Quick Survey (29th

Nov’12)

OpenSees: This has been increasingly used along the west coast for SSI.

Title: Seismic response of a typical highway bridge in liquefiable soil

Authors: HyungSuk Shin, Pedro Arduino, Steven L. Kramer and Kevin Mackie

They have borrowed a typical bridge structure from elsewhere and introduced soil as continua inside

OpenSees. It has a liquefiable loose sand layer in the profile. They have used several types of ‘interface

springs’ to model SSI which are available in OpenSees. The parameters of these interface elements reflect

the existence of different soil types, ground water conditions, pile group effects, and passive earth

pressures in the pile caps and abutments. After dynamic analysis with two different accelerometer records

they investigated the displacement and pore water pressure ratios at soil, then response spectra at different

pier base and also response at the springs and finally the global response of the whole bridge.

Title: Influence of Soil-Foundation-Structure Interaction on Seismic Response of the I-880 Viaduct

Authors: Boris Jeremic, Sashi Kunnath and Feng Xiong

The role of Soil-Foundation-Structure (SFS) interaction on seismic behavior of an elevated highway

bridge (the I-880 viaduct) bent with deep foundations is investigated in this paper. This study incorporates

SFS interaction through the use of equivalent soil springs with elastic behavior in OpenSees. The spring

properties are derived from three dimensional finite element analysis of the pile foundation in a layered

soil system which was also modeled in OpenSees.

Title: Evaluation of soil-structure interaction effects of PNW bridges (This is a project overview on

PAC TRANS website)

PIs: Andre Barbosa and Ben Mason (OSU)

Project period: 03/01/2012 – 11/01/2013

In this research they propose to create a finite element model of a typical PNW (Pacific Northwest) soil-

bridge system within the program OpenSees. They are going to consider different soil conditions by

using a series of complex, nonlinear Winkler springs. The focus of this research will be large, subduction

zone earthquakes, because this scenario is possibly the most damaging event in the PNW. They will also

examine shallow, crustal earthquakes as well as longer-return period basin-and-range earthquakes. The

end-product of the research will be guidance for how a typical bridge in varying soil conditions performs

during differing, realistic earthquake motions.

FB-Multipier:

This software was developed in University of Florida. Florida and Arizona DOT used this software for

study of bridges. It is a 3D FEM code, it has nonlinear capabilities for both soil (continua but separate

box-shaped soil around each pier) and structure, response spectrum analysis is not validated for entire

bridge although can simulate with ground motions applied at the base.

Title: Simplified lateral analysis of deep foundation supported bridge bents: Driven pile case

studies. Authors: Brent Robinson, Vinicio Suarez, Mohammed A. Gabr and Mervyn Kowalsky

In this study static analysis was done with FB-Multipier on simple bridge bents in NC state assuming

non-linear properties for both soil and structure components and being compared with other methods.

CSIBridge

We cannot include soil as a continuum. Rather have linear/non-linear soil springs which can be attached

to the pile. These springs have stiffness equal to the stiffness of soil. Capable of running both response

spectra and time history analysis.

Title: Design of the SR 99 bored tunnel in Seattle, Washington.

Authors: Michaela Pilotto and Yang Jiang

In this tunnel construction project only the structural components were modeled and analyzed in

CSIBridge. Soil continua are replaced by springs. Both static and dynamic time-history analysis of the

structure were done.

LUSAS:

LUSAS is a full proper Nonlinear Finite Element Analysis software. Can model both structure and soil

(as continua) and non-linear dynamic analysis available for both. Both time-history and response

spectrum analysis can be done. Constitutive soil models include Tresca, von Mises, Drucker Prager, Mohr

Coulomb, Modified Cam Clay, and others for use in all types of soil-structure interaction modeling.

LUSAS can model soil as a 2D plane strain (with linear or quadratic elements) or as axisymmetric or as

solid elements (again linear or quadratic bricks). Soil can also be modeled as springs. This UK based

software has huge application in industry in Europe. Luisiana DOT has already used it for Integrated

Abutment Bridge studies.