Blog Archives

Checking the Building for Level

Posted by on 23/ 11/ 15

Using a transit or laser is the best way to check for level. A water level can also be used. Once a level foundation has been established, you are ready to cut, drill, and set the mudsill in place.

The foundation and/or slab should be ready for you to start framing when you first arrive. Sometimes, however, this is not the case, and time will be needed to “shoot" (measure using a transit or laser) a foundation and slab. Time must also be allotted to fix any problems in the concrete. It will be your responsibility to check and make a suggestion if you think corrective work is necessary. Start by checking and recording your findings. Record your findings in a way that lets you use the information if you decide the concrete needs corrective work...

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High Mast Power Connection

Posted by on 23/ 11/ 15

The conventional method of supplying electric energy to the high mast ring, with the luminaires at the top of the pole, uses a normal twist-lock plug and cap set. Some of these have a neoprene cover to provide some degree of waterproofing, but oftentimes this cover is either poorly installed or missing entirely. The result has been premature failure of the plug and cap set due to moisture. In some cases, the connectors will short-circuit between phases, and in others a large hole is burned through the connector body where the electricity arcs to a grounded structure. This latter case is particularly dangerous to the maintenance technician who attempts to reset a tripped circuit breaker while standing directly in front of the power cord connector...

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PERMEABILITY

Posted by on 23/ 11/ 15

For many people the surface appearance of an SMA course gives the impression of being excessively water permeable. Indeed, SMA differs from AC due to a substan­tially deeper macrotexture. SMA courses with an increased content of voids may occasionally be seen in practice, most frequently when the mixture was improperly compacted on a work site (such cases were elaborated on in Chapter 11). However, there is more to permeability than work site error.

Permeability is related to the content of air voids and the size, distribution, and existence of interconnections between internal pores. The permeability of a mixture depends on the maximum aggregate size, the thickness of the course, and the level of compaction (WsDOT, 2005)...

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CONSTRUCTION CONSIDERATIONS

Posted by on 23/ 11/ 15

7.28.1 Conduit on Bridges and Median Barriers

The current design standards for bridge rail and median barrier rail are very similar. Consequently, the method for installing conduit for one is applicable to the other. In the past, the most common method for installing bridge conduit was to attach it to the underside of the bridge deck. This required both the installer and the maintenance crews to work outside the bridge rail and underneath the slab by constructing special scaffolding or using expensive trucks with articulating booms. A method has recently been developed that places the conduit and junction boxes within the bridge rail. The conduit may be galvanized rigid, PVC, or high-density polyethylene (HDPE). HDPE is available on large reels in lengths up to 60 ft (1500 m)...

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K-out-of-ДО parallel systems

Posted by on 23/ 11/ 15

This is a parallel system of M component for which the system would function if K (K < M) or more components function. This type of system also is called a partially redundant system. The general reliability formula for this system is rather cumbersome. For components having an identical reliability function, that is, ps, m(t) = ps(t), the system reliability and unreliability, when component performances are independent, are

M

Ps, sys(t) = 53 Cm, j [Ps(t)]j [1 – Ps(t)]M-j (7.58a)

j =k

K-1

and pf, sys(t) = ]T Cm, j [Ps(t)]j [1 – Ps(t)]M-j (7.58b)

j =0

in which CM, j = M!/[j!(M – j)!] is a binomial constant. Computationally, whether to calculate ps, sys(t) or pf, sys(t) is dictated by the number of terms
involved in the summation...

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TRUSS WITH ABBREVIATED EAVE

Posted by on 23/ 11/ 15

TRUSS WITH OVERHANGING EAVE

Exposed or Boxed-ln Eave

ENGINEERED HEEL TIED TO WEB SYSTEM OF TRUSS ALLOWS DEEP CEILING INSULATION SEE 198-199

TRUSS WITH ABBREVIATED EAVE

 

TRUSS WITH ABBREVIATED EAVE

TRUSS WITH SOFFITED EAVE

TRUSS WITH SOFFITED EAVE

TRUSS WITH ABBREVIATED EAVETRUSS WITH ABBREVIATED EAVEПодпись:

Because roofs are the highest part of a building and are the least weighted down by other parts of the build­ing, they are the most vulnerable to the effects of wind. In areas prone to high winds, the design and detailing of roofs is one of the most critical concerns for the longevity of a building. The bracing of buildings to resist lateral wind forces is discussed in Chapter 3 (see 77 & 82).

Wind generally moves horizontally to impose lateral forces on buildings, much as earthquakes do...

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The Bedroom as Sanctuary

Posted by on 23/ 11/ 15

When J. D. was 51 years old he consulted Dr. Elliott complaining of insomnia, asthma, and fatigue. It became clear from an exhaustive environmental history that J. D.’s symptoms began during the time he lived downwind from a location where aerial spraying was carried out seasonally for pest control. The repeated pesticide exposures appar­ently had left the patient feeling debilitated, with­out his usual zest for life, and with multiple medical problems, including allergies and sensitivities to a wide range of substances.

As part of his treatment program, J. D. was ad­vised to reduce his exposure to toxins in his home...

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ANTISPRAY AND LIGHT REFLECTION PROPERTIES

Posted by on 23/ 11/ 15

The safety provided by wearing course mixtures is of primary importance. The anti­spray properties of some mixes enhance safety by preventing the buildup of water mist behind vehicles. After rainfall (or melting snow), drops of water are raised up from a pavement by vehicle tires, especially the tires of large, fast-moving vehicles. Consequently, a certain amount of water in the form of mist remains suspended in the air surrounding fast-moving vehicles (Figure 12.7). Then it settles on wind­screens, reducing visibility.

The generation of water mist and splash may be decreased by enabling quick water discharge after rainfall (through transverse cross-falls and having no ruts to hold water), a suitable depth of macrotexture, or a high content of air voids in a course...

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Example of the Pollutant Transport Modelling in the Pavement and Embankment

Posted by on 23/ 11/ 15

The transport model of pollutant leaching from the secondary road construction material was developed by the Environmental Research Group from the University of New Hampshire, USA (Apul et al., 2003). Water flow in a Minnesota highway embankment was modelled in one dimension for several rain events and calibrated to the field condition (Fig. 11.20). The test facility consists of 40 and 152m-long

Number of load cycles, N

Fig. 11.19 Comparison of maximum rut depths measured on the experimental pavement and pre­dictions with ORNI (rutting of UGM and subgrade, different temperatures)

hot mix asphalt and Portland cement concrete test sections with varying structural designs. Each test section is instrumented to monitor strength and hydraulic proper­ties...

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Design Questions and Plans

Posted by on 23/ 11/ 15

We had several conversations about the use of the new space, where the door and windows would go, and the like. We agreed that we wanted plenty of south-facing windows and that they would have to be of some opening style with a screen option. We found some excellent Caradco™ double-hung windows at a good price, but what really sold Jaki on them was that both the upper and lower sashes could be rotated 180 degrees for easy cleaning. After all, there would be no easy access to the windows exterior on the second story.

A nagging question was whether or not we would be able to maintain the same i:i2 roof slope in an upstairs addition and still have sufficient headroom...

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