performance based design, value naveed anwar, phd

Dr. Naveed Anwar

Performance Based Design, Value Engineering and Peer Review

Naveed Anwar, PhD

Dr. Naveed Anwar2

Excellencethe quality of being outstanding or

extremely good

Dr. Naveed Anwar3

To be Excellent, something must be above average, better than standard,and of higher performance

How to achieve excellence through innovative, explicit, verifiable and demontratable process

Dr. Naveed Anwar4

Building Industry relies on Codes and Standards

• Codes Specify requirements

• Give acceptable solutions

• Prescribe (detailed) procedures, rules, limits

• (Mostly based on research and experience but not always rational)

Spirit of the code isto help ensure Public Safety and provide formal/legal basis for design decisions

Compliance to letter of the code is indented to meet the spirit

Dr. Naveed Anwar5

The First Code - Hammurabi's (1772 BC)

Clause 229: If a builder builds a house for someone, and

does not construct it properly, and the house which he

built falls in and kills its owner, then that builder

shall be put to death.

Implicit Requirements

Consequence of non-Performance

Explicit Collapse Performance

Dr. Naveed Anwar6

Public Safety and the Codes

-

“In case you build a new house, you must also make a parapet for your roof, that you may not place bloodguilt upon your house because someone falling might fall from it”

Modern Codes, c2000

PrescriptiveLaw of Moses (1300 BC)

The Bible, Book of Deuteronomy, Chapter 22, Verse 8

Performance Oriented

Ref: Teh Kem, Associate Prof. NUS

Dr. Naveed Anwar7

Public Safety and Codes

Railing height “deemed” sufficient by the code(Acceptable to residents of lower floors)

Railing height added by resident to “feel safe”

and reduce “”risk” (Only done by residents of higher floors)

Dr. Naveed Anwar8

The Responsibility

Building Officials

Structural Designer

Architect Structural Design Codes

General Building Codes

Legal and Justice System

Public/ Users/ Occupants

Client/Owner

Law Makers

Builder/Contractor

Peer Reviewer

Geotech Consultants

Dr. Naveed Anwar9

Population

Urbanization and Un-

planned

development

Inappropriate

Built

Environment

Lack of Resources

for Communities

Natural or

Man-made

Phenomena

Disaster Hazard ExposureVulnerability

To reduce risk of disaster and increase safety,

we need tp estimate hazard properly,

and Reduce Vulnerability

Risk

Dr. Naveed Anwar10

How modern codes intent to ensure “Safety”

• Define appropriate/estimated hazard or load levels

• Prescribe limits on structural systems, members, materials

• Define procedures for analysis and design

• Provide rules for detailing

• Provide specifications for construction and monitoring

•Hope that all of this will lead to reduced vulnerability and safer structures …

Dr. Naveed Anwar

The Modern Codes – With “intent” to make buildings safe for public

11

(ACI 318 – 14)

Extremely Detailed prescriptions and equations using

seemingly arbitrary, rounded limits with

implicit meaning

(IS 456-2000)

Dr. Naveed Anwar12

A Move Towards Performance Based

• Prescriptive Codes restrict and discourage innovation

• Performance Based approach encourages and liberates it

Objective RequirementsPrescribed

Solution

Objective RequirementsAlternate Solution

Dr. Naveed Anwar

Ensuring Explicit Safety Performance(And increase Disaster Resilience)

Dr. Naveed Anwar

Design Approaches

Intuitive Design

Code Based Design

Performance Based Design

-

Wind

Earthquake

Dr. Naveed Anwar15

Performance based design

can be applied to any type

of loads, but was initially

developed and targeted for

earthquake loads

Earthquakes as a Catylist for PBD

Dr. Naveed Anwar16

Explicit Performance Objective in PBD

Performance based design investigates at least two

performance objectives explicitly

Service-level Assessment

Ensure continuity of service for frequent hazards

(Earthquake having a return period of about 50)

Collapse-level Assessment

Ensure Collapse prevention under extreme hazards

(the largest earthquake with a return period of 2500 years)

Codes arbitrary

implicit “Design Level”

Dr. Naveed Anwar17

Performance Level Definitions

Owner

Will the building be safe?

