Event Title

2D Hydraulic Modeling of the State Route 76 Hatchie River Bridge Replacement in West Tennessee Using SRH-2D

Presenter Information

Draghina Icobescu, TDOT

Streaming Media

Duration

00:23:14

Start Date

8-20-2014 10:55 AM

End Date

8-20-2014 11:20 AM

Abstract

State Route 76 (SR-76) over the Hatchie River is the first project designed by Tennessee Department of Transportation (TDOT) using SMS SRH-2D. The bridge replacement over the Hatchie River includes a floodplain approximately four miles wide. There are a total of 13 overflow bridges on SR-76. Also, about 0.40 miles downstream is Interstate40 (I-40), which also crosses the Hatchie River floodplain. I- 40 includes the main river crossing and an additional four overflow bridges. All nineteen bridges are currently listed scour critical. This replacement project will also allow for an updated scour analysis and rating on all the bridges in the floodplain.

The need to have accurate hydraulic data available for these 19 sites is also critical for TDOT due to the nature of the site and the sensitivity of its surroundings. This site is part of the Hatchie National Wildlife Refuge and includes the only river in West Tennessee which has not been straightened by the Corps of Engineers or other agricultural interests.

With SMS SRH-2D both routes and all 19 structures are in a single model which would not have been possible in HEC-RAS. Consultation with FHWA revealed that SMS SRH -2D is the most reliable software available at present for this site.

Fortunately for such a large floodplain, LIDAR data from the NRCS was available at no cost for virtually all of West Tennessee. This data was found to be readily available and very useful for this project.

This presentation will cover various issues encountered during the design process including : processing the raw LIDAR data, hardware and software capability to process the enormous file sizes used in the model, the manipulation of LIDAR data using Geopak to achieve a format acceptable to SMS SRH-2D, and hydraulic design results.

The selection of SMS SRH-2D as the design tool for this project permitted easily accessible graphical and numerical results including: water surface elevation, water depth, velocity magnitude, Froude number, bridge discharge, and flow area. The ability to extract information from the 2D model for use in evaluating bridge contraction scour and pier scour for all 19 bridges proved to be valuable to a successful project design as well.

Contact Information

Ms. Draghina Icobescu

Transportation Project Specialist 2

TDOT Structures-Hydraulics

J.K. Polk Bldg. Suite 1200

Nashville, TN 32743

Phone: 615-532-5767

email: Draghina.Icobescu@tn.gov

Speaker's Biography

I was born and raised in Timisoara, Romania, the youngest of twelve children. I received my Bachelor’s Degree in 2004 from “Politechnica” University of Timisoara - Faculty of Hydrotechnica. I moved to the United States of America in 2004 to further my engineering education. In 2008 I received my Master’s Degree in Engineering from Tennessee State University. I began working for the Tennessee Department of Transportation, Structures Division – Hydraulics Section, in December 2005. Since then I have been fortunate and blessed to work on projects which have enabled me to expand my knowledge and expertise in the hydraulic design of bridges and roadways.

Rights

Copyright © 2014, Draghina Icobescu

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Aug 20th, 10:55 AM Aug 20th, 11:20 AM

2D Hydraulic Modeling of the State Route 76 Hatchie River Bridge Replacement in West Tennessee Using SRH-2D

State Route 76 (SR-76) over the Hatchie River is the first project designed by Tennessee Department of Transportation (TDOT) using SMS SRH-2D. The bridge replacement over the Hatchie River includes a floodplain approximately four miles wide. There are a total of 13 overflow bridges on SR-76. Also, about 0.40 miles downstream is Interstate40 (I-40), which also crosses the Hatchie River floodplain. I- 40 includes the main river crossing and an additional four overflow bridges. All nineteen bridges are currently listed scour critical. This replacement project will also allow for an updated scour analysis and rating on all the bridges in the floodplain.

The need to have accurate hydraulic data available for these 19 sites is also critical for TDOT due to the nature of the site and the sensitivity of its surroundings. This site is part of the Hatchie National Wildlife Refuge and includes the only river in West Tennessee which has not been straightened by the Corps of Engineers or other agricultural interests.

With SMS SRH-2D both routes and all 19 structures are in a single model which would not have been possible in HEC-RAS. Consultation with FHWA revealed that SMS SRH -2D is the most reliable software available at present for this site.

Fortunately for such a large floodplain, LIDAR data from the NRCS was available at no cost for virtually all of West Tennessee. This data was found to be readily available and very useful for this project.

This presentation will cover various issues encountered during the design process including : processing the raw LIDAR data, hardware and software capability to process the enormous file sizes used in the model, the manipulation of LIDAR data using Geopak to achieve a format acceptable to SMS SRH-2D, and hydraulic design results.

The selection of SMS SRH-2D as the design tool for this project permitted easily accessible graphical and numerical results including: water surface elevation, water depth, velocity magnitude, Froude number, bridge discharge, and flow area. The ability to extract information from the 2D model for use in evaluating bridge contraction scour and pier scour for all 19 bridges proved to be valuable to a successful project design as well.