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Contract drawings are the group of drawings that are created by the architect, structural engineer, civil engineer, mechanical engineer, and electrical engineer.
These drawings are categorized by Civil, Landscape, Architectural, Structural, Mechanical and Electrical sheets. The Civil drawing number system will begin with a C, landscape drawings with an L, architectural drawings with an A, structural drawings with an S, mechanical drawings with an M, and electrical drawings with an E. Most numbering systems for contract drawings work this way, but there are the exceptions. Therefore, you will need to temper this information with what you are given for your prospective project.
Steel for the project is mostly shown in the A and S drawings. On occasion there may be steel items that are shown only on the Civil, Landscape (e.g., pipe bollards, site handrail, trash enclosures), and Mechanical drawings (support brackets for mechanical). These would need to be provided by the steel fabricator. Therefore, all drawings will need to be checked for steel items in the initial review prior to take off.
The numbering system that is used most often for each group begins with the letter to designate the type of work. After the letter, the drawings are placed numerically, although there appears to be no standardized system. Most designers use a numbering system that will let them insert drawings later, providing for more details. The need for this flexibility is individual to the job. Therefore, numbering systems vary, although generally the lettering indicators remain the same.
Figure 5.1 Plan view of a building’s foundation
Although there are industry standards regarding the creation of drawings, different design teams have their own style of presentation. As with any spoken language, inflections and accents come out in speech; the same happens in bid document drawings. When you begin to recognize these design professionals’ traits, the drawings become easier for you to read and understand.
Reading contract drawings is a skill you learn by doing. Designers have individual styles for presenting the information in their drawings. It’s your job to understand their language. If you don’t understand what they are trying to show, find out. Call the architect or engineer who prepared the drawings; ask them to help you. Another option is to contact one of the trusted general contractors for assistance. Ultimately, the best help for interpreting drawings will come from the designers who created them; after all, they should know what they were trying to accomplish.
Sometimes the detail cuts are in the wrong place or have not been made where they are needed. Catching such errors or omissions can be important not only for the steel estimators, but also for other contractors who use the drawings.
A Plan View drawing is a map or a floor plan where you are looking down on the building. It is standard that the drawing is laid out so that the nominal north of the building is at the top of the sheet, south at the bottom, and thus west at the left and east at your right. (Note: The drawing will also indicate “true” north, which may not be the same as the directional north on the sheet.) This method, which makes the drawings easier to read, ensures that everyone is on the same page.
To explain how to read these drawings, we will look at a typical floor plan view and an elevation section, then review the subsequent details given to help us see the designer’s intent.
Although every project is different, the general application of the plans, section views, and detail views remain the same. This is true for the architectural drawings and structural drawings alike. Look for clues like grid line locations, which will remain consistent from the plan view to the elevation views, to verify how you view the picture. Elevation cuts and detail section arrows point the way that you need to look when reviewing the sections and details.
Keep in mind the size of the elements you are viewing. Buildings can be hundreds of feet long; the grid lines section the buildings into 20-, 30-, and sometimes even 40- or 50-foot increments. Each section and detail gives you closer views of the building, much like a microscope gives you a closer look.
Figure 5.2 Building elevation views
Figure 5.3 Exterior wall section
First, we will examine a sample plan view from an architectural sheet of a building’s foundation (see Figure 5.1). The plan view has a section view indicator (A/A3.3) at the south end of this building, continuing all the way through the building until it ends at the north or top of this picture. This indicator tells us there is an elevation view through the building—a sideways view, usually beginning at the nearest grid line location.
The grid lines identify the quadrants of the building, indicated by a line through specific locations, usually dimensioned; a number or letter identifies each particular grid. These will be located at the top and to the left or right of the page in the plan views. In Figure 5.1, we see grids 16 through 22 at the top and grids A through F on the right of the drawing.
A plan view looks down on a building from above; a horizontal cut has been made through the building, removing the roof or floor above. The effect is like looking down on a box with the top cut off. The inside elevation view cuts through a building vertically from ceiling to floor—like looking at the inside walls and what is on those walls. (Another example is when a child opens a dollhouse and you can see the height of the upright walls, the windows, doors, stairs, etc.)
To see the inside elevation view, place a box on a flat surface so that you are looking directly into the box from the top—its plan view. For purposes of this example, mark the bottom or plan surface with a P, and mark the left or west side surface of the box as A/A3.3. Now, cut through the corners of the box so that its sides lie down flat on the table. It will form a cross, with the part P in the middle and the one marked A/A3.3 on your left. This is the elevation that the cut intends for you to see.
Thus, Elevation Section A/A3.3 looks to the left of the plan view. The grid lines are shown on the elevation so that grid line E is to the left and grid line A is to the right in Figure 5.2. Compare these locations of the grids to the plan view in Figure 5.1 to understand their relationship to the building.
In the elevation view in Figure 5.2 we can see the grid line locations E through A at the top. To the left of its title, this building section lists all of the drawings from which this section is cut. The building elevations are indicated at the right side of this drawing. Another section cut, 2/A3.6, is also named; this section cut will give us a close up of that wall, allowing us to see more information about how this building is put together. These listings provide detail layering. For example, in this section 2/A3.6, we will find more details called out, providing us even closer views of particular areas of the structure.