Can I use the building after the hazard?

How much will repair cost in case of damage?

How long will it take to repair?

Engineer

Free to choose solutions, but ensure amount of yielding,

buckling, cracking, permanent deformation, acceleration, that structure, members and materials

experiences

Need a third party to ensure public safety and realistic Performance

GuidelinesPeer Review

Dr. Naveed Anwar18

Performance Objectives for Seismic Design

Level of Earthquake Seismic Performance Objective

Frequent/Service (SLE): 50% probability of

exceedance in 30 years (43-year return

period)

Serviceability: Structure to remain

essentially elastic with minor damage to

structural and non-structural elements

Design Basis Earthquake (DBE): 10%

probability of exceedance in 50 years

(475-year return period)

Code Level: Moderate structural

damage; extensive repairs may be

required

Maximum Considered Earthquake (MCE):

2% probability of exceedance in 50 years


Collapse Prevention: Extensive structural

damage; repairs are required and may

not be economically feasible

Dr. Naveed Anwar

Define Performance Levels

19

Based on FEMA 451 B

Dr. Naveed Anwar

Link the Hazard to Performance Levels

20

Structural Displacement

Lo

adin

g S

ever

ity

Resta

urant

Resta

urant

Resta

uran

t

Haz

ard

Vulnerability

Consequences

Dr. Naveed Anwar21

Performance-based design

• More explicit evaluation of the safety and reliability of structures.

• Provides opportunity to clearly define the levels of hazards to be designed against, with the corresponding performance to be achieved.

• Code provisions are intended to provide a minimum level of safety.

• Shortcoming of traditional building codes (for seismic design) is that the performance objectives are considered implicitly.

• Code provisions contain requirements that are not specifically applicable to tall buildings which may results in designs that are less than optimal, both from a cost and safety perspective.

• Verify that code-intended seismic performance objectives are met.

Dr. Naveed Anwar

How to Apply PBD

Dr. Naveed Anwar23

The Building Structural System - Conceptual

• The Gravity Load Resisting System• The structural system (beams, slab, girders, columns, etc.) that acts primarily

to support the gravity or vertical loads

• The Lateral Load Resisting System• The structural system (columns, shear walls, bracing, etc.) that primarily acts

to resist the lateral loads

• The Floor Diaphragm• The structural system that transfers lateral loads to the lateral load resisting

system and provides in-plane floor stiffness

Dr. Naveed Anwar24

Structural System

Source: NEHRP Seismic Design Technical Brief No. 3

Dr. Naveed Anwar25

PBD Guidelines

• PEER 2010/05, “Tall Building Initiative, Guidelines

for Performance Based Seismic Design of Tall

Buildings”

• PEER/ATC 72-1, “Modeling and Acceptance

Criteria for Seismic Design and Analysis of Tall

Buildings”

• ASCE/SEI 41-13, “Seismic Evaluation and Retrofit

of Existing Buildings”

• LATBSDC 2014, “An Alternative Procedure for

Seismic Analysis and Design of Tall Buildings Located

in the Los Angeles Region”

Dr. Naveed Anwar26

Required Information

• Basis of design

• Geotechnical investigation report

• Site-specific probabilistic seismic hazard assessment report

• Wind tunnel test report

Dr. Naveed Anwar27

Basis of Design

• Description of building

• Structural system

• Codes, standards, and references

• Loading criteria• Gravity load, seismic load, wind load

• Materials

• Modeling, analysis, and design procedures

• Acceptance criteria

Dr. Naveed Anwar28

Geotechnical Investigation Report

• SPT values

• Soil stratification and properties

• Soil type for seismic loading

• Ground water level

• Allowable bearing capacity (Factors to increase in capacity for transient loads and stress peaks)

• Sub-grade modulus (Vertical and lateral)

