Under a few of the 25+ delivery orders received under our contract with the Pittsburgh District COE, Tri-State Design performed the design and prepared construction documents for several miter gates for various locks and dams along the Allegheny, Monongahela and Ohio Rivers. Gate sizes varied from 56' to 110' wide and 21' to 43' high. In all, 13 different miter gates were designed. Design of the 84' miter gates at the new Charleroi Lock and Dam included design of the anchorage system and all components.

The design was performed using STAAD Pro software and Micro Station CADD System. Some of the major miter gates included:

1. 56' Chamber Miter Gates for Locks & Dam #4, Allegheny River
2. 56' Chamber Miter Gates for Montgomery Locks & Dam, Ohio River
3. 110' Chamber Miter Gates for New Cumberland Locks & Dam, Ohio River
4. 84' Chamber Miter Gates for Charleroi Locks & Dam, Monongahela River

Tri-State Design, under three different work orders, performed (i) design of new service bridge for Charleroi Locks and Dam; (ii) in-depth inspection, analysis and preparation of reports for two service bridges over Emsworth Locks and Dam, front and back channels; and (iii) performed independent technical reviews of ten (10) COE-inspected service bridges at various locations.

Analysis of two (2) 800' multispan service bridges was performed using BAR7 (Bridge Analysis and Rating) program for designated crane and monorail loading. The inspection report included the findings of the inspections (deficiencies), analysis, inspection drawings, recommendations for immediate and long-term repairs, and estimated construction costs.

The scope of our services under this delivery order included field inspection, field measurements, survey, design and preparation of construction documents for sloped concrete erosion protection devices, design modifications to the existing dam, design of the new maintenance building, and access road.

The design was based on the COE-prepared "Tygart Dam Safety Design Memorandum" and consisted of constructing concrete channels along the slope of the dam which would divert the water over the crest into the river, thus preventing the erosion and overturning of Tygart Dam in the event of a probabilistic 500-year flood. A model was created and analyzed by COE. Tri-State Design performed the design in accordance with the recommendations.

Under three different delivery orders, Tri-State Design performed various stability, reliability/risk assessments for various river structures. Results of the analysis were to be utilized for an Economic Analysis to be performed by COE and subsequent requests for major rehabilitation funding. Various software programs were used to perform the analysis.

The following projects were analyzed under this category of services:

Reliability/Risk Assessment Study for Land, Middle, and River Lock/Wall Concrete Monoliths - 9 projects at various locations

Reliability/Risk Assessment Study of the Vertical Lift Gates, Emsworth Locks and Dam - The analysis included the investigation into structural integrity and stability of the truss and truck wheel assemblies of the vertical lift gates. A model was developed that utilized the probabilistic methods to evaluate stability based on limit states--stability (buckling), strength and deflection, for operating loading, fatigue criteria and corrosion projected over a 60-year period. The analysis was performed using STAADPRO© and @ Risk© software linked to Excel.

Reliability/Risk Assessment Study for Piers & Stilling Basins, Emsworth Locks and Dam - Structural and Reliability Analyses were performed to determine the stability of the existing stilling basins and piers of the Emsworth Locks and Dam and the probability of failure of a pier due to scour under the stilling basin.

A model was developed of the dam pier and stilling basin in front of the dam that included the piling and basin base. The soil properties were determined and used to develop the p-y and q-z curves for the piles. Loads were applied to the model, along with scour of the piles beneath the stilling basin. Ensoft GROUP© 4.0 and STAADPRO© models were used to develop the forces and displacements. The @Risk© program (linked to EXCEL) combined the variables to determine the outcomes (failure of the pier) due to the scour.