

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.
The facility features an activated sludge process system. Additionally, the facility is equipped with an emergency standby diesel generator.
Engineering design and construction phase services of water, sewer, drainage and paving for four subdivision sections and off-site channel (123 acres out of a 400 acre subdivision). There was 60-feet of elevation difference on this site and wooded lots were left in their natural state which required the installation of retaining walls.
EHRA was selected as one of two firms to provide professional surveying services under contract to Houston Community College System.
Facilities requiring expansion were also common wall construction, and the EHRA team converted the facilities into aerobic digesters and sludge thickeners.
Mass timber building advocates are encouraged by the results of the world’s first blast tests on full-scale structures framed with the renewable construction material. The performance metrics and design guidance produced from the tests, largely on cross-laminated timber frames, will help developers and blast engineers use CLT walls and floors as framing for target buildings that require hardening based on perceived security risks.
“No live tests had ever been done on cross-laminated timber,” says Bill Parsons, chief operating officer for WoodWorks Wood Products Council, which organized the seven tests. The only previous tests had been shock tube tests, which shot air waves at CLT panels to mimic an explosive.
Tests at Tyndall Air Force Base in Florida, on loaded and unloaded specimens, varied the blast force, the material grade, the number of plies and other factors. In all tests, three conducted in the fall of 2016 and four last fall, the structures remained intact under “significant explosive loading well beyond their design capacity,” according to WoodWorks. Based on the results, “mass timber structural systems can effectively resist blast loads in the elastic response range with little noticeable damage,” says Mark Weaver, principal of Karagozian & Case Inc.
Source: http://enr.com