UPRR INDUSTRIAL LEAD BRIDGE T-WALL RETAINING WALL SYSTEM 5.0 x 7.5 UNITS DESIGN UNIT 018 WORK PACKAGE 04

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1 UPRR INDUSTRIAL LEAD BRIDGE T-WALL RETAINING WALL SYSTEM 5.0 x 7.5 UNITS DESIGN UNIT 018 WORK PACKAGE Description This work shall consist of the design, manufacture and construction of a T-WALL structure in accordance with this specification and in close conformity with the lines, grades, design, and dimensions shown in the Contract Documents & Plans or established by the Project Engineer. The Contractor shall make arrangements to acquire the T-WALL design, precast reinforced concrete units and joint materials from The Neel Company (TNC), 8328-D Traford Lane, Springfield, Virginia 22152, ( ) or an authorized licensee of The Neel Company. 2. Design 2.1. Primary Design References AREMA Manual for Railway Engineering, 2012 edition. AASHTO Standard Specifications for Highway Bridges, 17th Edition 2002, with interims Loads The live load surcharge (Cooper E-80) is calculated per AREMA Section c. The lateral earth pressure from the live load surcharge is calculated as a strip load based on a Boussinesq distribution, AREMA Section Foundation Analysis The T-WALL design shall be in accordance with the soil and foundation parameters specified in the contract documents Stability Analysis 2.2.Submittals Use the Rankine stability analysis for sliding, overturning and pullout. Minimum factors or safety are: Sliding 1.5 Overturning 2.0 soil 1.5 rock Pullout All submittals shall be sealed by a Professional Engineer licensed to practice in the State where the project is to be constructed Contractor shall submit the required copies of complete shop drawings, design calculations and fabrication drawings for all T-WALL retaining walls on the project in accordance with the details shown in the Contract drawings Shop Drawings

2 Shop drawings shall show details dimensions and cross sections necessary to construct the wall including: a. The retaining wall plan, layout and wall elevations b. Typical wall sections c. Types, locations and properties of all drainage materials, utilities, appurtenances and any special installation requirements as shown in the contract drawings Fabrication Drawings Fabrication Drawings shall include unit-reinforcing diagrams and rebar schedules, special hardware requirements and dimensioning for custom cast pieces. 3. Materials 3.1. Primary Material References 3.2. T-WALL Units AREMA Manual for Railway Engineering, 2012 Edition. Chapter 8 ACI CRSI The T-WALL units shall be manufactured in an NPCA, PCI or DOT certified precast concrete plant. A quality control plan shall be submitted by the precaster and approved prior to start of production. The concrete mix design shall be Self-Consolidating Concrete (SCC) with a minimum compressive strength of 5,000 psi at 28 days. The mix design shall be submitted and approved by the Engineer prior to the manufacture of any units Testing and Inspection Acceptability of the concrete for the precast units will be determined on the basis of compression tests, certifications and visual inspection. The concrete strength requirements for the precast units shall be considered satisfied regardless of curing age when compression test results indicate that the concrete strength will conform to 28-day specifications. The precast manufacturer shall furnish facilities and perform all necessary sampling and testing in an expeditious and satisfactory manner Casting The units shall be cast in steel forms with dimensional tolerances that will assure the production of uniform units Curing The curing method shall be as submitted and approved in the quality control plan Removal of Forms

3 The forms shall remain in place until the units can be removed from the forms without damage to the unit Marking of Precast Units Clearly and permanently mark each precast unit on the butt end of the stem with the unit type, the date of manufacture, the lot number if applicable, and the trademark T-WALL T-WALL Unit Finish and Tolerances a. Steel Form Finish - Unit Tolerances - all dimensions shall be within ± 1/4 inch. b. Surface Finish - all honeycomb or open texture shall be properly repaired. c. Architectural Form Liner Finish shall be as called for on the Contract drawings. d. Front Face Tolerance - length and height of front face shall be within ±1/4 inch Rejection of Precast Components Precast concrete wall components not meeting the quality standards of this Section and referenced Specifications will be rejected or repaired. In addition, any of the following defects may be sufficient cause for rejection if not satisfactorily repaired: Defects that indicate unsatisfactory molding Defects indicating honeycombed or open texture concrete Defects in the physical characteristics Handling, Storage and Shipping All units shall be handled, stored, and shipped in such a manner as to avoid chipping, cracking, fracturing and excessive bending stresses Reinforcing Steel Must meet the requirements of ASTM A 615 grade 60. Reinforcing steel shall be plain black rebars unless otherwise noted on the contract drawings. The minimum concrete cover for the reinforcing steel shall be in accordance with the referenced specifications. Primary Reinforcement Stirrups, ties 2 inches 1-1/2 inches Rebar cage fabrication by welding is not permitted and is cause for rejection 3.3. Joint Materials a. Horizontal Joints

