CIV E 638 - SEDIMENTATION AND RIVER ENGINEERING
FALL 2020
HOMEWORK No. 7:  BRIDGE SCOUR

  1. Use ONLINE_SCOUR_MELVILLE to calculate local scour for the Guadalupe Bridge, located in the Guadalupe valley, Ensenada, Baja California, Mexico.

    INPUT DATA:

    1. Stream/river: Guadalupe

    2. Select: SI units (metric)

    3. LEFT ABUTMENT

    3a. Length of left abutment Ll (m): 1

    3b. Shape of left abutment: Vertical wall

    3c. Angle of alignment of left abutment θl°: 60

    3d. Does the left abutment extend to the main channel?: No

    4. RIGHT ABUTMENT

    4a. Length of right abutment Lr (m): 1

    4b. Shape of right abutment: Vertical wall

    4c. Angle of alignment of right abutment θr°: 90

    4d. Does the right abutment extend to the main channel?: No

    5. FLOW DEPTH

    5a. Flow depth in the main channel y (m): 5.334

    5b. Flow depth in the flood channel y* (m): 1.68

    6. FLOW VELOCITY

    6a. Flow velocity in the main channel V (m/s): 7.15

    6b. Flow velocity in the flood channel V* (m/s): 3.23

    7. PIER DATA

    7a. Shape of pier: Square nosed

    7b. Width of pier b (m): 1.2

    7c. Length of pier l (m): 5.1

    7d. Angle of alignment of pier θ°: 0

    7e. Where is the pier located?: Main channel

    7f. [Shape of] pier cross-section [in the vertical]: Nonuniform

    7g. If pier shape is nonuniform [in the vertical], please enter the following data; otherwise, leave blank:

    • Height z (m): 1.8

    • Diameter D (m): 1.2

    • Diameter D* (m): 4.52

    8. DEBRIS CONTAMINATION

    8a. Is pier subject to debris contamination?: No

    8b. If pier is subject to debris contamination, please enter the following data:

    • Thickness Td (m): [Blank]

    • Diameter Dd (m): [Blank]

    9. SEDIMENT DATA

    9a. Median particle size d50 (m): 0.0011

    9b. Is the geometric standard deviation of the particle size distribution σg ≤ 1.3?: No

    9c. If sediment is nonuniform [answer to input 9b is No], please enter maximum particle size dmax (m) [otherwise, leave blank]: 0.00475

    10. MANNING n

    10a. Manning roughness coefficient for the main channel, n: 0.032

    10b. Manning roughness coefficient for the flood channel, n*: 0.035

    11. WIDTH OF THE FLOOD CHANNEL

    11a. If left abutment extends to the main channel, please enter the following data [otherwise, leave blank]:

    • Left width of the flood channel Ll* (m): [Blank]

    11b. If right abutment extends to the main channel, please enter the following data [otherwise, leave blank]:

    • Right width of the flood channel Lr* (m): [Blank]

  2. Use ONLINE_SCOUR_HEC18 to calculate bridge scour for the Guadalupe Bridge, Guadalupe valley, Baja California, Mexico.

    INPUT DATA:

    Units: SI (metric)

    Flow depth y1 = 5.334 m

    Flow velocity v1 = 7.15 m/s

    Pier width a = 4.52 m

    Pier length L = 5.1 m

    Angle of attack θ of the flow = 0o

    Pier nose shape: Circular cylinder

    Bed condition: Clear-water scour

  3. Based on the above results, estimate the design depth at which to base the bridge foundation.