Refer back to the floor plan in Figure 5.1. The building section A/A3.3 is located at the bottom of this plan view, just to the right of grid line 18. Section A/A3.3 is cut through the entire building, from below grid line F up to above grid line A. The circle or ‘detail bubble’ around the call out A/A3.3 has a darkened triangle underneath the left side half of the circle. This triangle is pointing to the left (or west) of the page, indicating that the user should look to the left (or west) side of the building to see what the designer is trying to show. Note also that the grid line A is at the top right hand side of the plan.
Figure 5.4 Elevations and parapets
In Figure 5.2, this same grid line A is shown at the top right of the page. The proximity of these grid lines helps you see how the section is cut to make sure you are viewing it correctly. For example, if the section were cut at the plan view looking to the right or east end of the building, the grid line A at the elevation view would then be at the top left of the page.
In Figure 5.3—the elevation cut through the wall—we can see the glazing (windows) that interrupt the vertical plane of the wall, set at about mid-span between the first and second floors, and then again above the second floor, below the roof. We can see the suspended ceiling below the 2nd floor. We can see the steel beams just under the 2nd floor and also just under the roof, set just to the left of the wall.
The elevations are the dimensions that are taken “above sea level” (see Figure 5.4). These elevations can be used to calculate the dimension between the first and second floor, and from second floor to the top of parapet. The parapet is the section of the wall that extends above the roof level. In looking at the parapet, we see additional elevations. From this observation, we know that the parapet elevations vary in this building.
In Figure 5.4, detail 2/A3.6 circles the wall itself using a broken line to indicate that there is a larger view of this area of the wall. In looking at the wall section 2/A3.6, more detail areas are cut at the specific floor and roof levels.
From Figure 5.3, we can see that more information will be shown at the foundation level (1/A6.1, Figure 5.5), floor level (8/A6.1, Figure 5.6), and roof level (1/A7.2, Figure 5.7). This information enables the architect to tell us in more detail how this building is built.
Starting at the bottom and working our way up, Figure 5.5 shows us the foundation detail 1/A6.1, the concrete curb on which the wall sits. Notice the insulation that is outside the curb (the 1 1/2” thick rigid perimeter insulation area is indicated by the little squares), and also the siding and insulation (indicated by the radius lines) sitting on top of the wall. The indicators 4A, 4B, and 4C in the diamonds joined by the horizontal line that touches the wall refer to drawing notes provided elsewhere in the drawing set. We have not shown those sheets here as they all refer to items that are not steel. We talk about them here to help you understand what the detail is intended to show the reader.
The bent sheet metal pieces that support and enclose the siding and the insulation—the cont (continuous) sealant, the 4” rubber case, the continuous resilient channel, the continuous prefinished metal drip flashing, the neoprene profile closure—all these items make up the base of the wall that we saw in Section cut 2/A3.3, Exterior Wall Section, Figure 5.4.
Figure 5.5 Foundation detail 1/A6.1
As you look back and forth between 2/A3.3 and this detail, you will become more familiar with how this detail is used to show more closely what the physical makeup is of this part of the building. What is important to the fabricator on this detail is that no additional steel is shown here.
The detail 8/S6.1 (see Figure 5.6) shows the framing as it exists on the 2nd floor.
We see the same information for the 2nd floor with regard to the siding, insulation, and flashing that we saw in Figure 5.5 for the foundation. We see the end view of a steel beam with another beam framing into it just under the concrete floor. This is our first look at the steel in this building and how it looks in relation to the rest of the building that the framing supports.
Because this drawing is an architectural one, the structural steel framing will not be identified here. Instead, the steel is identified in the structural set of drawings, set aside specifically for that purpose. The dimensioning shown for these close-up areas help the individual trades know how and where their materials are to be placed.
Figure 5.6 Second floor detail 8/S6.1
Having the structural steel, mechanical, and electrical drawings separate from the architectural plans allows for a more organized and specific presentation of the information, especially when the architect displays the entire make-up of the building.
Figure 5.7 shows the detail 1/A7.2, the building’s roof level. We can see the steel beam at the roof coming at us in the page, as well as the side view or elevation of the beam that frames into it. Behind the beam, we can see the metal siding, wall panels, and insulation. We can also see the roof decking with the roof board on top, the 5/8” gypsum sheathing, the roof membrane, and the makeup of the parapet.
Figure 5.7 Roof level detail 1/A7.2
The conditions we have just reviewed are the same conditions by which we will read the structural drawings. First we will review the plan views. Next, we will go to the elevation cuts, and then the individual detail cuts so we can understand how the building is structured. This format is standard for drawing presentation. Although every building is different, how the designers show the detailed information is generally the same.
The designers do try to show all the information necessary to build the buildings that they can. Still, information which we require to build our steel may be missing. This omission is to be expected as the application of trade specific information will not be shown at these contract drawings; that type information requires detailing even beyond what is required of the designers. Thus we have steel detailers and RFIs—Requests for Information. The RFI is the tool used to fill in the gaps, necessary for us to achieve the goal of completed and accurate shop detail drawings as well as the provision of the subsequent fabricated steel.
This chapter reviewed the drawing floor plan, together with the subsequent elevation view and section cuts. The discussion on detail layering should help steel estimators begin to understand how the drawings are designed. More information on reading drawings is given in Chapter 7 (Reading Structural Drawings), Chapter 8 (Structural Steel Material Listing), and Chapter 9 (Reading Architectural Drawings). The application of the basics indicated in this chapter remains the same.
