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Logo of Eurocode 2 An example of a concrete structure. In the Eurocode series of European standards (EN) related to construction, Eurocode 2: Design of concrete structures (abbreviated EN 1992 or, informally, EC 2) specifies technical rules for the design of concrete, reinforced concrete and prestressed concrete structures, using the limit state design philosophy.
According to ASME Y14.5, the fundamental rules of GD&T are as follows, [2]: 7–8 All dimensions must have a tolerance. Plus and minus tolerances may be applied directly to dimensions or applied from a general tolerance block or general note. For basic dimensions, geometric tolerances are indirectly applied in a related feature control frame.
From IT6 to IT18, the standard tolerances are multiplied by the factor 10 at each fifth step. This rule applies to all standard tolerances and may be used to extrapolate values for IT grades not given in Table 1. For example, the nominal size range 120 mm up to and including 180 mm, the value of IT20 is: IT20 = IT15 × 10 = 1.6 mm × 10 = 16 mm [2]
H7/h6 is a very common standard tolerance which gives a tight fit. The tolerances work in such a way that for a hole H7 means that the hole should be made slightly larger than the base dimension (in this case for an ISO fit 10+0.015−0, meaning that it may be up to 0.015 mm larger than the base dimension, and 0 mm smaller).
When coating metric threaded parts it is necessary to keep to the tolerances defined in ISO 965 so that the bolt's thread does not get gummed up and the coefficient of friction can be set accordingly. Hot-dip galvanised fasteners with a typical coating thickness of 80-200 μm have to be grooved again retrospectively in order to expose the thread.
Since flowable fill is normally a comparatively low-strength material, there are no strict quality requirements for fly ash used in flowable fill or controlled low strength material mixtures. Fly ash is well suited for use in flowable fill mixtures. Its fine particle sizing (nonplastic silt) and spherical particle shape enhances mix flowability.
Tolerance analysis is the general term for activities related to the study of accumulated variation in mechanical parts and assemblies. Its methods may be used on ...
The modern standard can trace its roots to the military standard MIL-STD-8 published in 1949. [4] It was revised by MIL-STD-8A in 1953, which introduced the concept of modern GD&T "Rule 1". [ 5 ] [ 6 ] Further revisions have continued to add new concepts and address new technology like computer aided design and model-based definition .