Soil-Structure Interaction (SSI)

SOIL-STRUCTURE INTERACTION ANALYSIS

U N M ATCH ED EX P ERT ISE I N SSI

40+

Y E ARS O F EX P ERIENCE

Building for tomorrow: flexible & resilient design

Employing technology to optimize outcomes

You’re Grounded!

Performance-based seismic engineering

Our static and dynamic SSI analyses accurately predict the behavior of structures and the ground and buildings around them, enabling us to create designs that are safer and more resilient against seismic events and changes in the soil. With our comprehensive suite of geotechnical and structural services working together to manage risk and save you time and money, we’ll support your project from the ground up. Literally.

SOIL-STRUCTURE INTERACTION ANALYSIS

WHY US?

Long-span expertise

Static SSI Dynamic SSI Here’s How

Firm-wide support

STRUCTURAL ENGINEERING VIBRATION MEASUREMENT & MONITORING

TRANSPORTATION & INFRASTRUCTURE

Creative solutions for complex challenges

CONSTRUCTION ENGINEERING

Salesforce Transit Center, San Francisco, California

GEOTECHNICAL & SEISMIC ENGINEERING

RESILIENCE & SUSTAINABILITY

PROTECTIVE DESIGN & SECURITY Impact vibration analysis

High-performance building design 3

TRUSTED PARTNER When you work with us, we’ve got your back, every time.

ADVANCED ANALYSES FOR EXTREME EVENTS Projects of every type and size, all over the world.

HOLISTIC DESIGN FOR MULTIPLE HAZARDS Creative, integrated problem-solving yields constructable designs for complex forms.

CREATIVE SOLUTIONS/DEEP BENCH OF EXPERTS Our experienced engineers use cutting-edge tools to carve out new ways of solving difficult problems.

INTERDISCIPLINARY COLLABORATION & COORDINATION We work with all team members to ensure the best results for the project.

SOIL-STRUCTURE INTERACTION ANALYSIS

WHY US? Static SSI Dynamic SSI Here’s How

Excavations. Tunnels. Bridge and building foundations, and more. We’ve performed soil-structure analyses for every type of below-grade structure you can think of. In Salesforce Transit Center, San Francisco, California

fact, with 40+ years of experience, Thornton Tomasetti is a pioneer in the field. Our highly trained engineers and sophisticated software – including our powerful in-house FLEX family of programs – assure the most realistic soil-deformation, foundation-design and below-grade structural assessments available anywhere.

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SOIL-STRUCTURE INTERACTION ANALYSIS

WHY US? Static SSI Dynamic SSI Here’s How

STATIC SSI Our expertise in geotechnical and structural engineering – along with our advanced analytical capabilities – enables us to more realistically predict the coupled behavior of structures and the surrounding soil, providing our clients invaluable data for confidently managing the risks associated with below-grade construction.

DYNAMIC SSI Manhattan Bridge, New York, New York

Accurate prediction of the dynamic interaction between soil and structure is crucial to the design of buildings and infrastructure that can withstand ground motions. Our engineers have decades of experience in performing this type of analysis.

SOIL-STRUCTURE INTERACTION EXPERTISE & EXPERIENCE 7

Static SSI

CONF I DE NT I A L P R OJECT – G R OU P P I L E A N A LYS IS

Our team evaluated the performance of a pile-supported raft foundation and the complex behaviors of groups of piles, based on numerical simulations and field load tests for a single pile. We used static SSI analysis to evaluate differential settlement (uneven or unequal settling or sinking) in the raft foundation. Our work gave the client a realistic solution for adjustment of the piles to limit differential settlement in the raft foundation.

GEOTECHNICAL ENGINEERING, STRUCTURAL ENGINEERING, SUSTAINABILITY

Displacement contour from soil-pile foundation model.

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? S TAT I C S S I Dynamic SSI Here’s How

DIFFERENTIA L SETT L EMEN T ?

NO PROBLEM!

Our analysis considered the complex interactions of pile groups, enabling us to recommend adjustments that limited differential settlement of the raft foundation.

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Static SSI

MI T S OU T H OF M A IN ( S O M A ) SI T ES 3 , 4 & 5 S LU R RY WA L L D ES IG N Cambridge, Massachusetts TREVIICOS

We performed geostructural design services for the construction of a topdown slurry wall for a six-level underground parking garage that will serve as a foundation for three multistory above-grade structures. We worked with the design team to significantly reduce the number of necessary reinforcements, saving time and reducing costs for our client. Based on our SSI analysis, our team accurately predicted the performance of the earth-retention system during construction.

