Northern Arizona University

Senior Capstone Project Spring 2006

Chosen Design

On Monday, February 28th Robert McFadden received an email from Don Sluyk stating that he was only interested in a steel or timber bridge spanning the entire length of the ravine, preferably over its deepest point.  Based on the 30% cost estimates for the steel and timber bridges, we concluded that the timber bridge would be the most economical option to pursue.

New design criteria was submitted to Western Wood Structures for preliminary cost estimation.  Due to the fact that the new timber bridge will span the deepest point of the ravine, its new length will be 105 feet.  The cost for this new timber bridge is $123,000.  Shown below is the 60% cost estimation for the total project and an AutoCAD rendering of the proposed design.

 

 

Timber Bridge

 

 

 

 

 

 

 

 

 

 

 

 

 

Material

Quantity

 

Unit Cost

Cost

Contingency

Est. Cost

Earth Fill Excavation, Load

75

Cubic Yards

35

2,625

0.1

2,887

Backfill

75

Cubic Yards

35

2,625

0.1

2,887

Reinforced Concrete Abutment

20

Cubic Yards

400

8,000

0.1

8,800

Concrete Apron

1.5

Cubic Yards

225

337.5

0.1

371.25

Geotechnical Analysis

1

Report

10000

10,000

0.1

11,000

Prefabricated Timber Bridge

1

Bridge

123,500

123,500

0.1

135,850

 

 

 

 

147,088

0.1

162,000