Wednesday, 12 February 2014

the bridge i will be making is a beam

The beam bridge is the most common bridge form. A beam carries vertical loads by bending. As the beam bridge bends, it undergoes horizontal compression on the top. At the same time, the bottom of the beam is subjected to horizontal tension. The supports carry the loads from the beam by compression vertically to the foundations.

When a bridge is made up of beams spanning between only two supports, it is called a simply supported beam bridge. If two or more beams are joined rigidly together over supports, the bridge becomes continuous.


All bridges need to be secure at the foundations and abutments. In the case of a typical overpass beam bridge with one support in the middle, construction begins with the casting of concrete footings for the pier and abutments. Where the soil is especially weak, wooden or steel piles are driven to support the footings. After the concrete piers and abutments have hardened sufficiently, the erection of a concrete or steel superstructure begins. Steel beams are generally made in a factory, shipped to the site, and set in place by cranes. For short spans, steel beams are usually formed as a single unit. At the site, they are placed parallel to each other, with temporary forms between them so that a concrete deck can be cast on top. The beams usually have metal pieces welded on their top flanges, around which the concrete is poured. These pieces provide a connection between beam and slab, thus producing a composite structure. 

Sunday, 26 January 2014

Chairs and Ergonomics

What Features Should a Good Ergonomic  Chair Possess?

  • Seat height. Office chair seat height should be easily adjustable. A pneumatic adjustment lever is the easiest way to do this. A seat height that ranges from about 16 to 21 inches off the floor should work for most people. This allows the user to have his or her feet flat on the floor, with thighs horizontal and arms even with the height of the desk.
  • Seat width and depth. The seat should have enough width and depth to support any user comfortably. Usually 17-20 inches wide is the standard. The depth (from front to back of the seat) needs to be enough so that the user can sit with his or her back against the backrest of the ergonomic office chair while leaving approximately 2 to 4 inches between the back of the knees and the seat of the chair. The forward or backward tilt of the seat should be adjustable.
  • Backrest. The backrest of an ergonomic office chair should be 12 to 19 inches wide. If the backrest is separate from the seat, it should be adjustable in height and angle. It should be able to support the natural curve of the spine, again with special attention paid to proper support of the lumbar region. If the office chair has the seat and backrest together as one piece, the backrest should be adjustable in forward and back angles, with a locking mechanism to secure it from going too far backward once the user has determined the appropriate angle.
  • Seat material. The material on the office chair seat and back should have enough padding to be comfortable to sit on for extended periods of time. Having a cloth fabric that breathes is preferable to a harder surface
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Tuesday, 17 December 2013


This DVD cover show an unclear male face this could mean that the movie is a serious story about a man from Mexico because the eyes are covered with the Mexican flag ,the font is in black and is bold and the space in between the letters are all linked with minor gaps.
 
This cover shows that it is targeted at kids, the letters are all miss shaped and stone like, showwing that it is based in the stone age.
 
The black and yellow shows that it has to stand out like a light so it my thaughts were that it looked like a casino as every one was dressed smart and the font looks like it was from the 20th century.

 The lettering is circular and the C has a moon behind it to show an eclipse and the story had something to do with the film so you can relate the wording to the film