Saturday 23 March 2013

Bridge plans

Bridge plans are generally attached as supplements to the roadway construction plans. The basic types of sheets in a set of bridge plans include the following.

TITLE AND INDEX SHEET
The title and index sheet identifies the bridge by contract number and location and contains an index of all other sheets in the plans.

BORING DATA SHEETS
The boring data sheets indicate the results of soil borings made at the bridge site prior to construction. The Bridge Technician uses these sheets to identify the types of soils that are encountered during structure excavation, and to determine the approximate depths at which the types of soils occur.

LAYOUT SHEET
The layout sheet consists primarily of a topographical situation plan of the bridge site and a profile view of the proposed bridge grade. The situation plan identifies the landowners and natural and manmade features in the contract area. The plan also delineates right of way limits, limits of construction, and the locations of benchmarks used for grade control. The layout sheet also may include a list of utilities in the contract area that may be affected by the contract.

GENERAL PLAN
The General Plan sheet includes a plan view, which is the bridge seen from above, and an elevation view, which is the bridge seen from the side.
The plan view identifies:
1) The exact location of the bridge in terms of the contract station numbers and the obstacle the bridge is intended to cross

2) The degree of skew, if any

3) All important centerlines for the structure, roadway, and bearing

4) The overall length of the bridge and the lengths of all intermediate spans

5) All significant widths for the “out to outs,” roadways, shoulders, sidewalks, and parapets

The elevation view identifies:
1) Original and projected ground lines

2) Elevations of railroads, low water lines, highways, etc., to be crossed and any minimum vertical clearance requirements

3) Minimum tip elevation for piling, if used, and the planned bottom-of-footing elevations
4) The locations of fixed and expansion bearings

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