How To Read Steel Structure Drawing

Structural drawings are a serial of pages which explicate and illustrate the structural framing of a building or structure including its force, member size and stiffness characteristics.

If you are in the construction industry or renovating your own business firm, the ability to read structural drawings and plans is a very important skill to have and its relatively easy to learn.

When I was a wee Structural Engineer studying at university, reading structural drawings was non a skill my course provided. I constitute myself as a graduate engineer staring at linework having no idea what I was looking at

It wasn't until several months into my career that I started to understand what it all meant and how to read Structural Drawings. This was largely a process of osmosis for me as being part of a busy structural engineering science consulting house I didn't receive the "Structural Drawings 101" class, notwithstanding dear reader, this is what I volition endeavor to provide for you in this commodity.

Equally e'er, we need to properly ascertain what we are going to learn before jumping in…

What are Structural Drawings?

Structural drawings are a series of pages which explain and illustrate the structural blueprint intent of a edifice or structure. The aim of a good set of structural drawings is to provide the reader with enough information to:

• Construct that building or construction if you lot are a contractor
• Provide enough data to sympathise the size, shape and layout of the structural framing if you are an architect, role of the wider design team or a developer/owner.

To construct a building, many disciplines need to exist coordinated, non just the Structure and Architecture. A set of structural drawings are normally read along with drawings from these other disciplines including:

• Mechanical: Ducts for heating and cooling, ventilation and smoke systems etc.
• Hydraulic: Sewer, hot and cold water supply, fire sprinkler system etc.
• Electrical: Loftier and Low voltage ability, lighting etc.
• Data: Smart building systems, building management system, security system etc.
• Vertical Transport: Lifts, elevators, dock levellers, travellators etc.
• Civil: Road and pavement details besides as tempest water drainage.

Structural drawings are not to be confused with architectural drawings, these separate drawing sets provide very different pieces of information…

What is the Difference Betwixt Architectural and Structural Drawings?

In general terms, Structural drawings show detailed information on the building elements which provide support and stability to the structure including cloth strength grades and reinforcement while Architectural drawings provide detailed data on the buildings aesthetics and usage such every bit colours, patterns and finishes.

For example, a load-bearing column is shown on both the Structural and Architectural drawings yet the data provided for that cavalcade between the 2 sets of drawings is quite different:

• In the case of Architectural drawings , the dimensions and appearance of the column are important to the architecture of the building so information such as the following is illustrated:
  Dimensions: Length, width or diameter.
  Appearance: Paint colour if its a painted terminate or details on the materials if cladding is required.
  
• In the instance of Structural drawings , the force and stiffness characteristics of the column are important so information such as the post-obit is illustrated:
  Physical/Steel Grade: The force grade of the material used atmospheric condition it be concrete, steel or timber.
  Reinforcement: In the example of a reinforced concrete column; the quantity, size and grade of the vertical reinforcement and ligatures.

Here is an example of an Architectural (elevation) and Structural (bottom) drawing illustrating the aforementioned office flooring in the same building…

Example of an architectural plan drawing

Instance of a structural plan drawing.

These examples are taken from a typical floor in an function building. At the bottom of the drawings is the location of the elevator/stair shaft including the bathroom facilities.

Y'all can come across that the architectural drawing goes into much more than detail on the await and usage of this zone with specifications on toilet pan locations, tiling, cubicle doors then on. All of these elements are non-structural so they don't announced at all on the structural cartoon. just the structural slab thickness is shown (in this instance 250mm thick or ix.84inch thick for those playing at home in the US).

Outside of the lift/stair shaft on the top of the drawings is the office floor plate. Its planned to be an open space office ready for the tenant to fitout exactly how they like with flexibility for partition walls for meeting rooms, office cubicles etc. That ways that the base of operations architecture for the office floor plan layout is carpet and ceiling with footling else. The structural drawings on the other hand appears to accept a bit more going on in this expanse, with slab thicknesses indicated (180-200mm or 7.08-7.87inch) besides as some boosted dashed lines… this we will get into more particular later on.

