Uploaded bycastigadordekill
PDF, PPTX465 views

Shear wall design - muros de corte Etabs

The document discusses modeling and analysis of shear walls. It describes various modeling techniques including frame models using beam-column elements, plate/shell element models, and truss models. Truss models approximate shear wall behavior using vertical elements for axial/flexural resistance and diagonal elements for shear resistance. The document compares deformation, stresses, and forces from shell and truss models. It also provides guidance on constructing initial truss models for shear wall analysis.

Embed presentation

Download as PDF, PPTX
Buddhi S. Sharma ACECO MS, AIT Design of Shear Walls Using ETABS O-SCAAD-1 May 21, 2002, AIT, Bangkok
ACECOMS, AIT Design of Shear Walls The Basic Issues • What is a Shear Wall? • Modeling and analysis issues – Transfer of loads to shear walls – Modeling of shear walls in 2D – Modeling of shear Walls in 3D – Interaction of shear-walls with frames • Design and detaining issues – Determination of rebars for flexure – Determination of rebars for shear – Detailing of rebars near openings and corners – Design and detailing of connection between various components of cellular shear walls
Shear Wall Definition
ACECOMS, AIT Design of Shear Walls What is a Shear Wall? • How can we “tell” when a member is a shear wall • Is the definition based on? – Intended Use – Shape in Cross-section – Geometry in Elevation – Loading Type and Intensity – Behavior and Theory – Location, Direction, Orientation
ACECOMS, AIT Design of Shear Walls Shear Wall or Column Wall Column
ACECOMS, AIT Design of Shear Walls Shear Wall or Frame Shear Wall Frame Shear Wall or Frame ?
ACECOMS, AIT Design of Shear Walls Shear Wall or Truss?
ACECOMS, AIT Design of Shear Walls Planner Walls Planer Stiffened Regular Openings Irregular Openings
ACECOMS, AIT Design of Shear Walls Cellular Walls
Location and Layout of Shear Walls
ACECOMS, AIT Design of Shear Walls Purpose of Shear Walls • Resist the lateral loads for medium rise buildings up to 40 floors – Reduce total deflection and story drift – Increase lateral stiffness – Reduce moments in columns and floor members due to lateral loads – Reduce the overall cost of the structural system – Can also serve as elevator shafts, service ducts, etc,
ACECOMS, AIT Design of Shear Walls Loads Transferred to Shear Walls • Distribution of lateral loads to individual shear walls, to moment resisting frames, to wall-frames and to individual columns depends on: – Stiffness of each column and wall – Lateral stiffness of each frame or wall frame – Location of the the vertical unit with respect to the load building lateral stiffness center – Location of the load center with respect to the stiffness center – The geometry and in-plane stiffness of the floor slab system
ACECOMS, AIT Design of Shear Walls Load Transferred to Shear Walls f Building Plan D F Stiffness Center Load Center ? ?
ACECOMS, AIT Design of Shear Walls How to Locate the Walls • Reduce the eccentricity between the stiffness center and the load center – Consider Eccentricity due to Wind Loads, depending on overall geometry of the structure – Consider Eccentricity due to Earthquake Loads, depending on Mass Distribution – Consider Eccentricity not only at foundation level but at various heights • Reduce the in-plane bending in the slab system and Evenly distribute the stiffness in both directions • Use building layout in plan to enhance overall stiffness and reduce need for shear walls
ACECOMS, AIT Design of Shear Walls How to Check Eccentricity! • For Wind Loads – Apply Wind load in X-Direction and check nodal displacements. If displacement in Y-Directions are nearly zero or very small, then there is no eccentricity between wind load and and stiffness center in Y-direction – Repeat the same for Y-Direction Load • Seismic Loads – Assign the Mass properties to the building and carryout a Modal Analysis: If the first two modes are Translational, and third mode is Torsional, then there is no eccentricity between the mass center and Stiffness Center in Both Directions
ACECOMS, AIT Design of Shear Walls Eccentric and Concentric Response F No Eccentricity D F Eccentric Shear Wall
ACECOMS, AIT Design of Shear Walls Eccentric and Concentric Response Mode-1 Mode-2 Mode-3 Symmetrical Mass and Stiffness Unsymmetrical Mass and Stiffness
ACECOMS, AIT Design of Shear Walls Avoid Eccentricity in Plan Or
ACECOMS, AIT Design of Shear Walls Reduce In-plane Bending in Floor
ACECOMS, AIT Design of Shear Walls Vertical Irregularity Expansion Joint Balanced Shear Walls at All Levels No Shear Walls Using Expansion Joints to eliminate some walls
ACECOMS, AIT Design of Shear Walls Using Efficient Building Plan Shape
Shear Wall Behavior
ACECOMS, AIT Design of Shear Walls Shear Wall and Frame Behavior Shear Wall Behavior Frame Behavior
ACECOMS, AIT Design of Shear Walls 2 5 10 Axial Stresses in Planer Walls
ACECOMS, AIT Design of Shear Walls 2 5 10 Axial Stresses in Cellular Walls Uniaxial Bending
ACECOMS, AIT Design of Shear Walls 2 5 10 Axial Stresses in Cellular Walls Biaxial Bending
Modeling of Shear Walls
ACECOMS, AIT Design of Shear Walls Modeling of Planer Walls Using Beam and Column Using Panels, Plates and Beams Using Truss
ACECOMS, AIT Design of Shear Walls Modeling of Shear Walls Using Beam Elements
ACECOMS, AIT Design of Shear Walls Frame Models for Shear Walls – 4-Node plane element does not accurately capture the linear bending, because constant shear distribution is assumed in formulation but actually shear stress distribution is parabolic – Since the basic philosophy of RC design is based on cracked sections, it is not possible to use the finite elements results directly for design – Very simple model (beam-column) which accurately captures the behavior of the structure, and the results can be used directly to design the concrete elements
ACECOMS, AIT Design of Shear Walls Modeling of Walls using 1D Elements L t x h L t H2 H1 Simple beam elements L t Beam elements with rigid ends Beam elements in “Truss Model”
ACECOMS, AIT Design of Shear Walls Frame Model for Planer Walls Rigid Zones • Specially Suitable when H/B is more than 5 • The shear wall is represented by a column of section “B x t” • The beam up to the edge of the wall is modeled as normal beam • The “column” is connected to beam by rigid zones or very large cross-section B H t
ACECOMS, AIT Design of Shear Walls Frame Models for Cellular Walls • Difficult to extend the concept to Non-planer walls • Core Wall must be converted to “equivalent” column and appropriate “rigid” elements • Can be used in 2D analysis but more complicated for 3D analysis • After the core wall is converted to planer wall, the simplified procedure cab used for modeling B H t B H 2t t
ACECOMS, AIT Design of Shear Walls Modeling of Shear Walls Using Plate/Shell Elements 1 2 3 U1, R1 Node 3 U3, R3 U2, R2 U1, R1 Node 1 U3, R3 U2, R2 U1, R1 Node 4 U3, R3 U2, R2 U1, R1 Node 2 U3, R3 U2, R2 Shell
