Blog Archives

FOUNDATIONS

Posted by on 23/ 11/ 15

The foundation for a luminaire pole must provide sufficient resistance to overturning moments caused by the static load of the mast arm plus a wind and/or an ice load. It must be capable of maintaining the correct alignment of the luminaire and able to withstand the impact should the pole be struck. For breakaway poles, the foundation must be rigid enough to allow the breakaway device to operate while not becoming a hazard itself.

Luminaire foundations are perhaps one of the most dangerous constructed hazards on the right-of-way. This is due to their placement or location, structural design, and unsafe wiring systems. Historically, pole foundations have been poured-in-place concrete with steel reinforcing rods and anchor bolts...

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Experimental Pavement and Modelling Hypotheses

Posted by on 23/ 11/ 15

In the European project SAMARIS, the predictions obtained with ORNI have been compared with the response of a low traffic pavement tested on the LCPC pavement test track. The pavement consisted of:

• a bituminous concrete wearing course, with an average thickness of 66 mm;

• A 50 cm thick granular base and sub-base (crushed gneiss);

• A clayey sand subgrade (thickness 2.20 m), resting on a rigid concrete slab.

As in the previous example (Section 11.4.5) the pavement was instrumented to measure strains, temperatures and water contents in the various layers. The loading consisted in applying 1.5 million heavy vehicle loads (dual wheels, with a load of 65 kN).

In the modelling of the resilient behaviour (with CVCR), the bituminous concrete and the soil were assumed linear elastic, and t...

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Determining total rise and run

Posted by on 23/ 11/ 15

One of the most important parts of stairbuilding is to determine the total rise, or vertical distance between finish floors that are connected by a stairway (see the drawing on p. 160). While figur­ing the distance between the two floors is simple, a problem can arise because stairs are usually built before the finish floors are in place. So the measurements are actually taken from rough floor to rough floor but must account for the finish floor material at both the top and bottom.

I once built several stairs in an apartment house, not realizing that the plans called for ІУ2-ІП. lightweight fire-resistant con­crete on the upstairs landings. I was called back to explain why every riser was 7 in. except the last, which became 8У2 in. once the concrete was poured...

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Example of Modelling of Permanent Deformations

Posted by on 23/ 11/ 15

The modelling of permanent deformations of pavements is more complex than the modelling of the resilient behaviour because it is necessary to simulate the response of the pavement to large numbers of load cycles (typically 105-106 cycles), with variable loading and environmental conditions.

A programme for the prediction of rutting of low traffic pavements, called ORNI, is also implemented in the finite element code CESAR-LCPC (El Abd et al., 2005; Hornych & El Abd, 2006). To determine the permanent deformations due to large numbers of load cycles, this programme proposes a simplified approach, based on a separate calculation of the elastic response and of the plastic strains. It comprises 3 steps:

i) The first step consists in calculating the resilient response of the pavement, for the di...

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STEP 4 Install the Corner Bead

Posted by on 23/ 11/ 15

Once all the drywall is in place, metal or vinyl corner bead is installed on all outside corners, including wall corners, window wraps, closet doorways, and the attic access hole. This bead protects corners from impact and forms a straight, finished edge. Both metal and vinyl

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Finish Carpentry

Posted by on 23/ 11/ 15

After framing and

wires, insulating, and hanging drywall, it’s time to install interior trim. Somewhat like a picture frame, trim is decorative. But it’s also functional, concealing gaps and rough edges where walls meet floors, ceilings, doors, and windows. Although finish carpentry is not as fundamental as structural framing or foundation work, it com­pletes the picture, and often makes or breaks a renovation project.

Interior trim is often called casing, or molding if its face is shaped. Trim helps establish the character of a room, so it’s wise to respect exist­ing trim when replacing or supplementing it. Carefully remove and save existing molding if it’s in decent condition. If that type is no longer available, try to locate new molding with a simi­lar feeling...

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Shower Curtains and Liners

Posted by on 23/ 11/ 15

New PVC liners and shower curtains have a strong odor from outgassing toxins. Many shower curtains are treated with harmful chemicals to create mildew resistance. Cotton duck cloth shower curtains are naturally water repellent, wrinkle resistant, and attractive but they take a long time to dry and must be treated to resist mildew growth. They can be machine washed and dried. They are available through several mail order companies includ­ing Gaiam and Heart of Vermont. Natural hemp curtains are now available through Real Goods. A glass shower enclosure, although more expensive to install, will be a permanent, low-maintenance, and healthy solution.

Beds and Bedding

The most important furniture decision with regard to health is the choice of beds and bed­ding...

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A HIP FRAMING WITH TRUSSES

Posted by on 23/ 11/ 15

Framing a valley with trusses is a simple matter of attaching a series of progressively smaller trusses to the top chords of the trusses of the main roof. The main-roof trusses do not have to be oversize since the only extra weight they will cany is the dead weight of the jack trusses themselves. Simple as this system is, many builders still prefer to frame these roof inter­sections as a farmers valley (see 137) with solid-sawn lumber.

VALLEY FRAMING WITH TRUSSES

Valley Jack Trusses

Rectangular openings for skylights or chimneys may be constructed in a truss roof. Small openings less than one truss space wide may be simply framed between trusses as they would be in a rafter-framed roof (see 135-136)...

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THERMAL EXPANSION

Posted by on 23/ 11/ 15

Thermal expansion can occur in pipes when there are temperature fluctua­tions. Damage can result from this expansion if the pipe is not installed prop­erly. In order to avoid damage, refer to Figures 11.7, 11.8, and 11.9 to learn about the tolerances needed for various types of pipe (Fig. 11.10).

THERMAL EXPANSION

Coefficient

Pipe material

in/in/°F

(°С)

Metallic pipe

Carbon steel

0.000005

(14.0)

Stainless steel

0.000115

(69)

Cast iron

0.0000056

(1.0)

Copper

0.000010

(1.8)

Aluminum

0.0000980

(1.7)

Brass (yellow)

0.000001

(1.8)

Brass (red)

0.000009

(1.4)

Plastic pipe

ABS

0.00005

(8)

PVC

0.000060

(33)

PB

0.000150

(72)

PE

0.000080

(14.4)

CPVC

0.000035

(6.3)

Styrene

0.000060

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ELECTRICAL HAZARD

Posted by on 23/ 11/ 15

One problem that has recently been identified is the potential deadly threat posed by the electric circuits after pole impact by an errant vehicle. There are many documented deaths of motorists who survived the impact with a luminaire pole only to be subsequently killed from the resulting explosion and fire. The explosion and fire are usually caused when the fuel tank ruptures, the vehicle having been caught on an improperly constructed foundation, and the electrical system sparks repeatedly until the fuel explodes. In other incidences, medical personnel have been delayed from attending victims because of the risk of electrical shock from exposed conductors near or under a vehicle.

Past research efforts have concentrated on evaluating the structural breakaway characteristics of luminaire p...

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