conventional symbols for rivets driven in the shop and in the field. Figure 7-7, view B, shows the same truss with only the names of some members and the sizes of the gusset plates (a, c, and d) between the angles. Figure 7-7, view C, is the same truss with only a few of the required dimensions to make it easier for you to read the complete structural shop drawing. DRAWINGS  OF  STEEL  STRUCTURES Blueprints used far the fabrication and erection of steel structures usually consist of a group of different types of drawings, such as layout, general, fabrication, erection, and falsework. These drawings are described in  the  following  paragraphs. LAYOUT  DRAWINGS Layout drawings are also called general plans and profile   drawings. They   provide   the   necessary information  on  the  location,  alignment,  and  elevation  of the structure and its principal parts in relation to the ground at the site. They also provide other important details, such as the nature of the underlying soil or the location  of  adjacent  structures  and  roads.  These drawings  are  supplemented  by  instructions  and information known as written specifications. GENERAL  PLANS General plans contain information on the size, material, and makeup of all main members of the structure,  their  relative  position  and  method  of connection, as well as the attachment of other parts of the  structure.  The  number  of  general  plan  drawings supplied is determined by such factors as the size and nature of the structure, and the complexity of operations. General plans consist of plan views, elevations, and sections of the structure and its various parts. The amount  of  information  required  determines  the  number and  location  of  sections  and  elevations. FABRICATION  DRAWINGS Fabrication  drawings,  or  shop  drawings,  contain necessary information on the size, shape, material, and provisions for connections and attachments for each member. This information is in enough detail to permit ordering the material for the member concerned and its fabrication in the shop or yard. Component parts of the 7-10 members are shown in the fabrication drawing, as well as  dimensions  and  assembly  marks. ERECTION   DRAWINGS Erection drawings, or erection diagrams, show the location and position of the various members in the finished  structure.  They  are  especially  useful  to personnel performing the erection in the field.  For instance,  the  erection  drawings  supply  the  approximate weight of heavy pieces, the number of pieces, and other helpful  data. FALSEWORK   DRAWINGS The term falsework refers to temporary supports of timber  or  steel  that  sometimes  are  required  in  the  erection of difficult or important structures. When falsework is required on an elaborate scale, drawings similar to the general and detail drawings already described may be provided to guide construction. For simple falsework, field  sketches  may  be  all  that  is  needed. CONSTRUCTION PLANS Construction drawings are those in which as much construction  information  as  possible  is  presented graphically,  or  by  means  of  pictures.  Most  construction drawings  consist  of  orthographic  views.  General drawings consist of plans and elevations drawn on relatively small scale. Detail drawings consist of sections and details drawn on a relatively large scale; we will discuss detail drawing in greater depth later in this chapter. A plan view is a view of an object or area as it would appear if projected onto a horizontal plane passed through or held above the object area. The most common construction plans are plot plans (also called site plans), foundation plans, floor plans, and framing plans. We will discuss each of them in the following paragraphs. A plot plan shows the contours, boundaries, roads, utilities,  trees,  structures,  and  other  significant  physical features  about  structures  on  their  sites.  The  locations  of the proposed structures are indicated by appropriate outlines or floor plans.  As an example, a plot may locate the comers of a proposed structure at a given distance from a reference or base line. Since the reference or base line can be located at the site, the plot plan provides essential data for those who will lay out the building lines.  The plot also can have contour lines that show the elevations of existing and proposed earth surfaces, and can  provide  essential  data  for  the  graders  and excavators.