ACECOMS, AIT Design of Shear Walls Modeling Walls using 2D Elements • Walls are subjected to in-plane deformations so 2D elements that have transnational DOF need to be used • A coarse mesh can be used to capture the overall stiffness and deformation of the wall • A fine mesh should be used to capture in-plane bending or curvature • General Shell Element or Membrane Elements can be used to model Shear Walls
ACECOMS, AIT Design of Shear Walls Modeling Walls Using Membrane Nodes: 4 DOFs: 2 (or 3) DOFs /Node Ux and Uy 2-Translation, 0 or 1 rotation Dimension: 2 dimension element Shape: Regular / Irregular Properties: Modulus of Elasticity(E), Poisson ratio(v), Thickness( t )
ACECOMS, AIT Design of Shear Walls Modeling Walls using Shell Elements Nodes: 4 DOFs: 5 or 6 DOFs /Node Ux and Uy 3 Translation, 2 or 3 rotation Dimension: 2 dimension element Shape: Regular / Irregular Properties: Modulus of Elasticity(E), Poisson ratio(v), Thickness( t ) 1 2 3 U1, R1 Node 3 U3, R3 U2, R2 U1, R1 Node 1 U3, R3 U2, R2 U1, R1 Node 4 U3, R3 U2, R2 U1, R1 Node 2 U3, R3 U2, R2 Shell
ACECOMS, AIT Design of Shear Walls Using Panel/ Plate Elements Modeling Shear-Walls using Panels only (No Moment continuity with Beams and Columns unless 6 DOF Shell is used) Modeling Shear-Walls using Panels, Beams, Columns (Full Moment continuity with Beams and Columns is restored by using additional beams)
ACECOMS, AIT Design of Shear Walls Using Plates to Model Walls Multiple elements greater accuracy in determination of stress distribution and allow easy modeling of openings Using Plate Elements only (No Moment continuity with Beams and Columns unless 6 DOF Shell is used) Using Plate Elements with Beams, Columns (Full Moment continuity with Beams and Columns)
ACECOMS, AIT Design of Shear Walls Connecting Walls to Slab In general the mesh in the slab should match with mesh in the wall to establish connection Some software automatically establishes connectivity by using constraints or “Zipper” elements “Zipper”
ACECOMS, AIT Design of Shear Walls Modeling of Shear Walls Using Truss Models C t B t x 2t t x t
ACECOMS, AIT Design of Shear Walls Using Trusses to Model Shear Walls • The behavior of shear walls can be closely approximated by truss models: – The vertical elements provide the axial-flexural resistance – The diagonal elements provide the shear resistance • Truss models are derived from the “strut-tie” concepts • This model represents the “cracked” state of the wall where all tension is taken by ties and compression by concrete
ACECOMS, AIT Design of Shear Walls 2 5 10 Truss Model for Shear Walls Comparing Deformation and Deflections of Shell Model with Truss Model
ACECOMS, AIT Design of Shear Walls Truss Model for Shear Walls 2 5 10 Comparing Deformation and Deflections of Shell Model with Truss Model
ACECOMS, AIT Design of Shear Walls 2 5 10 Truss Models for Shear Walls Comparing Axial Stress and Axial Force Patterns
ACECOMS, AIT Design of Shear Walls 2 5 10 Truss Models for Shear Walls Uniaxial Biaxial
ACECOMS, AIT Design of Shear Walls How to Construct Truss Models • For the purpose of analysis, assume the main truss layout based on wall width and floor levels • Initial member sizes can be estimated as t x 2t for main axial members and t x t for diagonal members • Use frame elements to model the truss. It is not necessary to use truss elements • Generally single diagonal is sufficient for modeling but double diagonal may be used for easier interpretation of results • The floor beams and slabs can be connected directly to truss elements C t B t x 2t t x t
ACECOMS, AIT Design of Shear Walls Modeling of Shear Walls Openings in Shear Walls
ACECOMS, AIT Design of Shear Walls Very Large Openings may convert the Wall to Frame Very Small Openings may not alter wall behavior Openings in Shear Walls Medium Openings may convert shear wall to Pier and Spandrel System Pier Pier Spandrel Column Beam Wall
ACECOMS, AIT Design of Shear Walls Openings in Shear Walls - Cellular 2 5
ACECOMS, AIT Design of Shear Walls Openings in Shear Walls - Planer
ACECOMS, AIT Design of Shear Walls Modeling Walls with Opening Plate-Shell Model Rigid Frame Model Truss Model
ACECOMS, AIT Design of Shear Walls Frame Model of Shear Walls 3 DOF per rigid zone Rigid Zones Beams Columns A: Shear Wall with Line Loads B: Finite Element Model C: Define Beams & Columns D: Beam-Column Model Based on Concept proposed by E.L. Wilson
Design of Shear Walls
ACECOMS, AIT Design of Shear Walls Basic Design Considerations • Main Shear Wall – Flexural Design – Shear Design • Spandrels and Links – Flexural Design – Shear Design • Ductility Considerations • Anchorage with Footings • Connection with Floor Slab/ Beams
ACECOMS, AIT Design of Shear Walls Flexural Design
ACECOMS, AIT Design of Shear Walls Flexural Design As Single Flexural Member
ACECOMS, AIT Design of Shear Walls Designing as A Flexural Member • Approach – Design the Wall as “Big Column” – Follow the normal axial-flexural concept and provisions • Input Needed – P, Mx , (and My) – Wall Dimensions • Problems – Does not consider the non-linear strain distribution – In efficient rebar distribution
ACECOMS, AIT Design of Shear Walls Design Procedure 1. Obtain Design Actions from Analysis 2. Assume rebar sizes, amount and distribution 3. Determine Cross-section capacity as column in form of Interaction Surfaces and Curves 4. Check if all action sets (P, Mx, My) fall within the interaction surface. The extreme values should be near the surface 5. If required, revise cross-section and repeat
ACECOMS, AIT Design of Shear Walls Getting Result from Frame Model Design actions (P, Mx, My and V) are obtained directly Vx Vy P Mx My V P M
ACECOMS, AIT Design of Shear Walls Getting Results from Truss Model C T D Tension Member Compression Member V P M ) cos( ) sin( ) sin(    D V x D Cx Tx M D C T P d c t        xc xt xd
ACECOMS, AIT Design of Shear Walls Getting Results From Shell Model f1, f2, …..fn are the nodal stresses at section A-A , obtained from analysis CL of wall A A           n i i i i n i i n i i i i i v A V x F M F P f A F 1 1 1 f1 f2 f3 f4 f5 C T 1 x x1 t V P M
ACECOMS, AIT Design of Shear Walls Assuming Reinforcement • Assume larger bars on the corners • Assume more bars on predominant tension direction/ location • Assume uniform reinforcement on wall sides • Total Rebars ratio should preferably be more than 0.8% and less than 3% for economical design
ACECOMS, AIT Design of Shear Walls Obtaining Section Capacity Curves • Can be done manually by using linear strain distribution and equilibrium conditions – Generate few control points on the curve – Difficult to apply for Cellular and non rectangular walls • Can be obtained in more complete form using Software – CSI-Section Builder – GEAR – Column Section Module – PCA Column
ACECOMS, AIT Design of Shear Walls Interaction Curves - Uniaxial The curve is generated by varying the neutral axis depth                       zi N i si z A c ny N i si A c nx d A f dz da f M A f da f N si b si b 1 1 . ) ( ) (     Safe Un-safe
