Project 2 - MODELLING, ANALYSIS & DESIGN OF COMPOSITE STUCTURES IN COMFLOR & ETABS

a. Modelling

1. Structural Framing Plans

• Two Options:

  • Option A: Primary beams along grid lines, secondary beams spanning between primaries

  • Option B: One-way spanning system with integrated core transfer beams

• Use ETABS Floor Plan View to layout both options and compare beam spacing.

2. Member Definitions

• Import steel profiles from ETABS library (ISMB, ISHB, rectangular tubes, etc.)

• Define custom composite sections for beams using Comflor output (i.e., ISMB + slab width)

3. Deck Slab Selection

• Based on ComFlor manual:

  • Typical for high-rises: ComFlor 60/80 or 210

  • Consider span length, fire rating (60 min), construction stage performance

  • Define as Shell thin in ETABS and assign deck direction

4. Composite Modelling in ETABS

• Composite Beams: Assign composite deck + specify effective width

• Composite Columns: Use Concrete-filled Tubes (CFTs) or Encased I-sections

  • Define as composite in ETABS properties using built-in templates or user-defined

5. Other Elements

• Define steel bracings (angle/pipe sections)

• Assign RC core wall (M60+) as wall objects

• Group elements by type and floor level for easy design and reporting

b. Loadings & Load Combinations

1. ComFlor Load Inputs

• Wet Concrete Load = slab self-weight + reinforcement + construction load (typically 1.5–2.5 kN/m²)

• Include construction load case separately

2. ETABS Load Patterns

• Use Project 1’s existing load combinations

• Add:

  • Pre-composite DL (metal deck, beam, etc.)

  • Footfall loading (1–2 Hz frequency input for vibration check)

3. Load Combinations

Include:

• ULS: 1.5(DL + LL)

• SLS: DL + LL

• Construction Stage Combinations (for checking decking capacity before composite action)

c. Structural Analysis

1. ComFlor Analysis

• Design composite slab using selected ComFlor profile

• Get:

  • Moment and shear capacity

  • Slab thickness and reinforcement

  • Vibration and fire checks

• Export full ComFlor Report (PDF)

2. ETABS Analysis

• Run linear static and modal analysis

• Get:

  • Beam and column shear force & moment diagrams

  • Base reactions (cross-check with hand calcs)

  • Gravity load path (trace using “Display → Load Path” or manually)

3. Vibration Checks

• Extract natural frequency (Hz) for floors

• Ensure f > 3 Hz (minimum comfort)

  • If not, increase slab thickness, reduce beam spacing, or stiffen beams

d. Design of Structural Members

1. ComFlor Design

• Check:

  • Span/load ratio

  • Reinforcement for fire (top mesh)

  • Deflection during construction & final stages

• Design shear studs: spacing, count per beam

2. ETABS Design Interpretation

• Review:

  • Demand/Capacity ratios (DCRs)

  • Stress contours and interaction ratios for composite beams/columns

• Design steel bracing and transfer elements

• Export ETABS Report (PDF)

3. Pre-Camber Criteria

• For long beams, check camber requirement

  • Usually camber 80–100% of dead load deflection

  • ComFlor/ETABS will give estimated deflection to be cambered

Key Deliverables Checklist

Deliverable	File Type	Tool
✅ ComFlor model	.cfl or .xls	ComFlor Software
✅ ComFlor Report	.pdf	Exported from ComFlor
✅ ETABS Structural Model	.edb	ETABS
✅ ETABS Project Report	.pdf	ETABS Export
✅ Project Calculations & Justifications	.docx or .pdf	MS Word / LaTeX

1. ETABS Model Setup Guide (Composite System)

General Steps:

1. Grid & Storey Setup

   • Define grid lines based on architectural layout (e.g., 6m x 6m or per Project 1)

   • Set storey heights (e.g., 3.3 m typical)

2. Material Properties

   • Concrete (e.g., M30, M50 for core)

   • Steel (Fe345 or Fe410)

   • Composite slab (define slab with metal deck equivalent)

3. Section Properties

   • Import ISMB600, ISHB, Pipe sections, HSS, etc.

   • Define Composite Columns:

     • CFT (Concrete-filled tube)

     • Encased I-section (steel encased in concrete)

   • Define Composite Beams:

     • Use "Add Composite Beam" in ETABS

     • Assign deck direction, effective slab width, shear studs

4. Deck Slab Modeling

   • Use Shell thin element

   • Deck profile direction must be correctly oriented

   • Assign live load reduction factors if needed

5. Bracing & Core Walls

   • Model core walls as RC walls (Shells)

   • Use diagonal bracing where needed (e.g., X-bracing)

2. ComFlor Sheet Template

• ComFlor 60 with 130 mm slab

• Span = 2750 mm

• Live + SDL = 5.75 kN/m²

• Fire rating = 60 minutes

• Shear studs calculated

• Vibration and construction check included

3. Final Report Template (MS Word / LaTeX)

Structure:

1. Cover Page

   • Project Title

   • Your Name

   • Institute

   • Date

2. Table of Contents

3. 1. Introduction

   • Scope of project

   • Summary of structure

   • Design software used

4. 2. Modeling in ETABS

   • Grid and framing layout

   • Section definitions

   • Deck modeling

   • Composite members

5. 3. Load Definitions

   • DL, LL, Construction Load

   • Pre-composite load

   • Footfall/vibration loading

6. 4. Structural Analysis

   • Gravity load path

   • Moment and shear diagrams

   • Natural frequency results

7. 5. Composite Deck Design

   • ComFlor deck selection

   • Stud spacing

   • Vibration and fire checks

8. 6. Design of Members

   • Beams (with camber check)

   • Columns

   • Bracing

   • Core wall

9. 7. ETABS Output Interpretation

   • Stress checks

   • Deflection and D/C ratios

Parameter	Value
Deck Profile	ComFlor 60
Overall Slab Depth	130 mm
Span (mm)	2750 mm
Deck Span Type	Single Span
Construction Stage Load	3.0 kN/m²
Final Stage Load	5.75 kN/m²
Fire Rating (min)	60
Slab Width per Beam	3000 mm
Steel Beam (ISMB)	ISMB600
Studs per Beam	9
Stud Spacing	300 mm
Effective Width	1500 mm
Moment Capacity (kNm)	45.2
Shear Capacity (kN)	85.6
Deflection Limit (mm)	9.2
Max Deflection (mm)	7.8
Vibration Check (Hz)	3.8
Fire Cover (mm)	25 mm