360R-06 Design of Slabs-on-Ground
—Geotechnical engineering reports
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| 3.2—Geotechnical engineering reports
3.2.1 Introduction—Geotechnical engineering investigations are now commonly performed for most building projects to supply subsurface site information for design and construction and to meet building code requirements. The primary purpose of these field investigations is to supply information for the design and construction of the building foundation elements. Within the geotechnical engineering report, slab- on-ground support is frequently discussed, and subgrade drainage and preparation recommendations are given. Even if slab support is not discussed in detail, information given within such reports, such as boring or test pit logs, field and laboratory test results, and discussions of subsurface conditions, are useful in evaluating subgrade conditions relative to slab- on-ground design and construction. 3.2.2 Boring or test pit logs—Descriptions given on boring or test pit logs are useful because they give informa- tion on the texture of the soils encountered and their moisture condition and relative density, if noncohesive; or consis- tency, if cohesive. Field test results, such as the standard penetration test (ASTM D 1586) in blows per 6 in. (150 mm) interval values, are presented on these logs. The location of the water table at the time the boring is made and depths to shallow bedrock are also denoted on the log. Laboratory test results, such as the moisture content and dry density of cohesive soils, are often included on the boring logs or in the geotechnical report, as well as the Atterberg limits. Also, the soil is classified, as will be discussed in Section 3.3. 3.2.3 Report evaluations and recommendations—In many cases, the geotechnical engineer writing the report has not been given complete information on the design requirements of the slab-on-ground. Evaluations and recommendations relative to the existing subgrade material, its compaction, and resulting supporting capability can be included in the report, and should be evaluated against the actual design requirements. Suggestions can also be given by the geotech- nical engineer for possible subbase and base course materials. In some cases, local materials that are peculiar to that area, such as crushed sea shells, mine tailings, bottom ash, and other waste products, can be economically used. The geotechnical engineer is generally knowledgeable about the use and experience with these materials in the project area. The expected performance characteristics of the slab-on- ground should be made known to the geotechnical engineer before the subsurface investigation to obtain the best evaluation and recommendations. For example, the use of the facility and the proposed floor elevation should always be given to the geotechnical engineer; however, information concerning the type and magnitude of anticipated loads, environmental conditions of the building space, levelness and flatness criteria for the floors, and floor-covering requirements should also be conveyed to the geotechnical engineer. In some cases, it may be beneficial for the geotechnical engineer to visit local buildings or other facilities of the client having similar use. Coordination between the geotechnical engineer and the slab-on-ground designer from the beginning of the project can lead to an adequate and economical slab-on-ground. tải về 2.35 Mb. Chia sẻ với bạn bè của bạn:
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