Soil-bearing pressures

Soil-bearing pressures, 99-100 Soldering, 448 Solid-waste disposal, 88-90 Space velocity, definition of 728 Specific gravities of liquids, 882 of solids, 883... 

Bf= allowable soil bearing pressure, psf Cf=wind force coefficient, from table Ci.Ca = NBC coefficients... 

A foundation bearing pressure computation against which the second restart criterion can be tested is not available for SRS. A calculation performed by DOE staff determined that the maximum soil bearing pressure during an earthquake would be 8.24 ksf. The value is well below the design bearing capacity which has been shown to be in excess of 500 ksf. 

The bearing pressure of the tank and contents must not exceed the bearing strength of the soil. Focal building codes usually specify aUowable soil loading. Some approximate bearing values are ... 

Approximate allowable bearing pressures on sedimentary rock and soils may be taken from Table 2-31 [1 and 37]. Where questionable surface and subsurface soil conditions exist allowable bearing pressures can be determined with the aid of field sampling, field tests (both surface and subsurface through borings), and laboratory tests. 

Because the. initial foundation. dimcn.sions-ie,sult in acceptable foundatipn-sbil interface bearing- pressures and acceptable. subsurface pres.sures. on-weaker underlying layers of soil, the square foundation of 7.4 ft is the final foundation... 

If the pipe is anchored by bearing at the bend, care shall be taken to distribute the load on the soil so that the bearing pressure is within the capability of the soil involved. 

Under blast conditions, maximum soil bearing and passive pressures are selected to prevent excessive foundation movement, The following design criteria are often used in equivalent static design for foundations ... 

Preliminary design of the foundation will include evaluating overturning, bearing pressures and lateral load resistance. The foundation must be able to resist the applied blast loads with a degree of safety to account for uncertainties in prediction of soil properties. Foundation failure can cause serious collapse hazards, thus it is prudent to maintain a conservative design. Also, should an incident occur, it is many times desirable to be able to remove the building structure and rebuild on the same foundation. 

The length of time pesticides persist in the forest floor and soil bears strongly on the probability they will be lost by volatilization (28-31). The phenoxy herbicides are commonly applied to forests as the low-volatile esters. These esters are readily hydrolyzed to their respective acids in soil or on the forest floor. For example, Smith (32) reported that no traces of 2,4,5-T and 2,4-D esters were observed in any of four moist soils after 48 and 72 hours, respectively, and most of them were hydrolyzed in less than 24 hours. The vapor pressures of the acids are much lower than the esters and this hydrolysis, along with subsequent degradation of the acids, results in a very low potential for volatilization of these materials from soil. 

The allowable bearing pressure varies for different types of soils, and the soil should be checked at the surface and at various depths to determine the bearing characteristics. The allowable bearing pressure for rock is 30 or more ton/ft2 (30 X 104 kg/m2), while that for soft clay may be as low as 1 ton/ft2 (1 x 104 kg/m2). Intermediate values of 4 to 10 ton/ft2 (4 X 104 to 10 X 104 kg/m2) apply for mixtures of gravel with sand, hard clay, and hardpan. 

The constitutive model parameters for PZ-III model were calibrated using the centrifuge test data from the loose, level sand bed test series shown in Figure 7. All the FE analysis results reported in this article are for an 18m deep, loose sand layer and are presented at prototype scale. In Figure 9 the FE discretisation used in these analyses is presented. A series of FE analyses were carried out for different bearing pressures applied by the bridge foundation on to the foundation soil for a sinusoidal input motion of 0. Ig. In Figure 10, the time histories obtained from the FE analyses for... 

Subsequent studies, which included performance evaluations of foundations designed in accord with the original recommendations, have indicated that modification of the original design criteria is necessary where greater allowable bearing pressures can be permitted. When SPT values are used for foundation design, the field blow counts need to be corrected to reflect the effect of sample depth on actual soil properties. 

Figure 4.11 presents design criteria for shallow footings with the bearing pressures intended to be values that produce a maximum settlement to the order of one inch. It is assumed that the value of point resistance, qc is representative of the soil zone below the base of the footing to a depth extending approximately 1.55 further, and the water table is deep. 

Where, q es = foundation design bearing pressure minus the vertical pressure of the soil overburden adjacent to the foundation base Bo = a. reference dimension, equal to 0.6 m or 2 ft, B = width or diameter of the foundation, provided that B is equal to or greater than Bo or = rheological or creep deformation factor, which depends on the soil type and the ratio (Table 4.6) EJ Pi — g ) Ac, = shape factors that are based on length-to-width ratio of the foundation (Table 4.7) ... 

Allowable foundation bearing values that are related to the visual classification of a site s bearing soil, a type of design information that conventionally appears as part of the building codes, are termed presumptive bearing pressures. Examples are shown in Table 4.8. 

The series of dynamic centrifuge tests included an experiment (CT-A) intended to evaluate the fundamental behavior of the system through the analysis of a benchmark problem for further comparison with the subsequent tests. This test was also carried out to establish the influence of the bearing pressure induced by the shallow foundation on the liquefiable ground on the performance of the soil-structure system under seismic loading and to assess potential interaction effects between the structures placed in the same model. Figure 24.2 presents a scheme of the model... 

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