ACECOMS, AIT Design of Shear Walls Interaction Surface - Biaxial The surface is generated by changing Angle and Depth of Neutral Axis + Mz - My +P + My - Mz Pu A cross-section of interaction surface at P u Safe Un-safe                                                 ... ) , ( 1 ... . , 1 ... ) , ( 1 ... . , 1 ... ) , ( 1 ... , 1 1 2 1 3 1 2 1 2 1 2 1 1 i n i i i x y y i n i i i x y x x y n i i i z x y x A x dy dx y x M y y x A y dy dx y x M y x A dy dx y x N               
ACECOMS, AIT Design of Shear Walls Interaction Surface and Curves
ACECOMS, AIT Design of Shear Walls Narrow Planner Walls The capacity is almost completely un- axial Moment capacity can be increased by providing Rebars at the corners
ACECOMS, AIT Design of Shear Walls Cellular Wall – No Opening The capacity is almost completely biaxial
ACECOMS, AIT Design of Shear Walls Single Cell Walls
ACECOMS, AIT Design of Shear Walls Double Cell Walls
ACECOMS, AIT Design of Shear Walls Flexural Design Using Axial Zones
ACECOMS, AIT Design of Shear Walls Design Walls in Zones • Basic Concept – Design the wall to resist the external actions by compression, tension and shear zones – More intuitive and more economical – Zone of high tension designed as tension member with concentrated rebars – Zone of high compression designed as compression member with appropriate rebar limits – Zone of low stress design as wall with nominal wall rebars
ACECOMS, AIT Design of Shear Walls Designing as Axial Zones
ACECOMS, AIT Design of Shear Walls Design Procedure 1. Obtain Design Actions from Analysis 2. Compute Axial Forces 3. For each axial force, assume section, assume rebars and check capacity 4. If capacity not enough, revise section, re- compute Axial Forces, and continue until required section for each force is designed 5. Provide nominal wall reinforcement in between the axial zones
ACECOMS, AIT Design of Shear Walls Getting Result from Frame Model Compute Forces from Actions P Mx My P M 2 2 1 1 / 5 . 0 / 5 . 0 x M P F x M P F     i y i x i x M y M P F    4 x1 x2 yi F1 F2 Fi
ACECOMS, AIT Design of Shear Walls Getting Results from Truss Model C T D Tension Member Compression Member xc xt xd Results obtained from truss analysis can be used Directly F1 = T F2 = C
ACECOMS, AIT Design of Shear Walls Getting Results From Shell Model f1, f2, …..fn are the nodal stresses at section A-A , obtained from analysis CL of wall A A i i i i i f A F t x A   f1 f2 f3 f4 f5 C T 1 x x1 t F1=T F2=C
ACECOMS, AIT Design of Shear Walls Axial Zone Model – Planer Wall
ACECOMS, AIT Design of Shear Walls Axial Zones for Box Wall
ACECOMS, AIT Design of Shear Walls Design as Truss: Strut and Tie • Directly design the tension members for reinforcement • Directly design the compression members as columns • The design is similar to the “Axial Zones” concept
ACECOMS, AIT Design of Shear Walls Concrete Shear Wall Design in ETABS • 2D wall pier design and boundary-member checks • 2D wall spandrel design • 3D wall pier check for provided reinforcement • Graphical Section Designer for concrete rebar location • Graphical display of reinforcement and stress ratios • Interactive design and review • Summary and detailed reports including database formats
ACECOMS, AIT Design of Shear Walls Shear Design Spandrel Pier
ACECOMS, AIT Design of Shear Walls Shear Design Procedure • For Walls without Openings – Design the wall as piers • For Walls with Openings – Design the Piers, the vertical part – Design the Spandrels, the horizontal part
ACECOMS, AIT Design of Shear Walls Shear Design of Pier • Determine Concrete shear capacity, Vc • Check if Vc exceeds the limit, if it does, section needs to be revised • Determine steel Rebars for Vs=V-Vc • Check additional steel for seismic requirements p L p t
ACECOMS, AIT Design of Shear Walls ACI Equations for Pier Design     p p u p p c LW c L L . P L . t f R . V 4 8 0 8 0 3 3      p p p u u p p u c LW p c LW c L . t L V M Abs t L P . f R . L f R . V 8 0 2 2 0 25 1 6 0                                         p ys c u v L . f V V Abs A 8 0        p p c LW u L . t f R V Abs 8 0 10    Basic Concrete Shear Capacity Concrete not to Exceed the limit Area of Steel Computed as
ACECOMS, AIT Design of Shear Walls Shear Design for Spandrel top r d  bot r d  a c s h s t s h s L Elevation Section • Determine Concrete shear capacity, Vc • Check if Vc exceeds the limit, if it does, section needs to be revised • Determine steel Rebars for Vs=V-Vc • Check additional steel for seismic requirements
ACECOMS, AIT Design of Shear Walls ACI Equations for Spandrel Design s s c LW c d t f R V   2 c u c n s V V V V V      s s c LW s d t f R V   8 s ys s v d f V A  Basic Concrete Shear Capacity Concrete not to Exceed the limit Area of Steel Computed as Check for minimum steel and spacing etc.
ACECOMS, AIT Design of Shear Walls ACI Equations for Spandrel Design 5  s s d L When and c u V . V 5 0   0 50   min h ys s min v A f t A When 5  s s d L and c u V . V 5 0   0   min h min v A A When 5 2   s s d L Check s s c LW s s u d t f R d L V            10 3 2  s min h s min v t . A t . A 0025 0 0015 0  
ACECOMS, AIT Design of Shear Walls Notations for Shear Design top r d  bot r d  s h s t = Thickness of Spandrel = Distance from top of spandrel to the centroid of top reinforcing = Distance from bottom of spandrel to the centroid of bottom reinforcing = Total depth of spandrel LW R = Shear reduction factor as specified in the concrete material properties for light weight concrete. s d = Effective depth of spandrel s V = Portion of Shear force in spandrel carried by reinforcing steel c V = Portion of Shear force in spandrel carried by concrete s L = Length of Spandrel
ACECOMS, AIT Design of Shear Walls Notations for Shear Design p t = Thickness of Pier p L = Length of Pier min v A = Minimum vertical required area of distributed shear reinforcing min h A = Minimum horizontal required area of distributed shear reinforcing n V = Nominal Shear strength ys f = Shear yield strength of steel c f  = Concrete Compressive Strength
Detailing of Shear Walls
ACECOMS, AIT Design of Shear Walls Wall Section • Place more reinforcement at the ends and distribute the remaining in the middle portion • Confine the Rebars at the end for improved ductility and increased moment capacity Option -1 Option -2 Option -3
ACECOMS, AIT Design of Shear Walls Effect of Rebar Layout Moment Capacity for 1% Rebars a) Uniform Distribution b) Concentrated Bars Max M= 380 Max M= 475 Nearly 25% increase for same steel
ACECOMS, AIT Design of Shear Walls Wall Section • Place more reinforcement at the corners and distribute the remaining in the middle portion • Confine the Rebars at the corners for improved ductility and increased moment capacity • Provide U-Bars at the corners for easier construction and improved laps
ACECOMS, AIT Design of Shear Walls Effect of Rebar Layout Moment Capacity for 1% Rebars a) Uniform Distribution b) Concentrated Bars Nearly 20% increase for same steel Max M= 16500 Max M= 19600
ACECOMS, AIT Design of Shear Walls Rebar Detailing For Openings