4 Neoprene blocks with a minimum durometer of 60 placed as shown in the approved T-WALL drawings. b. Joint Filter Fabric Horizontal and vertical joints shall be backed by a 12-inch wide geotextile fabric such as Mirafi 1120N or approved equal c. Shear Keys Precast shear keys shall be made of the same concrete mix as the T-WALL units and cured in the same manner. d. Shear Key Wrap The shear keys are to be wrapped with a 1/4 closed cell polyethylene foam such as AVI Astro-Foam or equal Select Granular Backfill The general gradation requirement of this backfill material is: Sieve Size Percent Passing 3 inch 100 3/4 inch No Locally produced materials with a gradation that falls between the upper and lower limits stated above would be considered satisfactory. General Design Parameters Angle of Internal Friction 34 Unit Weight (density) 125 pcf or as specified in the Contract Compaction - 95% of Standard Proctor, ASTM D-698 If the locally available material meets the gradation and angle of internal friction requirements stated above, but not the unit weight, the wall design may be modified to reflect the actual properties of the available material. Backfill between the T-WALL Units meeting the above criteria may be one of the following locally available materials: Crushed or natural sand Crushed or uncrushed gravel Recycled concrete Old ballast 3.5. Unclassified Backfill This is the backfill material beyond the limit of the concrete stems. Angle of Internal Friction 30 Minimum Unit Weight (density) 125 pcf or as specified in the Contract Compaction - 95% of Standard Proctor, ASTM D Leveling Pad Concrete The leveling pad concrete shall have a nominal minimum compressive strength of 2,500 psi at 28-days. Under normal circumstances the leveling pad strength is considered acceptable for placement of the T-WALL units after 24 hours.

5 No rebar is required in the cast-in-place leveling pad. 4. Construction Requirements Installation procedure shall be in accordance with the T-WALL Retaining Wall System Construction Manual for Railroad Projects, ( Site Examination Verify locations of utilities and existing structures prior to excavation. Promptly notify the Engineer in writing of any conditions that may interfere with the proper construction of the T-WALL wall or delay completion. Promptly notify the Engineer of site conditions that may affect wall performance, soil conditions observed other than those assumed, or other conditions that may require a reevaluation of the wall design Structure Excavation Contractor shall excavate to the lines and grades shown on the contract drawings. The foundation for the T-WALL structure shall be excavated and graded level for a width equal to or exceeding the length of the T-WALL stem using the top of the leveling pad as the grade elevation. The contractor shall be careful not to disturb base beyond the lines indicated and shall be responsible for slope stability and protection of the open excavation. Over-excavated areas shall be filled with suitable base or backfill material and compacted to 95% modified proctor Foundation Preparation The foundation soil shall be evaluated by a Geotechnical Engineer, retained by the contractor or the Owner, to ensure that the bearing soils meet or exceed the design conditions, the assumptions in the geotechnical report and the approved T-WALL design. Compact the graded area with an appropriate roller weighing a minimum of 8 tons by at least 3 passes or as directed by the Engineer. Remove and replace any soft or loose foundation soils to insure that there is adequate bearing capacity as directed by the Geotechnical Engineer or the Engineer. The soil foundation shall be approved, by the owner or certified by the Geotechnical engineer, prior to installation of the T-WALL units Leveling Pads At each unit foundation level, two concrete leveling pads shall be provided as shown on the approved T-WALL drawings. Leveling pads shall be level and flat within ±1/4 inch per 15 feet and shall not exceed a 1/4 inch overall over 100 feet. Leveling pads that do not meet this requirement shall be repaired or replaced as directed by the Engineer at no additional cost.

