Blog Archives

Suction

Posted by on 14/ 11/ 15

Soil suction or capillary pressure head can be measured either in the laboratory in an undisturbed sample of soil or directly in the field. Soil suction or total suc­tion consists of the matric suction and the osmotic suction. Their magnitudes can range from 0 to 1 GPa (Rahardjo & Leong, 2006). Today no single instrument or technique exists that can measure the entire range with reasonable accuracy. Suction measurement instruments can only measure suction up to about 10 MPa. In the highway environment soil suction in the low range (0-100 kPa) or the mid range (100kPa-1 MPa) is of most concern. There are different measurement tech­niques depending on which component of suction one wants to measure, matric or total...

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SHIMMING THE FRAME

Posted by on 14/ 11/ 15

Plumb the hinge jamb first, using a 6-ft. level for accuracy. Or you can hang a plumb bob from a nail in the top of the jamb, as shown in the left photo on p. 102, and measure from the plumb line. When the jamb is plumb, all measurements from the jamb to the line will be equal.

1. If jack studs (trimmer studs) on either side are square to the face of the opening, pair shims so that their tapers alternate, creating a flat sur­face behind the jamb. However, if jack studs are twisted, you may need to insert an odd number of shims to build up the low edge of the twisted stud. Adjust shims in and out, constantly check­ing for plumb and square till both the face and the edges of the hinge jamb are plumb. This takes patience. Most installers start shimming behind the top hinge.

Interior doors a...

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FITTING SHEATHING

Posted by on 14/ 11/ 15

Sometimes a little extra persuasion is needed to unite tongue-and – groove sheathing panels. Have one person stand on the edge of the sheet and hold it flat and snug against the previous row of sheathing. Another person can lay a scrap of 2x (to protect the groove from dam­age) against the sheet and hit it with a sledgehammer. A couple of licks should bring the two sheets together. If not, check the edge for damage or for an obstruction that may be holding the two sheets apart.

Coax panels into place. A couple of good wallops with a sledge will usually seat even an ornery sheet of tongue-and-groove sheathing. [Photo by Don Charles Blom]

FITTING SHEATHINGПодпись: Modify cabinets for wheelchair access. Lower countertops and desk-type openings can make the kitchen much more accessible. [Photo by Steve Culpepper, courtesy Fine Homebuilding magazine © The Taunton Press, Inc.]

Habitat

for Humanity6

HABITAT BUILDS BARRIER-FREE HOMES

Simple, single-story houses are not only less expensive to build but also lend themselves well t...

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On Beams with a Round Cross-section, or Vigas

Posted by on 14/ 11/ 15

Подпись: Fig. 2.6: With rectilinear structures, alternate large and small ends of viga-type joists or rafters. The drawing is exaggerated to make the pointimage16

Many old barns and houses make use of floor joists and rafters that were made from locally grown straight tree trunks. Sometimes the builder would flatten one edge of the timber with an adz, so that roofing or flooring could be more easily nailed to it. In Mexico and the Southwest, exposed vigas (beams of round cross-section) are a common and attractive architectural feature.

Owner-builders today sometimes make use of their own home-grown timbers. They can be taken to a sawmill for squaring, they can be milled in the forest with a portable sawmill, or they can be barked and used in their natural round cross-sectional shape.

While this book is mostly concerned with the use of timbers milled on four sides, the author is in no way opposed to the use of viga-type beams, which can be quite bea...

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Installing an Interior Door

Posted by on 14/ 11/ 15

There are many ways to hang a door. Thus, the installation sequences that follow occasionally offer alternative methods.

ASSESSING AND PREPPING THE OPENING

Prehung doors usually come preassembled with the door hung on hinges in the jamb and held tight by a screw through the latch jamb into the door. Or the door may be secured with a remov­able plastic plug through the predrilled hole where the lock will go.

1. Start by measuring the height and width of the opening. Rough openings (ROs) are typi­cally 52 in. to 1 in. wider and taller than the out­side dimensions of the door frame, or about 252 in. taller and wider than an unframed door.