More Related Content

PPTX
Designing pile caps according to ACI 318-19.pptx
byErbil Polytechnic University
 
PDF
Manual for Detailing Reinforced Concrete Structures to EC2
by0984
 
PDF
Tower design-Chapter 2-pile caps design
byNada Zarrak
 
PPTX
CE72.52 - Lecture 2 - Material Behavior
byFawad Najam
 
PDF
Etabs (atkins)
byAlbert deGuzman
 
PDF
Etabs tutorial
byAsaye Dilbo
 
PDF
Matching base shear in Etabs 2016
byVamsi krishna reddy
 
PPT
Column Analysis and Design
byWaqas Javaid
 
Designing pile caps according to ACI 318-19.pptx
byErbil Polytechnic University
 
Manual for Detailing Reinforced Concrete Structures to EC2
by0984
 
Tower design-Chapter 2-pile caps design
byNada Zarrak
 
CE72.52 - Lecture 2 - Material Behavior
byFawad Najam
 
Etabs (atkins)
byAlbert deGuzman
 
Etabs tutorial
byAsaye Dilbo
 
Matching base shear in Etabs 2016
byVamsi krishna reddy
 
Column Analysis and Design
byWaqas Javaid
 

What's hot

PDF
Moment Resisting Frame.pdf
byZeinab Awada
 
PDF
CE 72.32 (January 2016 Semester) Lecture 3 - Design Criteria
byFawad Najam
 
PDF
8. analysis of truss part ii, method of section, by-ghumare s m
bysmghumare
 
PPSX
Seismic Design Of Structures Project
byGunjan Shetye
 
PDF
Staad pro notes
byudhayasankar Ramasamy
 
PDF
Iii design-of-steel-structures-unit-2
bysaibabu48
 
PPTX
Design of concrete beam
bysathananthankartheep
 
PDF
CSI ETABS & SAFE MANUAL: Slab Analysis and Design to EC2
byEur Ing Valentinos Neophytou BEng (Hons), MSc, CEng MICE
 
PDF
Etabs example-rc building seismic load response-
byBhaskar Alapati
 
PDF
STAAD.Pro_Trg_Course_Material
byVAIBHAV JAIN
 
PDF
Tower design using etabs- Nada Zarrak
byNada Zarrak
 
PDF
Anchorage and lap splicing Detailing of slabs, columns, beams, footings
bykarthickcivic
 
PDF
Module4 plastic theory- rajesh sir
bySHAMJITH KM
 
PDF
ETABS Modelling
byEur Ing Valentinos Neophytou BEng (Hons), MSc, CEng MICE
 
PDF
Isolated footing design
bysrinu_anduri
 
PDF
Chapter27
byPriyabrata Behera
 
PPTX
Retaining wall - design of reinforced concrete structure
byKavin Raval
 
PPTX
DESIGN OF G+20 MULTISTOREY BUILDING
byAnjneya Srivastava
 
PPTX
CE 72.32 (January 2016 Semester) Lecture 8 - Structural Analysis for Lateral ...
byFawad Najam
 
PDF
Etabs modeling - Design of slab according to EC2
byEur Ing Valentinos Neophytou BEng (Hons), MSc, CEng MICE
 
Moment Resisting Frame.pdf
byZeinab Awada
 
CE 72.32 (January 2016 Semester) Lecture 3 - Design Criteria
byFawad Najam
 
8. analysis of truss part ii, method of section, by-ghumare s m
bysmghumare
 
Seismic Design Of Structures Project
byGunjan Shetye
 
Staad pro notes
byudhayasankar Ramasamy
 
Iii design-of-steel-structures-unit-2
bysaibabu48
 
Design of concrete beam
bysathananthankartheep
 
CSI ETABS & SAFE MANUAL: Slab Analysis and Design to EC2
byEur Ing Valentinos Neophytou BEng (Hons), MSc, CEng MICE
 
Etabs example-rc building seismic load response-
byBhaskar Alapati
 
STAAD.Pro_Trg_Course_Material
byVAIBHAV JAIN
 
Tower design using etabs- Nada Zarrak
byNada Zarrak
 
Anchorage and lap splicing Detailing of slabs, columns, beams, footings
bykarthickcivic
 
Module4 plastic theory- rajesh sir
bySHAMJITH KM
 
ETABS Modelling
byEur Ing Valentinos Neophytou BEng (Hons), MSc, CEng MICE
 
Isolated footing design
bysrinu_anduri
 
Chapter27
byPriyabrata Behera
 
Retaining wall - design of reinforced concrete structure
byKavin Raval
 
DESIGN OF G+20 MULTISTOREY BUILDING
byAnjneya Srivastava
 
CE 72.32 (January 2016 Semester) Lecture 8 - Structural Analysis for Lateral ...
byFawad Najam
 
Etabs modeling - Design of slab according to EC2
byEur Ing Valentinos Neophytou BEng (Hons), MSc, CEng MICE
 

Similar to Shear wall design - muros de corte Etabs

PDF
Shear walls
byRajat Nainwal
 
PDF
Shear Wall
byRutvik Sabhaya
 
PDF
Shear wall
by321nilesh
 
PPT
L-3 Shear Wall Part-2.ppt
byRukhsarJoue
 
PDF
Shear wall
byUma M
 
PDF
ANALYSIS AND DESIGN OPTIMIZATION OF SHEAR-WALL IN CASE OF HIGH-RISE BUILDING ...
byIRJET Journal
 
PDF
COMPARATIVE STUDY ON G+10 STOREY RCC BULDING WITH AND WITHOUT SHEAR WALL USIN...
byIRJET Journal
 
PPT
shear-walls-frame-design.ppt
byMuhammad Ilyas
 
PDF
Analysis and Design of shear wall
byIRJET Journal
 
PDF
Study of Strength of RC Shear Wall at Different Location on Multi-Storied Res...
byIJERA Editor
 
PDF
BEHAVIOUR OF G+10 BUILDING WITH SHEAR-WALLS AT DIFFERENT POSITIONS
byIRJET Journal
 
PDF
IRJET- Seismic Analysis of Multistoried Building with and without Shear Wall ...
byIRJET Journal
 
PDF
Lec05 STRUCTURE SYSTEMS to resist EARTHQUAKE (Earthquake Engineering هندسة ال...
byHossam Shafiq II
 
PDF
Effect of shear wall position in multi-storied building
byIRJET Journal
 
PPTX
Thesis ppt (2).pptx this is for mtech student
byErJyotirmayaDalai
 
PPT
hngmjhkmhhmnmnvbghLecture-Shear-Wall-ppt.ppt
bysiddeshhaaedbm
 
PDF
Bdp shear aci
byOscar A
 
PDF
IRJET- Significance of Shear Wall in Multistory Building with Seismic Ana...
byIRJET Journal
 
PDF
23
bySomeshwar Sriramoju
 
PDF
IRJET- Effective Location of Shear Wall on Performance of Building Frame ...
byIRJET Journal
 
