Wilshire Grand Redevelopment Project

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Wilshire Grand Redevelopment ProjectProject Highlights

December 15, 2016

Wilshire GrandRedevelopment Project

WILSHIRE GRAND PROJECT

• Facility Overview• Construction Highlights• Mass Concrete – Thermal Control• Structural Design – Seismic• Foundation Settlement & Tower

Shortening• Pre-Loading of Upper BRBs

Facility Overview

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PROJECT LOCATION 900 Wilshire Blvd

Size: 2,100,000 SF

73-stories

892 key hotel

16 stories of offices – 365,000 SF

7 levels of podium (amenities)

5 levels below grade parking

Completion: 2nd Quarter 2017

Owner: Hanjin International Corp/Korean Air Lines

Architect: A.C. Martin Partners

StructuralEngineers: Brandow & Johnston

Thornton TomasettiProject Manager: Martin Project Mgmt

General Contractor: Turner

Level 70 Sky Lobby

Level 70 Sky Lobby

Level 70 Bar

Level 70 Club Lounge

Level 73 Sky Deck

Level 5 Pre-function Area

Level 5 Grand Ballroom

Level 7 Ballroom

Level 7 Health & Fitness Club

Level 7 Shower & Spa

Level 7 Pool

View from Figueroa Street

Level 1 Porte Cochere

Construction Highlights

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January 2013

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May 2013

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June 2013

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November 2013

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The Grand Pour – Feb 15, 2014

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Rebar Erection

EFCO FORM SYSTEM

June 2014

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Year-end 2014

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Mid-year 2015

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3rd Quarter 2015

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Year-end 2015

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Summer 2016

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Current – Dec 2016

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Mass Concrete - Thermal Control

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Mass concrete is the performance definition of such concrete placement, that may develop potentially detrimental high absolute temperature and/or temperature difference due to:• volume and shape• specific amount and rate of heat generation upon hydration and

hardening, and • boundary conditions,

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The Grand Pour – Feb 15, 2014

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Largest Continuous Concrete Pour

39 Guinness World Record

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Thermal Control Measures

• Cooling Pipe System with Recirculating Chilled Water

• Thermal Blanket Insulation

• Curing Procedure

• QC Temperature Monitoring

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• Maximum temperature is limited through proper thermal control measures in order to prevent delayed ettringite formation (DEF).

• Maximum temperature difference is limited through proper thermal control measures in order to prevent cracking due to thermal stresses.

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Structural Design

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SLDE Service Level Design EQ– Frequent occurrence (43-yr return period EQ)

– Performance Objective: Designed to stay linear in ‘elastic limit’

– Lateral system rebounds to zero deformation w/ limited arch & structdamage, remains serviceable

– Moderate EQ (475-yr return period) damage reparable

MCE Maximum Considered EQ Event ‘Major Event’ – Extreme / Severe (2475-yr return period EQ)

– Performance Objective: Designed to prevent collapse, mitigate loss of life

– Lateral system utilizes ductility, performs numerous cycles ‘plastic yield’ demand

PERFORMANCE CRITERIA

PERFORMANCE BASE DESIGNDesigned for known local seismicity

– Design consideration: 29 major faults deemed active distance from 0.2 mi. to 46 mi. from site

– Nearest quake considered is from Upper Elysian Park Thrust Fault (0.2 mi)

– Largest quake considered is from San Andreas Fault (46 mi.)

Wind Design – 1700-yr cycle, 160 mph, 3-sec gusts– Wind Tunnel Studies and Computer Simulation

– Rigid enough for comfort service-level wind loads

– No ‘Tuned Mass Damper’ required, adequate lateral stiffness for comfort

PERFORMANCE BASE DESIGNPeer Review Approach Favorable over CBC Prescriptive Design

– Peer Review Panel members

– Establish Performance Objectives with SEOR

– PRP Provided Comprehensive Code Compliance Check

– Requires full ‘redundant back-up’ system in addition to ‘Core Wall Design’

– Typically results in Conventional Tube Steel Frame with ‘deep girders’ + ‘closer columns’

Benefits Early Collaboration of PRP w/ SEOR = Early Delivery

Upper Outrigger Trusses – 3 Stories10 bays-1BRB w/2200 k each

Middle Outrigger Trusses – 6 Stories10 bays-Total 12 BRBs w/800 kips each

Lower Outrigger Trusses – 3 Stories10 bays-Cluster 4-BRBs w/2200 kips each

Structure: • Concrete Core w/4 Vertical Cells

• Steel Floor Frame w/ Composite Metal Deck

Structural Statistics:• Steel: 19,000 tons (17.2 million kg)

• Concrete: 160,000 cu yds = 16,000 trucks (122K cu m)

• Rebar: 70 million lbs = 35,000 tons (31.7 million kg)

METRICS – STRUCTURAL OVERVIEW

LA Live (NYA)

BRB’sSpecialty structural brace element consisting of an axial force resisting steel core encased by a system that prevents buckling of the steel core.

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Lower Outriggers

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Upper Outriggers

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LOWER OUTRIGGER EMBED ERECTED

Foundation Settlement &Tower Shortening

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Adjustments Due to Foundation Settlement & Tower Shortening

233’

582’

869.5’

1053.5’

1125.5’

1210.2’

1384’Spire

Sail

70th

53rd

28th

Top ofMat

Foundation Settlement- Differential settlement

Core Walls- Reinforced Concrete- Strain due to loading - Shrinkage and Creep

Exterior Columns- Built-Up Structural Steel Box Columns - Filled with Concrete- Strain due to loading

Tower Axial ShorteningDesign accounted for axial displacements due to:• sequential loading phases during construction• and long term effects (shrinkage and creep)

Prevent undue stresses different from design values

Perform periodic on‐site measurements 

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Pre-Loading Upper BRBs

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Adjustments Due to Long Term Creep

233’

582’

869.5’

1053.5’

1125.5’

1210.2’

1384’Spire

Sail

70th

53rd

28th

Top ofMat

• Single 2,200 kips BRBs

• Sensitive to differential movements due to elastic shortening, shrinkage and creep.

• Pre-compressing BRBs

Pre-loading with Hydraulic Jacks

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Protect the building from permanent deformation in the 50-yr windevent

At 50-yr wind event, the BRB strains are approximately 50% ofyield strain

Pre-compressing the BRB eliminates permanent deformation after50 years of creep and shrinkage

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Top of Spire – Prior to Beacon Installation

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