Design Project #1Replacement of Vehicle Bridge over Spring Creek

Centre County, PAIntroduction to Engineering Design

EDGSN 100 Section 001Team Armadillo

Design Team Number 7Marisa Coltabaugh

James RossArianna Vetrano

Dan Weisner

Presented to: Prof. Berezniak

Fall 2015

Statement of Problem

2

A bridge to Mt Nittany Medical Center, vital for emergency access, was recently destroyed by a hundred years flood.

*Not the actual Spring Creek bridge

Objective

PennDOT has initiated a fast track project to design and build a new bridge over Spring Creek.

3

spring creek

Design Criteria

PennDOT District 2-0 has established the design criteria for the replacement bridge to

include: standard abutments, no piers (one span), deck material shall be medium strength

concrete (0.23 meters thick), no cable anchorages and designed for the load of two AASHTO

H20-44 trucks (225kN) with one in each traffic lane. The bridge deck elevation shall be set at

20 meters and the deck span shall be exactly 40 meters. Both a Warren through truss bridge

and a Howe through truss bridge shall be analyzed. All other design criteria, such as: steel

member type, steel cross section type, and steel member size shall be selected by each

EDSGN100 design team.

4

Technical Approach Phase 1: Economic Efficiency

5

Results Phase 1: Economic Efficiency

Final Cost: $210, 905.88

6

Technical Approach Phase 2: Structural Efficiency

7

Results Phase 2: Structural Efficiency

The Howe Truss Bridge’s Structural Efficiency was 195.6

8

Technical Approach Phase 1: Economic Efficiency

9

High Strength Steel

Carbon Steel

Results Phase 1: Economic Efficiency

10

Final Cost: $246,355.81.

Technical Approach Phase 2: Structural Efficiency

11

Results Phase 2: Structural Efficiency

The Warren Truss Bridge’s Structural Efficiency was 334.7

12

Best Solution

To incorporate economic efficiency strategies from the Howe through truss bridge, with the structural efficiency of the Warren through truss bridge.

13

ConclusionsThe economic efficiency for the Howe through truss bridge was achieved by using hollow tubes in compression, and solid beams in tension. Smaller dimension members were applied in areas with smaller forces. However, the price was kept minimal by maintaining some uniformity in dimension sizes.

For structural efficiency, the top and bottom chords, as well as highest force members (both tension and compression) were reinforced and supported by the highest quality beams. However, it is believed that struts were not properly secured; that the hot glue did not set adequately.

The economic efficiency for the Warren through truss bridge was achieved by using the same size tubing for most of the bridge and then adjusting size and material as needed, per the weakest members.

For structural efficiency, we had seven triangles in our truss rather than five. The truss was doubled and tripled in certain sections for increased strength.

14

Recommendations

15

The previous bridge destroyed by the recent extreme flood event was not structurally stable and able to resist such flood. Therefore, tests should be done to assure that the next bridge will be able to withstand storms that may occur in the area. In addition, the piers should be taller and stronger so that the bridge will not collapse. The next step that should be accomplished to advance the project into Final Design for the replacement bridge is to contact fabricators and contract. For our physical bridges, make sure they are more structurally stable, for example, reducing the wobble.