Understanding the RISA Model as a Foundation for Drawings

The structural model created in RISA is more than just an analysis file; it is the single source of truth for all downstream documentation. Before generating any drawings, engineers must audit the model for completeness and accuracy. This includes verifying that all load combinations are correctly defined, member end releases are properly assigned, and material properties match the project specifications. A model with missing loads or incorrect supports will produce drawings that lead to costly field modifications. Taking the time to run a final analysis check and review reaction forces, deflection results, and member unity ratios ensures the model itself is structurally valid. Only then should you proceed to output for drafting. Additionally, confirm that the coordinate system is consistent across all stories or frames. Inconsistent coordinates can cause misaligned plans and elevations, forcing rework downstream.

Organizing the RISA Model for Efficient Detailing

Naming Conventions and Grouping

Adopt a clear, project-wide naming convention for all structural elements. For example, use “B1-A” for a first-level beam in gridline A, or “C-3-2” for a column on the third floor. Group members by type, floor, and structural system. RISA allows the creation of named groups, which can be exported as layer filters in CAD. This organization streamlines the selection of elements when generating plan views, sections, or connection details. It also enables quick isolation of specific member categories, such as all roof beams, when annotating or adding dimensions.

Leveraging RISA’s Drawing Layout Features

RISA offers tools to create basic foundation, framing, and elevation layouts within the software. While not a full CAD environment, these layouts serve as a starting point for detailed drawings. Use them to generate preliminary views that capture member locations, section sizes, and support conditions. Export these layouts in DXF or DWG format to a CAD platform like AutoCAD or BricsCAD. Maintaining the same coordinate system between RISA and CAD avoids scaling issues and allows direct overlay with architectural backgrounds. Consider exporting each floor or elevation as a separate file to keep drawing sizes manageable.

Exporting RISA Data for CAD Detailing

Data Formats and Their Uses

RISA can export data in several formats: DXF for geometry, CSV for schedules, and IFC for BIM workflows. For traditional 2D drawings, DXF remains the workhorse. Export both linework and text (member labels) as separate layers. For example, send beam centerlines to one layer and column outlines to another. CSV exports are powerful for creating material takeoffs, bolt schedules, or reinforcement lists that can be linked to CAD tables. For projects requiring BIM coordination, the IFC export allows RISA models to be integrated into software like Revit or Tekla, reducing manual redrafting.

Mapping RISA Members to CAD Layers

Define a layer mapping strategy before exporting. Standard layers might include:

  • A-BEAM-OUTL for beam outlines
  • A-COL-OUTL for column profiles
  • A-FNDN-OUTL for footing outlines
  • A-ANNO-TEXT for member labels and notes
  • A-ANNO-DIMS for dimensions

Using a consistent layer standard (such as the AIA National CAD Standard) ensures that drawings are easily readable by all project stakeholders. Many firms have their own layer naming convention; apply that in the RISA export settings if possible. If not, create a post-export script to rename layers en masse.

Creating Detailed Structural Drawings: Best Practices

Plan Views: Framing and Foundation

Start with a clean base export of the RISA model. In CAD, overlay the architectural background on a locked layer to verify that structural elements align with walls, columns, and openings. For framing plans, generate separate drawings for each floor level. Show all beams, girders, joists, and columns with their sizes and locations. Use dimensions to establish grid line relationships (typically to the nearest 1/8 inch). Include a general note block that lists design codes, material strengths, and load assumptions. For foundation plans, detail footing sizes, elevations, reinforcing steel, and anchor bolt locations. Call out any special concrete mix designs or waterproofing requirements.

Elevations and Sections

Structural elevations are essential for braced frames, moment frames, and shear walls. Derive these directly from the model by creating a view orthogonal to the frame plane. Ensure that member depths, connection plates, and stiffeners are visible. Add vertical dimensions from floor to floor, and horizontal dimensions for bay widths. Sections cut through complex areas such as stair openings, roof ridges, or transfer beams. Show not only the main structure but also secondary elements like girts, purlins, and bracing. Use hatches or shading to differentiate materials (e.g., concrete vs. steel).

Connection Details

One of the most critical parts of structural drawings is the connection details. For steel structures, detail typical moment connections, simple shear connections, and brace gusset plates. Include bolt sizes, grades, numbers, spacing, and edge distances. For welded connections, specify weld type, size, and length. Use standard connection design references such as the AISC Manual to verify capacities. For concrete structures, detail rebar placement in beams, columns, and slabs. Show bar bends, lap lengths, hooks, and concrete cover. For post-tensioned members, indicate tendon profiles and stressing end locations. Each detail should have a unique number referenced in the plan views.

Annotations and Dimensions

Clear annotations prevent misinterpretation. Use a standard text style with consistent height (e.g., 3/32” for notes, 1/8” for dimensions). Place dimensions in a logical, non-overlapping manner. Use aligned dimensions for sloped members. Add leaders to call out specific items like web stiffeners or shear studs. Include a legend that explains all symbols, abbreviations, and hatching. For reinforcement, use standard rebar marks (e.g., #4 @ 12” o.c.). Avoid overcrowding by using callout bubbles that reference detailed sheets. Consider using dynamic blocks in CAD for commonly used details (such as column base plates or beam end plates) to speed up repetition.

