrete Cantilever

• MSE

13

Geotechnical Design Team

• Subsurface Investigations, Ret Wall Geotechnical Reports, Roadway Soils

• Ground Improvement Design, Modeling

• Supplemental Subsurface Investigations

• Early work on TH 53 Embankments

• Lateral Pile Stability

mndot.gov/

Column Supported Embankment Design

• Designed by consultants (Barr

Engineering and Itasca Engineering)

• Most economical column is full

displacement grouted column

• Diameters 16-18 in.

• Column Spacing 8-10 ft.

• Rough Unit Cost ~ $40/sq. ft.

• Includes wall cost

15

Subsurface Investigations

• 120 Historic Borings from 1960’s (poorly located, ±50 ft.)

• 150 Cone Penetration Test (CPT) soundings

• 250 Modern SPT Foundation Borings

• Dozen or so Test Pits

16

General Subsurface Conditions

9/24/2019 mndot.gov 17

Main Intersection US 53 Garfield Interchange

Very Dense

Sand

>150 ft.

Bedrock

Dense Sand

Org Silty

Clay

Sand fill

Bedrock

Vert Dense

Sand/Silt

Clay

Stiff Silt and

Clay

Sand fill

Dense Sand

40-60 ft

100 ft.

150 ft.

10-55 ft.

thick

Clay

Var.

Soil Variability

9/24/2019 mndot.gov 18

Soil Variability

9/24/2019 mndot.gov 19

107 ft.

54 ft.41 ft.

Miller Creek Culvert InletBridge 69902 West Abut

35 ft.

Sloping Bedrock

9/24/2019 mndot.gov 20

90 ft.

500 ft.

Bedrock

Miller/Coffee Creek Culvet

3D Soil Model

21

High Ground Water Table

22

Lake Superior

603.5 MSL

Existing Grade ~606

Lake Tides

• Strong North Wind = 1-2 “tide”

23

Soil Contamination

24

Soil Contamination

• Petroleum, lead, arsenic, PAH, Asbestos

25

Big Geotechnical Challenges

• Avoiding any excavation to limit cost of treating

contaminated soil and groundwater

• Possible Steel Corrosion from contaminated soil

• Construction Staging does not allow for

embankment settlement wait periods

• High groundwater

• Urban fill

26

Bigger Geotechnical Challenges

• Interaction of CSE foundation elements with

bridge/wall driven piles

• Ground heave/lateral displacement from

“forest” of full displacement columns

• Low fill ground improvement

• Building bridge/walls/embankments over in-

place utilities

• Reviewing designs using finite difference

method

27

Low Embankments

• No excavation

• No settlement wait periods

• 1 inch of long term

allowable settlement

289/24/2019 mndot.gov 28

4-6 ft. fill

Weak Soils,

highly

contaminated

30-60 ft.

Dense Soils

Low Embankment Foundation Design

• Columns Supported Embankment

• Driven piles or grouted columns

• 10 ft. center spacing

• 1 ft. thick reinforced concrete LTP

299/24/2019 mndot.gov 29

LTP

Dense Soils

4-6 ft. fill

Interaction of CSE columns and bridge piles

30

Ground Heave/Lateral Displacement Problem

9/24/2019 mndot.gov 31

Driven Piles

Full

Displacement

Columns

Column Test Project

• 63 CMC column 18 in. dia. 65 ft.

• Wick drains ½ area

• Driven 16 in. pipe pile

• Two Static Load Tests on columns

• Instruments

9/24/2019 mndot.gov 32

Column Test Layout

33

Test Area Soils

9/24/2019 mndot.gov 34

65 ft.

