HDR Engineering, Inc.

8404 Indian Hills Drive

Omaha, NE 68114-4098

Phone (402) 399-1000

Fax (402) 399-4979

www.hdrinc.com

Page 1 of 2

Memo

To:

John Clute Iowa Department of Transportation, Bridge Division

From:

Gary Krupicka

Project:

NHSX - 34 -1(68) -- 3H - 65

CC:

Brad Hofer (IaDOT), Matt Tondl (HDR)

Date

:

April 10, 2006

Job No:

14925

RE: US 34 – Missouri River Crossing – Bellevue Bridge

Project No. NHSX-34-1(68)—3H-65

Approach Span Bridge Options

Introduction

This memo summarizes the options considered for the approach spans for the new US 34 alignment. The

options considered are 1) steel plate girder, 2) BTD-series prestressed beams with a maximum span length of

137 feet, 3A) BT-series prestressed beams with a maximum span length of 150 feet, 3B) Nebraska NU2000

prestressed beams with a maximum span length of 150 feet, and 3C) BTE-series prestressed beams with a

maximum span length of 150 feet. Costs and span layouts are based on a Nebraska approach with a length

of 412’-6” and an Iowa approach with a length of 1,476’-6”, for a total length of approaches of 1889’ -0”. The

abutment locations were set based on a 3-t o-1 slope from the top of the levee. A two course deck is

considered for the deck slab with an out -to-out width of 89’-2”. The design vehicle considered is the AASHTO

HL-93 with a limiting deflection of L/800. The span layout options are shown in Figure 1. The corresponding

cross-sections are shown in Figure 2.

Option 1: Steel Plate Girder

A constant depth multi-girder system was studied for the steel plate girder option. Girder optimizations were

performed for various girder spacings, web depths and span length configurations. Relative costs were

computed incorporating the various girder and substructure configurations. Two 4-span units vs. two 5-span

units were considered for the Iowa approach. The resulting optimal span configuration is a 2-span unit with

207’-0” maximum spans for the Nebraska approach and two 5-span units with 160’ -0” maximum spans for the

Iowa approach, for a total of 12 spans (Figure 1). The proposed cross-sections is an 8 girder system with 72”

webs spaced at 11’ -8” (Figure 2).

Option 2: BTD-Series Pretensioned Prestressed Concrete Beam (PPCB)

Option 2 was developed using a maximum span length of 137 feet based on the IaDOT standard sheet for the

BTD135 Beam. The design data for the BTD135 shows a beam span length (center-center of bearings) of

135’-0” and a permissible maximum spacing of 8’-3”. For the Nebraska approach, a 127 foot span was

centered over the levee to minimize the impact to the levee during footing construction. The height of the fill

at the Nebraska levee and the 127 foot span over the levee resulted in a 61’-0” end span. The resulting

proposed span configuration is a 4-span unit with 127’-0” maximum spans for the Nebraska approach and a

6-span unit and a 5-span unit with 137’ -0” typical spans for the Iowa approach, for a total of 15 spans (Figure

1). The proposed cross-section is an 11 beam system with BTD beams spaced at 8’ -3” (Figure 2).

Option 3A: BT-Series Pretensioned Prestressed Concrete Beam (PPCB)

Option 3A was developed for maximum span lengths of about 150 feet based on design information provided

by IaDOT for the BT-series Beam. The design information indicated that special designs for a BT145 and a

BT150 beam with a spacing of 9’-0” could be used. Span lengths for the Nebraska approach are the same as

those used for Option 2, since reconfiguration of the Option 2 layout to eliminate a pier would place a pier well

into the Nebraska levee. The resulting proposed span configuration is a 4-span unit with 127’-0” maximum

HDR Engineering, Inc.

8404 Indian Hills Drive

Omaha, NE 68114-4098

Phone (402) 399-1000

Fax (402) 399-4979

www.hdrinc.com

Page 2 of 2

spans for the Nebraska approach and two 5-span units with 147’ -6” typical spans for the Iowa approach, for a

total of 14 spans (Figure 1). The proposed cross-section is a 10 beam system with BT beams spaced at 9’-2”

(Figure 2, Option 3A). Note that the BTD beams could be used at the Nebraska approach for this option,

even though BT beams are used for the cost estimates.

