Prepared for: Tennessee Department of Transportation
Prepared by: West and East Engineering Associates
04/16/2009

 Hydraulic Design Process
 Site Overview
 Analysis of Existing Bridge
 HEC-RAS Modeling
 Deck Drain Locations
 Scour Analysis
 Overview of Proposed Bridge

 Structural Design Process
 Slab Design
 Load Determination
 Girder Analysis
 Girder Design and Transverse Stiffener Calculation
 Lateral Load Calculations
 Pier Cap, Pier Column, and Pier Footing Design

•Duck River over
Industrial Park Road
•SR 3209
•Channel Mile 128+/-
•Latitude: 35.6356
•Longitude: -87.0709
Data Sources
•APR
•USGS
•TVA
•FEMA

• Driftwood, Debris, and
Sedimentation around the pier
reducing flow of water
• Confirmed aquatic life exists on site
(reported by United States Fish and
Wildlife Service, USFWS)

Current Bridge Concerns
•Steep Vertical Curve of Approaches
• Sharp Horizontal Curve of Approaches
• Exposed Steel Reinforcing Bars
• Corroded Steel

• Land slide occurrence due to unstable slope
• Concrete was poured on the unstable slope to control the situation

Design Steps and Provisions:
1. Check previous studies
• TVA, FEMA’s FIS, USGS
Drainage Area: 1330 mi2
2. HEC-RAS Models
• Existing, Proposed,
Natural
3. Deck Drains Locations
Proposed Bridge:
• Model for Upstream, Bridge, and Downstream Elevations
4. Scour Analysis

Deck Drain Analysis
• All produced bypass flow < 0.05
• Deck drain at least 5ft from pier
•Avoid Ponding at Low Elevations
•Bridge Lowest Point: 113+88.25
•12 Total Deck Drains
• 113+20.00 : 56%
• 113+40.00 : 65%
• 113+60.00 : 74%
• 113+83.00 : 73%
•113+93.00 : 74%
• 114+25.00 : 86%

FREQUENCY 2 YEAR 10 YEAR 50 YEAR 100 YEAR 500 YEAR MAX
FLOOD
TOTAL FLOW
(cfs)
27 490 45 710 62 770 70 280 89 060 171 000
FLOW (cfs)
27 490 45 123 61 207 68 223 85 677 142 401
VELOCITY (fps)
4.22 4.92 5.43 5.62 6.32 8.58
CONTRACTION
SCOUR (ft)
-0.4 0.22 2.77 4.02 7.15 10.69
PIER SCOUR (ft)
7.96 8.77 9.32 9.52 10.15 12.01
TOTAL SCOUR
(ft)
7.96 8.99 12.09 13.54 17.30 22.7

 Assumptions:
 8.5’’ Deck Thickness
 f’c=4 ksi
I I I I
 Fy= 60 ksi C S S S C
 Design Spreadsheet: LLDF_LRFD4_2.1
 Determination of Girder Spacing (S)
 Determination of Overhang (C)
 Balance of Positive and Negative Moments
 S : 10.917 feet (10’-11’’)
 C: 4.25 feet (4’-3’’)

Design LLDF, Lanes / Girder
 Distribution Factors (Lanes Per
Interior 0.755 (M)
Beam)
1.012 (V)
 Moment in Interior Beam
 Shear in Interior Beam 0.725 (FATIGUE)
 Moment in Exterior Beam Exterior 0.985 (M)
 Shear in Exterior Beam
0.985 (V)
 Girder Specifications 0.821 (FATIGUE)
 Web Plate: 45’’ x ½’’
 Flange Plates: 24’’ x 2.25’’
 AASHTO Code Specifications

 Dead Loads:
 Deck: 150 lb/ft3
 Filler: 2.75’’ Thick Over Beams
 Beam Weight: 2.25% over weight estimate
 Parapet Weight: 390 lb/ft
 Weight of Asphalt Overlay: 35 psf
 Two Phase Construction:
 Phase 1: Setting of Beams, Cross Frames
Connected, Splices Made, Deck Poured
 Phase 2: Parapets Installed, Asphalt Overlay,
Traffic Allowed
 Component and Wearing Surface Loads
 DC1: 1.59 klf per Girder
 DW1: O klf per Girder
 DC2: .2 klf per Girder
 DW2: .34 klf per Girder

 SAP2000 Model
 Bridge Geometry and Bracing Cases
 Dead and Live Loads Applied
 Lateral Loads Applied
 Lanes Per Girder Factors

 Positive Moment Section:
 Top Flange in Compression, Bottom Flange in Tension
 Necessary Load Cases:
 Cross Section Proportion Limits
 Strength Limit State
Moments
 Constructability
 Service Limit State •DC1: 1883 K-ft
 Fatigue Limit State •DC2: 261 K-ft
•DW: 443 K-ft
•LL: 2145 K-ft
 Excel Sheet: WPG_Props_2.0

