ductile detailing
DESCRIPTION
deatiling of structures is 13920TRANSCRIPT
Fire Testing of an Earthquake Damaged R.C. Frame
Presented by: U.K. Sharma/Pradeep Bhargava
Under UKIERI Project being Jointly Investigated by:
Indian Institute of Technology Roorkee
University of Edinburgh, U.K.
Indian Institute of Science Bangalore
INTRODUCTION
Major earthquakes have been followed by multiple ignitions
• San Francisco, 1906
• Tokyo, 1923
• San Fernando, 1971
• Northridge, 1994
• Hanshin (Kobe), 1995
• Izmit (crude and naptha tanks), 1999
Fire Following Earthquake
• Due to rapid urbanisation, there is an increasing risk of Fire Following Earthquake (F.F.E.) events.
• FFE events have added a new dimension to disaster management and call for substantial research effort to address the relevant challenges .
• The collaborative research project between the University of Edinburgh, Indian Institute of Technology Roorkee and the Indian Institute of Science Bangalore proposes to conduct large-scale tests to investigate the behaviour of (earthquake-induced) pre-damaged R.C. frames in fire.
Simulated seismic damage
Fire loading Aftermath
1 Displacement beyond peak lateral force
900oC -1000oC* Residual lateral capacity test*
2 None 900oC -1000oC for 1 hr Residual lateral capacity test
3 Moderate (30% of the displacement corresponding to peak lateral force)†
900oC -1000oC for 1 hr Residual lateral capacity test
4 Severe (70% of the displacement corresponding to peak lateral force)†
900oC -1000oC for 1 hr Residual lateral capacity test
Summary of the proposed frame tests
*for as long as considered safe (maximum 1 hr) †applied incrementally and cyclically
3000 3000 3000 3000
3000
3000
3000
4000
4000
PO R T IO N O FBU ILD IN G
C O N SID ER ED
P LA N O F B U ILD IN G[4 S TO R E Y (G + 3)]
3000 3000 3000 3000
3000
3000
3000
E LE V A T IO N
3000
PO R T IO N O FBU ILD IN G
C O N SID ER ED
4500
4000
Plan and elevation of the frame sub-assemblage proposed to be tested
3000 3000 3000 3000
3000
3000
3000
4000
4000
PO R T IO N O FBU ILD IN G
C O N SID ER ED
P LA N O F B U ILD IN G[4 S TO R E Y (G + 3)]
3000 3000 3000 3000
3000
3000
3000
E LE V A TIO N30
00
PO R T IO N O FBU ILD IN G
C O N SID ER ED
4500
4000
Detailing of the frame sub-assemblage
230
C O L. 300 X 300
L-SECTION OF BEAM (230 X 230)
C O L. 300 X 300
3 -16
2
2
8-2 Legged S tirrups@ 100 m m c /cth roughou t
SECTION 2-2
8-2 Legged S tirrups@ 100 m m c /cth roughou t
120
230
3-16
3-16
18025 25
Detailing of a typical beam
1500
3000
800
300
500
75
150
230
500
8 bo lts32
150 20 @ 100c/c
bothways
Extended (1200 m m )in ra ft foundation
10-3 LeggedStr. @ 75 m m c/c
10-3 LeggedStr. @ 75 m m c/c
10-2 LeggedStr. @ 150 m m c/c
10-2 LeggedStr. @ 150 m m c/c
10-3 LeggedStr. @ 75 m m c/c
10-2 LeggedStr. @ 150 m m c/c
10-3 LeggedStr. @ 75 m m c/c
10-2 LeggedStr. @ 150 m m c/c
500
500
230
AA AA
BB
40 220 40
300
8 -2010-2 LeggedStirrups @150 m m c/c
40220
40
300
8 -2010-3 LeggedStirrups@ 75 m m c/c
SECTION A-A
SECTION B-B
300
300
150 800 150
FOOTING PLAN
REINFORCEMENT OF COLUMN (300 X 300)
8 Bolts o f 32Extended inR aft Foundation
1100
8-20 1100
250 250
Detailing of the column and footing
PLAN SHOW INGBOTTOM REIN. OF SLAB (120 THICK)
PLAN SHOW INGTOP REIN. OF SLAB (120 THICK)
230
120
900 900
750750
8 @500 c/c
8 @250 c/c
8 @500 c/c
500 500
8 @250 c/c
8 @ 250 c /cB o thw ays
8 @ 250c/cbothways
8 @ 250c/cbothways
SECTION THROUGH SLAB
Detailing of the slab
F
Brick masonry infill 115 thick
3000 c/c both ways
All Columns- 300x300 mm
Fire compartment
All Beams-230x230
4300 both ways
Beam
Column
Framing plan of the frame sub-assemblage
120 thickslab
Test set-up configuration
3000
1500
1300
R aft top R aft top
500
Ventilationopening
Fire level/Topof beam
Typical colum n,300 x 300
Plinth beam ,230 x 230
Footing,1100 x 1100 x 500
B ricked box con ta ine r filledw ith sand w ith fue l tray on top
(leve l w ith the top o f beam )
Roof slab120 thk
