Steel Structures

Completed Projects

Studies on cold-formed steel building components

Studies on cold-formed steel building components

  • Cold-formed steel sections are derived at room temperature through press braking and roll forms CFS sections are thin and light-weight
  • Applicable to use for low rise residential buildings
Studies on cold-formed steel building components
Studies on cold-formed steel building components
  • Experimental and numerical studies on lipped channel compression members
  • Experimental and numerical studies on plain channel compression members
  • Experimental studies flexural members
  • Development of self-drilling screw connection
Studies on cold-formed steel building components

Studies on lipped channel axial compression members

Studies on cold-formed steel building components

Studies on lipped channel axial compression members

  • Intermediate length columns   
    • Varying
    • Thickness
    • Flange width
    • Depth of the section                                            
Studies on cold-formed steel building components

Load-deflection behaviour

Studies on cold-formed steel building components

Experimental Set-up

Studies on cold-formed steel building components
Studies on cold-formed steel building components

Distortional buckling FE & Exp

  • Buckling Modes
    • Local buckling (L)
    • Distortional buckling (D)
    • Flexural buckling (F)
    • Torsional buckling (T)
  • Failure Modes:
    • L+T
    • L+F+D
    • L+D+F-T

    Studies on plain channel under eccentric compression loading

  • Under Eccentric loading
  • Varying
    • Depth of the section
    • Eccentricity of loading
    • Towards and away from shear centre
  • Buckling Modes
    • Local buckling (L)
    • Flexural buckling (F)
  • Supports : Fixed-fixed
  • Displacement controlled loading
  • Failure Mode: Combined
    • Local buckling of web
    • Local buckling of flange
Studies on cold-formed steel building components

Experimental Set-up

Studies on cold-formed steel building components

local  buckling

Studies on cold-formed steel building components

local  buckling

Studies on cold-formed steel building components

local  buckling

Distortional buckling of flexural members

  • Lipped channel sections
  • Symmetrical loading at shear-centre is ensured by combined section
  • Simple supports
  • The beam assembly is restrained,  except at constant moment region
  • Buckling Modes
    • Local buckling (L)
    • Distortional buckling (F)
    • Failure: distortional buckling followed by local buckling of the compression flange
Studies on cold-formed steel building components

Experimental Set-up

Studies on cold-formed steel building components

Distortional buckling

Studies on cold-formed steel building components

FEA results

Self-drilling screw joints

  • In India, self-drilling screws are used to connect secondary elements    (Roofing sheets, side cladding, purlins)
  • Literature: Self-drilling screws can  transfer shear efficientlyAttempt has been made to utilize these screws to connect  cold-formed steel beam and column
  • Lap joints have been tested under tensile loading
  • Screw head is in contact with thick sheets
  • Failure modes
    • Bearing
    • Tilting
    • Bearing-tilting
Studies on cold-formed steel building components
Studies on cold-formed steel building components

Novel Pre-Engineered Load-Bearing Steel-Foamed Concrete Composite Panels

Novel Pre-Engineered Load-Bearing Steel-Foamed Concrete Composite Panels

  • For the first time in India, composite panels, a novel building component comprising of outer skins of cold formed steel sheeting with infill light weight cellular foam concrete of density 1250kg/m3 is developed
  • Foam concrete – Uniform distribution of air bubbles throughout the mass of concrete by adding special foam to mortar slurry (cement, sand & fly ash)
  • Improved ductile behaviour after post-peak with controlled lateral deformation of the panels due to steel sheets interconnected with studs
  • Due to their high ductility characteristics (ductility factor – 6), these panels have a huge potential in enhancing seismic performance/retrofit strategies for buildings
  • Alternative to load carrying brick walls and floor/roof slabs in low rise construction

Experimental Studies on Composite Wall and Floor/Roof Panels

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels
Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Axial Compression & Flexural Behaviour of Composite Panel

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Failure of  Composite Wall Panel

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Failure of  Composite Wall Panel

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Failure of  Composite Floor Panel

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Failure of  Composite Floor Panel

LFC Production Process

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

LFC Production machine

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Foam Generator

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Foam Concrete

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Casted Panels

In-Plane Shear Behaviour of Composite Panel

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Static Behaviour

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Cyclic Behaviour

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Cyclic Behaviour

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Cyclic Behaviour

Experimental Studies on Composite Wall – Slab Connection

Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels
Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels
Novel Pre-Engineered Load-Bearing  Steel-Foamed Concrete Composite Panels