2. Measure the thickness of the wall, from finish surface to finish surface. Standard 2×4 walls covered with drywall are 452 in...

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Permeability Tests of Unsaturated Soils

Posted by on 14/ 11/ 15

As introduced in Chapter 2, the flow of water in saturated soils is commonly de­scribed using Darcy’s law which relates the rate of water flow to the hydraulic gra­dient (Eq. 2.16). Furthermore the coefficient of permeability is relatively constant for a specific soil. Darcy’s law applies also to the flow of water through unsaturated soils. However the permeability of unsaturated soils can not be assumed generally to be constant (Richards, 1931; Fredlund & Rahardjo, 1993; Fredlund 1997). Per­meability now becomes predominantly a function of either the water content or the matric suction (see Chapter 2, Section 2.8). The main reason for this is linked to the fact that the pores in the material are the channels through which the wa­ter flows...

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PAVEMENT DESIGN AND. REHABILITATION

Posted by on 14/ 11/ 15

Aric A. Morse, P. E.

Pavement Design Engineer
Ohio Department of Transportation
Columbus, Ohio

Roger L. Green, P. E.

Pavement Research Engineer
Ohio Department of Transportation
Columbus, Ohio

The movement of people and goods throughout the world is primarily dependent upon a transportation network consisting of roadways. Most, if not all, business economies, personal economies, and public economies are the result of this transportation system. Considering the high initial and annual costs of roadways, and since each roadway serves many users, the only prudent owner of roadways is the public sector. Thus it is the discipline of civil engineering that manages the vast network of roadways.

The surface of these roadways, the pavement, must have sufficient smoothness to allow a reasonable speed of...

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Guerilla Housing

Posted by on 14/ 11/ 15

image28We are in the midst of a housing crisis. The Bureau of the Census has determined that more than for­ty percent of this country’s families cannot afford to buy a house in the U. S. Over 1,500 square miles of ru­ral land are lost to compulsory new housing each year. An immense portion of this will be used for noth­ing more than misguided exhibi­tionism. We clearly need to change our codes and financing structure and, most importantly, our current attitudes about house size.

Minimum-size standards are slowly eroding as common sense gradually makes its way back onto the housing scene. Where negotiation and political pressure have failed to eradicate antiquated codes, lawsuits have generally succeeded. But these measures all take more time, money and patience than many of us can muster...

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Comparison of Results of Example II Using German Proportions of SMA Composition

Posted by on 14/ 11/ 15

In Chapter 2, Table 2.1 cites the recommended ratios of individual SMA coarse aggregate fractions from the German DAV handbook (Druschner and Schafer, 2000). The comparison of the achieved result from Example II with ratios required in Germany is shown in Table 6.10.

The comparison in Table 6.10 shows that our SMA differs both from the origi­nal Zichner proportions and the contemporary ones recommended in Germany. The original German SMA does not contain such a great amount of the coarsest grains. Therefore let us design the same mix according to the German DAV proportions. The result is shown in Figure 6.8. The gradation curves of DAV and Zichner have a gentler shape, making laydown and compaction easier...

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A Practical Look at Deep-Energy Retrofits

Posted by on 14/ 11/ 15

Подпись: ENERGY EFFICIENCY■ BY MARTIN HOLLADAY

I

f you pay any attention to building sci­ence, you have probably seen the term "deep-energy retrofit"—a phrase being thrown around with the colloquiality of "sustainability" and "green." Like the word "green," the term "deep-energy retrofit" is poorly defined and somewhat ambiguous. In most cases, though, "deep-energy retro­fit" is used to describe remodeling projects designed to reduce a house’s energy use by 50% to 90%.

Remodelers have been performing deep – energy retrofits—originally called "superin­sulation retrofits"—since the 1980s. Most deep-energy retrofit projects are predomi­nantly focused on reducing heating and cooling loads, not on the upgrade of appli­ances, lighting, or finish materials.

While a deep-energy retrofit yields a home that ...

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