Full general Drawing Elements

First nosotros will get through the general drawing elements which are usually mutual beyond the disciplines.

Cartoon Reference Grids:

Reference grids are similar the gum that ties all of the engineering and architectural drawings together. They provide reference points which helps the reader identify the same locations on each disciplines cartoon set.

The reference grids are read like to the old fashioned game of battle transport; a row of grids following sequential numbers (for example running horizontally) and a row of grids following sequential letters (for example running vertically).

This ways that a grid reference of E2 on the architectural cartoon should be the exact same location in the building as the filigree reference E2 on the structural drawing (y'all sank my battle ship, or in this instance, column!)

Cartoon reference grids are read like to the quondam school game of battleship

A grid reference of E2 on the Architectural drawings (left) is the exact same location within the edifice as grid reference E2 on the Structural drawings.

Face Sheet / Title Folio:

Building drawings are read similar to a volume, and merely like a volume the drawings need a comprehend page. This is ofttimes referred to equally a Confront Sheet or a Title Page.

The confront canvas will ofttimes incorporate a drawing contents table (similar to a book; a list of cartoon titles and their corresponding drawing number).

The Confront Sheet will too have the name of the project (often simply the project address or if the developer has started to brand the development, it may be the projects make name).

The consultant may also utilise this opportunity to show an overall site plan to give the reader context of where the site is located and the neighbouring buildings nearby.

If the projection has been documented by the consultant in a 3D modelling bundle, a 3D perspective view of the edifice or structure may be displayed on the face up sheet as well.

Case of a face sheet which is the offset drawing in the structural drawing set.

Title Cake:

A championship cake is commonly included on every drawing in the structural cartoon gear up (and all other discipline'south drawings for that matter)

An example of a cartoon title block.

The title block is located on the bottom boarder of the drawing or the correct mitt side (depending on the drawing size/orientation and set-up) and will mostly include the following cardinal information…

1. Revision Box: This portion keeps track of the revision history of that item drawing. Hither yous can see the revision number/letter history, a cursory summary of what the changes were for that revision (in the amendment department) and the engagement that that revision was issued.
2. Consultants Company Logo: Here may include the organisations logo, accost, subject and professional person registration number (required for practicing engineers dependant on the state and state they are in).
3. Copyright Disclaimer: There is mostly an inclusion of some form of intellectual property statement protecting the rights of the cartoon creator.

Example portion of a cartoon title block

4. North Point Indicator: In the case of a floor plan, this shows the orientation of that plan in relation to true northward. This is generally left blank for detail drawings, summit drawings and general notes drawings.
5. Evolution Address: Contains the projects address and sometimes is development proper noun likewise.
6. Proper noun of the Cartoon: An explanation of what the title of the cartoon is.
vii. Name of the Client: Generally the name of the person or company who has engaged the consultant to produce the drawings and the design.
8. Cartoon Size and Calibration Details: Two pieces of information; the intended drawing sheet size and the scale the drawing is at when printed at that sheet size (more on drawing scales later on).
9. Quality Assurance Data of the Drawings: Contains the QA and administrative information for the cartoon including the initials of the people who drew it and checked information technology. This section may also include the project number which is usually a number assigned by the technology consultant business firm which follows its visitor project numbering system. Finally the drawing number and revision is also provided.

General Notes:

Subsequently the face canvass, a serial of general notes sheets then follow and brand up the first few sheets of the drawing set.

Full general notes drawings provide very important information on the structural detailing of the building. The general notes provide projection-wide specifications and, for efficiency purposes, they are provided in a consolidated location to prevent the need to repeat them on later drawings multiple times. This information may include the post-obit (and more than!):

• Concrete encompass/grade/slump
• Structural steel grades
• Reinforcement and postal service-tensioning grades
• Specifications for the functioning of formwork
• Founding depth and material for foundations
• Standard lap lengths of reinforcing bar
• Performance specification for shoring systems
• Structural loading assumptions
• General notes and guidance on how to read and translate the drawing ready

Typical Details:

Immediately following the general notes section are a series of typical standard detail sheets. These standard details are usually typical repetitive details which will be adopted at multiple locations on the project. These details likewise generally friction match the mutual construction approach used by the local industry where the drawings were produced and therefore are normally used from project to project on multiple occasions.

