SOP: Structure Analysis
1. Purpose
To ensure structural analysis is carried out correctly, safely, and consistently before structural design, checking, and construction.
This SOP helps the team:
- understand structural behavior
- determine forces and reactions
- verify safety and serviceability
- reduce design mistakes
- produce reliable structural reports and drawings
2. Scope
This SOP applies to structural analysis for:
- houses
- villas
- low-rise buildings
- reinforced concrete structures
- steel structures
- simple retaining or framed structures
It covers:
- collection of input data
- modeling
- load definition
- load combinations
- analysis
- review of results
- reporting
3. Objective
The objective is to produce a structural analysis model that is:
- technically correct
- based on actual project conditions
- code-compliant
- easy to check
- ready for design and detailing
4. Responsibility
Structural Engineer
- collect project data
- prepare structural model
- define loads
- run analysis
- review results
- issue analysis report
Checker / Senior Engineer
- review assumptions
- verify model logic
- check critical results
- approve or return for correction
Draftsman / BIM Modeler
- provide architectural and structural geometry support
- revise drawings based on engineer comments
Project Manager
- coordinate timeline
- ensure required inputs are available
- control submission schedule
5. Required Inputs
Before starting analysis, collect the following:
A. Architectural Information
- architectural drawings
- floor plans
- elevations
- sections
- roof layout
- wall locations
- opening locations
B. Structural Information
- column grid
- beam layout
- slab thickness
- preliminary member sizes
- foundation concept
C. Site Information
- soil report
- allowable bearing capacity
- groundwater condition
- site constraints
D. Design Criteria
- design code
- concrete strength
- steel strength
- load requirements
- serviceability limits
E. Project Requirements
- intended use of building
- number of floors
- future expansion if any
- special equipment loads
- water tank or roof loads
6. Tools / Software
Common tools may include:
- hand calculation
- Excel
- Mathcad
- ETABS
- SAP2000
- Robot Structural Analysis
- MIDAS
- SAFE
- AutoCAD / BIM software
7. Procedure
Step 1: Review Project Documents
Study all available documents carefully.
Check:
- building use
- span lengths
- floor levels
- structural system
- wall positions
- stair positions
- large openings
- roof type
Output:
Clear understanding of the building and structural system.
Step 2: Define Structural System
Select the structural system based on project needs.
Examples:
- beam-column-slab system
- load-bearing wall system
- steel frame system
- flat slab system
Engineer must confirm:
- load path
- support conditions
- lateral stability system
- expansion joints if needed
Output:
Chosen structural system with engineering assumptions.
Step 3: Set Design Criteria
Define design basis before modeling.
Include:
- design code used
- material strengths
- dead load assumptions
- live load values
- wind load criteria
- seismic criteria if applicable
- deflection limits
- crack control requirements
Output:
Design criteria sheet.
Step 4: Prepare Preliminary Member Sizes
Use engineering judgment to set initial member sizes.
Examples:
- slab thickness
- beam width and depth
- column size
- footing size estimate
These are preliminary and may change after analysis.
Output:
Initial structural sizing for model input.
Step 5: Build Structural Model
Create the analysis model in software.
Model must include:
- grids
- levels
- beams
- columns
- slabs
- walls
- supports
- releases if needed
Important checks:
- units are correct
- geometry is aligned
- members connect properly
- supports match reality
- slab meshing is reasonable
- no duplicate elements
Output:
Completed structural analysis model.
Step 6: Define Material Properties
Input material properties such as:
- concrete grade
- steel yield strength
- modulus of elasticity
- density / self-weight values
Make sure material properties match the project specification.
Output:
Correct material database in the model.
Step 7: Assign Section Properties
Assign proper cross-sections to all members.
Examples:
- beam size
- column size
- slab thickness
- wall thickness
- steel section type
Check that each member has the correct section.
Output:
All members assigned correctly.
Step 8: Define Loads
Loads must reflect real building conditions.
A. Dead Load
Include:
- self-weight
- floor finishes
- screed
- ceiling
- wall loads
- waterproofing
- roofing
- fixed equipment
B. Live Load
Based on building function:
- residential
- office
- storage
- corridor
- stairs
- roof maintenance load
C. Environmental Loads
If required:
- wind load
- seismic load
- rain load
- earth pressure
- water pressure
D. Special Loads
If any:
- tank loads
- machine loads
- solar panel loads
- façade loads
Output:
Complete loading system.