• Liquefaction potential

• Pile foundation• Ultimate end bearing pressure vs. pile length• Ultimate skin friction pressure vs. pile length• Allowable bearing capacity• Allowable pullout capacity

• Basement wall pressure

Dr. Naveed Anwar29

Site-specific Probabilistic Seismic Hazard Assessment Report

• Recommend response spectra (SLE, DBE, MCE)

• Ground motions scaled for MCE spectra

• If piles are modeled in nonlinear model,• Depth-varying ground motions along the pile length

• Springs and dashpots

• If vertical members are restrained at pile cap level,• Amplified ground motions at surface level

Dr. Naveed Anwar30

Depth-varying Ground Motions along Pile Length

Dr. Naveed Anwar31

0.0

0.5

1.0

1.5

2.0

2.5

0.0 2.0 4.0 6.0 8.0

SP

EC

TR

AL

AC

CELE

RA

TIO

N

NATURAL PERIOD (SEC)

Response Spectra

SLE (g)

DBE (g)

MCE (g)

Response Spectra

• Service Level Earthquake (SLE)• 50% of probability of exceedance in 30 years


• Design Basis Earthquake (DBE)• 10% of probability of exceedance in 50 years


• Maximum Considered Earthquake (MCE)• 2% of probability of exceedance in 50 years


Dr. Naveed Anwar32

Wind Tunnel Test Report

• Wind-induced structural loads and building

motion study

• 10-year return period wind load

• 50-year or 700-year return period wind load

• Comparison of wind tunnel test results with various

wind codes

• Floor accelerations (1-year, 5-year return periods)

• Rotational velocity (1-year return period)

• Natural frequency sensitivity study

Dr. Naveed Anwar

Performance-based Design Procedure

Dr. Naveed Anwar34

Overall PBD Process

Initial Investigations

Preliminary Design

Wind Tunnel

Test

Detailed Code Based Design

Service Level Evaluation

Collapse Level

Evaluation

Peer Review

Final Design

Dr. Naveed Anwar35

Preliminary design

Structural

system

development

• Bearing wall

system

• Dual system

• Special moment

resisting frame

• Intermediate

moment resisting

frame

Finite

element

modeling

• Linear analysis

models

• Different stiffness

assumptions for

seismic and wind

loadings

Check overall

response

•Modal analysis

• Natural period, mode

shapes, modal

participating mass

ratios

• Gravity load

response

• Building weight per

floor area

• Deflections

• Lateral load response

(DBE, Wind)

• Base shear, story drift,

displacement

Preliminary

member

sizing

• Structural density

ratios

• Slab thickness

• Shear wall thickness

• Coupling beam sizes

• Column sizes

Dr. Naveed Anwar36

Detailed Code-based Design

• Modeling• Nominal material properties are used.• Different cracked section properties for wind and seismic models• Springs representing the effects of soil on the foundation system and basement walls

• Gravity load design• Slab• Secondary beams

• Wind design• Apply wind loads from wind tunnel test in mathematical model• Ultimate strength design

• 50-year return period wind load x Load factor• 700-year return period wind load

• Serviceability check• Story drift ≤ 0.4%, Lateral displacement ≤ H/400 (10-year return period wind load)• Floor acceleration (1-year and 5-year return period wind load)

Dr. Naveed Anwar37

Detailed code-based design

• Seismic design (DBE)

• Use recommended design spectra of DBE from PSHA

• Apply seismic load in principal directions of the building

• Scaling of base shear from response spectrum analysis

• Consider accidental torsion, directional and orthogonal effects

• 5% of critical damping is used for un-modeled energy dissipation

• Define load combinations with load factors

• Design and detail reinforcement

Dr. Naveed Anwar38

Scaling of Response Spectrum Analysis Results

Source: FEMA P695 | June 2009

Dr. Naveed Anwar39

SLE Evaluation

• Linear model is used.

• Site-specific service level response spectrum is used without reduction by scale factors.• 2.5% of critical damping is used for un-modeled energy dissipation.

• 1.0D + 0.25 L ± 1.0 ESLE

• Seismic orthogonal effects are considered.

