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Request for Quotation (RFQ) No. DTRT5716Q80111 PR No. V3331012 Attachment No. 2

Department of Transportation Volpe National Transportation Systems Center Finite Element Analysis and Evaluation of Splitting/Bursting Performance of Pretensioned Concrete Prisms Statement of Work

Background One of the objectives of the ongoing Federal Railroad Administration (FRA) Broad Agency Announcement (BAA) project “Developing Qualification Tests to Ensure Proper Selection and Interaction of Pretensioned Concrete Railroad Tie Materials” by Kansas State University (KSU) is to develop qualification test standards that can ensure concrete tie performance in the splitting mode and prevent splitting/bursting failure during their expected service lives. Previous and current KSU projects demonstrated that small-scale pretensioned concrete prisms had excellent correlation in bond performance with concrete railroad ties that utilized 5.32-mm wires and three- or seven-wire strands. KSU proposed to use similar prisms to establish qualification tests and ensure sufficient factors-of-safety with respect to splitting-cracks forming around the longitudinal steel. In addition, several concrete tie manufacturers are considering the use of larger diameter reinforcement wires, thus the qualification test standards will need to be inclusive of these wires as well.

Scope of Work Factors that affect the splitting/bursting performance of concrete prisms include reinforcement diameter, reinforcement type (strand vs. wire, and wire indent characteristics), initial pretension force, concrete edge cover, reinforcement center-to-center spacing, concrete material properties, etc. This work statement seeks the application of the finite element analysis (FEA) method in examining the effects of these factors by adapting the Volpe concrete tie model(s). The Volpe Center has developed concrete tie FE models capable of predicting concrete tensile failure. Particularly, the Volpe Center has developed macroscale FE bond models for several reinforcement types in the form of user material subroutines for the commercial FE software Abaqus.

Requirements The contractor shall have expertise in the following areas:

· Advanced FEA skills;

· In-depth experience with applications of FEA in railroad engineering;

· Advanced and proficient user of Abaqus;

· Advanced knowledge and professional experience with pretensioned concrete members.

Period of Performance Period of performance is from date of award through June 30, 2017.

Place of Performance The work shall be done at the contractor’s location.

Work Requirements The work is broken down into the following tasks. The tasks are expected to be conducted in close collaboration with the Volpe Center and KSU.

Task 1.Determine a measure (or measures) for concrete splitting performance. Candidate performance measures include: no bursting/splitting cracks formed; bursting/splitting strains within limits or in “safe” proximity to reinforcements;
Task 2.Determine an appropriate prism length yielding equivalent splitting performance measures to those of actual ties;
Task 3.(Optional) Perform a few validation cases for the FE models (dependent upon availability of experimental data);
Task 4.Develop/adapt a prism model with a single reinforcement and examine splitting/bursting performance under combinations of the following factors, with given prism length and using normal modulus, release strength concrete (90 estimated combinations):
4.1.Reinforcement diameter (up to four variations, e.g., 5.32 mm, 7.5-8 mm and 10.5 mm wires and seven-wire strand);
4.2.Wire indent (up to three types with typical representation of transfer lengths), implemented by applying Volpe’s macroscale bond models;
4.3.Initial pretension force (e.g., allowable limits minus 10-25%);
4.4.Concrete edge cover (center-to-edge distance, e.g., current practice ±0.25-0.5 in.);
Task 5.Develop/adapt a prism model with four reinforcements and examine up to three variations in reinforcement center-to-center distance (e.g., current practice ±0.25-0.5 in.) under constant initial pretension force and concrete edge cover (up to 30 estimated combinations);
Task 6.Examine the effect of using reduced modulus, release strength concrete (i.e., repeat Task 4 and Task 5 with concrete assuming reduced modulus and release strength properties);
Task 7.Summarize a set of critical variable combinations that form the boundaries of acceptable performance for each wire or strand type;

Task 8. Progress updates with FRA, Volpe and KSU, and report/publications on methodology, results, interpretation of results, and findings.

Travel The Contractor has the option to travel to make a presentation on the research results at a conference venue approved by the Contracting Officer’s Representative (COR). All travel performed under this purchase order shall be performed in accordance with Federal Travel Regulations (FTR). The actual costs for lodging, meals, and incidental expenses will be considered reasonable and allowable if they do not exceed the maximum per diem rates in effect at the time of travel as set forth in the FTR. In accordance with FAR Subpart 31.205-46, a written justification must be provided to the COR for amounts higher than the FTR maximum amounts. Travel will be reimbursed at actual costs (with a copy of the receipts for expenses) in the following categories:

1.) Airline Tickets (commercial rates) 2.) Hotel Expenses (Government rates unless pre-approved by the COR) 3.) All Other Modes of Transportation (Taxi receipts are not required if less than $75.00) Food and other miscellaneous expenses will be reimbursed at the prevailing FTR reimbursement rates.

Travel shall not exceed $3,000.

Schedule and Deliverables List of schedule and deliverables:

CLIN
TASK
DELIVERABLE*
FORMAT
DUE DATE
0100
1
Determination of concrete splitting performance measure(s), including meeting with FRA, Volpe and KSU to reach consensus
Abaqus CAE and ODB files, MS PowerPoint, Web Meeting
Within 2 weeks of award
0101
1
Web meeting with FRA, Volpe and KSU to reach consensus on concrete splitting performance measure(s)
Web Meeting
Within 2 weeks of award
0200
2
Determination of prism length, including meeting with FRA, Volpe and KSU to reach consensus
Abaqus CAE and ODB files, MS PowerPoint, Web Meeting
Within 2 weeks of award
0201
2
Web meeting with FRA, Volpe and KSU to reach consensus on prism length (can be combined with CLIN 0101)
Web Meeting
Within 2 weeks of award
0300
3 (optional)
FEA models and results, comparison with experimental data
Abaqus CAE and ODB files, MS Word, MS Excel
September 15, 2016
0400
4
FEA models and results
Abaqus CAE and ODB files, MS Word, MS Excel
September 15, 2016
0500
5
FEA models and results
Abaqus CAE and ODB files, MS Word, MS Excel
September 15, 2016
0600
6
FEA models and results
Abaqus CAE and ODB files, MS Word, MS Excel
September 15, 2016
0700
7
Summary of critical variable combinations
MS Word (or MS PowerPoint), MS Excel
December 31, 2016
0800
8
Progress update meetings, including monthly meetings in July and August, 2016 and final meeting in December 2016
Web meeting
TBD before December 31, 2016
0801
8
Reports/publications
MS Word (or MS PowerPoint), MS Excel
December 31, 2016
0802 (TRAVEL)
8
Travel to make conference presentation, conference venue TBD
MS PowerPoint
TBD before June 30, 2017

*Deliverables will be emailed to the Contracting Officer’s Representative (COR) and Project Manager (PM)

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