civil engineering-->> the planning dilemma

The Planning Dilemma

The Planning Dilemma:

As indicated in Chapter 1, the United States is, for better or worse, tightly bound to the motor vehicle. Until the early or middle 1960s, the attitude of the public and their elected representatives toward highways, and particularly freeways, was highly favorable. Even today, such attitudes generally prevail toward highway investments in rural areas, although some critics blame the automobile for such problems as the removal of land from productive use, its failure or that of alternative transportation schemes to provide for the movement of rural residents, particularly the poor, and the overcrowding and despoiling of recreational and scenic areas. But a possibly large segment of the population and many social scientists and politicians charge the motor vehicle and the freeways and streets that serve it with primary responsibility for such urban problems as air and noise pollution, urban sprawl, displacement of the poor and minorities from their homes, and the detoriation of the central city and close-in residential areas. Thus, where a few years ago highway agencies proceeded with their urban programs with little interference and with a feeling of certainty, they now operate in an atmosphere of confusion, uncertainty and distrust. This situation is not peculiar to transportation, for agencies charged with other public responsibilities also are being subjected to strong criticism.

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civil engineering-->> overview of arches

Arches An arch is an opening spanned by a collection of wedge shaped pieces ( voussoirs ) which stay in position by pressing in on one another. The joints between the pieces appear to radiate from some central point lying within the opening, and sometimes from points which lie outside, so every type of arch has a characteristic curvature. The simplest and visually most natural shape for an arch is the semicircle but many other designs have been used. How an Arch "Works" The central voussoir ( keystone ) is traditionally the last to be set into position to "lock" the whole thing into a strong and stable structure. A keystone is not always necessary, however; there may be a joint at the apex instead, as is common in Gothic arches. Gravity tries to pull the keystone downwards, but the thrust is carried on either side by the voussoirs immediately flanking it. These in turn have their total thrust carried through the whole semicircle of pieces in a sideways direc...

civil engineering-->>Determinacy, Indeterminacy and Stability of Frames

Determinacy, Indeterminacy and Stability of Frames : Structural engineers must be able to apply judgment rather than stated rules. The most important aspect of structural design is not the ability to apply formulas or manipulate mathematics. The most important skill for the structural engineer is to be able to stand back, look at a drawing or sketch and determine whether a structure is stable, and if it is stable, to be able to determine how it will carry the applied loads. For a very complicated structure this might be more difficult and a computer can provide some help, but ultimately it is the skill and concern of a good structural engineer which produces good structural designs which have integrity. Another important closely related skill is the ability to determine whether, and to what degree, a structure is statically indeterminate. There really aren’t many rules and rules may be difficult to apply in any case. For this reason, we need experience. A skilled structural...

civil engineering-->> truss types

Modified-Queen-Scissors Baby Barn and Shed Trusses floor truss ...

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