Blog Archives

Lighting Design Values

Posted by on 23/ 11/ 15

Recommended values for illuminance, luminance, and small-target visibility are pub­lished as Tables 2, 3, and 4 in ANSI/IESNA RP-8-00, American National Standard Practice for Roadway Lighting, www. iesna. org. These lighting criteria for the three recognized calculation methods are typically adopted by AASHTO and published as a part of the AASHTO Guideline for Roadway Lighting. The Federal Highway Administration, in turn, historically has accepted the RP-8 criteria as adopted by AASHTO for lighting projects partially funded with federal funds. Refer to the latest edition of the AASHTO Roadway Lighting Design Guide for current recommended criteria. Each lighting designer should have access to the latest versions of these docu­ments, which sometimes contain substantial modifications.

7.17...

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Freezing Induced Water Flow

Posted by on 23/ 11/ 15

The significance of the coupling between heat and water transport will be illustrated using a freezing experiment performed by Mizoguchi (1990). He packed four iden­tical cylinders with Kanagawa sandy loam. Each cylinder was 20 cm long and had an internal diameter of 8 cm. The samples were prepared for the freezing test by bringing them to the same initial state involving a uniform temperature of 6.7 °C and a close to uniform volumetric water content of 0.33 throughout the cylinders. Water and soil in each cylinder was subjected to freezing from the top down, since their top covers were exposed to a circulating fluid with a temperature of -6 °C. One cylinder was used to obtain initial values, and the other three were removed from freezing after 12, 24 and 50 hours respectively...

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Simulating the Infiltration and Percolation in a Road After Rainfall

Posted by on 23/ 11/ 15

Hansson et al. (2005) made an attempt to illustrate the effect of a rain shower and fracture zone permeability on the subsurface flow pattern using a two-dimensional computer model; thus making the simulation domain more like reality (Fig. 11.6). The properties of the materials used in the various layers of the model road fulfil the requirements of the Swedish road design guide. In addition, it was assumed that the asphalt layer of the road had plenty of fractures over a relatively short distance, “a fracture zone”, which thus enabled the use of an equivalent homogeneous porous media model. More details about material properties, driving data etc. can be found in Hansson (2005).

Notice (Fig. 11...

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Examples

Posted by on 23/ 11/ 15

11.4.1 Modelling of Moisture Movements

Alonso (1998) presents, on the basis of in-situ measurements, relevant aspects of the water content development of pavement layers and its effect on the mechanical characteristics of granular bases and subgrades. A general model for the coupled analysis of transfer processes (water, heat) and stress-strain behaviour of unsatu­rated compacted soils is then presented. A review of some representative properties of compacted soils has been carried out from the perspective of modern concepts of unsaturated soil mechanics. As an application of the methods described a full simulation of a modern pavement structure under the effects of a Mediterranean cli­mate has been developed...

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STREETS AND HIGHWAYS OTHER THAN FREEWAYS

Posted by on 23/ 11/ 15

Fixed roadway lighting systems increase night visibility, as well as improve safety, traffic movement, and general roadway use. Traffic volume, numbers of pedestrians, at-grade intersections, turning movements, signalization, and unusual geometrics are some elements that make lighting of streets and highways desirable. Lighting, in addi­tion to its safety benefits, is a crime deterrent and a valuable aid to law enforcement agencies and often contributes to the pride of a community.

7.17.1 Warranting Conditions for Roadways Other Than Freeways [3]

It is not practical to establish specific warrants for the installation of roadway lighting to satisfy all prevailing or anticipated conditions...

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HARBINGER

Posted by on 23/ 11/ 15

The Harbinger is the Dutch hip version of the Bodega described on page 168. In this case, a bump – out provides enough space for an additional bedroom or sitting room downstairs. If one were to count the loft, this house would actually measure almost 600 square feet, or 700, with the add-on.

Square feet: 278

With add-on: 372 House width: 20’

House length: 20’

Porch: 6’ x 13У2

Great Room: 9’x13’ Kitchen: ІУ2 x ІУ2

Bathroom: 51/2’ x 51/2’

Addition: 93/V x 7’

Ceiling height: 7’ 6”

Loft height: 7’

-sizes are approximate

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Historical and cultural landmarks

Posted by on 23/ 11/ 15

The Bronze Age begins with the Shang Dynasty, succeeding the Xia Dynasty about 1600 BC. This aristocratic and cruel regime is well known in archaeology; the first texts scratched in bone come from it. The influence of this dynasty is limited to the valley of the Yellow river to Shandong. Then about 1100 BC the Zhou, coming from the valley of the Wei (a tributary of the Yellow River in Shaanxi) supplant the Shangs. Under their more humane domination the Chinese civilization reaches not only further to the north, but also and especially toward the south as far as the Yangtze valley. The Zhou estab­lish their capital near Luoyang where the river flows out onto the plain. But the Zhou regime does not have a structure that is capable of coping with the growth of their domain...

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From the beginnings of agriculture to the legendary founder of Chinese civ­ilization

Posted by on 23/ 11/ 15

Archaeology teaches us that grain cultivation, namely millet, appears in the middle basin of the Yellow River around 6000 BC.[370] [371] [372] Two cultures develop successively in this region: one is called the Yangshao at the end of the VIth millennium BC, during which small- scale farming develops (pork, poultry); the other is the Longshan, at the end of the IIIrd millennium BC, during which wheat and barley develop in addition to millet, and the first fortified villages appear. As a point of reference, recall that this is also the period of the grand civilization of Harappa on the Indus and its extensions in Bactria. The Chinese regions involved are Shaanxi, Shandong and especially Henan and Shanxi...

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Special Conditions That Warrant Lighting [3]

Posted by on 22/ 11/ 15

Continuous, complete, or partial interchange lighting is considered to be justified in

the following situations:

• In general, lighting is warranted where the local government agency finds sufficient benefit in the forms of convenience, safety, policing, community promotion, public relations, etc., to pay an appreciable percentage of the cost of the installation, main­tenance, and operation of the lighting system.

• Where there is continuous freeway lighting, there should be complete interchange lighting.

• Where complete interchange lighting is warranted but not initially fully installed, a partial lighting system that exceeds the normal partial installation in number of lighting units is considered to be justified.

• Lighting of crossroad ramp terminals is warranted regardless of ...

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Test Results

Posted by on 22/ 11/ 15

There are a number of impressive publications in the technical literature that describe the results of testing antinoise properties of various pavements. (Refer to the Bibliography at the end of this book.)

Olszacki (2005) tested the sound-absorbing power of different asphalt surfacing types with diversified void contents. Figure 12.5 shows the relationship between the noise absorption coefficient and sound frequency. It is evident that SMA is character­ized by better properties than mixtures of AC, but not as good as porous asphalt with a much higher content of voids, from 10-22% (v/v).

Other research has also stated that pavement noise increases along with an increase in the maximum particle size of the wearing course mixture...

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