Option 3B: Nebraska NU2000 Pretensioned Prestressed Concrete Beam (PPCB)

The Nebraska NU2000 beam was also considered for the Option 3 span configuration, as Option 3B. The

NU2000 beam is 79” deep and has a cross-sectional area of 904 in

2

(vs. 71” and 788 in

2

for the BT beam).

The NU2000 beam has been used for spans up to 165 feet with 11’-0” spacings when designed continuous

and using release and final strengths of 7,000 psi and10,000 psi respectively. Additional information on the

Nebraska NU-series beam is included in Appendix B. The proposed cross-section for the NU2000 beam for

the Option 3 span configuration is a 9 beam system with beams spaced at 10’ -4” (Figure 2, Option 3B).

Option 3C: BT-Series Pretensioned Prestressed Concrete Beam (PPCB)

A new BTE-series beam was also considered for the Option 3 span configuration, as Option 3C. The BTE-

series beam is a 63” PPCB with cross section dimensions as shown in Figure 3. IaDOT indicated that the

BTE-series beam is currently under development and will be available well in advance of final design. IaDOT

also indicated that the span lengths, beam spacing, and unit cost should be similar to those shown for the BT-

series beam. Based on a preliminary design of the BTE beam the proposed cross-section for the Option 3

span configuration is a 10 beam configuration with beams spaced at 9’-2” (Figure 2, Option 3C).

Cost Estimates

Itemized cost estimates for each option are included in Appendix A. Unit rates, in general, are based on

current IaDOT bid tab summaries. A $1.60/LB unit price for steel plate girder structural steel is used based

on a review of current bid tabs and based on discussions with PDM Steel. Unit rates for the prestressed

beams are based on a review of current bid tabs for Iowa and Nebraska, and based on discussions with Iowa

Prestressed Concrete, Concrete Industries, and Cramer and Associates. The unit rates for the prestressed

beams fabricated, shipped and erected are $190/LF for the BDT beams (A=749 in

2

), $210/LF for the BT

beams (A=788 in

2

), and $245/LF for the NU2000 beam (A=904in

2

). Unit rates for the BTE beams are

considered the same as for the BT beams.

The following table summarizes the cost estimates for each option:

Option Type No. of Spans Total Cost $ / SQ.FT.

1 Steel Plate Girder 12 $16,350,666 $97

2 BTD Beam 15 $14,557,825 $86

3A or 3C BT Beam or BTE Beam 14 $14,308,578 $85

3B NU2000 Beam 14 $14,524,178 $86

Other consideration

In addition to the cost difference there are advantages and disadvantages as noted:

Advantage Steel: Can haunch web depth at transition pier for aesthetics (Figure 1).

Advantage concrete beams: Reduced long term maintenance and inspection cost.

Disadvantage NU2000: Thin ends of the top flanges susceptible to damage if deck removed for deck

replacement.

Recommendation

Based on review of the cost information and various configurations, IaDOT recommended that the BTE beam

series (Option 3C) be utilized for the approach spans, with the span configurations as shown for Option 3.

3/31/2006

7 Spaces @ 11'-8 = 81'-8

7'-0

2% SLOPE

1'-7

LANE

3'-9

12'-0 12'-0

PGL

LANE

12'-0

2% SLOPE

12'-0

PGLUS-34

7'-0 12'-0

LANE

89'-2

CL

LANE

12'-0

1'-7

8.1'

72" WEB

US-34 APPROACH SPANS

CL

US-34

3'-9

OPTION 1: STEEL PLATE GIRDER

OPTION 2: BTD-SERIES PPCB

6.3'

3'-4

10 Spaces @ 8'-3 = 82'-6

CL

US-34

54" BTD

3'-4

OPTION 3A: BT-SERIES PPCB

7.8'

3'-4

9 Spaces @ 9'-2 = 82'-6

CL

US-34

72" BT

3'-4

PGL

PGL

PGL

2% SLOPE

2% SLOPE

2% SLOPE

2% SLOPE

% SLOPE

OPTION 3B: Nebraska NU2000 PPCB

8.4'

3'-3

PGL

2 % SLOPE

8 Spaces @ 10'-4 = 82'-8

US-34

CL

2

79" NU2000

3'-3

10 1/2 " two-course deck

10" two-course deck

A=904 in^2

A=788 in^2

A=749 in^2

A*9=8136 in^2

A*10=7880 in^2

A*11=8239 in^2

10" two-course deck

10" two-course deck

FIGURE 2

% SLOPE

7.1'

