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Constructions and related matters relevant to environmental health
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
John Bryson, Stephen Battersby
Foundations, also referred to as “footings”, are a fundamental feature of construction as they provide the necessary support for the whole structure. They should take into account the geological conditions in the area and the intended function of the structure. A shallow foundation, which is the most common for housing and smaller commercial buildings is usually embedded a metre or so into the ground. One common type is the spread footing which consists of strips or pads of concrete (or other materials) which extend below the frost line and transfer the weight from walls and columns to the soil or bedrock. The frost line is most commonly the depth to which the groundwater in soil is expected to freeze. The frost depth depends on the climatic conditions of an area, the heat transfer properties of the soil and adjacent materials, and on nearby heat sources.
Wind
Published in Dorothy Gerring, Renewable Energy Systems for Building Designers, 2023
Compare figures 15.11 and 15.13 (left plan) to see the guyed tilt-up tower in both elevation and plan. Note that concrete foundations are required at the tower base and as anchors for the guy wires. Local requirements for depth of foundation need to be followed so foundations are below the frost line and suitable to support the gravity loads of the tower and turbine plus the overturning loads created by the wind. Note that the guy radius is 35–60% of the tower height. The gin pole will be 75–100% of the guy radius and remains in place. Note that the gin pole is parallel to one of the four sets of guy wires and that the full length of the tower height must be open on the other side of the gin pole in order to raise and lower the tower. The pink kite shape defined by the guy anchors and the height of the tower is the minimum area that must be kept clear around the tower.
Receptors
Published in Heinz M. Schlicke, Electromagnetic Compossibility, 2020
Frost nullifies grounding. As we saw in Chapter 2, frost may reduce the conductivity of soil by many decades. This is particularly significant in the arctic; but even in the northern United States, in cold winters, the frost line may be 2 m deep.
SWM and urban water: Smart management for an absurd system?
Published in Water International, 2020
Smart technologies have been developed to find leaks in buried water mains, such as sonic devices that can ‘hear’ water under pressure escaping from pipes. The question becomes: Is the cost of producing that water higher than the cost of stopping the leak? Consider that water mains must be below the depth to which frost penetrates under the roadway. In Canada and parts of the northern United States, the frost line can be over two metres deep (in Ottawa, it is three metres). To repair a leak or to replace an old water main, the asphalt or concrete roadway must be removed and a trench dug down to the pipe, which is typically underneath the infrastructure of other utilities, providing gas, telecommunications, and electrical power to communities. The sanitary sewer and storm sewers may also need to be circumvented, although these are often deeper than the purified water system pipes. Representatives from other utilities must provide location information for their service lines, traffic has to be diverted, heavy equipment brought in for the excavation, and proper safety measures used at all times, such as an excavation trench box to prevent suffocation of the workers if the earthen sides of the trench collapse.