Foundations dead load

Foundation Loads and Pressures. Foundations should be designed to support the weight of the structure, the live load, and the load effect on the structure and its foundation due to such other loads as v. ind. In general, for foundation designs, a safety factor of 3 is used for dead loads or live loads independently. A safety factor of 2 is used for combination loads including transient loads [38,40]. 

It is intended that a spread foundation be designed for a concentric load of 300,000 lb (dead load plus live load). This foundation is to be placed on the surface (brown silty sand and gravel) of the soil and bedrock column shown in Figure 2-61. If a square foundation can be made to support the 300,000-lb load, what should be the dimensions of this foundation ... 

Another option would be to add steel or fiber reinforced shotcrctc layer to the exterior surface of a CMU wall. The shotcrete adds significant ductility to the wall, increases the inertia mass and bonds the existing blocks This prevents the blocks from becoming dislodged when the wall undergoes defied ions. This type of exterior construction can be accomplished with minimal interruptions to the building functions. Foundation modifications may be needed to accommodate additional dead load from shotcrete application. 

The poorest stability occurs just before the tower is placed on the foundation. To calculate the tower s stability. Si must be replaced with Si , which is the minimum soil loading caused by the dead load, psf. 

This is the dead load under the poorest stability condition. Since it is greater than the overturning stress (S2 = 800), the soil below the foundation will always be under compression at all points, which indicates that the foundation is stable. 

There are two forces acting on foundations of the type under consideration the dead load, acting in a vertical direction and the wind load, acting in a horizontal direction. The combined action of these two forces has the same effect as an eccentric vertical load. It is not necessary to calculate the eccentricity to determine the stability of the foundation. However, because there are definite relationships between eccentricity and stability, they will be explained as a matter of interest. 

In Example 1 it was shown that the foundation is stable, since the overturning stress S2 is less than the minimum dead load stress S tn ... 

The value of e calculated from equation (11-11) is maximum for any particular foundation, which is the value governing stability. We are now concerned with the maximum soil loading (toe pressure) which occurs when the dead load is maximum. It is therefore necessary to substitute W in place of Wf in equation (11-11) ... 

It was shown by equation (11-1) that the total soil loading, to be considered in the design of tower foundations, is the sum of Si, the dead load, and S2, the load caused by the overturning or wind moment. There is no overturning moment on guyed towers however, the wind pressure does have an important effect on the foundation, as the soil is required to resist the vertical component of the pull on the guy wires. 

The foundations should also be as wide as the tank, built below the frost line, and of a size dependent on the load. The load is a dead load,... 

W is the effective seismic weight. It includes the total dead load above the foundation or above the top of a rigid basement and applicable portions of other loads (live load and snow). For instance, in areas used for permanent storage such as library shelves, fixed equipments, etc., the total floor live load should be applicable. In areas used for housing or administrative purposes, only a percentage (20-30 %) of the floor live load should be applicable. 

The derrick or mast must also be designed to withstand wind loads. Wind loads are imposed by the wind acting on the outer and inner surfaces of the open structure. When designing for wind loads, the designer must consider that the drill pipe or other tubulars may be out of the hole and stacked in the structure. This means that there will be loads imposed on the structure by the pipe weight (i.e., setback load) in addition to the additional loads imposed by the wind. The horizontal forces due to wind are counteracted by the lattice structure that is firmly secured to the structure s foundation. Additional support to the structure can be accomplished by the guy lines attached to the structure and to a dead man anchor some distance away from it. The dead man anchor is buried in the ground to firmly support the tension loads in the guy line. The guy lines are pretensioned when attached to the dead man anchor. 

The standard dead weight loading oedometer is the one in general use The alternative is the hydraulic oedometer (Rowe cell) in which the vertical loading and the pore pressures can be independently controlled Reasonable assessments of the magnitudes of foundation settlements can be made if... 

To conduct a static load test, there must be a means of applying the desired loads to the foundation and measuring the resulting settlement. The most common method is the kentlegde system whereby dead weights such as precast concrete blocks are stacked on top of the foundation, as shown in Figure 11.1. An alternative is to provide multiple support in the form of reaction pile and use them as a reaction for a hydraulic jack (Figure 11.2). 

The Disassembly Basins were designed and constructed to be qualified for a blast load and a nominal O.lg earthquake statical applied to the dead and live load (Ref 8-28). This included a foundation investigafion by the US Army Corps of En neers. The Disassembly Basin walls interi dng whh the reactor building were later reviewed (Blume) in 1967 for st-0 2g Housner response spectrum (Ref 8-28). A recent structural scoping study assessment reveals the K-Reactor Disassembly Basin exterior walls and foundations should be capable of vdtbstanding a... 

Note that no assumption on the potential type of external loading was Introduced In the development of Eqs. (4), (5) and (7). These equations were Illustrated In [5] using a simple model, an elastic cantilever beam attached to a rigid foundation, and subjected to a transverse force Q and a longitudinal force P (Fig. 3). The force P Is taken In two variants a dead force = 0) and a follower force ( = - 8v/8x). Deflections v(x) are assumed small, and the tip zone Is absent. 

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