PGL

3'-4

2

10" two-course deck

% SLOPE

9 Spaces @ 9'-2 = 82'-6

OPTION 3C: BTE-SERIES PPCB

US-34

CL

2

A*10=8074 in^2

A=807 in^2

63" BTE

3'-4

U.S. 34 CORRIDOR STUDY I-29 TO U.S. 75

FOUR LANES W/ MEDIAN BARRIER

MISSOURI RIVER BRIDGE APPROACH COST ESTIMATE

Page 1 of Approach

COST PER Total Cost SQ. FT.$/SQ. FT.

Steel Girder: SPG-72" web STEEL APPROACH (12 SPANS) $16,350,666 168,442 $97

Prestressed Beam: BTD-54"CONC. APPROACH (15 SPANS) $14,557,825 168,442 $86

Prestressed Beam: BT-72" or BTE-63"CONC. APPROACH (14 SPANS) $14,308,578 168,442 $85

Prestressed Beam: NU2000-79"CONC. APPROACH (14 SPANS) $14,524,178 168,442 $86

Deck width = 89.17'

3/16/2006

APPROACH: 3 UNITS @ 412.5', 739', 737.5' (207' MAX SPAN) APPR: 12 SPAN (1889')

8 Girders at 11'-8" spacing

ITEM UNIT PRICE UNIT QUANTITY COST

CONCRETE, STRUCTURAL $460.00 CU. YDS.10,000 $4,600,000

EXCAVATION FOR BRIDGES $20.00 CU. YDS.4,600 $92,000

JOINTS, STEEL EXT. W/ NEOPRENE - 4 IN.$125.00 LIN. FT.90 $11,250

MODULAR EXPANSION JOINT (6 IN.) $1,041.00 LIN. FT.90 $93,690

MODULAR EXPANSION JOINT (9 IN.) $1,338.00 LIN. FT.90 $120,420

PILING, FURNISH AND DRIVE HP 12 X 53 $17.50 LIN. FT.$0

PILING, FURNISH AND DRIVE HP 14 X 73 $33.50 LIN. FT.25,300 $847,550

RAIL, CONCRETE BARRIER $45.00 LIN. FT.5,700 $256,500

STEEL, STRUCTURAL $1.60 LBS.4,320,000 $6,912,000

STEEL, REINFORCING $0.80 LBS.2,000,000 $1,600,000

FLOOR DRAINS $744.00 EACH 28 $20,832

COFFERDAM $500,000.00 LUMP 0.5 $250,000

ROCK RIPRAP, TYPE A $30.00 TON 2,000.0 $60,000

SUB-TOTAL $14,864,242

10% CONTINGENCY $1,486,424

SUB-TOTAL WITH CONTINGENGY $16,350,666

APPROACH: 3 UNITS @ 412.5', 812.5', 664' (137' MAX SPAN) APPR: 15 SPAN (1889')

11 Girders at 8'-3" spacing

BEAMS, PRESTRESSED CONC. (BTD) $190.00 LIN. FT.20,800 $3,952,000

CONCRETE, STRUCTURAL $460.00 CU. YDS.11,700 $5,382,000

EXCAVATION FOR BRIDGES $20.00 CU. YDS.5,600 $112,000

JOINTS, STEEL EXT. W/ NEOPRENE - 4 IN.$125.00 LIN. FT.180 $22,500

MODULAR EXPANSION JOINT (6 IN.) $1,041.00 LIN. FT.90 $93,690

MODULAR EXPANSION JOINT (9 IN.) $1,338.00 LIN. FT.0 $0

PILING, FURNISH AND DRIVE HP 12 X 53 $17.50 LIN. FT.0 $0

PILING, FURNISH AND DRIVE HP 14 X 73 $33.50 LIN. FT.34,400 $1,152,400

RAIL, CONCRETE BARRIER $45.00 LIN. FT.5,700 $256,500

STEEL, STRUCTURAL $4.00 LBS.2,000 $8,000

STEEL, REINFORCING $0.80 LBS.2,400,000 $1,920,000

FLOOR DRAINS $744.00 EACH 34 $25,296

COFFERDAM $500,000.00 LUMP 0.5 $250,000

ROCK RIPRAP, TYPE A $30.00 TON 2,000 $60,000

SUB-TOTAL $13,234,386

10% CONTINGENCY $1,323,439

SUB-TOTAL W/ CONTINGENCY $14,557,825

STEEL PLATE GIRDER - 72" web

PRECAST "I" BEAM: BTD-54"