Coordination with Other Disciplines

Structural drawings do not exist in isolation. They must coordinate with architectural, mechanical, electrical, and plumbing (MEP) systems. During the detailing phase, overlay MEP rough-in drawings to check for clashes. For example, a large duct or pipe that penetrates a steel beam may require a reinforced opening or a beam relocation. Note these coordination items on the structural drawings using clouded revision marks or hold tags. Early coordination reduces change orders during construction. Using BIM coordination tools (Navisworks, Solibri) helps automate clash detection between the RISA model and other discipline models.

Quality Assurance and Quality Control

Peer Review and Checklist

Implement a peer review process where a senior engineer or experienced drafter reviews the drawing set before issue. Use a quality control checklist that covers:

  • Consistency with the RISA model (member sizes, spans, materials)
  • Proper dimensioning and scaling
  • Complete annotation of all connections
  • Correct referencing between plan views and detail sheets
  • Revision cloud tracking for changes
  • Title block information (project title, sheet number, issue date, scale)

Check that all critical dimensions match the model output. For example, verify that a column spacing shown as 30 ft on the plan matches the RISA model. Discrepancies as small as 1/4 inch can cause major issues in modular construction.

Automated Checks

Leverage software tools to automate some QC checks. Many CAD platforms support scripts that check for missing dimensions, duplicate layers, or unmatched reference files. For RISA, use the report generator to produce a list of all members with their sizes and compare that list to the drawing schedule. Additionally, use clash detection tools if working in a BIM environment.

Expanding Details for Specific Material Types

Steel Drawings

For steel structures, shop drawings are typically created by the fabricator, but the engineer’s design drawings must provide sufficient information to permit accurate bidding and fabrication. Include a steel column schedule showing the member size, length, and base plate details. For complex framing, provide bracing plans with elevations. Indicate connection types required: moment, simple, or partial restraint. Provide slip-critical bolt tension requirements and surface preparation notes for faying surfaces. Refer to ASTM specifications for material grades (e.g., ASTM A992 for wide flange shapes).

Concrete Drawings

Concrete drawings demand reinforcement detailing. Show all rebar in plan and section views. Use standard bar bends from ACI 315. Provide a rebar schedule listing bar mark, size, shape, length, quantity, and bending dimensions. For post-tensioned slabs, indicate tendon profiles and stressing pockets. Include concrete compressive strength (f’c), exposure class, and water-cement ratio. Detail construction joints, expansion joints, and waterstops where applicable.

Using Templates and Standards

Develop a company standard drawing template that includes a title block, border, general notes, and common symbols. This template saves significant time and ensures consistency across all projects. The template should be reviewed annually to incorporate code updates (e.g., ASCE 7-22, ACI 318-19). Store the template in a central location accessible to all team members. Additionally, create standard details that can be reused on multiple projects with minor modifications. For example, a typical column base plate detail with anchor bolts can be adapted to different column sizes by changing the plate dimensions. These standard details not only speed up drafting but also reduce errors.

Document Management and Revisions

Structural drawings are living documents that undergo revisions during design and construction. Implement a revision control system with clear Revision Identification (Rev A, Rev B, etc.) and clouded revisions. After each revision, update the RISA model to reflect the changes. Maintain a log of changes that cross-references the drawing revision to the model change. When issuing drawings for construction (IFC), lock the drawing files and issue them as PDFs with a digital signature. For bid sets, consider issuing complete sets to avoid confusion.

For large projects with multiple sheets, use a master file that references external drawings (Xrefs). This approach allows multiple drafters to work simultaneously without file conflicts. Ensure that the Xref paths are relative to avoid broken links when sharing with consultants or clients.

Incorporating Feedback from the Field

After construction begins, collect feedback from fabricators and erectors about the clarity and completeness of the drawings. Common issues include missing dimensions, ambiguous details, or unrealistic tolerances. Document these lessons learned and incorporate them into the next project’s template. For example, if a connection detail is often misinterpreted, add a clarifying isometric view. Continuous improvement of drawing standards reduces RFIs and change orders.

Leveraging Technology for Better Drawings

Modern structural engineering firms are adopting automation in detailing. For instance, scripts can automatically generate reinforcement schedules from RISA model data. Additionally, cloud-based collaboration tools (e.g., Bluebeam Revu, Trimble Connect) allow real-time review and markups of drawings. Consider using parametric modeling in CAD to link dimension strings directly to the RISA model’s numerical data, so that any change in the model updates the drawing automatically. While full parametric linking is still evolving, third-party plugins (such as those for Rhino.Inside or Dynamo) can bridge the gap.

External Resources for Further Guidance

For those looking to deepen their knowledge, the following external references provide authoritative guidance on structural detailing best practices:

Conclusion

Producing detailed structural drawings from RISA models is a discipline that blends structural engineering expertise with precise drafting skills. By investing time in model organization, thoughtful export strategies, clear annotation, and quality control, engineers can create drawing packages that minimize construction issues and maximize clarity. Following the best practices outlined in this article—including consistent naming, careful layer mapping, comprehensive detailing of connections, and robust coordination—will lead to smoother project execution and fewer costly field changes. As technology evolves, integrating automation and BIM workflows will further enhance the efficiency and accuracy of structural documentation. Ultimately, the goal is to translate the engineer’s intent from the RISA model into a set of drawings that serve as a reliable, complete, and unambiguous instruction manual for the construction team.