EXCAVATION & STABILITY ANALYSIS, GEOTECHNICAL ENGINEERING

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? S TAT I C S S I Dynamic SSI Here’s How

RISK REDUCTION TH ROU GH SSI A NA LYSIS

The process we developed using SSI analysis enabled us to predict soil deformation and reduce risk during construction of the slurry wall.

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Static SSI

B OSTON CH I L D RE N ’S HO S P ITA L HA L E FA M I LY C L IN ICA L B U IL D IN G E XCAVATIO N Boston, Massachusetts

Suffolk Construction & J.F. White Construction

We provided engineering services to enable below-grade construction in one of the most congested areas of Boston. Our work included the design of a support-of-excavation system using a slurry wall for a 75-foot-deep excavation and a 75-by-145-foot construction podium over the excavation site, all while minimizing settling of the adjacent buildings’ footings. Our computer simulation demonstrated exceptional agreement between wall movement measurements from our numerical simulations and those from actual field monitoring.

EXCAVATION & STABILITY ANALYSIS, GEOSTRUCTURAL ENGINEERING

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? S TAT I C S S I Dynamic SSI

Courtesy Suffolk Construction

Here’s How

SA FETY FIRST

To lessen the impact of the excavation on the adjacent hospitals and the underground utility tunnel, we performed scenario simulations for a variety of bracing elevations.

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Static SSI

L I QU E F I ED NAT U RA L G AS ( L N G ) FAC I L I T Y EXPA N S IO N Providence, Rhode Island Kiewit Corporation

Our SSI analysis aided in the design of a pile-supported embankment to mitigate the risk of flooding due to rising water levels. We evaluated the global stability of a range of scenarios and engineering options, using the shear strength reduction method, which measures the variance of soil strata and the structural contribution of proposed piles more accurately than traditional limited equilibrium methods. The piles not only support the embankment over soft soil – they also help stabilize it.

STABILITY ANALYSIS, GEOSTRUCTURAL ENGINEERING, GEOTECHNICAL ENGINEERING, RESILIENCE

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? S TAT I C S S I Dynamic SSI

Courtesy Peter Yihui Wu

Here’s How

FEDERA L STA MP OF A PPROVA L

Our work was reviewed and approved by the Federal Energy Regulatory Commission (FERC), which regulates the interstate transmission of electricity, natural gas and oil, 15

Static SSI

U NBRAC E D E L L IP T ICA L COF F ER DA M D ES IG N Boston, Massachusetts

Massachusetts Water Resources Authority (MWRA)

We designed a support-of-excavation system for the construction of a 15-million-gallon-per-day pump station 65 feet below-grade. Cofferdams are typically either rectangular or circular. But the rectangular shape requires multiple levels of bracing, while circular cofferdams have larger footprints. Our elliptical design minimized the footprint and eliminated the need for a lateral bracing system, simplifying construction, reducing costs and saving time.

GEOTECHNICAL ENGINEERING, GEOSTRUCTURAL ENGINEERING

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? S TAT I C S S I Dynamic SSI Here’s How

THINKING OUTSIDE THE BOX CIRCLE

Our innovative design combined the advantages of rectangular and circular cofferdams into a seldom-used elliptical shape.

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Dynamic SSI

TH R OGS NECK B RID G E SEI S M I C R ET R O F IT Bronx, New York

MTA Bridges and Tunnels

We performed a seismic retrofit of the bridge’s approach spans using lead core seismic isolators per the latest New York City Department of Transportation (NYCDOT) seismic guidelines and AASHTO, bringing the bridge up to current seismic design code. Our SSI analysis determined the stiffness of the pile foundations. The retrofit minimized the vulnerabilities of the piers, pier caps, piles, pile caps, main girder bearing stiffener and other bridge components.

SEISMIC ANALYSIS & RETROFIT, GEOSTRUCTURAL ENGINEERING, TRANSPORTATION & INFRASTRUCTURE

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? Static SSI DY N A M I C S S I Here’s How

SEISMIC SAVINGS

The lead core seismic isolator retrofit designed by our team is just as effective as – and more budgetfriendly than – traditional methods of column strengthening.

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Dynamic SSI

MANH AT TA N B R ID G E SEI S M I C R ET R O F IT New York, New York

New York City Department of Transportation (NYCDOT)

Our team assessed the seismic performance of the suspended and approach spans of the Manhattan Bridge, following NYCDOT seismic design and AASHTO guidelines. We incorporated dynamic SSI effects into our seismic analysis, helping determine which portions of the bridge were in need of retrofitting.

Our thorough analysis of the bridge’s structural members enabled us to design a retrofit that limited their seismic vulnerabilities.