APPENDIX A

Page 1 of 2

U.S. 34 CORRIDOR STUDY I-29 TO U.S. 75

FOUR LANES W/ MEDIAN BARRIER

MISSOURI RIVER BRIDGE APPROACH COST ESTIMATE

Page 2 of Approach

Deck width = 89.17'

3/16/2006

APPROACH: 3 UNITS @ 412.5', 739.3', 737.3' (148' MAX SPAN) APPR: 14 SPAN (1889')

10 Girders at 9'-2" spacing

ITEM UNIT PRICE UNIT QUANTITY COST

BEAMS, PRESTRESSED CONC. (BT or BTE) $210.00 LIN. FT.18,900 $3,969,000

CONCRETE, STRUCTURAL $460.00 CU. YDS.11,500 $5,290,000

EXCAVATION FOR BRIDGES $20.00 CU. YDS.5,500 $110,000

JOINTS, STEEL EXT. W/ NEOPRENE - 4 IN.$125.00 LIN. FT.180 $22,500

MODULAR EXPANSION JOINT (6 IN.) $1,041.00 LIN. FT.90 $93,690

MODULAR EXPANSION JOINT (9 IN.) $1,338.00 LIN. FT.0 $0

PILING, FURNISH AND DRIVE HP 12 X 53 $17.50 LIN. FT.0 $0

PILING, FURNISH AND DRIVE HP 14 X 73 $33.50 LIN. FT.33,800 $1,132,300

RAIL, CONCRETE BARRIER $45.00 LIN. FT.5,700 $256,500

STEEL, STRUCTURAL $4.00 LBS.2,000 $8,000

STEEL, REINFORCING $0.80 LBS.2,240,000 $1,792,000

FLOOR DRAINS $744.00 EACH 32 $23,808

COFFERDAM $500,000.00 LUMP 0.5 $250,000

ROCK RIPRAP, TYPE A $30.00 TON 2,000 $60,000

SUB-TOTAL $13,007,798

10% CONTINGENCY $1,300,780

SUB-TOTAL WITH CONTINGENGY $14,308,578

APPROACH: 3 UNITS @ 412.5', 739.3', 737.3' (148' MAX SPAN) APPR: 14 SPAN (1889')

9 Girders at 10'-4" spacing

BEAMS, PRESTRESSED CONC. (NU2000) $245.00 LIN. FT.17,000 $4,165,000

CONCRETE, STRUCTURAL $460.00 CU. YDS.11,500 $5,290,000

EXCAVATION FOR BRIDGES $20.00 CU. YDS.5,500 $110,000

JOINTS, STEEL EXT. W/ NEOPRENE - 4 IN.$125.00 LIN. FT.180 $22,500

MODULAR EXPANSION JOINT (6 IN.) $1,041.00 LIN. FT.90 $93,690

MODULAR EXPANSION JOINT (9 IN.) $1,338.00 LIN. FT.0 $0

PILING, FURNISH AND DRIVE HP 12 X 53 $17.50 LIN. FT.0 $0

PILING, FURNISH AND DRIVE HP 14 X 73 $33.50 LIN. FT.33,800 $1,132,300

RAIL, CONCRETE BARRIER $45.00 LIN. FT.5,700 $256,500

STEEL, STRUCTURAL $4.00 LBS.2,000 $8,000

STEEL, REINFORCING $0.80 LBS.2,240,000 $1,792,000

FLOOR DRAINS $744.00 EACH 32 $23,808

COFFERDAM $500,000.00 LUMP 0.5 $250,000

ROCK RIPRAP, TYPE A $30.00 TON 2,000 $60,000

SUB-TOTAL $13,203,798

10% CONTINGENCY $1,320,380

SUB-TOTAL W/ CONTINGENCY $14,524,178

PRECAST "I" BEAM: NU2000-79"

PRECAST "I" BEAM: BT-72" or BTE-63"

APPENDIX A

Page 2 of 2

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