6 4.5. Surface Drainage Contractor shall be responsible for the stability of all excavated slopes and shall assure that surface runoff is diverted away from the wall. The contractor is responsible for providing dewatering of excavated areas in order to maintain dry working conditions during construction of the wall Wall Drainage A wall drainage system shall be installed as required in the contract drawings Wall Erection: a. Tolerance and alignment shall be as follows: Horizontal joint openings between panels shall be 3/4 inch (+ 1/4 1/2 ) Vertical joint openings between panels shall be 1/2 inch ± 3/8 inch Vertical tolerance (plumbness) as the wall is constructed shall not exceed ±3/4 inch when measured with a 10-foot straight edge. Horizontal alignment tolerance as the wall is constructed shall not exceed ± 3/4 inch when measured with a 15 foot straight edge and shall not exceed 3/4 inch overall. The overall vertical tolerance of the wall (plumbness from top to bottom) shall not exceed ±3/4 inch per 10 feet of wall height.. b. Horizontal Joints Neoprene blocks with a minimum durometer of 60 placed as shown in the approved T-WALL drawings. A 12-inch width of geotextile fabric such as Mirafi 1120 N or approved equal shall be tacked with adhesive on the back face to cover the horizontal joints. Care shall be taken to avoid blocking the joints with adhesive. c. Vertical Joints A 12-inch width of geotextile fabric such as Mirafi 1120 N or approved equal shall be placed on the back face and held in place by the backfill to cover the vertical joints. d. Shear Keys Precast shear keys shall be made of the same concrete mix as the T-WALL units and cured in the same manner. The shear keys are to be wrapped with a closed cell polyethylene geotextile material (shear key wrap) to fit snugly into the T-WALL stem keyways Repairs Repairs to the units in the field are possible only with a pre-approved repair procedure and prior permission of the Owner and The Neel Company.

7 4.9. Field Quality Control Unless otherwise provided by the Owner, the contractor shall employ the services of an independent engineering firm to monitor soil testing and perform daily quality assurance and inspection for wall construction and soils work. Contractor shall provide any quality control testing or inspection not provided by the Owner. Contractor shall be responsible for proper installation and quality control of all T- WALL wall components and appurtenant materials. Quality Assurance shall include but not be limited to foundation soil inspection, frequent backfill compaction testing, verification of geotechnical design parameters and compliance with approved T-WALL shop drawings, T-WALL Retaining Wall System Construction Manual and Project Specifications Backfill Placement Backfill placement shall closely follow the erection of each course of T-WALL units. The backfill lifts should be uniform in thickness, not to exceed 12 inches. Each lift shall be compacted to 95% of standard proctor in accordance with ASTM D-698. Placement and compaction of the backfill shall be accomplished without displacement of the T-WALL units. Material certifications and test reports for the select and unclassified backfill shall be maintained by the Contractor. Conduct sampling and testing at a minimum frequency listed below: Cleaning Compaction Test: Each course of units at 100 ft intervals. Gradation Test: Weekly After completion of wall installation, remove construction debris and restore any adjacent finished areas affected by wall construction to their pre-construction state. Wash the wall face to remove soiling and stains. Do not use acid or detergents that may burn or discolor the face Staining, Sealing or Coatings If otherwise specified or noted on the contract drawings, field apply stain, sealer or coatings within the limits shown in the contract drawings and in accordance with manufacturers recommended procedures. 5. Measurement and Payment 5.1. T-WALL Installation Measurement and payment will be a unit price based on the actual square feet of surface area of the T-WALL units as shown in the approved T-WALL shop drawings from the top of leveling pad to the top of wall. The unit price includes the precast units, joint material, excavation, leveling pads, select backfill within the limits of the T-WALL stems, drainage materials for the wall, and all materials, labor, equipment, and incidentals necessary to complete the installation Fencing, Railings or Other Appurtenances If such bid items are included in the Contract Documents, payment for furnishing and installing will be paid under these items as appropriate.

8 5.3. Over Excavation and Foundation Improvement If required, over-excavation and replacement backfill for foundation improvement will be paid under a separate pay item. END OF SECTION