China
Africa
Explore chapters and articles related to this topic
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.
A foundation code for problematic arid soils
Published in P.G. Fookes, R.H.G. Parry, Engineering Characteristics of Arid Soils, 2020
Spread footings can be advantageous compared with the other types of shallow foundations for soils possessing moderate swell potential since they allow the concentration of load on individual footings, and give the expansive soil the freedom to move upward in the unloaded areas between footings. Spread footings should be executed on a sand cushion to reduce the effect of swelling pressure on the structure. Grade beams should be rigid enough to resist differential heave, and better be surrounded by sand cushions. Ground floor slabs should be constructed on replaced stable soil as well. Continuous or grid footings may be used to provide more rigidity. Design of raft foundation on expansive soil is quite complicated since the design procedure should be based on probable mechanism of distortion. Therefore, it is not recommended for swelling soils. If the swelling problem is more severe, and the loads are high, a pier foundation is a better choice. Special attention should be give to the tensile and lateral stresses. Upward skin friction exerted by the expansive soil should be taken into consideration. Precautions must be taken when using piers with enlarged base. Experience has shown that enlarging the hole is a hard job and good inspection is difficult to achieve, and the roof of excavation has the tendency to loosen so anchoring resistance is not fully developed.
Constructions and related matters relevant to environmental health
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2016
John Bryson, Stephen Battersby
Foundations, also referred to as ‘footings’, are arguably the most important 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 soil. 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.
Recorded acceleration responses of inverted Y-shaped towers in long span cable-stayed bridges during moderate earthquakes
Published in Structure and Infrastructure Engineering, 2023
Alemdar Bayraktar, Mehmet Akköse
The Nissibi bridge has two towers (pylons) named as P4 and P5. P4 is in Adıyaman side whereas P5 is in the Diyarbakır side. The two inverted Y-shaped towers have a structural height of 96.78 m from the foundation to the top of towers (Figure 4). The towers are made of reinforced concrete except for the top region of the 14-cable stay anchors, where the core is made of a steel box encased by a reinforced concrete out shell to form a composite section. The tower legs are connected at the base by the foundation as well as cross beam and a wall. The deck is supported by lead rubber bearings located on the tower cross beam. The towers are founded entirely on rock by means of spread footings. The tower foundations consist of 50mx20mx45m rectangular spread footings, while the typical pier foundation is founded on a 13.3x6mx1.5m spread footing and abutment foundation consists of a 28.7mx12.2mx1.5m spread footing.
Multiscale modelling of the seismic response of shallow foundations on saturated granular soils
Published in Geomechanics and Geoengineering, 2022
The proposed approach was used to investigate the response of a spread footing foundation system founded on saturated granular deposits. The system is assumed to be composed of isolated square footings (2.4 m2.4 m) equally spaced at 5.6 m in the two lateral directions. The foundation depth is 1.0 m below ground surface and the soil profile at the site is composed of 10.8 m of granular soil underlain by a rigid bedrock. The groundwater table (GWT) location was changed in two cases in this study . The first case resembles a deposit with relatively deep GWT (4.8 m below ground level). In the second case, the GWT was only 1.2 m below ground level. In the conducted simulations, the soil above the GWT was assumed to be completely dry while the soil below the GWT was fully saturated.
Impact of reinforcement granular soils on the behaviour of strip footing nearby an excavation
Published in Geomechanics and Geoengineering, 2021
Hussein Ahmad, Ahmad Mahboubi, Ali Noorzad, Mostafa Zamanian
The undrained bearing capacity of the strip footing placed close to a slope through the finite element technique and finite element limit analysis was assessed (Georgiadis 2010, Shiau et al. 2011, Naeini et al. 2012). The findings indicated that monitoring three failure surfaces can be performed in terms of the slope height relative to footing width (H/B) ratio (Georgiadis 2010, Beygi et al. 2020). An empirical analysis to assess the ultimate bearing capacity of the strip footing over the sandy slope was conducted by Salih Keskin and Laman (2013). Their findings showed that by increasing the setback distance, the strip footing’s ultimate bearing capacity incremented. The lower bound technique to evaluate the bearing capacity of the strip footing close to a slope was utilised after Mofidi Rouchi et al. (2014). By using limit analysis along with discontinuity layout optimisation, the bearing capacity of spread footing close to the slopes ofc-φwas computed after Leshchinsky and Xie (2017). The strip footing bearing capacity placed on the slope by the lower bound technique was calculated by Halder et al. (2017). Discontinuity layout optimisation was utilised to provide the diagrams for the bearing capacity of the strip footing located on the slope after Zhou et al. (2018). The findings proved that the nonlinearity with setback distance increased by the normalised bearing capacity.