Wilshire Grand Redevelopment Project
-
Upload
american-society-of-civil-engineers-orange-county-branch -
Category
Engineering
-
view
94 -
download
2
Transcript of Wilshire Grand Redevelopment Project
WILSHIRE GRAND PROJECT
• Facility Overview• Construction Highlights• Mass Concrete – Thermal Control• Structural Design – Seismic• Foundation Settlement & Tower
Shortening• Pre-Loading of Upper BRBs
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
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,
37
Thermal Control Measures
• Cooling Pipe System with Recirculating Chilled Water
• Thermal Blanket Insulation
• Curing Procedure
• QC Temperature Monitoring
41
• 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.
42
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.
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
57
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
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
62