• Accidental eccentricities are not considered in serviceability evaluation.

• Response modification coefficient, overstrength factor, redundancy factor and deflection amplification factor are not used in serviceability evaluation.

Dr. Naveed Anwar40

Acceptance Criteria (SLE)

• Demand to capacity ratios• ≤ 1.5 for deformation-controlled actions

• ≤ 0.7 for force-controlled actions

• Capacity is computed based on nominal material properties with the strength reduction factor of 1.

• Story drift shall not exceed 0.5% of story height in any story with the intention of providing some protection of nonstructural components and also to assure that permanent lateral displacement of the structure will be negligible.

Dr. Naveed Anwar41

MCE Evaluation

• Nonlinear model is used.

• Nonlinear response history analysis is conducted.

• Seven (or more) pairs of site-specific ground motions are used.

• 2.5% of constant modal damping is used with small fraction of Rayleigh damping for un-modeled energy dissipation.

• Average of demands from seven ground motions approach is used.

• Capacities are calculated using expected material properties and strength reduction factor of 1.0.

Dr. Naveed Anwar42

Expected Material Strengths

Source: LATBSDC 2014

Dr. Naveed Anwar43

Deformation-controlled Actions

Force-deformation relationship for deformation-controlled actions

Source: ASCE/SEI 41-13

• Behavior is ductile and reliable inelastic deformations can be reached with no substantial strength loss.

• Results are checked for mean value of demand from seven sets of ground motion records.

Dr. Naveed Anwar44

• Behavior is more brittle and reliable inelastic deformations cannot be reached.• Critical actions

• Actions in which failure mode poses severe consequences to structural stability under gravity and/or lateral loads.

• 1.5 times the mean value of demand from seven sets of ground motions is used.

• Non-critical actions• Actions in which failure does not result structural

instability or potentially life-threatening damage.

• Mean value of demand from seven sets of ground motions is used with a factor of 1.

Force-controlled Actions

Force-deformation relationship for force-controlled actions

Source: ASCE/SEI 41-13

Dr. Naveed Anwar45

Component Action Classification Criticality

Shear wallsFlexure Deformation-controlled N/A

Shear Force-controlled Critical

Coupling beams

(Conventional)

Flexure Deformation-controlled N/A

Shear Force-controlled Non-critical

Coupling beams (Diagonal) Shear Deformation-controlled N/A

GirdersFlexure Deformation-controlled N/A

Shear Force-controlled Non-critical

ColumnsAxial-Flexure Deformation-controlled N/A


Diaphragms

Flexure Force-controlled Non-critical

Shear (at podium and basements) Force-controlled Critical

Shear (tower) Force-controlled Non-critical

Basement wallsFlexure Force-controlled Non-critical


Mat foundationFlexure Force-controlled Non-critical


PilesAxial-Flexure Force-controlled Non-critical


Classification of Actions

Dr. Naveed Anwar46

Concrete Element SLE/Wind DBE MCE

Core walls/shear wallsFlexural – 0.75 IgShear – 1.0 Ag

Flexural – 0.6 IgShear – 1.0 Ag

Flexural – **

Shear – 0.2 Ag

Basement wallsFlexural – 1.0 IgShear – 1.0 Ag



Coupling beams

(Diagonal-reinforced)

Flexural –0.3 IgShear – 1.0 Ag



Coupling beams

(Conventional-reinforced)




Ground level diaphragm

(In-plane only)




Podium diaphragmsFlexural – 0.5 IgShear – 0.8 Ag



Tower diaphragmsFlexural – 1.0 IgShear – 1.0 Ag



GirdersFlexural – 0.7 IgShear – 1.0 Ag



ColumnsFlexural – 0.9 IgShear – 1.0 Ag



Stiffness Assumptions in Analysis Models

Dr. Naveed Anwar

Evaluation of Results

Dr. Naveed Anwar48

Evaluation of Results

• Results extraction, processing and converting them into presentable form takes additional time.

