Blog Archives

HIGHWAY LOCATION,. DESIGN, AND TRAFFIC

Posted by on 12/ 11/ 15

Larry J. Shannon, P. E.

Highway Technical Manager ms Consultants Columbus, Ohio

This chapter begins with a description of the overall transportation development process, and then presents comprehensive information on the various elements of high­way location and design. Included is the determination of horizontal and vertical align­ment, with attention to obtaining proper sight distance and superelevation. The design of roadway cross sections, intersections, ramps, and service roads is addressed. Traffic aspects include an introduction to intelligent vehicle highway systems and the use of high-occupancy vehicle lanes. A presentation on preparation of highway construction plans and organizing CADD drawings is also provided...

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BARS

Posted by on 12/ 11/ 15

Bars are solid-steel leverage tools. Depending on the size, a bar can be used for pulling nails, for prying open windows, or for demolition work. A carpenter uses several types of bars, such as the cat’s paw, the flat bar, and the wrecking bar.

After the hammer, the nail puller most often used is the cat’s paw. The cat’s paw has a nail slot between two sharp claws, which are designed to dig into the wood around a flush-driven nail.

To pull a nail with the cat’s paw, place the claws on the wood in front of the nail head. If you need to, drive the claws straight in for a couple of licks to get them below the head. Once the claws are under the head, pull back on the handle to lift out the nail (see the photo at right)...

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End Uses in Highways

Posted by on 12/ 11/ 15

It is apparent that there are many uses of recycled materials in highway construction and related applications. Table 1.19 provides a summary of these uses for reference.

1.6.1 Recycling Hazardous Wastes

Under Subtitle C of RCRA, EPA has the authority to regulate recyclable hazardous waste material. It is critical to determine the type of waste and the proposed method of recycling in determining whether it is regulated under Subtitle C. The definition of solid waste under Section 261.2 identifies four types of recycling activities for which recycled wastes may be subject to Subtitle C regulation: use constituting disposal, burning waste-derived fuels for energy recovery, reclamation, and speculative reclamation.

Use Constituting Disposal...

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Water Flow Theory for Saturated and Unsaturated Pavement Material

Posted by on 12/ 11/ 15

SigurOur Erlingsson[3], Mihael Brencic and Andrew Dawson

Abstract This chapter describes the relation between road structures and water giving the general water balance equation for the pavement structure. Aquifers are briefly introduced. The pavement and its associated embankment are divided into the saturated zone and the unsaturated zone. Porous media are also described briefly together with their grain size distributions and fundamental properties related to wa­ter movements. A short summary of water flow theory for saturated and unsaturated soils is then presented, including relevant discussion of the soil water characteristic curve and permeability of unsaturated soils.

Keywords Roads ■ water flow ■ porous media ■ saturated ■ unsaturated ■ permeability ■ soil water characteristic cu...

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FINDING THE AREA AND VOLUME OF A GIVEN SHAPE

Posted by on 12/ 11/ 15

Finding the area of a given shape is also done with the use of formulas. It’s no more difficult than what we have already been doing. In some ways, finding the area is easier than finding the perimeter. Most anyone in the trades knows how to find the square footage of a room. When you multiply the length of the room by the width of the room, you arrive at the square footage (Fig. 1.17). Well, this is exactly how you find the area of a rectan­gle or a square. There is no mystery or trick. Just multiply the length by the width for a rectangle or multiply one side by another side for a square, and you will have the area of the shape. To find the volume of a rectangle, you simply multiply the length by the width by the height...

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Nail Let-in Bracing

Posted by on 12/ 11/ 15

Nail Let-in Bracing

Подпись:Подпись: Let-in bracing is installed to prevent "racking" of the wall. Racking in a wall frame occurs when the top plate moves independently from the bottom plate.
Two 8d common nails or 3” x,131" nails each stud

Stud

Nail Let-in Bracing
1 x 4 let-in brace Bottom plate

Nail Let-in BracingNail End of Joist

Подпись: Three 16d common nails or four 3" x ,131" nails through rim joist Two 16d nails, or 3" x .131" nails toenail. One on each side of joists. Nail Let-in Bracing

Nail Let-in Bracing

This illustration shows the installation of a floor joist on top of the double plate. The rim joist provides not only a good nailing surface, but also a structural component as it spans the space between the studs and prevents lateral rotation of the joists.

Nail Rim Joist

Here the rim joist is being installed. It is a structural component that provides an edge for the building and an attachment for the joists to prevent lateral rotation.

 

Top plate

 

Rim joist

 

Double plate

 

16d at 6” O. C. or 8d at 6” O. C. or 3” x .131" at 6" O. C.

 

Nail Let-in Bracing

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Oversize AC Units Can Hide Many Big Problems

Posted by on 12/ 11/ 15

Oversize air-conditioning systems are the norm, not the exception. It’s easier to pick a huge system based on erroneous rules of thumb than to spend time designing a more suitable but smaller system. Oversize systems have the added problem of masking many
of the problems I’ve discussed here. Poor insulation, duct leaks, and more can be cov­ered up by blasting twice as much cold air through the ductwork as would be necessary if things were done correctly.

If you double the size of the AC unit, you can lose 50% of the performance and still provide enough comfort so that the home­owner won’t call you back. But a behemoth AC unit short-cycles (turns on and off too

1

Oversize HVAC Is Overkill

hen it comes to air-conditioning units, oversize air han­dlers waste energy, burn out faste...

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Pelletized Loose Fibers

Posted by on 12/ 11/ 15

Loose fibers may be pressed into pellets to keep the fibers together without bind­ing agents. Their shape makes metering of the SMA mix during production easier. Pelletized fibers are formed into different shapes; one example is presented in Figure 4.5. Automatic loading with pneumatic feeders is also possible and easy. The pellets are usually supplied in large packages (big-bags) and stored in silos. All other features of loose fibers remain unchanged.

When performing tests of SMA mixtures in a laboratory, pelletized fibers may be treated without any special preparations. A mechanical mixer is usually not required;

image33

FIGURE 4.5 An example of pellets—loose formed fibers. (Photo courtesy of J. Rettenmaier & Sohne GmbH + Co. KG, Germany.)

(a) (b)

image34

FIGURE 4...

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HVAC Ducts Can Leak One-Third of the Air They Transport

Posted by on 12/ 11/ 15

From 20% to 40% of the air that comes out of furnaces and air conditioners never gets to the rooms it’s supposed to heat or cool. When you consider that most of the ducts are in attics, garages, and vented crawlspaces, the effect of that loss is huge: We’re heat­ing and cooling the outdoors. Sometimes whole rooms are disconnected, as when the ductwork isn’t connected to the register and the duct spews conditioned air into the attic or crawlspace. Return ducts often leak more than supply ducts; although they cause less energy loss, these leaks lead to moisture problems and pressure imbalances that pose health and durability risks by contributing to mold, ice dams, and even carbon – monoxide poisoning.

Required by code, duct-sealing is rarely completed and even more rarely tested...

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My Air Smells Bad! What Can I Do?

Posted by on 12/ 11/ 15

Подпись: r

Identifying the cause of smelly indoor air can be a complex process. The English language is not a good tool for describing smells and there is of­ten little agreement about what an odor smells like, making it difficult for a professional to iden­tify the offending substance from a description of the smell. To make identification even more difficult, there are tens of thousands of synthetic compounds and thousands of naturally created compounds that produce odors. Complicating matters still further, many compounds in the air are broken down by the natural process of oxida­tion to form new compounds. The new material may smell when the old one did not, or the new material may smell completely different from the original...

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