Steel Compression Members under Simulated Corrosion and Elevated Temperature Effect

Steel Compression Members under Simulated Corrosion and Elevated Temperature Effect

Steel Compression Members under Simulated Corrosion

  • Experimental studies on corroded coupons
  • Experimental studies on behaviour of steel angle and tubular compression members under simulated corrosion
  • Monitoring corrosion using Fiber Bragg Grating (FBG) sensors
Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Alternate wetting and drying

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Electrochemical corrosion

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Monitoring corrosion using FBG sensors

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Unstressed condition

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Stressed condition

Localised simulation of corrosion in compression members

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Angle

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Tube

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Thickness measurement

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Load vs Axial deflection

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Buckling AUC-1

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Buckling AC-2

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Crippling

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

AC-3

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Methodology to quantify corrosion

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Microstructure analysis

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Crack Formation

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Reference Sample

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Corroded Sample

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Stress vs Strain

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Strain vs Time from FBG sensor under unstressed condition

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Test set up & Instrumentation

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Failure profile

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Load vs Axial deflection

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect
Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Outcomes

  • Microstructure analysis reveals that crack formation in intergranular regions of stressed and corroded samples could be possible reason for strength reduction
  • Loss of thickness due to corrosion leads to reduction in resistance area, producing a decreasing effect in structural performance in terms of strength
  • FBG sensors can be used to measure strain due to corrosion
Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Steel Compression Members under Elevated Temperature Effect

Simulation of elevated temperature effect

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Bulging outward

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Reference

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Sample

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Sample subjected

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

elevated temperature

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Temperature distribution  at salient points

Steel Compression Members under Simulated Corrosion  and Elevated Temperature Effect

Axial Load  vs  Axial Displacement

Microstructure analysis reveals that under elevated  temperature, grain size increased from 15μm to 30μm

Strength reduction of 37%, under elevated temperature of 600oC  sustained for a duration of 30 minutes

Seismic Performance Evaluation of Model of G+7 CRC Framed Structure

Seismic Performance Evaluation of Model of G+7 CRC Framed Structure

  • Analysis of the G+7 CRC framed structure for the seismic load as per IS code
  • To evaluate the seismic performance of model of a G+7 framed structure for a ground motion compatible to Zone-V spectrum
  • Study of the damage pattern and suggestion for improvement

    Bottom 4 storey square box section
    Top three storey lipped channel section
    Beam- lipped channel sections
    Bracings – plain channel sections
    Design checking : IS 801-draft

    First ever test in India of this magnitude carried out successfully on a shake table for cold rolled steel framed structure

Seismic Performance Evaluation of Model of  G+7 CRC Framed Structure

Scaled model of G+7 storey structure

Shake table testing

Peak ground accelerations (PGA) corresponding to Zones II, III, IV and V as per IS:1893-2002 code for soft soil conditions

The input time history in terms of accelerations and displacements corresponding to 0.08g, 0.16g, 0.24g and 0.36g

Seismic Performance Evaluation of Model of  G+7 CRC Framed Structure

Input time history for 0.36g

Seismic Performance Evaluation of Model of  G+7 CRC Framed Structure

Spectrum corresponding to soft soil conditions

Seismic Performance Evaluation of Model of  G+7 CRC Framed Structure

Spectrum corresponding to soft soil conditions

Seismic Performance Evaluation of Model of  G+7 CRC Framed Structure

Displacement response at top for 0.36g

Seismic Performance Evaluation of Model of  G+7 CRC Framed Structure

Acceleration response at top for 0.36g

Demonstrated that the overall performance of the scaled model is satisfactory

Response spectrum analysis

Dead and live load – IS:875 Part 1 &2

Seismic load – IS:1893-2002

Zone factor (Z) =0.36 for Zone V Importance factor (I) = 2

Response reduction factor for cold-formed steel building (R) = 2.5

Seismic Performance Evaluation of Model of  G+7 CRC Framed Structure

FE model and Lateral displacement of G+7 storey frame

Seismic Performance Evaluation of Model of  G+7 CRC Framed Structure

FE model and Lateral displacement of G+7 storey frame

Seismic Performance Evaluation of Model of  G+7 CRC Framed Structure

Finished building within 48 hrs at Mohali