Civil Engineer Expert

Shell structure is able to adapt to changing environmental conditions.

Weather conditions such as wind and snow loads can cause failure and collapse of supporting structures in roofs and similar constructions. Based on new hybrid intelligent construction elements (HICE), researchers at the University of Stuttgart have developed a shell structure which is able to adapt to changing environmental conditions. In a further step, the scientists will now use their knowledge to develop machines from these new structural elements which will also be able to react to their environments and adapt to given conditions.

According to experts, this development may eventually lead to a significant acceleration of entire construction processes in mechanical, electrical and control engineering.

A research group of six engineers from different fields such as civil, aerospace, mechanical and process engineering is funded by the Deutsche Forschungsgemeinschaft (German Research Foundation) with a grant of 1.858 m € assigned for the first three years of a six-year project. The research group has started to operate in June.

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Feasibility studies are preliminary investigations into the potential benefits associated with undertaking a specific activity or project.

The main purpose of the feasibility study is to consider all factors associated with the project, and determine if the investment of time and other resources will yield a desirable result. While considered a preliminary study, it is not unusual for a feasibility study to be highly detailed.

When a business is considering a new operation or the launch of a new product, the feasibility study is a logical tool to employ before any resources are invested in the new project. One of the most important aspects of the study is to make sure that the total investment needed to successfully bring the project to completion is considered. Often, this will include addressing components such as cash reserves, labor, construction, production facilities, outsourcing, and the cost of raw materials. Only when the feasibility study has addressed the total cost of completing the project can the study progress to the next level.

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Roof beams should have a continuous upward slope equivalent to 1/ 4 in/ft (20.8 mm/m) between a drain and the high point of a roof, in addition to minimum recommended camber to avoid ponding. When flat roofs have insufficient slope for drainage (less than 1 /4in/ft) (20.8 mm/m)

The stiffness of supporting members should be such that a 5-lb/ft2 (239.4 N/mm2) load causes no more than 1 /2 -in
(12.7-mm) deflection.
Because of ponding, snow loads or water trapped by gravel stops, parapet walls, or ice dams magnify stresses and deflec- tions from existing roof loads by

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The allowable withdrawal load per inch (25.4 mm) of penetration of a common nail or spike driven into side grain (perpendicular to fibers) of seasoned wood, or unseasoned wood that remains wet, is

p=1,380G5/2D

where

= p allowable load per inch (mm) of penetration into member receiving point, lb (N)

D= diameter of nail or spike, in (mm)

G= specific gravity of wood, oven dry

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Columns are divided into three categories, short, intermediate, and long. Let K denote a parameter defined by the equation

RECOMMENDATIONS OF THE FOREST PRODUCTS LABORATORY

The Wood Handbook gives advice on the design of solid wood columns. (Wood Handbook, USDA Forest Products Laboratory, Madison, Wisc, 1999.)

Columns are divided into three categories, short, intermediate, and long. Let K denote a parameter defined by the equation

K=0.64(E/fc)1/2

The range of the slenderness ratio and the allowable stress assigned to each category are next.

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 External forces offer rolling resistance to the motion of wheeled vehicles, such as tractors and scrapers. The engine has to supply power to overcome this resistance; the greater the resistance is, the more power needed to move a load. Rolling resistance depends on the weight on the wheels and the tire penetration into the ground:

R = Rf W + Rp PW

where
R = rolling resistance, lb (N)

Rf = rolling-resistance factor, lb/ton (N/tonne)

W = weight on wheels, ton (tonne)

Rp = tire-penetration factor, lb/ton in (N/tonne mm) penetration

p = tire penetration, in (mm)

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 The countdown to the Eurocodes changeover has begun. So we ask – how prepared are you?
Are you are a structural engineer and unaware of what Eurocodes are by now? If so, it is unlikely that you will have been working at the hard end of design. The clock is ticking and there is now only a year left until compulsory implementation of Eurocodes on public projects. If designers fail to get up to speed soon, they could well end up left on the shelf when it comes to winning work.

Eurocodes are causing the biggest shake-up in engineering since the UK went metric. They are a set of new building codes that will replace British Standards by March 2010. These codes are supported by national annexes which give country specific values and published documents (PDs) that contain guidance included in BritishStandards but not in Eurocodes. The full set of Eurocodes is now published, as are the majority of annexes.
“For engineers working on public projects, it seems there will be little choice but to use the Eurocode on projects procured after March 2010 under the requirements of the [European Union] Public Procurement Directive,” says Parsons Brinckerhoff (PB) director of bridge and structural engineering Steve Denton. “There has been a huge effort to finalise the UK National Annexes and provide other supporting information such as PDs and companion BSI British Standards Published Documents.

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