CIV E 530 - OPEN-CHANNEL HYDRAULICS
SPRING 2018
LAB No. 13:   HEC-RAS SCOUR USING CSU EQUATION

    Use HEC_RAS to calculate the scour from the Guadalupe Bridge on the Guadalupe river, Ensenada, Baja California, Mexico.

    Prior to performing scour analysis in HEC-RAS, a hydraulic model of the river that contains the bridge must first be developed.
    The following data is applicable:

    INPUT DATA:

    1. Select: SI units (metric)

    2. Stream/river: Guadalupe

    2a. Cross Section Stations: Sta-3200, Sta-2010, Sta-1990, Sta-0

    2b. Sta-3200: (0,356); (20,348); (130,348); (140,356)

          Downstream Reach Length: 1190 m

          Downstream slope: 0.0067

          Mannings n: 0.032 (typical)

    2c. Sta-2010: (0,348.027); (20,340.027); (130,340.027); (140,348.027)

          Downstream Reach Length: 20 m

          Downstream slope: 0.0067

    2d. Sta-1190: (0,347.955); (20,339.955); (130,339.955); (140,347.955)

          Downstream Reach Length: 1190 m

          Downstream slope: 0.0005

    2d. Sta-0: (0,347); (20,339); (130,339); (140,347)

          Downstream Reach Length: 0 m

    After setting up the river information, now it is time to enter cross section information for both the Guadalupe Bridge and its piers.

    3. BRIDGE DESIGN EDITOR

    3a. Station: 2000

    3b. Elevation of High Chord (Top of Road): 349

    3c. Elevation of Low Chord : 347.5

    4. PIER DATA EDITOR

    4a. Pier #1 Centerline Station Upstream/Downstream: 70

    4b. Width = 4.52 (typical)

    4c. Elevation = 341.8 (typical)

    4d. Width = 1.2 (typical)

    4e. Elevation = 348 (typical)

    4f. Pier #2 Centerline Station Upstream/Downstream: 120

    Once river, bridge, and pier data is input, it is time to input flow data.

    5. STEADY FLOW DATA EDITOR

    5a. Number of Reach Boundary Conditions : 1

    5b. Guadalupe Stream Peak Flow Rate: 2,618 m3

    6. STEADY FLOW ANALYSIS EDITOR/ FLOW DISTRIBUTION LOCATIONS

    6a. Upstream RS : 2010

    6b. Downstream RS: 1990

    Once steady flow analysis has been run, it is now possible to perform bridge scour analysis.

    7. HYDRAULIC DESIGN - BRIDGE SCOUR EDITOR

    7a. Contraction Scour (main channel):

    • Y1 = 5.334 m

    • V1 = 7.15 m/s

    • Y0 = 5.98 m

    • Q2 = 2,618 m3/s

    • W2 = 137.51 m

    • D50 = 1.1 mm

    • Equation = Default

    • Q1 = 2,618 m3/s

    • W1 = 140.17 m

    • S1 - channel = 0.000765

    • Water Temp (C) = 17.2

    7b. Pier Scour (main channel):

    • Y1V1 = Maximum

    • Pier # = Apply to all Piers

    • Pier Shape = Circular Cylinder

    • a = 4.5 mm

    • D50 = 1.1 mm

    • Y1 = 5.334 m

    • V1 = 7.15 m/s

    • Method= CSU Equation

    • Angle = 0

    • L = 5.1 m

    • K2 = 1

    • K3 = Clear-Water Scour

    • D95 = 4.75 mm

    • K4 = 1.00

    7c. Abutment Scour (main channel):

    • Length Left = 1 m

    • Length Right = 1m

    • K1 = Vertical Abutment

    • Skew - Left = 1 m

    • Skew - Right = 1 m

    • Equation = Default
Report Pier Scour (m).