Below is a standard detail which you may discover in the typical standard details portion of the drawing ready, it is a cross-section looking through a slab with an edge beam located to the left. Y'all volition detect that reinforcing bar sizing and spacing is not provide, however the general system of the reinforcement and the lapping requirements are. This allows the detail to exist adopted at multiple locations on the project, with the detailed bar spacing and size requirements being illustrated at the specific location afterward in the drawing ready.

Example representation of a typical structural detail.

General Arrangement Plans

Now that nosotros are familiar with the general elements which make upward the drawing set, lets offset to get into details.

A structural general arrangement plan is a birds-eye view of the flooring, roof or foundation arrangement (depending on which programme it is). It gives the reader a visual representation of the structural framing requirements for that level.

Lets accept a wait to see how a physical framed floor may look on a structural general arrangement plan (oft called a GA programme), lets not overwhelm ourselves and simply look at a modest portion of a larger floor plan…

Ok in that location'southward a lot going on here! lets break it down into individual elements…

1. Grid System: Piece of cake, we know this already!
2. Revision Cloud: The revision deject is unremarkably coupled with a revision "bubble" (the upside-downward triangle with the letter "C" in information technology). The revision cloud outlines a portion of the cartoon which has been altered, in this case something within this clouded zone has either been added, deleted or modified since the concluding revision (which would have been revision "B"). Since the revision cloud bubble says "C" that would make the drawing that this snapshot has been taken from too revision "C". In order to see exactly what has changed at this location, you lot will need to reference the revision "B" drawing and compare the two.
3. Axle Tags: This is the "name" of the beam and commonly it starts with a letter "B" (for axle) followed by a number. The GA programme is usually provided with a beam schedule, which is a tabular array of beam tags with their respective axle depths/widths (an instance is shown further below). The reason for non providing the dimensions of the beam on the full general arrangement program itself is to reduce the visual mess on the drawing to make it easier to read (although some engineering consultant firms will provide the dimensions on the GA and not use a schedule, depending on that offices cartoon standard).
4. Slab Depth Tag: Simply provides the structural depth of the slab.
5. Column Tag (Nether): Like to a beam tag, the column tag is the columns "name" and ordinarily starts with a "C" for column. The "U" in this case indicates that this is the column tag for the cavalcade beneath this floor. This is another master difference betwixt structural and architectural drawings; since the columns below are what supports this very floor, it is an important structural element as far equally this floor is concerned. Then therefore structural drawings will oft bear witness the reader what is happening not only to a higher place the floor merely beneath it also.
6. Column Tag (Over): Aforementioned for Column Tag (Under) even so this is for the column above the floor.
7. Soffit Step Line: A slab soffit is simply the bottom surface of the slab. A soffit stride line is an indication that the slab soffit is stepping upwards/downwardly at this location. Any steps or construction beneath a floor is ordinarily shown equally a dashed line.
8. Pinnacle Surface Step Line: This is also a step line, however instead of occurring on the lesser surface of the slab, it is a representation of a step which is occurring on the top surface of the slab.
9. Stride Indicator Tag: It is sometimes not clear which portion of the slab either side of a top surface step line is the high side or the low side. For this reason, a stride indicator tag is provided which shows a mini cross-section view of how the stride is orientated. in this example higher up the left-manus-side of the top surface footstep line is higher than the right-hand-side.

Instance of a structural beam schedule

Example of a reinforced concrete column schedule

Lets take a look at some other floor with a dissimilar structural framing type this time. The following image is a snapshot of another typical office floor however the structure is a composite steel floor organisation. As well the drawing is produced by a different technology consultant business firm, y'all tin can see there are some slight variations in the beam and column tag format with all letters instead of a mixture of messages and numbers.

