Houston Community College Campus Expansion

EHRA was selected as one of two firms to provide professional surveying services under contract to Houston Community College System.

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.

Towne Lake

EHRA was selected by the client to provide engineering design and to serve as District Engineer for the 2,400 acre Towne Lake Development. Our survey department retraced the overall boundary and performed a topographic survey of the site.

Harris County MUD 449 Wastewater Treatment Plant Expansion

Facilities requiring expansion were also common wall construction, and the EHRA team converted the facilities into aerobic digesters and sludge thickeners.

West Road Phase 2 Sidewalk

EHRA worked with the District to create a comprehensive Parks Master Plan, which included recommendations for the development of over two miles of hike/bike trails adjacent to local streets, and within flood control and utility pipeline easements. The District began implementation of the Plan by prioritizing the beautification of West Road, a major arterial street that runs through the District.

14 May 2018

Mystery Solved!

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Why has the Leaning Tower of Pisa survived the strong earthquakes that have hit the region since the middle ages? This is a long-standing question a research group of 16 engineers has investigated, including a leading expert in earthquake engineering and soil-structure interaction from the University of Bristol. Professor George Mylonakis, from Bristol's Department of Civil Engineering, was invited to join a 16-member research team, led by Professor Camillo Nuti at Roma Tre University, to explore this Leaning Tower of Pisa mystery that has puzzled engineers for many years. Despite leaning precariously at a five-degree angle, leading to an offset at the top of over five metres, the 58-metre tall Tower has managed to survive, undamaged, at least four strong earthquakes that have hit the region since 1280.

Given the vulnerability of the structure, which barely manages to stand vertically, it was expected to sustain serious damage or even collapse because of moderate seismic activity. Surprisingly this hasn't happened and until now this has mystified engineers for a long time. After studying available seismological, geotechnical and structural information, the research team concluded that the survival of the Tower can be attributed to a phenomenon known as dynamic soil-structure interaction (DSSI).

The considerable height and stiffness of the Tower combined with the softness of the foundation soil, causes the vibrational characteristics of the structure to be modified substantially, in such a way that the Tower does not resonate with earthquake ground motion. This has been the key to its survival. The unique combination of these characteristics gives the Tower of Pisa the world record in DSSI effects. Professor Mylonakis, Chair in Geotechnics and Soil-Structure Interaction, and Head of Earthquake and Geotechnical Engineering Research Group in the Department of Civil Engineering at the University of Bristol, said: "Ironically, the very same soil that caused the leaning instability and brought the Tower to the verge of collapse, can be credited for helping it survive these seismic events."

Results from the study have been presented to international workshops and will be formally announced at the 16th European Conference in Earthquake Engineering.

Story Source: Materials provided by University of Bristol/Science Daily