Column Test Embankment

9/24/2019 mndot.gov 35

Instrumentation

• 63 total gages

• Piezometers

• Survey targets

• Extensometers

• ShapeAccelArray

• Vertical and horizontal

• Strain Gages

9/24/2019 mndot.gov 36

Initial Instrumentation Results

37

Current Instrumentation Results

• Lateral Deflections ~4 inches near columns (3 ft), but only

½ inch 10 ft. away

• Heave – 1 inch

• Pore Pressures – dissipates quickly

38

Vertical SAA

39

If Ground Movement is Problem

• Use non-displacement columns or H pile

in “buffer zones”

9/24/2019 mndot.gov 40

Auger Cast

or H Pile

Full

Displacement

Columns

123

Sanitary Lift Station

41

42

43

Cross Section

44

Options

• Remove building

• Fill-in basement and drill

foundations through

floor

• Span over

45

Bridge Piling Adjustments

46

Reviewing CSE Designs

• How to check 2d, 2.5d and 3d Finite Difference

Method models

47

Thank you

Rich Lamb

rich.lamb@state.mn.us

651-366-5595

9/24/2019 mndot.gov 48

49

Column Supported Embankments 101

9/24/2019 mndot.gov 50

EmbankmentLoad Transfer

Platform

Weak Soils

Dense Soils

Rigid Inclusions

(columns/piles)(70-95% of

embankment load)

Rigid Inclusions (Columns or Piles)

• Full Displacement Grout Columns

• Non-displacement Grout Columns

• Driven piles

• H sections

• Pipe sections

• Typical Spacing 5-10 ft. centers

• Pile Caps typically used

9/24/2019 mndot.gov 51

$12-$20 / LF

$30-$40 / LF

52

CSE with misc Structures/Utilities

9/24/2019 mndot.gov 53

EmbankmentMSE Wall

CIP Wall

Storm Sewer

Exit 535 EB OH Sign

Light

Tower

Archaeological Concerns

• I-535 and Garfield Avenue

• Brown’s Trading Post

• North side of Piedmont Avenue

• Known Native Cemetery

• Some graves relocated in 1870 to Railyard

• Coffee Creek Banks

• Culvert built over stream and filled

• Beneath the structure

• Old Lakeshore

• Drilling in these areas suspended

54

9/24/2019 mndot.gov 55

Load Transfer Platform Design

• Acts as a pile cap – evenly distributes load to columns

• Select well graded granular fill (94-98% compaction) (MnDOT Class 5)

• Minimum of three horizontal biaxial geosynthetic reinforcement

layers with vertical spacing of 8-18 in.

• LTP thickness (½ the clear span between columns)

Full Displacement Columns

• “Drilled Displacement Piles”

• Very few spoils, low noise, vibration

• Reverse flight Augers push soils down and away from column

• May displace soils laterally – problem for adjacent structures

• Diameters of 12-24 inches, and typical lengths of 65-85 ft.

• Difficult to penetrate dense soil layers

9/24/2019 mndot.gov 56

Menard – Controlled Modulus Column

9/24/2019 mndot.gov 57

Non Displacement Columns

• “Auger Cast Pile” or

“Continuous Flight Auger Pile”

• Diameters of 12-24 in.

• Depths of 100 ft. or more

• Low noise, vibration

• Spoils much greater than FDC

9/24/2019 mndot.gov 58

Displacement Piles

9/24/2019 mndot.gov 59

Non-Displacement Piles

• “Pile Supported Embankment”

9/24/2019 mndot.gov 60

Questions or Comments?

Geology

• What has shaped the subsurface conditions the project

site?

• Volcanoes (igneous bedrock)

• Glaciers (dense soils)

• Lake Sediments (organics and soft clay)

• Erosion from stream flow (variability)

• Land use (surface fill material, contaminants)

mndot.gov/

Subsurface Investigations

• 120 Historical Borings (1960s)

(bridges)

• 100 Modern Borings (AET)

(bridges)

• 150 Cone Penetration Test

(CPT) Soundings

(embankments)

• 150 Future holes

9/24/2019 mndot.gov 63

75-100’

64

65

66

Tall Embankments

679/24/2019 mndot.gov 67

Embankment

20-40 ft.

Weak Soils

30-60 ft.

Dense Soils

Tall Embankments

689/24/2019 mndot.gov 68

Embankment

20-40 ft.

Weak Soils

30-60 ft.

Dense Soils

Typical Section I35 and Ramps

69

70

Org Chart - CMGC

71

Typical Section for CSE

72

Typical Section for CSE

73

Perched Abutments

74

Weak Soils,

highly

contaminated

30-60 ft.

MSE Wall

Dense Soils

Main Interchange

75

US 53 Bridges

76

Garfield Interchange

77