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Foundations
Published in Derek Worthing, Nigel Dann, Roger Heath, of Houses, 2021
Derek Worthing, Nigel Dann, Roger Heath
When designing buildings, engineers are primarily concerned with forces rather than weights and the unit of force most commonly used is the kilonewton (kN); 1 tonne is roughly equal to 10kN. Therefore, a building load of 120 tonnes exerts a force on the sub-soil of 1,200kN. If the load of a building is carried by the external walls and the perimeter of the building is 30m, simple calculation shows that each metre in length (i.e. metre run) of foundation is carrying about 4 tonnes or 40kN. In practice, allowance must be made for the nature of the loading which varies according to the direction of roof and floor spans. Furthermore, uneven loading can be caused by large openings such as patio doors. Once the average loading per metre run of the building is established, it must then be related to the safe bearing capacity of the sub-soil in order to enable the design of an appropriate foundation.
Bearing capacity of shallow foundations
Published in Hsai-Yang Fang, John L. Daniels, Introductory Geotechnical Engineering, 2017
Hsai-Yang Fang, John L. Daniels
To ensure satisfactory performance of a shallow foundation, it is necessary to provide adequate safety against shear failure of the foundation soil and to prevent excessive settlement of the foundation. These general requirements and related information are (a) subsurface conditions including soil type, depth of the groundwater table, frost penetration depth, and topographical features; and (b) footing characteristics including footing width, footing depth, footing shape, and footing base condition. There are numerous methods for determination of the bearing capacity of shallow foundations that can be further grouped into four basic approaches as theoretical approach, in situ measurement, correlation with other soil parameters, and building codes. Before discussing these various methods for determining the bearing capacity of ground soil, it is necessary to review the general ground stability analysis methods available.
Pitched roofs
Published in Duncan Marshall, Derek Worthing, Roger Heath, Nigel Dann, Understanding Housing Defects, 2013
Duncan Marshall, Derek Worthing, Roger Heath, Nigel Dann
The primary function of the roof is to provide protection to the building beneath from the weather. It should be constructed in a form that will meet the following five key performance criteria. Strength. It must be capable of supporting both its own weight and any loads that might be imposed upon it, e.g. snow, standing water, water tanks and other plant.Stability. The various components should not be subject to excessive movement nor should they create instability in other elements.Durability. The materials used, especially coverings, must be capable of performing for their designed life expectancy.Weathertightness. The roof covering must prevent moisture penetration. This is achieved by it being either thin and totally impervious (e.g. sheet roof coverings, slate) or by the use of a thicker, less dense material that is sloping and allows evaporation plus water shedding to take place (stone tiles, clay tiles).Thermal efficiency. In recent years it has become recognised that a roof must also provide good thermal insulation.
Building survey forms for heterogeneous urban areas in seismically hazardous zones. Application to the historical center of Valparaíso, Chile
Published in International Journal of Architectural Heritage, 2018
Belén Jiménez, Luca Pelà, Marcela Hurtado
The foundation soil of the study area is mainly of good characteristics. According to the geological cartography records of Valparaíso (Gana, Wall, and Gutiérrez 1996), the 86% of the buildings are located in hills with hard rock soil. Only the 14% of the buildings are located in the flat area, which presents loose and non-thrusting soil conditions, categorized as a poor category. Hillside’s buildings present very extreme slope conditions, as shown in Figure 22. In these cases, retaining walls are usually employed to counteract the thrusting effect of the soil, especially when the buildings are directly interacting with the terrain. Masonry gravity walls are employed on the 63% of the cases, as shown in Figure 22b. The foundations typologies were identified based on the original documentation of the buildings and on-site inspections of few buildings undergoing restoration works. Brick strip footings are typically employed in masonry and timber frame structures (39% of the cases), while RC strip footings (36%) are used in RC and mixed iron-RC structures. The construction of flat terraces or quarry stone platforms is a common strategy in staggered zones to level steeped terrains and reach stable foundation soils. All these evidences could show the general anti-seismic character of the structures as for the use of good quality foundations and retaining walls. Section 3 of the proposed survey form also helped to detect negative factors such as the extreme slope conditions leading to thrusting effects of the soil and level differences between foundations. According to GNDT (2007), this last factor can negatively affect the behavior of the foundations, thus it needs to be specially considered in future vulnerability analyses.
Attic ventilation and radiant heat barriers in naturally ventilated galvanized metal-Roofed buildings
Published in Advances in Building Energy Research, 2022
Jefrey I. Kindangen, Octavianus H. Rogi, Pierre H. Gosal, Veronica A. Kumurur
In addition to playing a role in realizing the visual appearance of an architectural object, the roof of a building, including the attic, is a very important component in conditioning the interior space of a building so that it is safe and comfortable for users from unfriendly external conditions, especially local climatic aspects such as rain, solar heat radiation, and others.