Blog Archives

Engineering Properties of Soils

Posted by on 23/ 11/ 15

The equation for shearing strength S (lb/ft2 or kPa) of a soil may be taken as follows:

S = c + a tan ф (8.3)

where c = cohesion, lb/ft2 (kPa)

a = confining pressure or normal stress, lb/ft2 (kPa) ф = angle of internal friction of the soil, degrees

The shearing strength of the soil should account for the effect of pore water pressure when present. Equation (8.3) can be modified as:

S = c + (a — u) tan ф (8.4)

where u = pore water pressure, lb/ft2 (kPa)

Soil consolidation is produced by load and is associated with changes in soil mois­ture. It is also a function of time. The time required for drainage to occur, which results from the change in soil moisture, is a function of the permeability of the soil and the distance the water must travel in the material to be released...

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Traffic Considerations

Posted by on 23/ 11/ 15

The structure of the traffic greatly influences the road run-off pollution load. As a general rule, pollution on low-density roads is smaller than on high-density roads. However, the relation between pollution and traffic density is not linear and it is very difficult to predict the run-off pollution from road traffic characteristics, al­though these characteristics have a large role in controlling contaminant fluxes. The pollution of road run-off is also highly dependent on the climatic regime.

Traffic characteristics on roads are defined according to the several criteria. The most general parameter is called annual average daily traffic – AADT – however this parameter doesn’t define the structure of the traffic...

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Bedrock

Posted by on 23/ 11/ 15

Bedrock is divided by geologists into three large groups, namely (1) igneous, (2) meta – morphic, and (3) sedimentary. Igneous rocks are those that have resulted from the cooling and crystallization of molten masses of mineral matter and gases either at or below the earth’s surface. Sedimentary rocks consist of the transported and subse­quently indurated products of weathering of previously existing rock types, while metamorphic rocks are frequently defined as those having characteristic textures and mineral compositions that have resulted from high temperatures and pressures and/or hot mineralizing solutions acting on a parent rock. Figures 8.16, 8.17, and 8.18 indi­cate easily recognizable descriptions for field classification of igneous, metamorphic, and sedimentary rock, respectively...

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STEP 7 PREPARE AND PAINT THE INTERIOR TRIM

Posted by on 23/ 11/ 15

Подпись:One nice aspect of new construction is that you can paint all the walls and ceilings before installing the cabinets, shelving, doors, and interior trim. Even though you’ll have more wall surface to cover, the work can go quickly because you don’t need to worry about getting paint on all the other finished surfaces. In the next chapter, we’ll see how trim and cabinets are installed. Just ahead, we’ll cover what you need to know about applying finish paint or stain on interior trim.

Подпись:There are several finishing options for interior trim. Instead of paint, the wood can either be stained or finished with clear polyure­thane. Both options allow the grain of the wood to show...

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Common Interior Glues

Posted by on 23/ 11/ 15

COMMON,

CHEMICAL NAME(S)

PROS

CONS

BRANDS

White carpenter’s, Polyvinyl acetate

Moderate strength; inexpensive

Runny; poor initial tack; clogs sandpaper

Elmer’s® Glue-All®

Yellow carpenter’s, polyvinyl acetate

Strong; good initial tack; sands well

Titebond® Original

Polyurethane

Bonds to most materials; sands well; takes stain; fills gaps; water resistant

Glue expansion can spread joints not tightly clamped; slow tacking time; stains skin

Gorilla Glue®; Titebond

Cyanocacrylate

Instant bond; great for nonstructural joints; bonds many materials

Expensive; can’t adjust pieces once placed, skin/eye hazards

Super Glue™; Hot Flash; Turbo Flash

Hot glue

Quick-tack glue to create thin plywood templates

Limited strength, but okay for temp...

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SOME FACTS ABOUT COPPER PIPE AND TUBING

Posted by on 23/ 11/ 15

Would you like some facts about copper pipe and tubing? Well, you’re in the right place. Let’s go over some data that could serve you well in your plumb­ing endeavors. Figure 11.20 will show you some size data for copper tubing. Are you interested in size details for copper that is used for drain, waste, and vent (DWV) applications? Refer to Figure 11.21 for this information.

Подпись:SOME FACTS ABOUT COPPER PIPE AND TUBINGПодпись:

SOME FACTS ABOUT COPPER PIPE AND TUBING

Copper is rated in terms of types. For example, Type K copper has a thick wall and is considered a stronger material than Type L or Type M copper. This type of tubing isn’t used often in residential work, but it is sometimes used for water services when the copper is supplied in its soft form...

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Risk and Hazard for Pollution

Posted by on 23/ 11/ 15

Pollutant emissions from roads and traffic present risks and hazards to water bodies where roads are in their recharge area or when they are in direct contact with road environment. Risk is defined as the probability that a particular adverse event will occur during a stated period of time, or it results from a particular challenge (Adams, 1995). Similarly ‘hazard’ is defined as the attribute that is the consequence of the probability of an adverse event and the degree of harm that can happen if this event occurs. A high hazard is present where the potential consequences to water bodies are significant.

Pollution risk depends not on vulnerability but on the existence of pollutant load­ing entering the subsurface environment...

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Soils Analysis

Posted by on 23/ 11/ 15

Retaining wall design engineers not fully trained in soil mechanics need to be acquainted with certain basic principles, in order to understand the data developed by the geotechnical engineer or geologist responsible for the subsurface exploration. Soil is a nonhomogeneous earthen material that varies laterally and vertically in mineral context, grain size, density, grain shape, moisture content, strength, consistency, and compressibility. For the design of retaining walls and other structure-type foundations, the engineering properties of the soil must be evaluated. Such an evaluation will

always require consideration of foundation soil classification, bearing capacity, and compressibility.

Soil Classification...

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Cut in around the edges

Posted by on 23/ 11/ 15

The two basic techniques for painting both ceilings and walls are cutting in and rolling. uCutting in” means brushing paint onto areas that can’t be reached with a roller. Painters usually begin working from a ladder, cutting in the corners where the ceilings meet the walls. Use a З-in. or 4-in. brush to make a cut-in band all around the ceilings and walls, as shown in the top photo on p. 234. This band will be overlapped when the large open spaces are painted with a roller. Professional painters prefer to use a brush for cutting in, but it can also be done with a paint pad, which is basi­cally just an absorbent sponge on a handle.

Take your time. Good brushes are easy to load with paint. Rather than painting with a

Подпись: CUT IN WITH A PAINT BRUSH. A roller can't reach corners and edges. A З-in.- to 4-in.-wide brush is ideal for painting these areas. Подпись: LOAD YOUR BRUSH WITH PAINT. A good brush can hold plenty of paint. Using a half-full paint bucket allows you to dip and load your brush by tapping it gently against the inside of the bucket. full can of paint, painters like to use a bucket that’s about half f...

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Paint prep is the key to a good paint job

Posted by on 23/ 11/ 15

Professional painters know from experience that the biggest part of a paint job is the preparation. You don’t just grab a bucket of paint and a roller and have at it. Take time to remove doors from their jambs before you start painting the walls and ceilings. Number or label the doors so you’ll know later where each one belongs.

Some drywall jobs create lots of dust that must be removed before you can paint. I use a vacuum cleaner to remove dust from the walls and ceilings, but a broom or a pole sander wrapped with a cotton cloth also works well. Take it easy, because topping compound is rel­atively soft and easily scratched. Pay special attention to dust in the corners...

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