NC NP BLRI 2A16_Scour_Analysis_Report_Amended.pdf
PDF 237 KB Posted
- Attached to
- Blue Ridge Parkway Federal contract opportunity
- Solicitation number
- 693C73-23-B-000013
About this file
This memorandum amends scour countermeasure recommendations for Bridge No. 5140-081P over Brush Creek. The original recommendation proposed using riprap Class 2 for scour protection. However, upon further discussion between bridge, construction, geotechnics, and hydraulics staff, it was determined that Class 2 riprap would be too small and prone to washing away. Class 4 riprap was preferred but deemed difficult to source and construct. As an alternative, the memorandum recommends using Class 3 riprap, which is expected to withstand stream forces better than Class 2 while presenting fewer construction challenges than Class 4. No additional hydraulic analysis was performed to support the amended recommendation.
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Other files for this federal contract opportunity
| File | Type | Posted |
|---|---|---|
| Results of Bid Opening - NC NP BLRI 2A16.pdf | ||
| Amendment 0004 - Project NC NP BLRI 2A16.pdf | ||
| Amendment 0003 - Project NC NP BLRI 2A16.pdf | ||
| Amendment 0002 - Project NC NP BLRI 2A16.pdf | ||
| Amendment 0001 - Project NC NP BLRI 2A16.pdf | ||
| NC NP BLRI 2A16_BIP_Report_5140-081P.pdf | ||
| NC NP BLRI 2A16_BIP_Report_5140-080P.pdf | ||
| Report No. 17-03 - BLRI 2A16S.pdf | ||
| ADV_Bidders Qualifications Form.doc | DOC document | |
| Plans - NC NP BLRI 2A16.pdf | ||
| IFB Solicitation - NC NP BLRI 2A16.pdf | ||
| NC NP BLRI 2A16_BIP_Report_5140-077P.pdf | ||
| VETS-4212 Form.pdf | ||
| FP14_Eng.pdf |
Show all 14
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Text version
FHWA:W. Hiciano:6218:RF:
M:\PROJECTS\blri\2a16\Techserv\Hydra\Correspondence\BLRI 2A16 Bridge Scour memo CC: Hydraulics, Geotech, Env, HD Engineer, TS Engineer, Bridge
Form FHWA-201 U.S. DEPARTMENT OF TRANSPORTATION (Rev. 11-87) FEDERAL HIGHWAY ADMINISTRATION
MINUTE - MEMO
Use this form in lieu of transmittal slips within Dept. of Trans. when message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of Form FHWA-121 for informal correspondence.
SUBJECT: BLRI 2A 16 Scour Countermeasures Amended Recommendations
TO MESSAGE/COMMENT FROM/DATE
Sheila Foronda Project Manager
Ashley Timm Highway Design Manager
This memo intends to summarize the final recommendations provided for Structure No. 5140-081P: Bridge #1 over Brush Creek.
Memo Update:
Scour analysis and design were completed in October 2017. The project had been on standby, until 2021 when the design was resumed for the project. A site field visit was conducted, where discussion between Bridge, Construction, Geotechnical, and Hydraulics team members discussed that the riprap size recommended for the structure for scour countermeasure class 2, would be small and there are concerns that riprap would wash away after a stream event and it was agreed that class 4 would be more suitable and stable.
Construction has brought up the concern that using Class 4, would be a constructability issue, and it is hard to source in the project vicinity, due availability. Based on this information, Hydraulics agrees that installing Class 3 could be used as scour countermeasure for Structure No. 5180-081P, and that riprap Class 3, should be able to withstand stream erodible forces and have better performance than the original recommendation of Class 2.
These changes are not based on additional hydraulic analysis, but on multi-disciplinary discussion. Hydraulic analysis has not been performed, and the need to perform additional hydraulic analysis would require updated stream survey, since the stream has changed since final survey was conducted in early 2016.
For your reference, please refer to the Final Bridge Hydraulics Memo and Scour Memo for any additional information.
Please let us know if you have any questions or concerns.
Wendy Hiciano Hydraulics Team Leader
6/6/2023
| 2023-06-06T12:26:27-0400 | |
| WENDY MERCEDES HICIANO |
File details come from the government source that posted it. Updated .