• Results interpretation i.e. converting “numbers we have already crunched” into “meaningful outcome for decision-making”.

• Since each of these performance levels are associated with a physical description of damage, obtained results are compared and evaluated based on this criterion to get performance insight.

Dr. Naveed Anwar49

Overall Response

• Base shear

• Ratio between inelastic base shear and elastic base shear

• Story drift (Transient drift, residual drift)

• Lateral displacement

• Floor acceleration

• Energy dissipation of each component type

• Energy error

Dr. Naveed Anwar50

Base Shear

30,878

81,161

269,170

201,762

160,409

133,233

57,826

39,137

0

50,000

100,000

150,000

200,000

250,000

300,000

X Y

Base s

hear

(kN

)

Along direction

Wind (50-yr) x 1.6 Elastic MCE Inelastic MCE-NLTHA Elastic SLE

1.68

4.42

14.67

11.00

8.74

7.26

3.15

2.13

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

X Y

Base s

hear

(%)

Along direction

Wind (50-yr) x 1.6 Elastic MCE Inelastic MCE-NLTHA Elastic SLE

Dr. Naveed Anwar51

0

10

20

30

40

50

60

70

-0.05 -0.04 -0.03 -0.02 -0.01 0.00 0.01 0.02 0.03 0.04 0.05

Sto

ry level

Drift ratio

Transient Drift

GM-1059

GM-65010

GM-CHY006

GM-JOS

GM-LINC

GM-STL

GM-UNIO

Average

Avg. Drift Limit

Max. Drift Limit

Dr. Naveed Anwar52

0

10

20

30

40

50

60

70

0.000 0.002 0.004 0.006 0.008 0.010 0.012 0.014 0.016

Sto

ry level

Drift ratio

Residual Drift

GM-1059

GM-65010

GM-CHY006

GM-JOS

GM-LINC

GM-STL

GM-UNIO

Average

Avg. Drift Limit

Max Drift Limit

Dr. Naveed Anwar53

0

10

20

30

40

50

60

70

-3 -2 -1 0 1 2 3

Sto

ry level

Lateral displacement (m)

Lateral Displacement

GM-1059

GM-65010

GM-CHY006

GM-JOS

GM-LINC

GM-STL

GM-UNIO

Average

Dr. Naveed Anwar54

0

10

20

30

40

50

60

70

-2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0

Sto

ry level

Absolute acceleration (g)

Floor Acceleration

GM-1059

GM-65010

GM-CHY006

GM-JOS

GM-LINC

GM-STL

GM-UNIO

Average

Dr. Naveed Anwar55

Energy Dissipation

Total dissipated energy

From shear walls Conventional reinforced coupling beams



Diagonal reinforced coupling

beams

Time (sec)

En

erg

y d

issip

ati

on (%

)

Time (sec)

Energ

y d

issip

ati

on

(%)

Energ

y d

issip

ati

on

(%)

Time (sec)

Dr. Naveed Anwar56

Component Responses

Component Response

Pile foundation Bearing capacity, pullout capacity, PMM, shear

Mat foundation Bearing capacity, flexure, shear

Shear wall Flexure (axial strain), shear

Column PMM or flexural rotation, axial, shear

Beams Flexural rotation, shear

Conventional reinforced coupling beam Flexural rotation, shear

Diagonal reinforced coupling beam Shear rotation, shear

Flat slab Flexural rotation, punching shear

Basement wall In-plane shear, out-of-plane flexure and shear

Diaphragm Shear, shear friction, tension and compression

Dr. Naveed Anwar57

How to Work with PBD

Dr. Naveed Anwar 58

Integrated PBD for Earthquake and Wind

Dr. Naveed Anwar

Earthquake and Wind PBD are Compatible!

