Amy Eitel, NSF Graduate Fellowship Student ake2@po.cwru.edu

Arthur Huckelbridge, Associate Professor aah4@po.cwru.edu

and

Nathan Capaldi, CWRU Graduate

Department of Civil Engineering

Case Western Reserve University

10900 Euclid Avenue

Cleveland, Ohio 44106

A large number of short-span reinforced concrete slab bridges exist throughout the United States, particularly on secondary highways, that were constructed in the first half of last century. Although little design documentation exists for these bridges, many are still in service and performing adequately. Most procedures currently available for evaluating these bridges are based on visual inspection alone, as in Ohio, or on conventional analytical methods, both of which result in low load ratings. An accurate assessment of their load carrying capacity is necessary.

This project involves developing a simplified non-destructive load test to be carried out by regular bridge inspection personnel to rate these bridges. It is a continuation of the previous work requested of Professor Arthur Huckelbridge by the Ohio Department of Transportation (ODOT) to assist in the rating of short span simply supported one-way concrete slab bridges in Ohio. Huckelbridge's and Capladi's previous study consisted of field testing eighteen 12-22 foot bridges with varying skew, guardrail types, slab widths, and deck thicknesses to develop a database of structural response information. Their investigation showed that an accurate analysis can be made with simple calculations and results obtained from a load test consisting of a weighted county vehicle and dial gages mounted under the bridge. Destructive tests will be performed on two of these type bridges to obtain actual ultimate strength. The bridges used for the destructive tests will have extensive instrumentation and associated finite element analyses so that the best assessment of the new rating procedure can be made. The rating procedure will require inspection personnel to obtain primary bridge dimensions and centerline midspan deflection under the known load. Computations will first determine if the slab is cracked and then establish a resulting rating factor.

The successful completion of this project will enable local bridge inspection personnel to begin using this simplified load test to ascertain more accurate ratings for short-span reinforced concrete bridges throughout Ohio. It is likely that higher bridge postings will ensue.