These rules are the official rules for the 2012 Northeast Pennsylvania Regional Bridge Building Competition to be held February 11, 2012 at the Viewmont Mall in Scranton (Exit 191 from I81). For the NEPA Competition, these rules WILL NOT be modified between now and Feb 11, 2012. These rules also will be used at the International Bridge Building Committee for the Thirty-Fifth International Bridge Building Contest to be held  in Las Vegas Nevada, USA, date TBA.

In order to receive Official wood and to participate in this contest, please contact Donald Kieffer (Email: DHKIEFFER@ALUM.LHUP.EDU; FAX: 570-587-1154; Phone: 570-586-0197; CELL: 570-561-3286). Students may participate in person, by proxy or by mail entry.

EACH BRIDGE MAY ONLY REPRESENT ONE STUDENT PARTICIPANT. NO GROUP BRIDGES WILL BE ALLOWED.

The object of this contest is to see who can design, construct, and test the most efficient bridge within the specifications. Model bridges are intended to be simplified versions of real-world bridges, which are designed to accept a load in any position and permit the load to travel across the entire bridge.
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1. Materials:

1. The bridge must be constructed only from the official 3/32 inch square cross-section basswood included in the kit and any commonly available adhesive.
2. The official basswood may be notched, cut, sanded or laminated in any manner but must still be identifiable as the original official basswood.
3. No other materials may be used. THE BRIDGE MAY NOT BE STAINED, PAINTED OR COATED IN ANY FASHION WITH ANY FOREIGN SUBSTANCES. SLOPPY GLUE JOINTS AND LAMINATIONS ARE CONSIDERED AS PAINTING & COATING.

2. CONSTRUCTION:

1. The bridge's mass may be NO GREATER THAN 25 GRAMS.
2. The bridge (see Figure 1) must span a gap (S) of 300 mm, have a minimum clearance (C) of 50 mm above the support surface at mid-span, be no longer (L) than 400 mm, be no taller (H) than 200 mm above the support surfaces, no wider (W) than 80 mm and no narrower than 25 mm at the loading surface.
3. The bridge must be constructed to provide a horizontal support for the loading plate at the three loading locations described in 2.2 above.  ANY PORTION OF THE STRUCTURE ABOVE THE LOADING SURFACE MUST PROVIDE CLEARANCE FOR THE LOADING PLATE TO BE LOWERED INTO POSITION FROM ABOVE AND BELOW FOR THE LOADING ROD.
4. The load will be applied with the center of the plate at one of the three (3)  loading locations on the longitudinal axis of the bridge: 1) the center, 2) 25 mm to the right of center, and 3) 45 mm to the left of center (see Figure 1). The three loading locations must lie in the same horizontal plane. The loading plane must be located on the roadbed and lie no more than a distance (P) of 100 mm above the base of the bridge (support surface).
5. The bridge must be constructed to allow a standard Ping-Pong ball, 38.1 mm diameter to be rolled along the roadbed, from end to end without falling off or through the bridge.  To test this requirement, the bridge will be placed at a 20 degree angle (from horizontal) and the ball will be placed on one end of the roadbed then released.  The ball must roll freely from one end to the other.  The roadbed must be continuous, horizontal, and at least 250 mm (R) in length.
6. The bridge structure may not project below the support surfaces (see Figure 1).

3. Loading:

a.    The load for NEPA Regionals will be applied from BELOW, by means of a 35 mm
             square plate that is 10 mm inthickness.  The plate will have a 10 mm diameter loading rod
             threaded into its center (see Figure 2).  The plate will be horizontal; it will not pivot on the
             loading rod, and during testingthe sides of the plate will be placed parallel to the
            longitudinal axis of the bridge.

b.    The load will be applied with the loading plate centered at one of the three positions
            described in section 2.4 above.

4. TESTING:

1. On the day of the competition, the judges will decide which one of the three loading locations will be used for the competition; it will be the same location for all bridges tested.
2. The loading plate will be located on the bridge at the specified loading location.  The load will be applied from BELOW FOE NEPA Regionals, as described in section 3a.
3. Competition loading will stop at 50 kg (approx. 110 lbs).  However, loading will continue until the bridge experiences failure.  Bridges failing above 50 kg will be considered to have held 50 kg for efficiency calculation.
4. Bridge failure is defined as the inability of the bridge to carry additional load or a deflection of 25 mm under the loading location, whichever occurs first.
5. The bridge with the highest structural efficiency, E, will be declared the winner.

                         
                     E = Load supported in grams (50,000 g maximum) / weight of bridge (25 g maximum)

5.  Qualification:

a.    All construction and material requirements will be checked prior to testing.  Bridges failing to
            meet these requirements will be disqualified.  If physically possible, disqualified bridge
        may be tested as exhibition bridges at the discretion of the builder and the contest directors.

b.    If, during testing of a bridge, a condition becomes apparent (i.e., use of ineligible materials,
             inability to support the loading plate, bridge optimized for a single loading point, etc.) which
             is a violation of the rules or prevents testing as described in Section 4, that bridge will be
            disqualified. If the disqualified bridge can accommodate loading, it may still be tested as an
            exhibition bridge as stated above.

c.    Decisions of the judges are final. THE ABOVE RULES WILL NOT BE MODIFIED FOR
            THE NEPA REGIONAL COMPETITION. But, the rules may be revised for the International
             Competition as experience shows the need.  Please check our web site,
             http:bridgecontest.phys.iit.edu after March 1, 2012, to learn whether any changes have
             been made.