2012 Competition Guide

Post Construction

Competitor Preparation:

• Make sure that you bridge meets all clearance and spatial requirements during design and fabrication.

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Host Equipment/Preparation:

• Have the construction site completely ready prior to the start of the competition
• Assign a Marshal to the bridge. The Marshal should have the judging forms for the bridge.
• A set of the rules and current clarifications at each construction lane.
• Templates for verifying that clearance and spatial requirements have been met.
  • Under bridge clearance
  • Elevated deck support clearances
  • Vehicle passageway
• String forchecking clearances when the supporting surface is not flat.
• Tape measure (25 ft or more).
• Plumb bob and/or four foot level for checking Rule 9.3.4.
• A clipboard with pencil for each construction lane.

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Clearance Check Video: Clearance.wmv, 3:24 minutes, 8.8 MB

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Once the Team Captain turns the bridge over to the Judges for the post construction check, the team can do no more work on the bridge. It is inspected 'as is' by the Judges. Judges are to use the judging checklist and rules to verify compliance of the bridge. Any violations are recorded on the judging form. Teams are NOT allowed to fix any violations found at this stage.

Once the Judges finish their work, they meet with the Team Captain to review the results. If the Team Captain disputes the findings or asks for clarifications he/she works with the Lane Judges to resolve the issues. If the disputes are not resolved, the Head Judge is called in to make a ruling.  At the end of this process the Team Captain is to sign the bottom of the form which, along with the rest of the judging forms, is then given to the Marshal who escorts the bridge to the next station.

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Common Violations

There are several common violations that seem to with disappointing frequency.  Some are design issues, others are either fabrication or erection issues.  The following sections are intended to warn bridge designers and to alert the judges.

Rules 9.3.6 & 9.3.7:

The bridge must be 3.1/2" below the decking support.  This was a new rule in 2010 and there have been a number of clearance issues since then. Pay particular attention to the drawings for all spatial requirements.

Rule 9.3.4:

Parts of the bridge (including fasteners and parts that bear on the ground) must not extend beyond the vertical plane defined by the ends of the decking support surfaces at each end of the bridge.

Common Error: Most of the violations have to do with fasteners or cross pieces extending beyond the plane defined in the rules.  A level or a plumb bob can be used to verify that a part of the bridge extends beyond the decking support.

Rules 9.3.6 & 9.3.7

The 2010 rules introduced an elevated deck support, which is being kept again this year.  The associated rules have been rewritten to make the intent clearer.  See the image to the right for how this is checked and an example of a violation.  Note that in 2012 the template for checking the elevated deck support is likely to part of the vehicle passageway template.

Rules 9.3.11 & 9.3.12:

The concept of clearance under the bridge and for a passage way is nothing new.  What is different the past few years is the passageway clearance has been below the deck.  This year the passage way has been moved to be above the decking support, allowing top chord bracing in the structure.  There is also a navigation clearance under the bridge.  There have always been clearance problems at the competition as teams, for some unknown reason, feel the need to push these limits.

The clearance is typically measured with a template. Alternatively, the judges may measure from a taunt string line if there is a question of the flatness of the floor. The height of this clearance varies from year to year and is likely to be different than shown in the accompanying image.

The concept of a "nominal centerline" was new with the 2007 rules and used through the 2010 competition.  The nominal centerline is not a part of the 2012 competition.

Rule 9.4.2:

We continue to see problems with teams not understanding the difference between a 'fastener' and a 'member' as defined in rules 10.2.3 and 10.2.4. The lack of understanding manifests itself in illegal connections.  The image shown to the right (Rule 9.4.2) is an extreme example which made it through the conference competition only to be caught at nationals.  Note that the connections shown were penalized for five Rule 9.4.2 violations.   One because the two crossing rods touch but they are not connected together anywhere, and for four connections without bolts.  In this case the U-bolts are considered members (Rule 10.2.4.1) as are each of the four nuts threaded onto them.  The nuts are not fasteners because a fastener is a bolt which is not part of a member and nut which is not part of a member--in this case the bolt part of the fastener is missing.  Consequently a 'fastener' is needed between each nut and U-bolt leg.

Rule 9.4.3:

New in 2011 was a rule limiting the number of members a fastener can connect.  This rule has been maintained this year.  In prior years, a fastener was permitted to fasten as many members as you liked, however, in 2011--and again this year--a fastener could only fasten two members together.