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CEEn-CPST-0

Ohio Power Plant Foundation

April 9, 2021 1

11

US/Guam Alliance

Austin KennedyChloe GogueWill Berger

Taylor Emmertson

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Introduction

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We will be justifying how we arrived at the specified foundation/ground improvement technique combination of each building.

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Project Tasks and Deliverables

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▪ We were tasked with researching foundation options and ground improvement techniques to ensure that the power plant would not settle more than 1 in.

▪ Each building was assessed and options were chosen based on economic feasibility and bearing capacity/settlement requirements

▪ The project was completed on time and in full, to the best of our ability considering our status as students and our low level of expertise.

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Design and Analysis

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Analysis of the power plant was done in separate sections, where we focused on one building at a time as they each of had unique soil profiles and collected data. This information was then used in our settlement calculations and helped in assigning proposed foundation types and ground improvement techniques.

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Design and Analysis Cont’d

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Below is a list of the soil conditions and anticipated settlement for each area.

Structure Soil Conditions Anticipated Settlement

Water Treatment Building - Sandy clay- High water table due to entrapped water

⅝ in.

Tank Farm - Sandy gravel- Entrapped water

⅝ in.

Cooling Tower - Sandy gravel- Half lies on entrapped water

½ in.

Admin Building - Clayey silty sand ½ in.

GSU/UAT - Gravelly sand- Must excavate top portion of clay so that deep dynamic compaction reaches intended soil

layers

⅝ in.

Turbine Building - Mostly well-graded gravel, with a patch of clay in the middle ⅝ in.

AUX BRL Building - Gravelly sand with a top layer of clay- Entrapped water

⅝ in.

HRSG - Well graded gravel with thin layer of lean clay with fine gravel ⅞ in.

Electrical/Ammonia Building - First two feet are clay and need to be excavated- The soil underneath is gravelly sand

½ in.

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Discussion of Results

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Challenges:▪ Limited knowledge on the subject ▪ Little outside verification from mentor▪ Hard to determine if we accounted for everything when determining our

recommendations▪ Unable to know if our list of options was exhaustive

Results:▪ The results were based on our limited interpretations of the data that was

given to us▪ We did our best to establish a soil profile of each building and determine

which recommendation options would be the best

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Discussion of Results Cont’d

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Possible foundation systems include:

Foundation System Application Advantages Drawbacks

Spread footing with slab - Wall loads present- Shallow

- Cost-effective- Non-skilled labor- Simple construction

- Higher settlement- Requires higher soil bearing capacity- May cause irregularity in future structure

Pier and Beam - Shallow- Steel buildings- Swelling soils

- Applicable in a variety of site locations

- Allows room for crawl space/ basement

- More expensive shallow option

Pile - Deep- Large Structures- Areas with unsuitable shallow soil- Areas with high groundwater table

- Bypasses shallow soil- High load capacity- Corrosion-

resistant

- Possible pile damage during construction- Located below ground level- Custom pile lengths common (increased

cost)

Matte foundation - Large distributed loads- Areas with weak soil- Buildings with basements

- Resists differential settlement- Very strong- Low cost when doubled as floor slab

- Swelling soils cause uplift- May need heavy reinforcement- Experienced labor needed

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Discussion of Results Cont’d

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Possible ground improvement techniques include:

Technique Application Advantage Drawback

Grouting - Filling pores in soil or rock - Decreased permeability- Higher shear strength

- Quality assurance is unknown- Difficult in shallow depths

Deep Dynamic Compaction - Densifies soil by dropping heavy steel/concrete weight with crane

- Increased density- Increased strength- Decreased settlement- Lower liquefaction potential- Higher bearing capacity

- Non-applicable in areas with soft cohesive soils

- Non-applicable within 100ft of existing building

Vibro-compaction/ Vibro- Replacement - Course aggregate added to existing hole and compacted using vibration

- Increased density- Reduced differential/total settlement- Higher bearing capacity

- Granular soil contains more than 12-15% silt or more

Rammed Aggregate Piers - Aggregate/grout columns added below slab

- No dewatering- Short construction time- Increased soil stiffness

- Limited Bearing capacity per pier- Increased cost per additional pier

Wick Drains - Drainage path for excess pore water in soft/compressible soil

- Reduced long term settlement - High equipment cost- Only viable in shallow depths

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Conclusions

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Lessons Learned:▪ Communication is key, especially if you are inexperienced and need

Zoom to get anything done▪ We got to learn lessons in reading test pit tables, cone penetration

tests, and boring logs to draw conclusions on soil conditions▪ Most of our recommendations will become more reasonable with

practice

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Conclusions Cont’d

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Recommendations

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Our final recommendations are as follows:

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Recommendations Cont’d

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Any Questions?

The End

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