Poche D.,Chance Inc.
Sea Technology | Year: 2011
Excavation sites on land are often a beehive of activity with excavators, bulldozers and backhoes digging up soil and rocks to ready the site. But when the excavation site is at a water depth of 300 feet with many unknowns, these excavations become a greater challenge in which detailed mapping is critical to success. Data from multibeam sonar are different in another significant way. Scanning sonar employs a single beam with a narrowly focused horizontal aperture and a wide vertical aperture; each ping continuously plots returned intensities of the echo, but it cannot discriminate where those returns are in the vertical plane. Fugro has used various off-the-shelf multibeam sonars for the rotary-mounted system, which weighs about 350 pounds and is about 4 feet long and 20 inches in diameter. Through planning on the decommissioning project, which began in April and lasted five months, it was deemed necessary to jet a 15-foot hole around each of four leg structures, which would allow divers access below the mud line.
Seider G.L.,Chance Inc.
Geotechnical Special Publication | Year: 2015
Hubbell Power Systems, Inc./CHANCE®, in conjunction with Sailors Engineering, Inc. has updated its Helical Design Capacity Software. This latest version, "HeliCAP® v2.0", is a state-of-The-art helical anchor and pile capacity program designed to operate in the Microsoft® environment. The program calculates the tension and compression capacity along with the frictional capacity, if applicable, of helical anchors and piles using design theories and methods adopted by the engineering staff at Hubbell Power Systems, Inc. This paper details the current state of practice employed by the software in the design methods and installation methodologies of helical anchors and piles. © ASCE 2015.
Cahoon D.R.,U.S. Geological Survey |
Perez B.C.,U.S. Geological Survey |
Segura B.D.,Johnson Controls |
Segura B.D.,Chance Inc. |
Lynch J.C.,U.S. Geological Survey
Estuarine, Coastal and Shelf Science | Year: 2011
Given the potential for a projected acceleration in sea-level rise to impact wetland sustainability over the next century, a better understanding is needed of climate-related drivers that influence the processes controlling wetland elevation. Changes in local hydrology and groundwater conditions can cause short-term perturbations to marsh elevation trends through shrink-swell of marsh soils. To better understand the magnitude of these perturbations and their impacts on marsh elevation trends, we measured vertical accretion and elevation dynamics in microtidal marshes in Texas and Louisiana during and after the extreme drought conditions that existed there from 1998 to 2000. In a Louisiana marsh, elevation was controlled by subsurface hydrologic fluxes occurring below the root zone but above the 4. m depth (i.e., the base of the surface elevation table benchmark) that were related to regional drought and local meteorological conditions, with marsh elevation tracking water level variations closely. In Texas, a rapid decline in marsh elevation was related to severe drought conditions, which lowered local groundwater levels. Unfragmented marshes experienced smaller water level drawdowns and more rapid marsh elevation recovery than fragmented marshes. It appears that extended drawdowns lead to increased substrate consolidation making it less resilient to respond to future favorable conditions. Overall, changes in water storage lead to rapid and large short-term impacts on marsh elevation that are as much as five times greater than the long-term elevation trend, indicating the importance of long-term, high-resolution elevation data sets to understand the prolonged effects of water deficits on marsh elevation change. © 2010 Elsevier Ltd.
Chance Inc. | Date: 2014-04-03
Chance Inc. | Date: 2013-11-06
Beer, ale and lager.