Soil strength boussinesq

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Description

This calculation pertains to the structural analysis of a specific bridge component—Bridge 1 - Crossing 1—as part of the Primrose Trail Reconstruction. Let’s break down the key aspects of this analysis:

1. Bridge Dimensions:

• The bridge has a length of 44 feet and a width of 6 feet.
• It relies on 2 stringers for support, each sized at 5 1/8' x 34.5'.
2. Self-Weight Calculation:

• We determine the self-weight of the two-stringer glulam (glued laminated timber).
• The result is a total dead load (DL) of 9,240 pounds for the structure.
3. Snow Load Calculation:

• Based on a 50-year mean recurrence interval (MRI), we calculate the unfactored snow load (SL) as 179 psf.
• The total snow load amounts to 47,256 pounds.
4. Total Factored Load:

• Combining the dead load and snow load with their respective load factors, we arrive at a total factored load of 94,248 pounds.
• This follows guidelines from the FSH 7709.56b - Transportation Structures Handbook.
5. Sills:

• The supporting sills have dimensions: 8 feet in length and 1.5 feet in width.

• The load per sill is calculated as 47,124 pounds, equivalent to 3,927 psf.
7. Stress Distribution:

• We employ Tsytovich’s method to analyze stress distribution.
• Parameters considered: depth (z) of 0.5 feet, width (b) of 0.75 feet, and length (l) of 4 feet.
• The stress multiplier from a chart value results in a stress at 6 inches of 3,679 psf.
8. Geocell:

• By incorporating a geocell, which enhances soil stability, the stress at 6 inches is reduced to 1,839 psf.
9. Allowable Soil Stress:

• Semi-empirical methods, with a resistance factor of 0.45, guide us in determining allowable soil stress.
• Bearing resistance values for different fine sand consistencies are provided, considering soil density.

Foundation Recommendations:

• The analysis informs the appropriate foundation type based on calculated loads and soil conditions.
• Notably, the use of geocell mitigates soil stress, ensuring stability and longevity.

In summary, this rigorous analysis ensures that the bridge can safely support expected loads, including its own weight and environmental factors like snow. It guides material selection and foundation design. N. Tsytovich’s chart, a valuable educational resource, enriches our understanding of soil behavior and contributes to safe infrastructure worldwide.

Calculation Preview

Hampton Coogle (hammeat)
13 May 2024
File Size: 930.38 Kb