BRIDGE BUILDING

Water channel bridge in Germany Water channel bridge in Germany. The Magdeburg Water Bridge is a navigable aqueduct connecting Elbe-Havel Canal to the Mittelandkanal crossing the Elbe River. http://www.amusingplanet.com/2011/04/incredible-magdeburg-water-bridge-in.html

Impact of Bridges: POLITICAL- relating to gov. , link countries together ECONOMIC- make possible the transportation of goods and the provision of services

ENVIRONMENTAL- effect on fish and other water animals CULTURAL- skills and arts developed during a certain period SOCIAL-communities can travel

SUBSTRUCTURE OF BRIDGES ABUTMENTS- support at the ends of a bridge usually made of concrete

PIERS- vertical structural supports placed between abutments in longer bridges. Piers are positioned to keep the longer bridge from sagging. Made of wood, metal or concrete.

Arch Bridge Yahoo image

TYPES OF BRIDGE SUPERSTRUCTURES Beam bridge- piers support beams that support spans of reinforced concrete slabs. This is most common and least expensive.

ARCH BRIDGE The load of the bridge is transferred along the arch to the abutments or piers at the end of the arch.

Arch Bridge Yahoo image

SUSPENSION BRIDGE These have two tall towers that support main cables that run the entire length of the bridge. These bridges are used to span long distances.

Suspension Bridge Yahoo image

Brooklyn Bridge Suspension Bridge in New York. The engineer who began the bridge died in a bridge related accident. His son continued to build the bridge It took 14 years and 30 lives. The workers were afraid to tie the cables. The engineers made pulleys and attached the cables themselves.

Golden Gate Bridge The Golden Gate Bridge is a suspension bridge spanning the Golden Gate, the opening of the San Francisco Bay into the Pacific Ocean. Yahoo image

TRUSS A truss is a triangular framework. It can be used above or below the roadway to support the bridge. Used in other types of bridges

Truss Bridge Yahoo image

These beams extend from each end of the bridge. CANTILEVER BRIDGE These beams extend from each end of the bridge.

Cantilever Bridge Yahoo image

MOVABLE BRIDGE These bridges are designed so that a portion of he roadway can be moved to allow large water vessels to pass underneath.

Moveable Bridge Yahoo image

Tacoma Narrows Bridge Washington Built in 1940 Collapsed 4 months after being built Called the Galloping Gertie Winds of 40 mph swayed the bridge enough to collapse it.

Tacoma Bridge Information http://www.enm.bris.ac.uk/research/nonlinear/tacoma/tacoma.html

Balsa Wood Bridge Project Google images

The Goal: To build a bridge with the design that produces the largest strength-to-weight ratio during the destructive test

Bridge Efficiency = mass held by bridge/ mass of bridge

The bridge shall be an open frame structure designed to allow a 3 inch test block to pass parallel to the base. The bridge must be free-standing and designed to span a distance of 10 inches.

The bridge must rest on a flat surface without the aid of external fasteners or bracing. The bridge must be a minimum of 12 inches in length and the roadbed must be open throughout the entire length and must have a minimum overhead clearance of 3 inches.

The bridge shall be designed to accept a dead weight from the load platform. The load will be applied through the bottom of the bridge and will be guided from a 1/4” diameter rod passing through the center of the bridge.

To facilitate the insertion of the rod, the bridge must have a 1/2” diameter vertical opening through its center. The load platform is designed such that the load is approximately centered on the bridge.

The bridge must be wholly constructed from the furnished balsa wood and glue. Other materials, such as straight pins, binder clips, tape, etc., may be used as aids for construction, but shall be removed from the bridge prior to submittal for testing.

The wood sticks may be cut and shaped at the discretion of the team The wood sticks may be cut and shaped at the discretion of the team. Single components may be combined to build-up members for use in final assembly.

No single piece of wood may have other pieces of wood laminated to more than two of its four faces. Do not paint or stain the bridge. Do not impregnate the bridge with glue. Glue must be confined to the points of contact between two pieces of wood.

MATERIALS Balsa Wood 6 sticks ( 1/4 x 1/4 x 36 inch) Super Glue 1 bottle (use sparingly…it is heavy) Hobby Knife (optional) Super Glue remover Sandpaper

Project Overview Balsa wood and glue construction 2” width, 12” length, 10” span (minimum) Accept a dead weight applied through the roadbed Free Standing 1/2” vertical opening

Web Design Support Check out the Building Big web site at: http://www.buildingbig.com Design your own bridge at: http://jhu.edu/virtlab/bridge/bridge.html http://jhu.edu/virtlab/bridge/truss.html http://www.pbs.org/wgbh/buidingbig/lab/forces.html http://www.pbslearningmedia.org/resource/lsps07.sci.phys.maf.dstruss/design-squad-truss-bridge/