Insert Presentation Photo Insert Presentation Photo Insert Presentation Photo Insert Conference Logo Advanced Modeling of Blast Response of Reinforced Concrete Walls with and without FRP Retrofit TAREK H. KEWAISY PhD, PE, PMP, BSCP Principal Associate [email protected]AHMED A. KHALIL PhD, PE Senior Structural Consultant [email protected]3/28/2018 Session on: FRP Design Methodology and Applications for Blast and Impact-Resistant Structures Sponsored By: ACI Committee 370 and 440 AYMAN ELFOULY PE Senior Structural Engineer [email protected]
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Advanced Modeling of Blast
Response of Reinforced Concrete
Walls with and without FRP Retrofit TAREK H. KEWAISY PhD, PE, PMP, BSCP
Applied Element Method (AEM) in Extreme Loading for Structures (ELS)
Implemented in ELS software
The continuum is discretized into Elements connected together with Nonlinear Springs.
The springs represent Material behavior, Axial and Shear Deformations.
Advanced Modeling of Blast Response of Reinforced Concrete Walls
with and without FRP Retrofit
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Element 1Element 1 Element 2Element 2
Element 1Element 1Element 1Element 1 Element 1Element 1
Normal SpringsNormal Springs Shear Springs Shear Springs xx -- zz Shear Springs Shear Springs yy-- zz
x
YZ Reinforcing bar
Applied Element Method (AEM) in Extreme Loading for Structures (ELS)Extreme Loading Software (ELS) - Reinforcing bars springs
Advanced Modeling of Blast Response of Reinforced Concrete Walls
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Applied Element Method (AEM) vsFinite Element Method (FEM)
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Tension CompressionFully path-dependent model for concrete(Okamura and Maekawa, 1991)
Applied Element Method (AEM: Constitutive Material ModelsAEM - Nonlinear Material Models
Advanced Modeling of Blast Response of Reinforced Concrete Walls
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Sheart model for concrete
Applied Element Method (AEM: Constitutive Material ModelsAEM - Nonlinear Material Models
Advanced Modeling of Blast Response of Reinforced Concrete Walls
with and without FRP Retrofit
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AEM/ ELS Validated Case:Testing of FRP Retrofitted Concrete Beam
Advanced Modeling of Blast Response of Reinforced Concrete Walls
with and without FRP Retrofit
ELS Model
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AEM/ ELS Validated Case:Testing of FRP Retrofitted Concrete Beam
Advanced Modeling of Blast Response of Reinforced Concrete Walls
with and without FRP Retrofit
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AEM/ ELS Model
Advanced Modeling of Blast Response of Reinforced Concrete Walls
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Single Degree Of Freedom (SDOF)
Advanced Modeling of Blast Response of Reinforced Concrete Walls
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SBEDS
• Developed by BakerRisk/PEC/ B&V and Distributed by USACE PDC
• SDOF Approach
• Various Structural Components of Different Materials Including RC and RC w/FRP Components
• Hysteretic Response
• Time History Loading
• P-I Option
• Industry Standard ATFPDesign Tool
3/28/2018Advanced Modeling of Blast Response of Reinforced Concrete Walls
with and without FRP Retrofit27
SBEDS determines component SDOF properties, dynamic flexural response, and support shears and reactions using accepted
engineering methodologies. The user is responsible for properly interpreting SBEDS results and ensuring members satisfy applicable
design requirements for response limits and shear strength. The user is also responsible for design of component connections and
attachments that satisfy applicable design requirements including application of appropriate load factors and strength
reduction/resistance/safety factors.
Single degree of freedom Blast Effects Design Spreadsheet
Version 5.1 1-June-2015
SBEDS is an engineering tool intended for users experienced in structural engineering, dynamics, and blast design. SBEDS is a
product of the U.S. Army Corps of Engineers (USACE). This software was developed primarily for antiterrorism design. It may
also be used for other types of blast design if appropriate blast load input, dynamic material properties, and response limits are used,
which may vary from default values in SBEDS, and its use is approved by the design team and governing authority. The USACE
Protective Design Center (PDC) contracted with several consulting engineering companies for the development of this software.
