6b) Detail in evaluate step in concrete structure

Review of Engineering Data

• A thorough review of all of the pertinent data relating to a structure should be accomplished early in the evaluation process. To understand the current condition of the concrete in a structure, it is imperative to consider how design, construction, operation, and maintenance have interacted over the years since the structure was designed and constructed. Sources of engineering data which can yield useful information of this nature include project design memoranda, plans and specifications, construction history reports, as-built drawings, concrete report or concrete records (including materials used, batch plant and field inspection records, and laboratory test data), instrumentation data, operation and maintenance records, and periodic inspection reports. Instrumentation data and monument survey data to detect movement of the structure should be examined.

Condition Survey

• A condition survey involves visual examination of exposed concrete for the purpose of identifying and defining areas of distress. A condition survey will usually include a mapping of the various types of concrete deficiencies that may be found, such as cracking, surface problems (disintegration and spalling), and joint deterioration. Cracks are usually mapped on fold-out sketches of the monolith surfaces. Mapping must include inspection and delineating of pipe and electrical galleries, filling and emptying culverts (if possible), and other similar openings. Additionally, a condition survey will frequently include core drilling to obtain specimens for laboratory testing and analysis. 

Reference:Stowe and Thornton (1984), American Concrete Institute (ACI) 207.3R, and ACI 364.

Condition Survey Report:

The results of the entire investigation should be summarized in a final report. This report generally includes

a brief description of the following basic areas addressed during the evaluation process:

a) Purpose and scope of investigation

b) Existing construction and documentation

c) Field observations and condition survey

d) Sampling and material testing

e) Evaluation

f) Findings and recommendations

The report should summarize the results of the strength evaluation of the structure. All assumptions made and methods used in the evaluation process should be clearly documented. A brief description of each repair

alternate (Corps of Engineers 1986) or strengthening method studied, along with sketches showing typical

details, cost estimates, and the impact of the repair method, should be included.