How to Prepare Structural Drawings?

Structural drawings are the sets of engineering drawings prepared for or intended to communicate the structural requirement for the design structure. Architectural drawing cannot just be enough for construction. The supplementary structural drawing needs to be referred to in conjunction with the architectural drawing during construction.

An enthusiastic structural engineer or drafter must know the key components for preparing design and drawing. This article hopes to provide an inside to structural drawings and how to prepare structural drawings for any civil engineering structure including buildings, culverts, bridges, etc.

What are Structural Drawings?

Structural drawings are sets of engineering drawings prepared by a certified engineer for designed buildings or any other structure which demands it. The sets of drawings should consist of every detail drawing of the structural components and building elements.

This is the last stage in the structural design by the structural engineer. The structural design and analysis are done for the given architectural design. It is very crucial to do a thorough study of the proposed architectural drawing before designing and analysing it. After designing and analysing one should start with drafting or preparing structural drawings. Otherwise, the design file should be handed over to the draft personnel for preparing the required drawings.

When is the Structure Drawing Prepared?

The structure drawing is demanded by those structures which require structural analysis and design to graphically represent on paper the accepted design along with design calculation or procedure. Structures like, bridges and culvert demands the structure drawing. Building construction also requires structure drawings.

Composition of Structural Drawings

The drawings should consist of all the necessary drawings. However, the following are the general considerations for the compilation of the drawings.

1. Structural Drawing note
2. Foundation and footing drawing
3. Column layout and section drawings
4. Beam layout and section drawing
5. Floor slab layout and section drawing
6. Staircase plan and section drawing
7. Truss layout and section drawings
8. Wall section details
9. Other documents such as designer certificate, design worksheet/calculation/result must be attached

As per the Building Regulation of Bhutan 2018

The structural drawings shall include the following:

1. Notes:

• Calculation note-sheets
• design codes (used for designing)
• material specification/ properties of the materials
• The geotechnical report for soil (soil bearing capacity) is attached with the drawing
• levels, measurement units and scale of the drawings

2. A foundation plan, foundation details, including the depth of the foundation and plinth level and in the case of foundations on different levels – retaining details

3. Details of the beam and slab layout plan of each floor, showing clearly the staircase opening, shaft opening and any other openings and depressions;
4. Concrete and reinforcement details of foundation, beams, slab, staircase, lintel, cornice, projections, zhu and Rabsel, wall and other features;
5. Truss elevations and connection details showing the holding-down details;
6. Details and location of separation gaps;
7. Details of splice locations and splice length for beams, columns, slab and staircase;
8. For load-bearing walls – details of plinth band, lintel band and roof band, including vertical bars at corners, opening jambs and wall junctions; and
9. The dimensions of all structural members, including:
10. Anchorage of beam bars in an existing beam-column junction; and
11. column ties and beam stirrup details.

Certification of The Drawings

Like other technical drawings, the structural drawing prepared should be certified by the designer for readiness and use on the construction site. However, the drawing must be approved by the government office (municipal or city corporation) or relevant authority before the execution of the works.

The drawing shall be signed by the owner, designer and drafter (if there). The owner’s signature is done to accept the prepared drawing. The person who prepares the drawing must sign with the contact details such as e-mail ID, contact number and address. The certificate of the designer must be attached with drawings.

Also, read: Structure Drawing Detailing for Reinforced Concrete Structures

Advantages of Structural Drawings

The advantages of structural drawings are as follows: –

• The drawing will guide the contractor, builder, workers or other engineer about the position of columns, beams, lintels, staircase, and wall elements.
• The quantity of materials such as steel, concrete and bricks can be estimated by referring to the drawings
• 35 to 40% of the construction cost can be known just by referring to structural drawings.
• It is also advantageous to the engineer and drafter to earn a side income by designing and preparing structural drawings.

Disadvantages of Structural Drawings

There are many disadvantages to structural drawings: –

• The drawing reading is not easy for the common people or untrained personnel.
• Not all the drawings are identical to each other and have different representations which may confuse the drawing reader
• It is time-consuming to prepare the structural drawing for untrained personnel.

Also, read: Scale In Engineering Drawings

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