59

Site specific Seismic Hazard Study

Site specific Climate Analysis

Various Earthquake levelsSLE, DBE, MCE etc

Various Wind Return period and Velocities

Hazard Response Spectrum Wind Force in Frequency Domain

Ground Motion Time History

Wind Tunnel Pressure in Time Domain

EarthquakeWind

Dr. Naveed Anwar60

Possible Way forward

Consider winds of higher intensity and

longer return periods

Determine static and dynamic impacts

through wind tunnel studies

Incorporate wind tunnel dynamic

measurements into dynamic analysis of structural models

Set appropriate performance criteria

for motion, deformation,

strength, ductility, energy decimation

etc.

Make the Wind PPD consistent with

Earthquake PBD

Dr. Naveed Anwar

Wind Pressure Variation and Dynamic effects

61

Dr. Naveed Anwar62

SuggestedStructural Performance Criteria for Wind

Wind Return Period

Wind Performance

Level

Structural System Response

Overall Damage

Wind Performance

ObjectiveDesign Criteria

1 yearPerception Threshold

No Permanent Interstory

UndamageNone Perception

of movementBldg. Acceleration <5

milli -g

10 years Motion Comfort No Permanent

InterstoryUndamage

Controlled Comfort

Bldg. Acceleration <15 milli -g

50 years OperationalNo Permanent

InterstoryUndamage

Non-Structural Damage

Story drift is limited to 0.2%

100 yearsLimited

InterruptionNo Permanent

InterstoryMinor

DamagesStructural Damage

Story drift is limited to 0.3%

475 years Life SafetyPermanent Interstory

Major Damages

No CollapseStory drift is limited

to 0.5% Residual Drift < h/600

1000 years

Collapse Prevention

Permanent Interstory

Extensive Damages

No Collapse

Story drift is limited to 1%

Residual Drift < h/500

Dr. Naveed Anwar63

Compare

PBD Wind and PBD Earthquake

(Using ASCE 41 as a sample)

Wind Earthquake

Time Varying Loading Wind Tunnel Testing Site Specific Investigation

LoadingMean + Fluctuating +

Resonant Fluctuating + Resonant

Overall Structural Damage ASCE 41-13 ASCE 41-13

Structural System Response ASCE 41-13 ASCE 41-13

Members Deformation Control Limits

ASCE 41-13 ASCE 41-13

Material Behavior Uncrack to Crack under yield to Crack beyond yield point

Crack under yield to Crack beyond yield point

Structural members controlled

Some members are Force and Deformation Controlled

Some Members are Force and Deformation Controlled

Dr. Naveed Anwar64

• Explicit confirmation of higher or expected performance level using innovative solutions

Performance Based Design

• Get the best “value” for resourcesValue Engineering

• Provide an independent view and confirmation

Peer Review

Dr. Naveed Anwar

Value Engineering

Balancing Cost and Performance

Dr. Naveed Anwar66

Cost and Performance

PCC

Cost Effective

Design

Can be done PC

General Belief

Easy to do !

PC

Highly Innovative

Design

Hard to do!

PC

High

Performance

Design

Can be done

Dr. Naveed Anwar67

What is the Cost of a Project?

• Cost may include– Financial Cost (loan, interest, etc)

– Planning and Design Cost

– Direct Construction Cost

– Maintenance Cost

– Incidental Cost

– Liquidated Cost (lost profit etc)

– Opportunistic Cost

– Environmental Cost

– Emotional Cost

– Non-determinist Resources

Cost may be:“Consumption of Particular Resources, at Particular Time”

Sustainability may be:<Consumption of all resources, and their impacts through throughout the life cycle>

Dr. Naveed Anwar68


• Enhancement of Performance• Dynamic response parameters

• Lateral load response

• Vertical load response

• Demand and capacity ratios

• Response irregularity, discontinuity

• Explicit Performance Evaluation at Service, DBE and MCE

• Cost Effectiveness• Capacity utilization ratio

• Reinforcement ratios

• Reinforcement volume ratios

• Concrete strength and quantity

• Rebar quantity

• Constructability, time and accommodation of other constraints

68

Dr. Naveed Anwar69

• Simple Example of a Column Stack – What and how can we optimize ?• Concrete Strength

• Steel Strength

• Column Size

• Rebar Amount

• Composite Section

• Material Cost, Labor Cost, Formwork Cost, Management and operations Cost, Time ??