Shear walls
byRajat Nainwal
 
Shear Wall
byRutvik Sabhaya
 
Shear wall
by321nilesh
 
L-3 Shear Wall Part-2.ppt
byRukhsarJoue
 
Shear wall
byUma M
 
ANALYSIS AND DESIGN OPTIMIZATION OF SHEAR-WALL IN CASE OF HIGH-RISE BUILDING ...
byIRJET Journal
 
COMPARATIVE STUDY ON G+10 STOREY RCC BULDING WITH AND WITHOUT SHEAR WALL USIN...
byIRJET Journal
 
shear-walls-frame-design.ppt
byMuhammad Ilyas
 
Analysis and Design of shear wall
byIRJET Journal
 
Study of Strength of RC Shear Wall at Different Location on Multi-Storied Res...
byIJERA Editor
 
BEHAVIOUR OF G+10 BUILDING WITH SHEAR-WALLS AT DIFFERENT POSITIONS
byIRJET Journal
 
IRJET- Seismic Analysis of Multistoried Building with and without Shear Wall ...
byIRJET Journal
 
Lec05 STRUCTURE SYSTEMS to resist EARTHQUAKE (Earthquake Engineering هندسة ال...
byHossam Shafiq II
 
Effect of shear wall position in multi-storied building
byIRJET Journal
 
Thesis ppt (2).pptx this is for mtech student
byErJyotirmayaDalai
 
hngmjhkmhhmnmnvbghLecture-Shear-Wall-ppt.ppt
bysiddeshhaaedbm
 
Bdp shear aci
byOscar A
 
IRJET- Significance of Shear Wall in Multistory Building with Seismic Ana...
byIRJET Journal
 
23
bySomeshwar Sriramoju
 
IRJET- Effective Location of Shear Wall on Performance of Building Frame ...
byIRJET Journal
 

Recently uploaded

PPT
Steam generation , types of steam, boilers and their classifications, mountin...
byPrashantPatunkar1
 
PPTX
pH-Responsive Polymers: Synthesis, Properties, and Biomedical Applications
byBURAKALPERENKARABULU
 
PPTX
Introduction to Physical Metallurgy II.pptx
byOcheriCyril2
 
PPTX
Unit 2 - ABRASIVE PROCESS AND BROACHING.pptx
byarivazhaganrajangam
 
PPTX
Lecture 2_Introduction to engineering design.pptx
bylynxvill3
 
PPTX
UNIT-1.pptx...................................
byRavinderKaur647214
 
PPTX
Introduction to Control Systems Chapter 2.pptx
byJosephHassen
 
PPTX
Slide sur les concepts_Module_5_STP.pptx
bydine46
 
PPTX
Chapter4- Continuous-Time Markov Models- Stpchastoc Processes- Dr. Zahedi.pptx
byzahedicourse
 
PDF
Arithmetic for computers and its types..
bysuganyapownaiya
 
PPT
Introduction to ARTIFICIAL INTELLIGENCES
byKAVITHAA49
 
PPTX
STM Unit 1 Complete notes for engineering students for better understanding
byLakshmiVivekaKesanap
 
PDF
Unconventional reservoirs in petroleum engineering
byMuhammadHaris61480
 
PPTX
narrow-band-dfr-presentation-megger.pptx
byssuser52ed331
 
PPTX
MOHSIN IJAZ PRESENTATION Final-climate.pptx
byakashhussain2851
 
PDF
Module 2 Python progr 1BPLCK105B-by Dr.SV.pdf
bySURESHA V
 
PPTX
reference material iso 45001_2018.pptx reference material iso 45001_2018.pptx
byMelwinPaul6
 
PPTX
SOFTWARE PROJECT MANAGEMENT PART 1-.pptx
byssuserbafe2d
 
PPT
CHAPTER 09 - Digital signatures cryptography note
bySherin Wilson
 
PPTX
AI INTRODUCTION New Microsoft Office PowerPoint Presentation.pptx
byb23cs183
 
Steam generation , types of steam, boilers and their classifications, mountin...
byPrashantPatunkar1
 
pH-Responsive Polymers: Synthesis, Properties, and Biomedical Applications
byBURAKALPERENKARABULU
 
Introduction to Physical Metallurgy II.pptx
byOcheriCyril2
 
Unit 2 - ABRASIVE PROCESS AND BROACHING.pptx
byarivazhaganrajangam
 
Lecture 2_Introduction to engineering design.pptx
bylynxvill3
 
UNIT-1.pptx...................................
byRavinderKaur647214
 
Introduction to Control Systems Chapter 2.pptx
byJosephHassen
 
Slide sur les concepts_Module_5_STP.pptx
bydine46
 
Chapter4- Continuous-Time Markov Models- Stpchastoc Processes- Dr. Zahedi.pptx
byzahedicourse
 
Arithmetic for computers and its types..
bysuganyapownaiya
 
Introduction to ARTIFICIAL INTELLIGENCES
byKAVITHAA49
 
STM Unit 1 Complete notes for engineering students for better understanding
byLakshmiVivekaKesanap
 
Unconventional reservoirs in petroleum engineering
byMuhammadHaris61480
 
narrow-band-dfr-presentation-megger.pptx
byssuser52ed331
 
MOHSIN IJAZ PRESENTATION Final-climate.pptx
byakashhussain2851
 
Module 2 Python progr 1BPLCK105B-by Dr.SV.pdf
bySURESHA V
 
reference material iso 45001_2018.pptx reference material iso 45001_2018.pptx
byMelwinPaul6
 
