Construction Cost Study Technical Report

This memorandum supplements the "Structural Study of Existing Lafayette Bridge No. 9800," dated March 1, 2007. The estimates of probable construction costs herein are intended to provide a comparison between the various alignment options and bridge type alternatives for selection of the preferred structure for bridge widening and also to provide information for future funding plans.

The estimates are based on estimated quantities and unit price extensions, which will allow for more convenient adjustments to be made in case the planned construction year is modified. The pay quantities should remain fairly constant, whereas the unit prices are subject to a variety of influences that are often difficult to predict. A spreadsheet for each combination of alignment option and bridge type alternative is included in the appendix. These spreadsheets show estimated quantities, unit prices, and cost extensions for the more significant pay items. They also show add-on percentages and costs for minor quantities and staged construction methods under traffic. The adjusted totals have had a contingency percentage added to arrive at the total costs that are stated in the Lafayette Bridge Structural Study report. Backup information providing the basis of the estimated quantities has been provided to Mn/DOT's project manager.