GEOTECHNICAL ENGINEERING, SEISMIC RETROFIT, TRANSPORTATION & INFRASTRUCTURE

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? Static SSI DY N A M I C S S I Here’s How

“ FUSES” CA N BLOW – SA F ELY

To ensure a cost-effective retrofit, we designed some high-stress, easy-to-replace elements as “fuse” members that can safely fail during a seismic event, protecting more essential elements.

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Dynamic SSI

R OBE RT F. K E N N E DY B RID G E New York, New York

New York City Department of Transportation (NYCDOT)

Based on project-specific design criteria and site-specific geotechnical data and seismic input, Thornton Tomasetti, in a joint venture, evaluated the vulnerabilities of the suspended span, along with several ramps and junction structures, taking into account the foundation stiffness and damping obtained through SSI analysis. Our study provided the client a detailed list of vulnerable structural components, including truss, girder, piers, footings, foundations, piles, and more, that should be retrofitted or strengthened.

GEOTECHNICAL INVESTIGATION, SEISMIC RETROFIT, SITE RESPONSE ANALYSIS, VIBRATION MEASUREMENT

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? Static SSI DY N A M I C S S I Here’s How

INSIGHT THRO UG H INVESTIGATIO N

Our analysis revealed that, in addition to multiple structural elements, many nonstructural but life-safety-related elements were vulnerable to earthquake damage and also required retrofitting.

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Dynamic SSI

SAL ES FOR C E T RA N S IT C E N T E R San Francisco, California

Transbay Joint Powers Authority

Our structural engineering services for this transit terminal topped by a 5.4acre public park employed performance-based design to create a structure that will survive maximum earthquake shaking without significant structural damage or loss of function. Our design of the structure included dynamic SSI analysis, performance-based design of the superstructure, and an extensive finite-element and experimental program to evaluate its unique connections.

GEOTECHNICAL ENGINEERING, SEISMIC ANALYSIS

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? Static SSI DY N A M I C S S I

Courtesy Transbay Joint Powers Authority

Here’s How

A NA LYSIS INFO RMS D ES IGN

Our study of the complex seismic interactions of the building and soil layers, which varied in depth and length, informed the performancebased design of the structure to withstand seismic effects.

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HE RE’S H OW Acoustics, Noise & Vibration Aviation Biomechanics & Life Sciences Commercial Construction Engineering Critical Facilities Cultural & Community Decarbonization Defense Education Energy Façades

We apply scientific and engineering principles to solve the world’s challenges – starting with yours.

Whether we’re focused on the design, construction and performance of buildings or expanding into new disciplines, we never limit ourselves, applying our expertise to all types of projects across a range of industries.

Forensics & Investigations

How can we help you?

Resilience

We offer solutions for an ever-widening range of services and sectors.

Special Structures

Government Healthcare Hospitality & Gaming Insurance Laboratory & Research Protective Design & Security Residential Restoration & Renewal Sports & Public Assembly Structural Design Sustainability Tall & Supertall Buildings Transportation & Infrastructure

SOIL-STRUCTURE INTERACTION ANALYSIS

Why Us? Static SSI Dynamic SSI HERE’S HOW

Liling Cao

John Mould

Senior Principal

Principal

LCao@ThorntonTomasetti.com

JMould@ThorntonTomasetti.com

+1.212.367.2995

+1.650.230.0334

NEW YORK

SANTA CLARA

Liling heads our advanced analytics group, focusing on nonlinear analysis of structural interactions and performance under extreme loads, including earthquakes, wind and blast.

John specializes in soil, rock and fluid-structure interaction analysis for blast, impact and shock applications and has developed algorithms and software to evaluate these coupled problems.

Ali Ashrafi

Maryam Tabbakhha

Principal

Senior Associate

AAshrafi@ThorntonTomasetti.com

MTabbakhha@ThorntonTomasetti.com

+1.212.367.3087

+1.415.365.6909

NEW YORK

SAN FRANCISCO

Ali has deep expertise in performance-based design of complex structures and dynamic soilstructure interaction. He has taught earthquake and wind engineering at Columbia University.

Maryam is skilled in multiphysics modeling, specializing in fluid-air-soil-structure interaction and assessing the performance of structures and infrastructure in earthquakes and floods.

We want to hear from you!

Please contact us if you’d like to collaborate or learn more about our services.

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Offices Worldwide 120 Broadway New York, NY 10271-0016 T +1.917.661.0016

Li l i n g C ao S e n i o r P ri n c i p a l LC a o @T h o r nto nTo m a s e t t i . c o m

+ 1.212.367.2995

Th o rnto nTo m a s ett i .co m/G e o st ruc t u ra l

Throgs Neck Bridge Bronx, New York ©Jeff Zhou/Shutterstock