SOFTWARE PROJECT MANAGEMENT PART 1-.pptx
byssuserbafe2d
 
CHAPTER 09 - Digital signatures cryptography note
bySherin Wilson
 
AI INTRODUCTION New Microsoft Office PowerPoint Presentation.pptx
byb23cs183
 

Shear wall design - muros de corte Etabs

  • 1.
    Buddhi S. Sharma ACECOMS, AIT Design of Shear Walls Using ETABS O-SCAAD-1 May 21, 2002, AIT, Bangkok
  • 2.
    ACECOMS, AIT Design ofShear Walls The Basic Issues • What is a Shear Wall? • Modeling and analysis issues – Transfer of loads to shear walls – Modeling of shear walls in 2D – Modeling of shear Walls in 3D – Interaction of shear-walls with frames • Design and detaining issues – Determination of rebars for flexure – Determination of rebars for shear – Detailing of rebars near openings and corners – Design and detailing of connection between various components of cellular shear walls
  • 3.
  • 4.
    ACECOMS, AIT Design ofShear Walls What is a Shear Wall? • How can we “tell” when a member is a shear wall • Is the definition based on? – Intended Use – Shape in Cross-section – Geometry in Elevation – Loading Type and Intensity – Behavior and Theory – Location, Direction, Orientation
  • 5.
    ACECOMS, AIT Design ofShear Walls Shear Wall or Column Wall Column
  • 6.
    ACECOMS, AIT Design ofShear Walls Shear Wall or Frame Shear Wall Frame Shear Wall or Frame ?
  • 7.
    ACECOMS, AIT Design ofShear Walls Shear Wall or Truss?
  • 8.
    ACECOMS, AIT Design ofShear Walls Planner Walls Planer Stiffened Regular Openings Irregular Openings
  • 9.
    ACECOMS, AIT Design ofShear Walls Cellular Walls
  • 10.
  • 11.
    ACECOMS, AIT Design ofShear Walls Purpose of Shear Walls • Resist the lateral loads for medium rise buildings up to 40 floors – Reduce total deflection and story drift – Increase lateral stiffness – Reduce moments in columns and floor members due to lateral loads – Reduce the overall cost of the structural system – Can also serve as elevator shafts, service ducts, etc,
  • 12.
    ACECOMS, AIT Design ofShear Walls Loads Transferred to Shear Walls • Distribution of lateral loads to individual shear walls, to moment resisting frames, to wall-frames and to individual columns depends on: – Stiffness of each column and wall – Lateral stiffness of each frame or wall frame – Location of the the vertical unit with respect to the load building lateral stiffness center – Location of the load center with respect to the stiffness center – The geometry and in-plane stiffness of the floor slab system
  • 13.
    ACECOMS, AIT Design ofShear Walls Load Transferred to Shear Walls f Building Plan D F Stiffness Center Load Center ? ?
  • 14.
    ACECOMS, AIT Design ofShear Walls How to Locate the Walls • Reduce the eccentricity between the stiffness center and the load center – Consider Eccentricity due to Wind Loads, depending on overall geometry of the structure – Consider Eccentricity due to Earthquake Loads, depending on Mass Distribution – Consider Eccentricity not only at foundation level but at various heights • Reduce the in-plane bending in the slab system and Evenly distribute the stiffness in both directions • Use building layout in plan to enhance overall stiffness and reduce need for shear walls
  • 15.
    ACECOMS, AIT Design ofShear Walls How to Check Eccentricity! • For Wind Loads – Apply Wind load in X-Direction and check nodal displacements. If displacement in Y-Directions are nearly zero or very small, then there is no eccentricity between wind load and and stiffness center in Y-direction – Repeat the same for Y-Direction Load • Seismic Loads – Assign the Mass properties to the building and carryout a Modal Analysis: If the first two modes are Translational, and third mode is Torsional, then there is no eccentricity between the mass center and Stiffness Center in Both Directions
  • 16.
    ACECOMS, AIT Design ofShear Walls Eccentric and Concentric Response F No Eccentricity D F Eccentric Shear Wall
  • 17.
    ACECOMS, AIT Design ofShear Walls Eccentric and Concentric Response Mode-1 Mode-2 Mode-3 Symmetrical Mass and Stiffness Unsymmetrical Mass and Stiffness
  • 18.
    ACECOMS, AIT Design ofShear Walls Avoid Eccentricity in Plan Or
  • 19.
    ACECOMS, AIT Design ofShear Walls Reduce In-plane Bending in Floor
  • 20.
    ACECOMS, AIT Design ofShear Walls Vertical Irregularity Expansion Joint Balanced Shear Walls at All Levels No Shear Walls Using Expansion Joints to eliminate some walls
  • 21.
    ACECOMS, AIT Design ofShear Walls Using Efficient Building Plan Shape
  • 22.
  • 23.
    ACECOMS, AIT Design ofShear Walls Shear Wall and Frame Behavior Shear Wall Behavior Frame Behavior
  • 24.
    ACECOMS, AIT Design ofShear Walls 2 5 10 Axial Stresses in Planer Walls
  • 25.
    ACECOMS, AIT Design ofShear Walls 2 5 10 Axial Stresses in Cellular Walls Uniaxial Bending
  • 26.
    ACECOMS, AIT Design ofShear Walls 2 5 10 Axial Stresses in Cellular Walls Biaxial Bending
  • 27.
  • 28.
    ACECOMS, AIT Design ofShear Walls Modeling of Planer Walls Using Beam and Column Using Panels, Plates and Beams Using Truss
  • 29.
    ACECOMS, AIT Design ofShear Walls Modeling of Shear Walls Using Beam Elements
  • 30.
    ACECOMS, AIT Design ofShear Walls Frame Models for Shear Walls – 4-Node plane element does not accurately capture the linear bending, because constant shear distribution is assumed in formulation but actually shear stress distribution is parabolic – Since the basic philosophy of RC design is based on cracked sections, it is not possible to use the finite elements results directly for design – Very simple model (beam-column) which accurately captures the behavior of the structure, and the results can be used directly to design the concrete elements
  • 31.
    ACECOMS, AIT Design ofShear Walls Modeling of Walls using 1D Elements L t x h L t H2 H1 Simple beam elements L t Beam elements with rigid ends Beam elements in “Truss Model”
  • 32.
    ACECOMS, AIT Design ofShear Walls Frame Model for Planer Walls Rigid Zones • Specially Suitable when H/B is more than 5 • The shear wall is represented by a column of section “B x t” • The beam up to the edge of the wall is modeled as normal beam • The “column” is connected to beam by rigid zones or very large cross-section B H t
  • 33.
    ACECOMS, AIT Design ofShear Walls Frame Models for Cellular Walls • Difficult to extend the concept to Non-planer walls • Core Wall must be converted to “equivalent” column and appropriate “rigid” elements • Can be used in 2D analysis but more complicated for 3D analysis • After the core wall is converted to planer wall, the simplified procedure cab used for modeling B H t B H 2t t
  • 34.
    ACECOMS, AIT Design ofShear Walls Modeling of Shear Walls Using Plate/Shell Elements 1 2 3 U1, R1 Node 3 U3, R3 U2, R2 U1, R1 Node 1 U3, R3 U2, R2 U1, R1 Node 4 U3, R3 U2, R2 U1, R1 Node 2 U3, R3 U2, R2 Shell
  • 35.
    ACECOMS, AIT Design ofShear Walls Modeling Walls using 2D Elements • Walls are subjected to in-plane deformations so 2D elements that have transnational DOF need to be used • A coarse mesh can be used to capture the overall stiffness and deformation of the wall • A fine mesh should be used to capture in-plane bending or curvature • General Shell Element or Membrane Elements can be used to model Shear Walls
