There are mainly two types of R.C.C. footings: 1. One way reinforced footings. 2. Two way reinforced footings. 1. One Way Reinforced Footing: These footings are for the walls. In these footings main reinforcements are in the transverse direction of wall. In longitudinal directions there will be only nominal reinforcement. 2. Two Way Reinforced Footings: For columns…
The rate of consolidation always slows down significantly toward the end of the consolidation period. The time between about 80 % and 95 % of primary consolidation can require as long time as that from start to 80 %, and the time from 95 % to, say, 98 % can take a very long time….
Carillo (1942 and Asaoka (1978) developed Eq. 4.2 to express the average degree of consolidation for the case of combined horizontal and vertical consolidation. Note, however, that (1) the small distance between the drains (the drain spacing), (2) that the horizontal coefficient of consolidation, ch, is larger than the vertical coefficient, cv, and (4) the…
Introduction All materials will undergo volume change when subjected to stress change and soils are no exception. Unlike steel or concrete and other solids, soils are made up of granular materials: grains. Moreover, the pores between the grains are usually filled with water, often a water and air (gas) mix. This fact makes the response…
The Janbu tangent modulus method is not different to—does not contrast or conflict with—the ‘conventional’ methods. The Janbu method for calculation of settlements and the conventional elastic modulus approach give identical results, as do the Janbu method and the conventional Cce0-method (Eqs. 3.4 and 3.5, and Eqs. 3.13, 3.14, and 3.15). There are simple direct…
General The Janbu approach, proposed by Nilmar Janbu in the early 1960s (Janbu 1963; 1965; 1967), and referenced by the Canadian Foundation Engineering Manual, CFEM (1985, 1992), combines the basic principles of linear and non-linear stress-strain behavior. The method applies to all soils, clays as well as sand. By the Janbu method, the relation between…
Linear stress-strain behavior follows Hooke’s law (“elastic modulus method”) according to Eq. 3.1. The “elastic modulus” is often called Young’s modulus. Strictly speaking, however, Young’s modulus is the modulus when lateral expansion is allowed. When no, or next to no, lateral expansion is “allowed”, the modulus is called “constrained modulus”, D (or M), and it…
Introduction A foundation is a constructed unit that transfers the load from a superstructure to the ground. With regard to vertical loads, most foundations receive a more or less concentrated load from the superstructure and transfer this load to the soil underneath the foundation, distributing the load as a stress over the “footprint” of the…
To provide a direct comparison between the Robertson (1990) profiling chart and the Eslami-Fellenius chart, three short series of CPTU data were compiled from sites with very different geologic origin where the soil profiles had been established independently of the CPTU. The borehole information provides soil description and water content of recovered samples. For one…
To investigate the use of cone penetrometer data in pile design, Eslami and Fellenius (1997) compiled a database consisting of CPT and CPTU data linked with results of boring, sampling, laboratory testing, and routine soil characteristics. The cases are from 18 sources reporting data from 20 sites in 5 countries. About half of the cases…