Roof beam230 x 230
Steel fram ingsystem
Sim ulated gravityloading of 2nd and 3rdabove floor
Superim posed live loadon floor 1
Extendedcolum n
Reactionwall
4300
5000
Hydraulicjack
Therm ocouples at fivedifferent elevation levelsin three plan locations offire com partm ent
Brick masonry infill wall in perimeter
Nominal location of thermo-couples and strain gauges
INSTRUMENTATION
Plinth beam230 x 230
Steel rebars
Typical colum n300 x 300
Roof beam230 x 230
30
00
4000
3300
3000
1 5
1 2
3 4
6 10 11 155 6
7 8
31 35
9 10
36 40
11 12
41 45
1817
2016
1615
2521
1413
3026
5046 5551 6056
Legend :
: Therm ocouple = 180 : Strain gauge = 72
Total
Nominal location of L.V.D.T.’s
4000
4000
Typical colum n300 x 300
Roof beam230 x 230
Legend :
Total LVDT = 13(PLAN VIEW )
NOMINAL LOCATION OF LVDT
LVD T
Nominal location of thermocouples and strain gauges in the slab
Analytical modeling of the frame sub-assemblage
• The sub-assemblage was designed as part of a 4-storey moment resistant R.C frame located in seismic zone IV of IS 1893 (Part 1):2002. Ductile detailing was carried out as per IS 13920.
(a) (b)
Detailing of a typical beam, (a), and a column, (b).
• When calibrated against the Eurocode 8, the design was found to be sufficiently ductile. However, a plastic analysis of the sub-assemblage indicated that the first hinge formed in a column instead of a beam
Finite element model of the frame sub-assemblage showing hinging in columns
Col. bars=8-12ø
Beam bars=2-12ø+3-16øat top and bottom
Col. bars=8-20ø
Beam bars=3-16øat top and bottom
Plastification atjoint
Beam hinging
The modification of detailing in the beams and columns resulted in a more Desirable pattern of hinging
Analytical load-displacement relationships
(a) SAP frame model (b) ABAQUS finite element model
Comparison of the predicted load-displacement relationships for the frame sub-assemblage from SAP and ABAQUS
Mock Fire Tests
Front elevation of the fire compartment for the mock tests
Thermocouple tree
Fuel tray
Post flash-over phase of the compartment fire
Time (Minutes)
0 5 10 15 20 25
Tem
pera
ture
(°C
)
0
200
400
600
800
1000
1200
1400
TC at 20 cm TC at 90 cm TC at 160 cm TC at 230 cm
Time-temperature relationships for the fire compartment near the centre of the back wall and opposite to the opening
Strong floor – reaction wall system
Detailing of rebars in the strong floor, dowels for the footing can also be seen
Freshly cast concrete in the strong floor, dowels for the orthogonal reaction walls can be seen in the background
Erection of the reinforcement cage for the reaction wall. Pipe sleeves for anchoring the loading jacks can also be seen
The quasi-static loads shall be applied with a pair of these 500 kN capacity double acting hydraulic jacks
Target displacement
Time
Earthquake loading simulation
Proposed (quasi-static) loading history for the frame sub-assemblage
OpenSees analysis of cyclic loading (plotted for 1 column)
Maximum base shear plot from OpenSees analyses
Another Aim of the Project: Stress-Strain Models for Pre-Damaged Materials
•Stressed Tests• Unstressed Tests• Residual Tests
Stress – strain relationships for concrete at elevated temperature
Structural Modelling Round-robinExercise
• The challenge: – To model blind the behaviour of a concrete
structure during fire following earthquake• Aiming to
– Identify strengths and weaknesses of modelling capabilities
• If interested contact Martin Gillie: – [email protected]– www.see.ed.ac.uk/~s0458490/UKIERI/
Predictions
• Horizontal and vertical deflections during the earthquake loading
• Temperature of the rebar during heating and cooling
• Horizontal and vertical deflections during heating and cooling
Dates
• Competition announced June 2010• Structural data on website Summer 2010• Date of test Late Summer 2010• Confirmation of required predictions Day
after test• Submission of predictions 1 March 2011• Results conference Spring 2011
THANK YOU