  • 36.
    ACECOMS, AIT Design ofShear Walls Modeling Walls Using Membrane Nodes: 4 DOFs: 2 (or 3) DOFs /Node Ux and Uy 2-Translation, 0 or 1 rotation Dimension: 2 dimension element Shape: Regular / Irregular Properties: Modulus of Elasticity(E), Poisson ratio(v), Thickness( t )
  • 37.
    ACECOMS, AIT Design ofShear Walls Modeling Walls using Shell Elements Nodes: 4 DOFs: 5 or 6 DOFs /Node Ux and Uy 3 Translation, 2 or 3 rotation Dimension: 2 dimension element Shape: Regular / Irregular Properties: Modulus of Elasticity(E), Poisson ratio(v), Thickness( t ) 1 2 3 U1, R1 Node 3 U3, R3 U2, R2 U1, R1 Node 1 U3, R3 U2, R2 U1, R1 Node 4 U3, R3 U2, R2 U1, R1 Node 2 U3, R3 U2, R2 Shell
  • 38.
    ACECOMS, AIT Design ofShear Walls Using Panel/ Plate Elements Modeling Shear-Walls using Panels only (No Moment continuity with Beams and Columns unless 6 DOF Shell is used) Modeling Shear-Walls using Panels, Beams, Columns (Full Moment continuity with Beams and Columns is restored by using additional beams)
  • 39.
    ACECOMS, AIT Design ofShear Walls Using Plates to Model Walls Multiple elements greater accuracy in determination of stress distribution and allow easy modeling of openings Using Plate Elements only (No Moment continuity with Beams and Columns unless 6 DOF Shell is used) Using Plate Elements with Beams, Columns (Full Moment continuity with Beams and Columns)
  • 40.
    ACECOMS, AIT Design ofShear Walls Connecting Walls to Slab In general the mesh in the slab should match with mesh in the wall to establish connection Some software automatically establishes connectivity by using constraints or “Zipper” elements “Zipper”
  • 41.
    ACECOMS, AIT Design ofShear Walls Modeling of Shear Walls Using Truss Models C t B t x 2t t x t
  • 42.
    ACECOMS, AIT Design ofShear Walls Using Trusses to Model Shear Walls • The behavior of shear walls can be closely approximated by truss models: – The vertical elements provide the axial-flexural resistance – The diagonal elements provide the shear resistance • Truss models are derived from the “strut-tie” concepts • This model represents the “cracked” state of the wall where all tension is taken by ties and compression by concrete
  • 43.
    ACECOMS, AIT Design ofShear Walls 2 5 10 Truss Model for Shear Walls Comparing Deformation and Deflections of Shell Model with Truss Model
  • 44.
    ACECOMS, AIT Design ofShear Walls Truss Model for Shear Walls 2 5 10 Comparing Deformation and Deflections of Shell Model with Truss Model
  • 45.
    ACECOMS, AIT Design ofShear Walls 2 5 10 Truss Models for Shear Walls Comparing Axial Stress and Axial Force Patterns
  • 46.
    ACECOMS, AIT Design ofShear Walls 2 5 10 Truss Models for Shear Walls Uniaxial Biaxial
  • 47.
    ACECOMS, AIT Design ofShear Walls How to Construct Truss Models • For the purpose of analysis, assume the main truss layout based on wall width and floor levels • Initial member sizes can be estimated as t x 2t for main axial members and t x t for diagonal members • Use frame elements to model the truss. It is not necessary to use truss elements • Generally single diagonal is sufficient for modeling but double diagonal may be used for easier interpretation of results • The floor beams and slabs can be connected directly to truss elements C t B t x 2t t x t
  • 48.
    ACECOMS, AIT Design ofShear Walls Modeling of Shear Walls Openings in Shear Walls
  • 49.
    ACECOMS, AIT Design ofShear Walls Very Large Openings may convert the Wall to Frame Very Small Openings may not alter wall behavior Openings in Shear Walls Medium Openings may convert shear wall to Pier and Spandrel System Pier Pier Spandrel Column Beam Wall
  • 50.
    ACECOMS, AIT Design ofShear Walls Openings in Shear Walls - Cellular 2 5
  • 51.
    ACECOMS, AIT Design ofShear Walls Openings in Shear Walls - Planer
  • 52.
    ACECOMS, AIT Design ofShear Walls Modeling Walls with Opening Plate-Shell Model Rigid Frame Model Truss Model
  • 53.
    ACECOMS, AIT Design ofShear Walls Frame Model of Shear Walls 3 DOF per rigid zone Rigid Zones Beams Columns A: Shear Wall with Line Loads B: Finite Element Model C: Define Beams & Columns D: Beam-Column Model Based on Concept proposed by E.L. Wilson
  • 54.
  • 55.
    ACECOMS, AIT Design ofShear Walls Basic Design Considerations • Main Shear Wall – Flexural Design – Shear Design • Spandrels and Links – Flexural Design – Shear Design • Ductility Considerations • Anchorage with Footings • Connection with Floor Slab/ Beams
  • 56.
    ACECOMS, AIT Design ofShear Walls Flexural Design
  • 57.
    ACECOMS, AIT Design ofShear Walls Flexural Design As Single Flexural Member
  • 58.
    ACECOMS, AIT Design ofShear Walls Designing as A Flexural Member • Approach – Design the Wall as “Big Column” – Follow the normal axial-flexural concept and provisions • Input Needed – P, Mx , (and My) – Wall Dimensions • Problems – Does not consider the non-linear strain distribution – In efficient rebar distribution
  • 59.
    ACECOMS, AIT Design ofShear Walls Design Procedure 1. Obtain Design Actions from Analysis 2. Assume rebar sizes, amount and distribution 3. Determine Cross-section capacity as column in form of Interaction Surfaces and Curves 4. Check if all action sets (P, Mx, My) fall within the interaction surface. The extreme values should be near the surface 5. If required, revise cross-section and repeat
  • 60.
    ACECOMS, AIT Design ofShear Walls Getting Result from Frame Model Design actions (P, Mx, My and V) are obtained directly Vx Vy P Mx My V P M
  • 61.
    ACECOMS, AIT Design ofShear Walls Getting Results from Truss Model C T D Tension Member Compression Member V P M ) cos( ) sin( ) sin(    D V x D Cx Tx M D C T P d c t        xc xt xd
  • 62.
    ACECOMS, AIT Design ofShear Walls Getting Results From Shell Model f1, f2, …..fn are the nodal stresses at section A-A , obtained from analysis CL of wall A A           n i i i i n i i n i i i i i v A V x F M F P f A F 1 1 1 f1 f2 f3 f4 f5 C T 1 x x1 t V P M
  • 63.
    ACECOMS, AIT Design ofShear Walls Assuming Reinforcement • Assume larger bars on the corners • Assume more bars on predominant tension direction/ location • Assume uniform reinforcement on wall sides • Total Rebars ratio should preferably be more than 0.8% and less than 3% for economical design
  • 64.
    ACECOMS, AIT Design ofShear Walls Obtaining Section Capacity Curves • Can be done manually by using linear strain distribution and equilibrium conditions – Generate few control points on the curve – Difficult to apply for Cellular and non rectangular walls • Can be obtained in more complete form using Software – CSI-Section Builder – GEAR – Column Section Module – PCA Column
  • 65.
    ACECOMS, AIT Design ofShear Walls Interaction Curves - Uniaxial The curve is generated by varying the neutral axis depth                       zi N i si z A c ny N i si A c nx d A f dz da f M A f da f N si b si b 1 1 . ) ( ) (     Safe Un-safe
  • 66.
