Blog Archives

ANTIsKID properties

Posted by on 23/ 11/ 15

Antiskid features of wearing courses of asphalt surfacing are described in terms of the friction coefficient, which depends on the micro-texture of the aggregate and the macro-texture of the placed mixture (Gardziejczyk and Wasilewska, 2003). As this property is very important, the range of available publications on the topic at issue is quite broad (Gardziejczyk, 2002; German DAV Report, 2001; Huschek, 2004; Jordens et al., 1999).

Different pavement qualities, in relation to the speed of vehicles, have a deci­sive impact on antiskid properties (Hunter, 1994)...

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ANALYTICAL APPROACH TO LIGHTING WARRANTS [3]

Posted by on 23/ 11/ 15

An analytical approach to determining if roadway lighting is warranted was developed through the National Cooperative Highway Research Program (NCHRP Report 152) using four comprehensive evaluation forms. The four forms relate to non-controlled – access roadways, intersections, freeways, and interchanges, and are presented in Figs. 7.61, 7.62, 7.63, and 7.64, respectively [10]. The forms are used by multiplying the rating of a characteristic by the difference in its unlighted and lighted weight to obtain a quantitative measure of the effect of that characteristic on driver visual infor­mation needs. After all the characteristics are rated, the scores are summed to obtain an overall measure of driver information needs.

There is an established “minimum warranting condition” of a given numbe...

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NEW VESICA

Posted by on 23/ 11/ 15

The New Vesica is essentally the Bodega turned sideways. The New Vesica is officially 278 square feet, but, if the loft were included, it would measure in at just over 450 square feet.

Square feet: 261

With add-on: 356 House width: 14’ House length: 24’ Porch: 6’ x 13%’

Great Room: 9’ x 13%’ Kitchen: 73/V x 8’

Bathroom: 7%’x5’

Addition: 7’ x 93%’

Ceiling height: 7’ 6”

Loft height: 7’

-sizes are approximate

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Warrants for Tunnel Lighting

Posted by on 23/ 11/ 15

The use of artificial daytime lighting is warranted when user visibility requirements are not satisfied by the natural sunlight. Overall tunnel visibility varies considerably with such factors as geometry of the tunnel and its approaches, traffic characteristics, roadway and environmental reflective surfaces, the climate and orientation of the tunnel, and visibility objectives. Comprehensive literature is available on the technical aspects of visibility and lighting of tunnels [9]. Information on lighting levels for tunnels requires a detailed analysis of the tunnel approach characteristics. Tunnel lighting requires considerable experience to achieve proper design.

7.19 ROADWAY REST AREAS [9] •

• Parking areas. The recommended average maintained lighting level is 1...

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Example of Modelling of the Resilient Behaviour of Pavements

Posted by on 23/ 11/ 15

To model the resilient behaviour of pavements, the French pavement laboratory, LCPC, has developed a finite element program called CVCR, which is a part of the finite element code CESAR-LCPC (Heck et al., 1998; Heck, 2001a, b). This program allows the modelling of the response of pavements in 3D, under moving wheel loads, and incorporates the following material models:

• Linear elasticity

• The Huet-Sayegh visco-elastic model for bituminous materials.

• Two non-linear elastic models for unbound granular materials: the Boyce model, modified to take into account anisotropy (Hornych et al., 1998) and the well known k-0 model (Hicks & Monismith, 1971). These models have been de­scribed in Chapter 9, Section 9.4.1.

The example below (Hornych et al...

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Organizing the Job Site

Posted by on 23/ 11/ 15

After the plan review, you need to organize the job site. Figure out what your initial manpower needs and schedule are, and what tools you’ll need for the job. The first day on the job site is usually a challenge.

1. Manpower needs. Typically, on the first day, your crew is ready to go to work and will be looking to you for instruction. At the same time you may not be sure if the concrete

is level or the right size. Meanwhile, the superintendent may be on his way over with his list of things you need to take care of. If you have too many framers, everyone might be standing around until you get the job organized. If your schedule allows, start with just a two-man crew to check the foundation or slab for level and size and to get some lines chalked and some detailing done.

2. Manpower tasks...

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FIGURING THE WEIGHT OF A PIPE

Posted by on 23/ 11/ 15

Figuring the weight of a pipe and its contents is necessary when you are choosing the needed strength of a pipe hanger. There is a formula that you can use to accomplish this goal. Let’s say that you want to know how much a

Nominal pipe size (NPS), in IP

ASHRAE std. wt. size, mm

AWWA pipe size, mm

NFPA pipe size, mm

ASTM copper tube size, mm

Nominal

pipe

size DN, mm

Vs

—

_

—

в

6

3/ie

—

—

—

8

8

У4

8

—

—

10

10

%

10

—

—

12

12

y2

15

12.7 & 13

12

15

15

%

—

—

18

18

3/4

20

—

—

22

20

1

25

25

25 & 25.4

28

25

Г/4

32

—

33

35

32

1У2

40

45

38 & 38.1

42

40

2

50

50 & 50.8

51

54

50

2Уг

65

63 & 63.5
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Numerical Simulation of Pavements Behaviour from Accelerated Tests

Posted by on 23/ 11/ 15

Erlingsson (2007) describes two thin pavement structures that were tested in ac­celerated testing by using a Heavy Vehicle Simulator. Both were surface dressed structures, one with 20 cm thick unbound base course layer and the other with the base course divided into a 10 cm bitumen stabilized base over 10 cm unbound base. Both structures were instrumented to estimate deflections, strains and stresses in various locations inside the structure. A numerical analysis was also carried out to simulate the response behaviour of the structure that could be compared with the actual measurements. The simulation was performed using different techniques: 3D and 2D axi-symmetric analyses, finite element and multi layer elastic theory, linear elastic and non-linear elastic base behaviour...

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TUNNEL LIGHTING

Posted by on 23/ 11/ 15

A tunnel is defined as a structure over a roadway that restricts the normal daytime illumi­nation of a roadway section so that the driver’s visibility is substantially diminished. Design of tunnel lighting requires adaptation for driver needs in the approach, and the

FIGURE 7.59 Lighting adaptation zones for tunnel lighting. Approach: The external roadway area leading to the tunnel. Portal: The plane of entrance into the tunnel. Threshold zone: The area inside the tunnel where a transition is made from the high natural lighting level to the beginning of the transition zone. Transition zone(s): Areas that allow the motorist to achieve appropriate eye adaptation by incre­mentally reducing the level of luminance required in the threshold zone to the luminance of the interior zone...

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ODD OR PROBLEMATIC SETTING BEDS

Posted by on 23/ 11/ 15

The beds described next may require special techniques and materials.

Plastic laminate countertops are acceptable setting beds if they’re solidly attached. Scuff the surface with 80-grit sandpaper, wipe with a rag dampened with solvent to remove grit and grease, and fill any voids. Then use an epoxy­based thinset to bond the tiles. Alternatively, you can cover the old laminate with!4-in. backer board, adhering it with an application of epoxy thinset, and 1-in. corrosion-resistant screws spaced every 6 in. around the perimeter of the countertop and every 8 in. in the field. Sink screw heads flush, vacuum the backer board, and then use latex or epoxy thinset adhesive to bond tiles...

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