By using the software you are agreeing to the terms and conditions stated below. Please read the terms below carefully; if you do
not agree, do NOT use the software.
US Army Corps
of Engineers US Army Corps
of Engineers
Building: Component: By: Date:
qmax = 1.51 deg.
m = 1.60 Vmax = 25.97 psi
Xmax = 0.69 in at time = 10.30 msec
Xmin = 0.00 in at time = 0.00 msec
Rmax = 52.69 psi at time = 10.30 msec Fiber 0.80 1/sec
Rmin = -6.62 psi at time = 63.20 msec Concrete 0.36 1/sec
Note: See General Items section of User's Guide for information on max imum time of calculated response. *Per Section 4.3 of UFC 3-340-02. Note:Based on max .response (instead of y ield) w hen ductility ratio<1.0
75% of Balanced Steel Reinforcement Ratio, 0.75rb: 0.017
Avg Cover Depth (inbound,rebound) 0.00 2.94 in 4,534.3 lb/in
Moment of Inertia, Icr_i: 3 in4/in 673.4 lb/in
Direct Shear at support:(See Note 6)
Check Shear Results, Provide Required Stirrups or Set Shear Flag >0 in Cell H45 and ReRun SDOF for Shear Controlled Response Stirrup Area per unit spacing, Avs,Required in Max Shear Region (2)
(Shear Flag =1 for Controlling Shear at Support, =2 for Controlling Shear at distance d from Support) For critical section @ support per unit spacing (s), Avs,req_s; 0.0000 in2/in2
Notes: For critical section at d per unit spacing (s), Avs,req_d; 0.0051 in2/in2
1 Used for clearing of reflected load Notes for Shear Information:2 Angle in degrees from normal3 This capacity assumes wall has positive lateral support at top and bottom, such as dowels or bearing angle. (2) Multiply Avs values by flexural bar spacing and stirrup spacing to get stirrup area
4 Shear controlled response typically has very limited ductility - a maximum value of 1 is assumed in SBEDS. The user should clearly understand shear-controlled response when using the shear flag - see User's Guide.5 Axial load per unit width on analyzed component from saved Dynamic Shear History file for
supported component. Dynamic axial load includes static gravity load of supported horizontal member.6 For internal loading, user must typically check if stirrups needed at support (SBEDS does not check this)7 Moment capacities controlled by tension strength fiber or compression crushing strain of concrete - see User's Guide.8 Response criteria is specific for FRP reinforced walls.IF there is no FRP on the loaded side of wall, the USER MUST
check that the rebound response meets the selected Response Criteria for reinforced concrete components using
the "See all COE Response Criteria for AT/FP" button.
(1) Based on larger of inbound and rebound maximum flexural resistance
Diagonal Shear Capacity: Vc,diag =
Error/Warning Messages Results
Check Shear Capacity<Flexural Capacity,SDOF Results Based on Flexural Capacity(See Message in Yellow Cells Below) Shear is OK
Diagonal Shear at distance d from support: Stirrups Required
Peak Reactions from Flexural Response at Rmax
Vu at support A =
Vu at support B =
Maximum Vu at distance d from support =
Shear Capacity (See Note 3)
Direct Shear Capacity, (monolithic joint) Vc,direct =
Xmin Rebound =
Rmax =
Rmin =
Shortest Yield Line Distance to Determine q:
Equivalent Static Reactions (1)
FRP Response Criteria is checked only for Inbound Response, See Note 8
Results Summary
VLLOP/Primary
Response DOES NOT MEET input design criteria
Xmax Inbound =
Response Criteria
0
m
1
Calculated Properties (Note 7)
N/A
N/A
N/A
Load Files-AXIAL(abov e),BLAST(below )
N/A
blast load.tx t
N/A
Blast Load Phase
N/A
Blast Load Orientation
N/A
Parameters for Reflected Loads
Charge Weight (W) and Standoff (R)
Explosive Type SDOF Properties
N/A Property
R (ft)
Max Recommended Time Step
Pressure-Time Input
Pressure (psi)
N/A
Solution Control
Pressure-time history file R constant =
Flexural Response Gravity Displacement
Structural & Material Properties None (vertical component)