CHALLENGING CONVENTIONS How Innovation, Risk and Resilience Creates Better Buildings and Greater Cost Efficiency Jade Kirk BE(Hons), MIPENZ, IntPE, CPEng, QSNdip Managing Director Kirk Roberts Consulting Engineers Limited
RISK RESILIENCE INNOVATION COST EFFICIENCY PRESENTATION OUTLINE: Early engagement, dialogue between disciplines and innovative new technologies, simple structures and performance based design manages risk, builds compliance and leads to costefficient and better buildings.
FEB 22, 2011 Building Collapse Fatalities Engineering Failures Business Interruption Led to: RISK ON THE GROUND Code Updates (Increased Seismic Loads) Conservative Engineering Increased Building Costs Damage Avoidance Design, Innovation
RISK KEY POINTS Volume 1 Summary Recommendations of (V1-3), Section 1 Irregular stiffness, torsion, strength and detailing lead to most failures (Non-Regular Buildings) There should be greater cooperation and dialogue (understanding) between structural and geotechnical engineers Structures should have sufficient strength and ductility to allow them to perform as required Methods of analysis predicting deformations and performance Engineers need to consider deformation compatibility Development of performance-based, low-damage technologies
Conservatism + Risk Aversion + Additional Scrutiny = HighCost Complacency Risk Aversion Major convincing process required (Public perception of Buildings (e.g. Height issue) Fear of being First Inherent Conservatism Building Cost Increases Geotechnical / Foundation Conservatism and Cost Increases Leadership and Appetite for Change RISK THE CHALLENGES
RESILIENCE KIRK ROBERTS THE WAY FORWARD Three Key Engineering Pathways Simple Structures Performance Based Designs New Technologies & Innovation
RESILIENCE SIMPLE SYSTEMS Simple Structures means High Performance and Cost Efficiency Conventional engineering techniques. Simplistic load paths. Create regular buildings with new or old technologies. Limit Torsion, (centre mass/centre of rigidity). Compatibility of stiffness & materials. (One type of lateral system). Localise, control damage and displacements. Improve constructability and timeframes. Invest in complex analysis, BIM modeling and high level documentation (remove risk). Avoids conservatism & over engineering. K.I.S.S. SIMPLE, RESOLVED SYSTEMS Are The Key to Economical Buildings and Structures
PERFORMANCE BASED DESIGNS Risk, Resilience, Innovation, and Economics Analysis and Design Complex Analysis Procedures Deisgn and Detailing Displacement Performance Localise and Control Damage Low-Damage Technology (LDT) (RIM) Displacement Based Designs Constructability Understand Client s Requirements, Social Requirements, Risk, Economic and Asset Protection RESILIENCE In performance-based design, owners and engineers work together to achieve the best possible balance between construction costs and ultimate performance.
RESILIENCE PERFORMANCE BASED DESIGNS Risk, Resilience, Innovation, and Economics Simplicity Conventional Systems. (Repairable, high cost) Precast Shear Walls Moment-Resisting Concrete Frames Moment-Resisting Steel Frame Structures Highly Ductile Systems High Energy Dissipation (Repairable, high cost) Eccentrically Braced Frames (RIM) (Replaceable Links Non-Replaceable Links) Buckling Restrained Braces (RIM) Tension Braced Frames (RIM) Self-Restoring Systems, Highly Ductile Excellent Energy Dissipation, Damage Protection. (Fully repairable, high performance in above-code events) PRESSS Technology (Shear Walls) (LDT) PRESSS Technology (Frames) (LDT) PRESSS Technology (Timber) (LDT) Base Isolation (Most expensive, highest protection) (LDT) PRESSS Precast Seismic Structural System RIM Repair Impact Minimisation LDT Low-Damage Technology
Design Of Ductile Jointed Self-Centering Precast/Timber Structures Performance Based Design (LDT) Low-Damage Technology (Damage avoidance) Low-Damage Structure Performance based System Inelastic Action which absorbs energy through movement of the joint Self-Centering Moment Resisting Joints. Post Tensioned Structural Elements Replaceable Ductile Energy Dissipaters The ability to withstand an earthquake well in excess of its design level (up to 1/2500) INNOVATION NEW TECHNOLOGIES CONCRETE/TIMBER (PRESSS)
Eccentrically Braced Frames (EBF) (RIM) (Replaceable Link) BRB, Buckling Restrained Braces (RIM) Repair Impact Minimisation Highly Ductile System (Link) Inelastic action which absorbs energy through rotation of the Active Link, (Shear) (If designed correctly) Some Self-Centering Properties Localised Damage, building frame protected. Replaceable Active Link. (If designed) INNOVATION NEW TECHNOLOGIES STEEL
Cost Efficiency vs Capital Value vs Asset Protection vs Social Impact Understand Client s Budget (IMPORTANT) The end game Building s Market, fit for purpose Capital Value of the Investment (yield & return) Asset Protection Social requirements of the structure Social Impact COST EFFICENCY COST EFFICENCY
COST EFFICENCY CASE STUDY BARBADOES STREET Cost Efficiency vs Capital Value vs Asset Protection vs Social Impact Barbadoes Street Developments + KR Building ( 3500m 2 ) Performance based Structure 1/1000 Probability of exceedance (code 1/500) Simplistic Structural System Limited Ductile Shear Walls, EBF frames Regular stiffness, efficient structures Simplistic Foundations & Geotechnical design Beam / Grillage foundations system + Raft Differential settlement mitigation Structural system matches geotechnical constraints Low Construction Costs Fit for Market, (Grade B+ to A-) office tenants
Cost Efficiency vs Capital Value vs Asset Protection vs Social Impact 299 Durham Street ( 3900m2) Performance based structure, Displacement based design 1/1000 event (Probability of exceedance, Code 1/500) Able maintain Strength and stiffness beyond 1/2500 event LDT Low-Damage technology PRESSS Shear Wall building Irregular building, efficient structure and stiffness. Simplistic Foundations & Geotechnical design Cost efficient foundation system, designed fit for purpose, (Screw piles) Low damage foundation performance, structural protection. Structural system match's geotechnical restraints. COST EFFICENCY CASE STUDY DURHAM STREET Low Construction Costs Fit for Market, (Grade A+) office tenants
COST EFFICENCY CASE STUDY YOUNG HUNTER HOUSE Cost Efficiency vs Capital Value vs Asset Protection vs Social Impact YOUNG HUNTER HOUSE Victoria Street ( 3000m 2 ) Performance based Structure, Displacement Based Design 1/500 event (Probability of exceedance, Code 1/500), normal structure Able maintain strength, stiffness and low damage beyond 1/2500 event LDT Low-Damage Technology PRESSS technology Timber LVL MRF Building Regular building, efficient structure and stiffness. Self Centering post tensioned LVL-MRF frames Replaceable ductile energy dissipaters Simplistic Foundations & Geotechnical Design Cost efficient foundation system, designed fit for purpose, (CFA Concrete piles, continuous flight auger) Low-damage foundation performance, structural protection. Structural system match's geotechnical restraints, distributed loads Low Construction Costs Fit for Market, (Grade A) Office Tenants
RISK RESILIENCE INNOVATION COST EFFICIENCY SUMMARY TO GO HOME WITH Early engagement, dialogue between disciplines and innovative new technologies, simple structures and performance based design manages risk, builds compliance and leads to cost efficient and better buildings.
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