The purpose of this project was to convert the existing at-grade crossing of Brazoria County Road 56 (CR 56) and State Highway 288 (SH 288) into a diamond interchange that includes a new overpass bridge and providing access to the newly developed Meridiana Development. Coordination with TXDOT, area landowners, utility companies, and Brazoria County was integral in obtaining approval and acceptance of the project.  The main design challenge for this project was to accommodate double intersections on the west side of SH 288 to tie into existing access roads with two-way traffic and a new southbound on-ramp within a close proximity.  EHRA coordinated with TxDOT throughout the project from preliminary concepts for the intersection and bridge through final design and construction.  Each component of this project was designed in accordance with TxDOT standards and criteria.

EHRA designed a 640-foot long bridge to span SH 288 in accordance with TxDOT green ribbon standards.  The purpose of the bridge was to facilitate traffic movement along CR 56 and across SH 288.  In addition to the bridge, EHRA designed and prepared construction drawings for the 2-lane frontage roads and intersection design for the project.  Roadway drainage was analyzed for the project through hydrologic and hydraulic analysis, which resulted in the design of 2 detention basins required to mitigate the increased runoff from the project.  Also as part of the project, EHRA designed and prepared construction sequencing/ traffic control plans and details that included construction phasing, location of construction signs, barricades, drums, and speed limits, and development of a detour plan for each construction phase.  Illumination design was also a part of the project with a focus on safety lighting at merge and diverge areas. Design included foundations, light poles and their spacing, mounting heights, voltage drop calculations, an electrical wiring diagram, electric service coordination, conduit runs. 

Drainage analyses have been performed on multiple phases of development including watershed flood hazard conditions to West Fork of Chocolate Bayou watershed, detention analysis with variable tailwater conditions, and hydraulic impacts. EHRA completed these nalysis to meet the requirements of the City of Iowa Colony and Brazoria County Drainage District No. 5 (BDD5) drainage criteria.

EHRA served as the Engineer for the overall development.  As such, engineering for the development includes all underground wet utilities, a master drainage plan, two water treatment plants, two wastewater treatment plants and associated sanitary lift stations throughout the Development.  

Location: 

CR 56 and SH 288 Interchange, Frontage Roads and Overpass

Completion Date: October 2016

Project Highlights:

•    Roadway Design
•    Bridge Design
•    Traffic Control Plan
•    Hydrologic and Hydraulic Analysis & Design
•    Illumination Design
•    Coordination with State and Local Agencies