    ACECOMS, AIT Design ofShear Walls Interaction Surface - Biaxial The surface is generated by changing Angle and Depth of Neutral Axis + Mz - My +P + My - Mz Pu A cross-section of interaction surface at P u Safe Un-safe                                                 ... ) , ( 1 ... . , 1 ... ) , ( 1 ... . , 1 ... ) , ( 1 ... , 1 1 2 1 3 1 2 1 2 1 2 1 1 i n i i i x y y i n i i i x y x x y n i i i z x y x A x dy dx y x M y y x A y dy dx y x M y x A dy dx y x N               
  • 67.
    ACECOMS, AIT Design ofShear Walls Interaction Surface and Curves
  • 68.
    ACECOMS, AIT Design ofShear Walls Narrow Planner Walls The capacity is almost completely un- axial Moment capacity can be increased by providing Rebars at the corners
  • 69.
    ACECOMS, AIT Design ofShear Walls Cellular Wall – No Opening The capacity is almost completely biaxial
  • 70.
    ACECOMS, AIT Design ofShear Walls Single Cell Walls
  • 71.
    ACECOMS, AIT Design ofShear Walls Double Cell Walls
  • 72.
    ACECOMS, AIT Design ofShear Walls Flexural Design Using Axial Zones
  • 73.
    ACECOMS, AIT Design ofShear Walls Design Walls in Zones • Basic Concept – Design the wall to resist the external actions by compression, tension and shear zones – More intuitive and more economical – Zone of high tension designed as tension member with concentrated rebars – Zone of high compression designed as compression member with appropriate rebar limits – Zone of low stress design as wall with nominal wall rebars
  • 74.
    ACECOMS, AIT Design ofShear Walls Designing as Axial Zones
  • 75.
    ACECOMS, AIT Design ofShear Walls Design Procedure 1. Obtain Design Actions from Analysis 2. Compute Axial Forces 3. For each axial force, assume section, assume rebars and check capacity 4. If capacity not enough, revise section, re- compute Axial Forces, and continue until required section for each force is designed 5. Provide nominal wall reinforcement in between the axial zones
  • 76.
    ACECOMS, AIT Design ofShear Walls Getting Result from Frame Model Compute Forces from Actions P Mx My P M 2 2 1 1 / 5 . 0 / 5 . 0 x M P F x M P F     i y i x i x M y M P F    4 x1 x2 yi F1 F2 Fi
  • 77.
    ACECOMS, AIT Design ofShear Walls Getting Results from Truss Model C T D Tension Member Compression Member xc xt xd Results obtained from truss analysis can be used Directly F1 = T F2 = C
  • 78.
    ACECOMS, AIT Design ofShear Walls Getting Results From Shell Model f1, f2, …..fn are the nodal stresses at section A-A , obtained from analysis CL of wall A A i i i i i f A F t x A   f1 f2 f3 f4 f5 C T 1 x x1 t F1=T F2=C
  • 79.
    ACECOMS, AIT Design ofShear Walls Axial Zone Model – Planer Wall
  • 80.
    ACECOMS, AIT Design ofShear Walls Axial Zones for Box Wall
  • 81.
    ACECOMS, AIT Design ofShear Walls Design as Truss: Strut and Tie • Directly design the tension members for reinforcement • Directly design the compression members as columns • The design is similar to the “Axial Zones” concept
  • 82.
    ACECOMS, AIT Design ofShear Walls Concrete Shear Wall Design in ETABS • 2D wall pier design and boundary-member checks • 2D wall spandrel design • 3D wall pier check for provided reinforcement • Graphical Section Designer for concrete rebar location • Graphical display of reinforcement and stress ratios • Interactive design and review • Summary and detailed reports including database formats
  • 83.
    ACECOMS, AIT Design ofShear Walls Shear Design Spandrel Pier
  • 84.
    ACECOMS, AIT Design ofShear Walls Shear Design Procedure • For Walls without Openings – Design the wall as piers • For Walls with Openings – Design the Piers, the vertical part – Design the Spandrels, the horizontal part
  • 85.
    ACECOMS, AIT Design ofShear Walls Shear Design of Pier • Determine Concrete shear capacity, Vc • Check if Vc exceeds the limit, if it does, section needs to be revised • Determine steel Rebars for Vs=V-Vc • Check additional steel for seismic requirements p L p t
  • 86.
    ACECOMS, AIT Design ofShear Walls ACI Equations for Pier Design     p p u p p c LW c L L . P L . t f R . V 4 8 0 8 0 3 3      p p p u u p p u c LW p c LW c L . t L V M Abs t L P . f R . L f R . V 8 0 2 2 0 25 1 6 0                                         p ys c u v L . f V V Abs A 8 0        p p c LW u L . t f R V Abs 8 0 10    Basic Concrete Shear Capacity Concrete not to Exceed the limit Area of Steel Computed as
  • 87.
    ACECOMS, AIT Design ofShear Walls Shear Design for Spandrel top r d  bot r d  a c s h s t s h s L Elevation Section • Determine Concrete shear capacity, Vc • Check if Vc exceeds the limit, if it does, section needs to be revised • Determine steel Rebars for Vs=V-Vc • Check additional steel for seismic requirements
  • 88.
    ACECOMS, AIT Design ofShear Walls ACI Equations for Spandrel Design s s c LW c d t f R V   2 c u c n s V V V V V      s s c LW s d t f R V   8 s ys s v d f V A  Basic Concrete Shear Capacity Concrete not to Exceed the limit Area of Steel Computed as Check for minimum steel and spacing etc.
  • 89.
    ACECOMS, AIT Design ofShear Walls ACI Equations for Spandrel Design 5  s s d L When and c u V . V 5 0   0 50   min h ys s min v A f t A When 5  s s d L and c u V . V 5 0   0   min h min v A A When 5 2   s s d L Check s s c LW s s u d t f R d L V            10 3 2  s min h s min v t . A t . A 0025 0 0015 0  
  • 90.
    ACECOMS, AIT Design ofShear Walls Notations for Shear Design top r d  bot r d  s h s t = Thickness of Spandrel = Distance from top of spandrel to the centroid of top reinforcing = Distance from bottom of spandrel to the centroid of bottom reinforcing = Total depth of spandrel LW R = Shear reduction factor as specified in the concrete material properties for light weight concrete. s d = Effective depth of spandrel s V = Portion of Shear force in spandrel carried by reinforcing steel c V = Portion of Shear force in spandrel carried by concrete s L = Length of Spandrel
  • 91.
    ACECOMS, AIT Design ofShear Walls Notations for Shear Design p t = Thickness of Pier p L = Length of Pier min v A = Minimum vertical required area of distributed shear reinforcing min h A = Minimum horizontal required area of distributed shear reinforcing n V = Nominal Shear strength ys f = Shear yield strength of steel c f  = Concrete Compressive Strength
  • 92.
  • 93.
    ACECOMS, AIT Design ofShear Walls Wall Section • Place more reinforcement at the ends and distribute the remaining in the middle portion • Confine the Rebars at the end for improved ductility and increased moment capacity Option -1 Option -2 Option -3
  • 94.
    ACECOMS, AIT Design ofShear Walls Effect of Rebar Layout Moment Capacity for 1% Rebars a) Uniform Distribution b) Concentrated Bars Max M= 380 Max M= 475 Nearly 25% increase for same steel
  • 95.
    ACECOMS, AIT Design ofShear Walls Wall Section • Place more reinforcement at the corners and distribute the remaining in the middle portion • Confine the Rebars at the corners for improved ductility and increased moment capacity • Provide U-Bars at the corners for easier construction and improved laps
  • 96.
    ACECOMS, AIT Design ofShear Walls Effect of Rebar Layout Moment Capacity for 1% Rebars a) Uniform Distribution b) Concentrated Bars Nearly 20% increase for same steel Max M= 16500 Max M= 19600
  • 97.
    ACECOMS, AIT Design ofShear Walls Rebar Detailing For Openings