PEER Reports

PEER Reports

Hybrid Simulation Theory for a Classical NonLinear Dynamical System, PEER Report 2016-07

Paul L. Drazin
Sanjay Govindjee
2016

Hybrid simulation is an experimental and computational technique that allows one to study the time evolution of a system by physically testing a subset of it while the remainder is represented by a numerical model that is attached to the physical portion via sensors and actuators. The technique allows the study of large or complicated mechanical systems while only requiring a subset of the complete system to be present in the laboratory. This results in vast cost savings as well as the ability to study systems that simply cannot be tested due to scale. However, the errors that arise from...

Detailing Requirements for Column Plastic Hinges subjected to Combined Flexural, Axial, and Torsional Seismic Loading, PEER Report 2016-09

Gabriel Hurtado
Jack P. Moehle
2016

Under earthquake loading, bridge superstructures will in general experience both translational and rotational motions. The rotational motions arise from a number of effects, including shaking response of asymmetrical structures, wave passage effects, and ground failure including fault rupture at the bridge site. As a consequence, supporting columns may be subjected to torsion, which is often ignored in typical design practice. The degree to which torsion reduces bridge safety because of reduced lateral strength and, more importantly, because of reduced deformation capacity, is unclear....

Performance-Based Robust Nonlinear Seismic Analysis with Application to Reinforced Concrete Highway Bridge Systems, PEER Report 2016-10

Xiao Liang
Khalid M. Mosalam
2016

The performance-based earthquake engineering (PBEE) approach, developed at the Pacific Earthquake Engineering Research Center (PEER), aims to robustly decompose the performance assessment and design process into four logical stages that can be studied and resolved in a systematic and consistent manner. However, the PBEE approach faces two key challenges: (1) an accurate seismic structural analysis and (2) the selection and modification of ground motions (GMs). This report addresses these two challenges with application to reinforced concrete (RC) bridge systems.

In nonlinear...

A Nonlinear Kinetic Model for Multi-Stage Friction Pendulum Systems, PEER Report 2017-07

Paul L. Drazin
Sanjay Govindjee
2017

Multi-stage friction pendulum systems (MSFPs), or more specifically the triple friction pendulum (TFP), are currently being developed as seismic isolation devices for buildings and other large structures. However, all current models are inadequate in properly modeling all facets of these devices. Either the model can only handle uni-directional ground motions while incorporating the kinetics of the TFP system, or the model ignores the kinetics and only models bi-directional motion. And in all cases, the model is linearized to simplify the equations.

This paper presents an all-in-one...

Response Spectrum Analysis of Concrete Gravity Dams Including Dam-Water-Foundation Interaction, PEER Report 2013-17

Arnkjell Løkke
Anil K. Chopra
2013

A response spectrum analysis (RSA) procedure, which estimates the peak response directly from the earthquake design spectrum, was developed in 1986 for the preliminary phase of design and safety evaluation of concrete gravity dams. The analysis procedure includes the effects of dam- water-foundation interaction, known to be important in the earthquake response of dams.

This report presents a comprehensive evaluation of the accuracy of the RSA procedure by comparing its results with those obtained from response history analysis (RHA) of the dam modeled as a finite element system,...

Identification of Site Parameters that Improve Predictions of Site Amplification, PEER Report 2013-18

Ellen M. Rathje
Sara Navidi
2013

The effects of the local soil conditions on earthquake shaking are of ten quantified via an amplification factor, which is defined as the ratio of the ground motion at the soil surface to the ground motion at a rock site at the same location. Site amplification models are empirical equations that predict site amplification based on the general characteristics of the site. Most of the current site amplification models predict amplification based on the average shear wave velocity in the top 30 m (V S30 ). However, additional site parameters influence site amplification and should...

Hanging-Wall Scaling using Finite-Fault Simulations, PEER Report 2013-14

Jennifer L. Donahue
Norman A. Abrahamson
2013

The hanging-wall (HW) effect is defined as the increase in ground motions observed during a reverse earthquake event, when in close proximity and while on the hanging-wall side of a fault. As observed in the empirical data, the short period ground motions over the hanging-wall may be twice the amplitude of the ground motions recorded on the footwall at the same rupture distance. Because there are only a few earthquakes with near-fault recordings, there is insufficient empirical data to constrain the dependence of the HW effect. Using finite-fault simulations, 34 reverse earthquake events...

NGA-West2 Models for Ground-Motion Directionality, PEER Report 2013-10

Shrey K. Shahi
Jack W. Baker
2013

The NGA-West2 research program, coordinated by the Pacific Earthquake Engineering Research Center (PEER), is a major effort to produce refined models for predicting ground-motion response spectra. This study presents new models for ground-motion directionality developed as part of that project. Using a database of recorded strong ground motions, empirical models have been developed for a variety of quantities related to direction-dependent spectra.

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NGA-West2 Model for Estimating Average Horizontal Values of Pseudo-Absolute Spectral Accelerations Generated by Crustal Earthquakes, PEER Report 2013-08

I. M. Idriss
2013

A model for estimating average horizontal values of pseudo-absolute spectral accelerations generated by crustal earthquakes is developed as part of this study. The NGA-West2 Project significantly expanded the data base of motions recorded during earthquakes and offered the opportunity to re-examine and update the NGA relationships published by the NGA developers in 2008. The new data set comprised 21,539 recordings obtained during earthquakes with magnitudes ranging from 3 to 7.9, recorded at distance ranging from 0.2 km to well over 300 km, and for recording stations with Vs30...

Epistemic Uncertainty for NGA-West2 Models, PEER Report 2013-11

Linda Al Atik
Robert R. Youngs
2013

Probabilistic seismic hazard studies typically address the epistemic uncertainty in ground motion estimation by using a weighted set of alternative ground motion models. This approach relies on the assumption that the alternative models are developed independently, and the resulting range of model predictions adequately captures the epistemic uncertainty in ground motion estimation. The development of the NGA-West2 ground motion prediction equations (GMPEs) is a collaborative effort with many interactions and exchange of ideas among the developers. Despite the fact that the NGA-West2...