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Presented to: Advances in Structural Design for Seismic Regions

Los Angeles Tall Building Structural Design Council

Colin Kumabe, S.E., M.S., M.B.A. Chief of Building Plan Check

City of Los Angeles, Department of Building and Safety

Purpose

Describe the process used by the City of Los Angeles, Department of Building and Safety, LADBS, for the approval of the buildings analyzed and designed using the Performance Based Design methodology.

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LADBS Involvement in Process

LADBS is involved in all steps of the Peer Review process.

LADBS sta will actively participate in all steps of the process by reviewing all design and analysis of structural components along with the Peer Reviewers.

Prior to issuing building permits, LADBS will use the recommendations from the Peer Reviewers as part of the nal plan check of the structure.

Process Overview

1. Developer acknowledge benets achieved with performance based design

2. Request LADBS to initiate process 3. LADBS selects Peer Review Panel 4. Discuss and approve Design Criteria and Ground

Motions 5. Approve nal analysis and construction plans

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Step 1: Developer Acknowledgement

Why is a Peer Review required? Section 16.2.5 of ASCE 7-05 and ASCE 7-10 require a review by an independent team when the non-linear time history method is used.

Step 2: Request LADBS to IniDate Peer Review Process

When should the Peer Review Process begin? As early as possible. Normally, with a diligent design team and Peer Review Panel, the process takes an average of 9 months.

Start at least 9 months before the full building permit is needed.

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Step 3: Panel ComposiDon

Section 16.2.5 of ASCE 7-05 and ASCE 7-10 require panel members to be of appropriate disciplines and others experienced in seismic analysis methods and the theory. One academic researcher One structural engineer One geotechnical engineer

Step 4: Comment ResoluDon Four Deliverables by the Peer Review Panel:

Ground Motions Proposed by the Design Team Approved by the Peer Review Panel based on site geology and structure type

Design Criteria Proposed by the Design Team (good to start with the LATBSDC methodology)

Approved by the Peer Review Panel

Final Non-Linear Time History Analysis Peer Review Panel reviews nal computer output

Location of Strong Motion Recorders

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Step 5: Final Approval Final Analysis is approved once the performance meets the approved design criteria by the Peer Reviewers. Along with the nal analysis the Strong Motion Recording device locations need to be approved.

Common Additional Approvals - Developers often request intermediate steps before the nal analysis is complete: Shoring approve excavation depth and width Foundation approve mat slab, footings or piles systems Shell Only nearly complete Final Analysis

LADBS InformaDon BulleDns P/BC 2011-048 - Specications for Strong-Motion Accelerographs & Requirements for Installation and Servicing devices used for code based design buildings http://ladbs.org/LADBSWeb/LADBS_Forms/InformationBulletins/IB-

P-BC2011-048StrongMotionAccelerographs.pdf P/BC 2011-117 - Structural Monitoring Equipment in Buildings Designed with Nonlinear Response History Procedure Special seismograph specications http://ladbs.org/LADBSWeb/LADBS_Forms/InformationBulletins/IB-

P-BC2011-117StrMonitoring4Non-LinearBldg.pdf P/BC 2011-123 - Alternative Design Procedure for Seismic Analysis and Design of Tall Buildings and Buildings Utilizing Complex Structural Systems adopts the LATBSDC methodology http://ladbs.org/LADBSWeb/LADBS_Forms/InformationBulletins/IB-

P-BC2011-123AltProc4SeisofTallComplexBldg.pdf

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Note on Strong MoDon Recorders Strong Motion Recorders are required by the California Building Code Section 1613.10 LA Building Code requires additional recorders to be installed when Performance Based Design methodology used. See amendments of CBC 1613.10 by LA City in LABC Section 1613.10.2.

Peer Review Panel approves recorder locations. Contact State of California Geologist to access SMIPP design assistance.

Thank you Questions?

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