 Negative Moment Section:
 Top Flange in Tension, Bottom Flange in Compression
 Necessary Load Cases:
 Cross Section Proportion Limits
 Strength Limit State Moments
 Constructability
 Service Limit State •DC1: -4188 K-ft
•DC2: -587 K-ft
 Fatigue Limit State
•DW: -998 K-ft
•LL: -1759K-ft
 Excel Sheet: WPG_Props_2.0

SAP2o00 Modeling of Lateral Loads
Lateral Load Types
 Wind Loading: 100 MPH Design Velocity
 Braking Force: Standard Design Truck (AASHTO 3.6.4)
 25 Percent of Axle Weight of Design Truck or Tandem
 5 Percent of Design Truck Plus Lane Load
 Thermal:
 DT=aL(Tmax.design – Tmin.design)
 Tmax=120 F, Tmin=0 F (Table Values From AASHTO Spec.)
 Stream Flow Pressure
 Seismic Loading: Periodic Response Curve
Load Combinations
Strength I, Strength III, Strength IV, Strength V, Service I, Fatigue, Extreme Event

 Girder Design – Negative Moment
 Top flange – Tension: 24’’x3.25’’
 Bottom flange – Compression, braced at 25 ft: 24’’x3.25’’
 AASHTO Proportion limits, Strength limit state
▪ Found to be within the allowed proportions
▪ Fbu+(1/3)Fl<φfFnc Max Positive Max Negative
Moment Moment
▪ 48.66ksi < 50ksi
▪ 43.91ksi < 45.52ksi

 Girder Design – Positive Moment
 Top flange – Compression, Continuously braced: 24’’x1.25’’
 Bottom flange – Tension: 24’’x1.75’’
 AASHTO Proportion limits, Strength limit state
▪ Found to be within the allowed proportions
▪ Strength limit state was satisfied
▪ Mu+(1/3)(FlSxt) <Mn, (7098 ft-k < 13,040.1 ft-k)

 Shear Capacity: Vn=366.8 k
φVn=330.12 k
Vn C (. 58 F yw Dt w )
 Dead Load = 154.3 k
 Live Load = 60.858 k
 Maximum Shear: Vu = 282.5 k
 Vu< φ Vn : Stiffeners not needed

 Girder Design – Shear Studs
 7/8” studs on top flange of each girder

 Pier Cap Design: Response 2000 – Interaction Diagram
 Steel flexural reinforcement
 Shear stirrup spacing at column face
 Shear forces from 2 girders and the weight of
the concrete.
 Shear and Moment Considered in Design
 Shear = 2211.5 kips
 Moment = -15194.5 kips-ft

 Pier Cap Design
 Analyzed Rectangular Cross Section
Girder Loads
Concrete Weight

 Axially loaded tied column with moments along both axes
 Analyzed six factored load cases
Strength Strength Strength Strength
1 3 4 5 Service 1 Service 2
Pu, kips 3358.95 2375.09 2375.09 3134.057 2412.45 2332.185
Mux, ft-k 1072.13 1065.62 990.547 1034.327 2019.52 1981.09
Muy, ft-k 6975.24 5362.86 5311 7359.725 5718.59 5182.11
8’
Pnx, kips 15,325 14,257 14,565 15,325 10,311 10,311
Pny, kips 7,536 6,812 6,993 6,631 6,450 6,993
Pn, kips 6,852 6,062 6,263 6,095 4,999 5,319 4’
0.700 0.700 0.700 0.700 0.700 0.700
Pn, kips 4,796 4,244 4,384 4,267 3,500 3,724
Pn / Pu 1.43 1.79 1.85 1.36 1.45 1.60

 Pier Footing Design : 12’ x 12’ x 4’
 Analyzed with 6 load cases including axial loads and moments
 Limiting Service Limit state soil pressure – 60 k/sf
P, kips Mx, ft-k Mz, ft-k
Service 1 2,412 2,020 5,719
Service 2 2,332 1,981 5,182 QNE, ksf QSE, ksf
Strength 1 3,359 1,072 6,975
46.704 31.945
Strength 3 2,375 1,066 5,363
Strength 4 3,375 991 5,311
Strength 5 3,134 1,034 7,360

 Estimation Technique: $100/sqf, 400’x40’ area
 Quick Estimate = $1,600,000
 APR data
 Right of Way - $35,000
 Approaches - $583,900
 Structure - $972,500
 Preliminary Engineering - $135,600
 Utilities - $31,1000
 Total - $1,758,100

Thank you for your time.