Step 9: Create Load Combinations
Prepare service and ultimate load combinations according to the design code.
Typical categories:
- dead + live
- dead + wind
- dead + seismic
- service combinations for deflection
- ultimate combinations for strength
Output:
Load combinations ready for analysis and design.
Step 10: Run Analysis
Perform structural analysis.
Check software warnings and errors before accepting results.
Look for:
- instability
- excessive displacement
- disconnected nodes
- unusual force jumps
- zero stiffness warnings
- unrealistic support reactions
Output:
Analysis results generated successfully.
Step 11: Review Global Behavior
Before checking individual members, review the whole structure.
Check:
- deformed shape
- support reactions
- load path
- overall drift
- sway behavior
- slab behavior
- symmetry or unexpected torsion
Ask:
- Does the building move logically?
- Are supports reacting correctly?
- Does the structure behave as expected?
Output:
Confirmed global structural behavior.
Step 12: Review Member Forces
Extract and review:
- bending moment
- shear force
- axial force
- torsion
- reaction force
- slab moments
- wall forces
Focus on critical members:
- longest beams
- transfer beams
- edge beams
- corner columns
- heavily loaded slabs
- stair beams
- foundation supports
Output:
Critical analysis results identified.
Step 13: Check Serviceability
Review serviceability performance.
Check:
- beam deflection
- slab deflection
- story drift
- vibration if needed
- crack-sensitive spans
Make sure service behavior is acceptable, not only strength.
Output:
Serviceability verified.
Step 14: Compare with Manual Check
Perform quick manual checks on important elements.
Examples:
- tributary area load estimation
- beam moment approximate check
- column axial load estimate
- reaction total vs total applied load
Purpose:
- confirm model is reasonable
- catch major mistakes early
Output:
Model sanity check completed.
Step 15: Revise Model if Needed
If results are not acceptable:
- modify member sizes
- revise support conditions
- correct loading
- improve structural layout
- refine slab mesh
- adjust stiffness assumptions if justified
Then rerun analysis.
Output:
Improved and stable model.
Step 16: Finalize Analysis Results
Once the model is correct, finalize results for design.
Prepare:
- governing load combinations
- design moments
- shears
- axial loads
- reactions for foundations
- slab design strips if needed
Output:
Final analysis data for design stage.
Step 17: Prepare Structural Analysis Report
The report should include:
- project title
- project description
- codes used
- material properties
- design assumptions
- load assumptions
- load combinations
- model images
- support conditions
- critical analysis results
- deflection / drift summary
- engineering comments
- conclusion
Output:
Formal structural analysis report.
8. Quality Control Checklist
Before approval, confirm:
- project drawings reviewed
- units correct
- geometry correct
- supports correct
- materials correct
- sections assigned properly
- all relevant loads included
- wall loads considered
- load combinations correct
- model stability confirmed
- abnormal results investigated
- manual spot checks completed
- report prepared clearly
9. Common Mistakes to Avoid
Do not:
- use wrong units
- forget wall load
- ignore stair load
- assign wrong support conditions
- leave disconnected members
- trust software without checking behavior
- use load combinations without code verification
- ignore deflection and serviceability
- forget roof water tank or equipment load
- skip manual checking
10. Acceptance Criteria
Structural analysis is accepted when:
- model represents actual structure
- loads are complete and reasonable
- analysis is stable
- results are logical
- serviceability is checked
- critical members are reviewed
- checker approves the model and report
11. Deliverables
Final deliverables may include:
- structural analysis model file
- structural analysis report
- load calculation sheet
- reaction summary for foundation design
- member force summary
- marked-up review comments
- approved design basis
12. Simple Workflow Summary
Receive project data
↓
Review drawings and soil report
↓
Choose structural system
↓
Set design criteria
↓
Create analysis model
↓
Assign materials, sections, supports
↓
Apply loads and combinations
↓
Run analysis
↓
Check global behavior and member forces
↓
Verify serviceability
↓
Do manual checks
↓
Revise if needed
↓
Finalize report and approve
13. Final Advice
A good structural analysis is not only about using software.
It is about:
- correct assumptions
- correct load path
- correct engineering judgment
- careful checking
Software gives numbers.
Engineer gives meaning.
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