·The convention(惯例)for support conditions is as follows:. Single hatching represents a simply supported edge; Double hatching represents a built-in edge; A line by itself represents a free edge. Negative yield line Simple support 777777777777 Simple support• The convention （惯例）for support conditions is as follows: Single hatching represents a simply supported edge; Double hatching represents a built-in edge; A line by itself represents a free edge