Tuesday, May 10, 2011

Truss Bridge 30 Facts

-          A truss is an arrangement of structural members that are connected together to form a rigid frame work.
-          Trusses have been used extensively in bridges since the early 19th Century.
-          Truss bridges are usually categorized in two different ways according to the location of the deck and according to the orientation of the vertical and diagonal members.
-          The Structural Stability of a truss is stable if all of its members are arranged in a network of interconnected triangles.
-          The triangular arrangement of members ensures the rigidity of a truss structure.
-          To fix an unstable truss, look for any "panel" of the structural model that is not a triangle, then add one or more members to transform that panel into a series of interconnected triangular  shapes.
- Modern trusses are made of structural steel.
- Some other types of bridges include arch, suspension, cable-swayed, and beam.
- Dunlap’s Creek Bridge was the first iron bridge built in the United States.
- The bridge was a vital link in the newly constructed National Road, which was the first important road built with Government funds.
- Dunlap’s Creek Bridge consisted of five parallel cast iron tubes spanning 80 feet.
- Dunlap’s Creek Bridge was built by Captain Richard Delafield of the Corps of Engineering.
- Dunlap’s Creek was designated a National Historic Civil Engineering Landmark in 1978.
- Truss bridges are usually categorized in two ways depending on the location of the deck and orientation of diagonal and vertical members.
- The deck truss has its deck located at the top chord.
- A through truss has its deck located at the bottom chord.
- A pony truss is like a through truss, but not as high and has no lateral bracing.
- Truss configurations are based on orientation of members.
- A number of standard truss configurations are commonly used in bridge structures.
- These configurations are defined primarily by the geometry of their members.
- Three of the most common standard configurations are Howe, Pratt, and Warren trusses.
- These trusses are named after the 19th century engineers who developed them.
- The major components of a typical truss are verticals, chords, diagonals, floor beams, deck, pinned support, roller support, and abutment.
- Loads include the weight of a bridge and vehicles that are on them.
- Loads can also include weather, such as snow.
- These forces must all be considered when developing a bridge.
- Yield stress is the strength of a metal.
- The strength of a metal must be determined before building a bridge.
- Supporting structures, such as beams and wires, are used commonly in bridges.

Monday, May 9, 2011

Bridge Definition

Antonio Johnson
5/9/11
Block#1
Definition
Tension - the act of stretching or straining.
Compression - the act of compressing.
Through Truss – a truss whose deck is located near the bottom chord.
Pony Truss – it is not as big as a regular trust because of its no lateral bracing between the top chords.
Deck Truss – a truss whose deck is located near the top chord.
Force – a load that is applied to a structure.
Load – forces applied to a structure.
Deck – is the floor of a bridge.
Yield Stress – is the strength of a metal.
Span –is its length from support to support.
Buckling – is the failure mode of a member that is located in compression.

Friday, April 1, 2011

3rd Try Reflection

In first block we tried to do an invention playhouse. From the Smithsonian Institution's National Museum of American History comes this wonderful resource for developing logical thinking, problem-solving, and collaboration - in students of any age level. There are four interactive puzzles - Puzzle Blocks, Cloud Dreamer, Word Play, and the especially addictive Tinker Ball - and all lend themselves to collaborative decision-making, innovative thinking, and a lot of just plain-old fun! This page is part of the larger site which deals with play as invention and invention as play. It's good to remember the preceding sentence should you need to justify your 73d attempt to get that darn Tinker Ball into the little cup!

Puzzle Reflection

In first block we created a puzzle on the computer. Puzzle Pirates is a historical-social MMORPG that casts the player as a pirate in an ocean town. To advance, one must play minigames that are patterned after traditional pirate and sailing tasks or games. Through playing on-board games, a group may sail a ship out to earn in-game gold pieces, which may then be exchanged for goods and services. Players may also wager on many of the minigames, as well as engage in several forms of PvP through them. While the basic game is free, there are certain places and opportunities off limits to free accounts. Also, some of the minigames and competitions only run one or two days a week for non-subscribers/premium customers. There are two forms of paid upgrades - subscriptions cost $9.95 a month, or an a la carte option (doubloons) may be purchased indvidually.

Puzzle

3rd Try