1. Beam Tag: The same as previous yet notice "SB" is used instead of "B" (different engineering firms take unlike drawing standards). The beams are indicated as dashed lines equally they are beneath the blended slab. Each beam is shown equally three separate dashed lines, the outer lines represent the extremes of the beam flanges and the centre line indicating the heart-line of the axle.
2. Beam Tag: Aforementioned as previous
3. Column tag: Aforementioned equally previous
4. Slab Depth Tag: Indicates the depth of the composite slab, and is also coupled with a symbol which looks like something Zorro may accept written. This arrow type symbol indicates the span direction of the metal tray deck (in this case the bridge direction is upward/down of screen).

Lets take a look at another cartoon example simply this time with a couple new symbols…

Instance portion of a structural drawing indicating void cross and section bubble.

1. Void Cantankerous: Ii solid crossing lines generally stand for a void in the construction (better known every bit a hole). The case above is showing a large rectangular hole in this floor slab.
2. Section Bubble: A section bubble indicates that a cross-section has been drawn for a specific piece of the slab and is located inside the drawing set. There are a few pieces of data here… the section is given a unique identifier (in this case 1000.04 which is basically the name of the department). The bubble too gives a drawing reference where this section is located (in this case the drawing number is South-P3-N-2114). The orientation of the bubble which is pointing left of screen indicates that the cross section has been drawn assuming that the viewer is looking to the left of screen. The corresponding section bubble tail indicates how wide the section has been fatigued (the extent of the section).

Turning to cartoon number Southward-P3-North-2114 in this example drawing set and looking for section G.04 allows us to see what this section looks like in society to better understand what is shown on this general arrangement plan…

Now we can run into the department view of this slice, nosotros can also encounter our large hole/void within the slab which was indicated on the GA program.

What are Drawing Scales?

A scaled drawing is a drawing which properly represents an objects size and proportions reduced or enlarged past a certain percentage. The calibration of that drawing is an indication of the pct that the cartoon is smaller or larger than the real-world object. The calibration is represented past a unit length on the drawing, followed past a colon (":") then past the corresponding length of the real-world object.

In order for structural drawings to fit on a manageable sized drawing sail, the drawing is usually a small fraction of the real-earth size. A scale of i:100 is a very common scale to use for a structural framing plan. That is, a 1mm measurement taken on the cartoon represents a 100mm length of the real-earth object.

It is very important to understand scales when measuring off from printed drawings. If the drawing is not printed on the correct sheet size the intended drawing calibration is not accurately represented. Sometimes information technology is preferable to print a cartoon on a smaller canvass size every bit smaller sheets are easier to store and bear. If you would like to accept a hard copy of the drawing on a smaller sail size, it can still be measured using a scale ruler, all the same the calibration needs to be converted accordingly depending if the sheet you are printing to is smaller or larger than the required original drawing canvass size….

Cartoon Calibration Converter

Size	A0	A1	A2	A3	A4	A5	A6
A0	100%	71%	50%	35%	25%	xviii%	12.five%
A1	141%	100%	71%	50%	35%	25%	xviii%
A2	200%	141%	100%	71%	50%	35%	25%
A3	283%	200%	141%	100%	71%	50%	35%
A4	400%	283%	200%	141%	100%	71%	50%
A5	566%	400%	283%	200%	141%	100%	71%
A6	800%	566%	400%	284%	200%	141%	100%

Conclusion

That was a run through of what I learned in my first few months beingness a structural engineer fresh out of Academy all those years ago. I hope some of you out in that location have constitute this useful and sped up your learning experience into this small fraction of the art of structural applied science.

Delight experience free to leave a comment below on topics you would like to see covered on hereafter posts on Sheer Forcefulness Engineering.

Source: https://sheerforceeng.com/how-to-read-structural-drawings-a-deep-dive-from-a-to-z/

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