Blog Archives

Needle Beams

Posted by on 17/ 11/ 15

image429Подпись: Where joists run parallel to the foundation wall, remove a section of siding and run a temporary needle beam through the wall as shown. To prevent its deflection under pressure, double the rim (outer) joist and run solid blocking to the next joist inward.

When replacing a mudsill or sections of a foundation whose joists run perpendicular to that foundation wall (see p. 210), place a 4×8 or 4×10 carrying beam on edge under the house, within 2 ft. of the foundation. A jack every 6 ft. under the beam should suffice.

When joists run parallel to the foundation wall being replaced, you’ll need to run needle beams through exterior walls, and support each beam with one post underneath the house and a second post outside, roughly 2 ft. beyond the foundation wall. For this, you’ll need to remove sections of siding so you can insert a beam every 6 ft. to 8 ft. If the siding is stucco, you’ll need to punch large holes through it. To keep the rim (outer) joist from deflecting under the load, nail a second rim joist to it, doubling it before jacking...

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Subgrade Drainage

Posted by on 17/ 11/ 15

As indicated previously, subgrade drainage is designed to handle surface water inflow, whereas subdrains are designed to accommodate encroaching groundwater. Surface water can enter the pavement subsection through joints, cracks, and infiltration of the pavement. Rapid drainage of the pavement structural section is necessary to minimize piping and swelling of the subgrade material, and the subsequent increased deflections and cracking of the pavement surface. This rapid drainage can best be achieved by placing a highly permeable drainage layer under the full width of the pavement and allowing it to drain the infiltration to an edge drain. Figure 5...

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A Buyer’s Guide to Windows

Posted by on 17/ 11/ 15

■ BY SEAN GROOM

W

hen you roll up to a house for the first time, you can’t help but notice the windows. Their size, style, and place­ment determine if they’re appropriate to the architectural style and, to some degree, if the house will be a pleasure to be in.

For most people, that’s as much thought as they give to windows. And that’s too bad, because picking the right windows can lower heating and/or cooling costs, improve comfort inside the house, and improve indoor-air quality by dramatically limiting condensation.

To buy the best-performing windows for your house, though, you need to know a bit about how they work and what they need to do.

A Window Has Four Basic Jobs

The first thing a window has to do is con­trol heat gain and loss...

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Mixing SMA with a Granulated Stabilizer

Posted by on 17/ 11/ 15

There is a widespread opinion among a large body of practitioners in the field of SMA production that, after all, the sequence of mixing should vary, depending on the kind of stabilizer. In the case of a granulated stabilizer, this is typically batched with the filler and then mixed with the aggregate without any special extra time for dry mixing (Figure 9.3). The extension of mixing time comes after the binder injec­tion into the pugmill, where an additional 10 seconds of wet mixing time is provided (Graf, 2006). In Figure 9.4, another approach to the mixing sequences of granulated stabilizer is shown.

Although some claim that the use of granulated stabilizers does not involve the extension of the dry mixing time, we might—depending on job site results (i. e...

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Sequence of Mixing Constituents in a Batch Asphalt Plant

Posted by on 17/ 11/ 15

Establishing the sequence of putting materials into the pugmill is chiefly aimed at securing the final homogeneity of a mixture. Mixing constituents consists of the fol­lowing two stages:

• Dry mixing—this starts the moment the aggregate is deposited into the pugmill, and it ends the moment the binder batching starts.

• Wet mixing—this starts the moment the binder batching begins, and it ends the moment the mixture is discharged into a trolley delivering hot material to a silo (the pugmill’s opening).

With regards to the aforementioned stages of mixing, the following universal principles are well-known: [57]

image82,image83

0 10 20 30 40 50 60

Seconds

FIGURE 9.2 The batching sequence in a batch-type asphalt plant according to German DAV handbook. (From Druschner, L. and Schafer, V...

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Materials METAL ROOFS

Posted by on 17/ 11/ 15

Materials METAL ROOFSMaterials METAL ROOFS

METAL ROOFS HAVE been around for a long time. One of the outbuildings at our prairie home had a corrugated metal roof. It was rusty and rattled in the wind, but it shed water. Today, you can buy metal roofs in a variety of colors and styles. They are lightweight and fireproof and don’t hold heat the way asphalt shingles do. Metal roofs work well in snow country because they shed snow so well.

With extra fasteners, they can be used in high wind areas, too.

The initial cost of a metal roof is greater than that of a shingled roof, but a metal roof will last much longer. Roofs with concealed fasteners usually cost more than those with exposed fasteners. The neoprene gasket on an exposed fastener may leak after several years in the sun, so it will need to be replaced...

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EXAMPLES FROM THE DEMONSTRATION PROJECTS

Posted by on 17/ 11/ 15

Подпись: Knox County, TennesseeAt Woodpointe, the Knoxville/ Knox County Planning Commission approved modifications in right-of-way, road width, and road construction require­ments, as follows:

• The right-of-way width requirement was reduced from 50 feet to 35 feet on streets leading into cul-de – sacs, and from 50 feet to 30 feet on other streets.

• The street width requirement was reduced from 26 feet to 22 feet, with a further reduction to 20 feet on deadend streets where there was no possibility of future extension.

• The thickness requirement for the base layer of the roadway was reduced from 8 inches to 6 inches crushed stone, and the surface coarse was reduced from 2 inches to 11/4 inches.

Woodpointe employed two approaches to reducing the costs associated with traditional cul-de-sac construction.

In the ...

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JACKING SAFELY

Posted by on 17/ 11/ 15

For safe jacking, you need to proceed slowly and observe the following precautions.

Preparatory steps

► Survey the building, noting structural failings and their probable causes as well as which walls are load bearing. Also determine whether joists or beams are deflecting because of heavy furniture, such as a piano; which pipes, ducts, or wires might complicate your repairs; where the gas pipe shutoff is; and so on.

► Have a plan that anticipates everything.

If excavation is necessary, who’s going to do it? And where will you put the displaced dirt? (Disturbed dirt has roughly twice the volume of compacted soil...

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Finding Riser & Tread Dimensions

Posted by on 17/ 11/ 15

If the riser and tread dimensions are not given on the plans, then you need to calculate them. To do this you should consider the following points:

• You want the steps to feel comfortable.

— When walking up steps, a person’s mind determines the height of the riser based on the first step. Make sure all risers and treads are equal, so the stairs will not cause people to fall.

— The lower the riser, the longer the tread needs to be to feel comfortable.

• Common dimensions for riser and tread are 7" rise and 10%" tread.

• Use the following three rules to check to see if your stair dimensions are in the comfortable range.

— Rule 1: Two risers and one tread added

should equal 24" to 25".

— Rule 2: One riser and one tread added

should equal 17" to 18".

— Rule 3: Multiply one riser...

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Subsurface Drainage

Posted by on 17/ 11/ 15

Saturation of the structural section under the roadway (subgrade and base course) and the foundation materials is a primary cause of early roadbed failure because of decreased ability to support heavy truck loads. Saturated conditions can lead to piping of fines and frost damage or icing of the roadway surface. Designs to prevent water from infiltrating beneath the pavement will lead to longer-lasting and more economical roadbed sections. Designs typically include subsurface drainage (subdrains) to intercept and reroute encroaching groundwater and subgrade drainage to handle surface water inflow.

The design of subsurface drainage begins with flow determination. Although this may be determined by analytical methods, it is usually cumbersome and unsatisfactory to do so...

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