League Line

EHRA performed preliminary drainage area delineations for nine creek crossings and calculated approximate 100-year flows for each culvert crossing. Culvert structures were sized for each of the six crossings, ranging from 48” round pipe culverts up to dual 5’x5’ box culverts.

Ventana Lakes Development

Project totaled 640 acres including 1256 Residential Lots. EHRA designed, created construction plans, publicly bid and preformed Construction management.

Towne Lake

In 2006, Caldwell Companies sought to create Towne Lake as a community where residents and services could be connected by water. Their vision included boat docks and marinas augmenting traditional walking trails to navigate a vibrant residential community. EHRA was the perfect partner to take Caldwell Companies’ vision and create this livable suburban oasis.

Meridiana

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.

Northpark Drive Mobility Project

EHRA completed preliminary engineering, phase one environmental site assessment and schematic development for the widening of Northpark Dr. between US 59 and Woodland Hills Dr. EHRA also provided program management, drainage analysis and design, traffic engineering, environmental documentation and schematic design for the roadway, as well as grade separation at the Loop 494/UPRR railroad crossing.

EHRA conducted traffic operations and access management studies for the Northpark Dr. corridor. This corridor is approximately 2.2 miles long and has major signalized and unsignalized intersections and driveways that access various subdivisions and industrial developments. These studies laid the groundwork for the widening of Northpark Dr. from a four-lane boulevard cross-section to a six-lane boulevard complete street. The new street design includes low impact development drainage, conventional drainage, a grade separation at the UPRR crossing with mechanically stabilized earth retaining walls, two at-grade crossings for bi-directional frontage access, reconstruction of two concrete bridges over a diversion channel, intersection improvements, a roadway-adjacent multiuse path and traffic signal improvements.

Drainage analysis and design included hydrologic and hydraulic studies of both existing and proposed conditions to demonstrate that proposed project components would not adversely affect the 100-year floodplain in the area. The roadway and traffic designs contained horizontal and vertical alignments, cross-sections, plan and profile, sidewalk and bicycle accommodations, intersection layouts, traffic control plans and signing and pavement markings.

As the program management firm, EHRA coordinated with TxDOT, UPRR, the City of Houston Council District E, COH Planning and Development Department, COH Public Works and Engineering Department, Montgomery County, Harris County, HCFCD and area residents throughout the project.

19 September 2018

Weather on Bridges

Admin

Bad weather can happen anywhere and at any time. In the past, bridges were designed and built specifically to a standard degree. However, flaws and unexpected damage affecting the overall structural integrity result in extreme safety hazards for the thousands that cross them. It is because of this that engineering has evolved to anticipate the inevitable and the unpredictable.

In 1971, a dozen of bridges collapsed onto freeways in California during an earthquake. When events like this happen, engineers observe what went wrong and how to fix bridge designs and strengthen existing bridges. After learning that different designs need to be put in place, now, bridges in California have metal retainer cables that tie the bridges down. Having restrainers put in place cause the bridge to place support on the piers so they do not fall down. Also, engineers are building shake tables where they can test simulations of an earthquakes shaking on a bridge.

During Hurricane Katrina in 2005, engineers discovered the impact that water has on bridges. Bridges in and around the New Orleans area were severely damaged from the storm surges. Now, engineers are building bridges high enough so no waves touch any side. Also, new models are in place to see the impact on waves and bridges.

According to Dr. Michael Chajes, professor of civil and environmental engineering at the University of Delaware, it is imperative in designing bridges to have backup systems in place. He uses the comparison to flying a plane and taking precaution to make sure everything goes smoothly. “The component you really don’t want things to go wrong with is the engine, and airplanes are designed to be able to fly with one engine.” Chajes said. “Even if it started out with four engines, in theory, if three of them went bad, the fourth one would still be enough for the pilot to land safely.”