Local Vs Global Optimization

Dr. Naveed Anwar70


(Base Cost and Performance)

(Increased Performance, Same Cost)

(Base Cost and Performance)

(Reduced Cost for Same Performance)

P

M

P

M

Dr. Naveed Anwar71

Demand Capacity (DC Ratio)

• Definition of D/C: It is an index that gives an overall relationshipbetween affects of load and ability of member to resists thoseaffects.

• This is a normalized factor that means D/C ratio value of 1 indicatesthat the capacity (strength, deformation etc) member is justenough to fulfill the load demand.

• Two types of D/C ratio Members with brittle behavior D/C is checked by Strength (Elastic) Members with ductile behavior D/C is checked by deformation (Inelastic)

• Total D/C ratio of the member is combined of these two.

Dr. Naveed Anwar72

Cost Effectiveness > Utilization Ratio

• Utilization Ratio• Compare, What is

Needed against What is Required

• One measure • The Demand/

Capacity Ratio (D/C)

Demand/ CapacityColumns

No. %

D/C<0.5 178 16%

0.5<D/C<0.7 534 49%

0.7<D/C<1 346 31%

1<D/C<1.5 30 3%

1.5<D/C<2.5 12 1%

D/C>2.5 0 0%

Total 1100 100.00%

Ideal

Not Cost Effective

Not Safe

Dr. Naveed Anwar73

Focus should be

“Maximum Value for Resources”

Cost effective, not Low Cost

Dr. Naveed Anwar

Peer ReviewTo ensure Basic Design the Performance Evaluation and Value Enginering are done right

Dr. Naveed Anwar75

The Responsibility

Building Officials

Structural Designer

Architect Structural Design Codes

General Building Codes

Legal and Justice System

Public/ Users/ Occupants

Client/Owner

Law Makers

Builder/Contractor

Peer Reviewer

Geotech Consultants

Dr. Naveed Anwar76

Peer Review

• What exactly is design peer review?• It is a process whereby a design project (or aspect of) is reviewed and

evaluated by a person, or team, not directly involved with the project, but appropriately qualified to provide input that will either reinforce a design solution, or provide a route to an improved alternative.

• Why is it so important?• Very few can claim to be all-encompassing experts. The invaluable input from

broad base and independent experience at each stage of a design project will often result in technical improvements, lower costs, avoidance of sourcing issues, and improved performance.

Dr. Naveed Anwar77

When is Peer Review needed

• Structural Peer Review is required for: • Buildings included in Structural Occupancy Category

IV as defined in the Building Code.

• Buildings with aspect ratios of seven or greater.

• Buildings greater than 500 feet (160 m) in height or more than 1,000,000 square feet (100,000 Sqm) in gross floor area.

• Buildings taller than seven stories where any element supports in aggregate more than 15 percent of the building area.

• Buildings designed using nonlinear time history analysis, pushover analysis or progressive loading techniques.

New York Building Code, adopted by many cities

Important

Slender

Tall or large

Critical

Use NLA

Dr. Naveed Anwar78

Responsibility

• Structural Engineer of Record (SER). • The structural engineer of record shall retain

sole responsibility for the structural design. The activities and reports of the Reviewing Engineer shall not relieve the structural engineer of record of this responsibility.

• Reviewing Engineer. • The Reviewing Engineer’s report states his or her

opinion regarding the design by the engineer of record.

• The standard of care to which the Reviewing Engineer shall be consistent with Structural Peer Review services performed by professional engineers licensed/approved

Retains Responsibility

Evaluates, and gives opinion that may or may not be accepted by

Client or SER

Dr. Naveed Anwar79

Client

PBD Value Engineering

Peer Review

Basic Design

Public Officials

Design Codes and Guidelines

High performance, Higher safetyhigher value, cost effectiveSustainable

Excellence is Structures

Dr. Naveed Anwar80

performance based design, value naveed anwar, phd

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