PEER Reports

PEER Reports

PEER Preliminary Notes and Observations on the August 24, 2014 South Napa Earthquake, PEER Report 2014-13

Grace S. Kang
Stephen A. Mahin
2014

At 3:20 AM, on the morning of August 24, 2014, the San Francisco Bay ar ea was shaken by the South Napa, California, earthquake. According to the USGS, the earthquake had a magnitude (M w) of 6, making it the largest earthquake to strike the San Francisco Bay Area since 1989, when the region was shaken by the magnitude 6. 9 Loma Prieta earthquake. The epicenter was located about 8 km (5 miles) SSW of Napa, a city of about 77,000 people. Other nearby cities include American Canyon, Vallejo, and Sonoma. Located on the north ern shores of San Francisco Bay, this region is a popular tourist...

Stochastic Modeling and Simulation of Near-Fault Ground Motions for Performance-Based Earthquake Engineering, PEER Report 2014-20

Mayssa Dabaghi
Armen Der Kiureghian
2014

A comprehensive parameterized stochastic model of near-fault ground motions in two orthogonal horizontal directions is developed. The proposed model uniquely combines several existing and new sub-models to represent major characteristics of recorded near-fault ground motions. These characteristics include near-fault effects of directivity and fling step; temporal and spectral non-stationarity; intensity, duration and frequency content characteristics; directionality of components, as well as the natural variability of motions for a given earthquake and site scenario. By fitting the model...

NGA-East: Adjustments to Median Ground-Motion Models for Central and Eastern North America, PEER Report 2015-08

2015

This report documents a series of adjustments developed for the median ground-motion models (GMMs) developed as part of the Next Generation Attenuation for Central and Eastern North America (CENA) project (NGA-East). NGA-East is a multi-disciplinary research project coordinated by the Pacific Earthquake Engineering Research Center (PEER) that involves a large number of participating junior and senior researchers, practitioners, and end-users. Various organizations have provided technical input to the project from academia, industry, and government agencies. The objective of NGA-East is to...

Structural Behavior of Column-Bent Cap Beam-Box Girder Systems in Reinforced Concrete Bridges Subjected to Gravity and Seismic Load, Part I: Pre-test Analysis and Quasi-Static Experiments, PEER Report 2015-09

Mohamed A. Moustafa
Khalid M. Mosalam
2015

This report presents a study for investigating the behavior of a column-bent cap beam-box girder bridge subassembly with special focus on the bent cap structural behavior. The main objective of this study was to accurately estimate the contributions of the deck and soffit slabs framing into the bent cap in reinforced concrete box-girder bridge systems under the combined effect of vertical and lateral loading. In particular, the study estimated the effective flange width of the bent cap beam due to the box-girder slabs contributions for more accurate and effective consideration of the...

Structural Behavior of Column-Bent Cap Beam-Box Girder Systems in Reinforced Concrete Bridges Subjected to Gravity and Seismic Load, Part II: Hybrid Simulation and Post-Test Analysis, PEER Report 2015-10

Mohamed A. Moustafa
Khalid M. Mosalam
2015

This report presents the second half of the discussion of a mixed experimental-computational study that aimed at investigating the structural and seismic behavior of integral bent caps in reinforced concrete (RC) box-girder bridges. The main objective of the study was to accurately estimate the contributions of the deck and soffit slabs framing into the bent cap in as-built and retrofitted RC bridge systems under the combined effect of vertical and lateral loading. In particular, the study estimated the effective flange width of the bent cap beam due to the box-girder slabs contributions...

Selection and Scaling of Ground Motions for Nonlinear Response History Analysis of Buildings in Performance-Based Earthquake Engineering, PEER Report 2015-11

N. Simon Kwong
Anil K. Chopra
2015

This report investigates the issue of selecting and scaling ground motions as input excitations for response history analyses of buildings in performance-based earthquake engineering. Many ground motion selection and modification (GMSM) procedures have been developed to select ground motions for a wide variety of objectives. This report focuses on the selection and scaling of single, horizontal components of ground motion for estimating seismic demand hazard curves (SDHCs) of multistory frames at a given site.

Chapter 2 develops a framework for evaluating GMSM procedures in their...

Simulation Confidence in Tsunami-Driven Overland Flow, PEER Report 2016-03

Patrick Lynett
2016

Numerical models are a key component for methodologies used to estimate tsunami risk, and model predictions are essential for the development of Tsunami Hazard Assessments (THAs). By better understanding model bias and uncertainties and, if possible, minimizing them, a more reliable THA will result. This study compares the run-up height, inundation lines, and flow- velocity field measurements between GeoClaw and the Method of Splitting Tsunami (MOST) model predictions in the Sendai Plain. In general, run-up elevation and average inundation distance are overpredicted by the models. However...

The Mw 6.0 South Napa Earthquake of August 24, 2014: A Wake-up Call for Renewed Investment in Seismic Resilience across California, PEER Report 2016-04

Laurie A. Johnson
Stephen A. Mahin
2016

The magnitude 6.0 South Napa Earthquake of August 24, 2014, took the lives of two people, injured 300 others, and caused moderate to severe damage to more than 2,000 structures. It is one of the first damaging earthquakes to strike a major metropolitan area in the State of California in over two decades. During that time period, California’s population has grown by over 25%, the state’s economy has tripled, and a great many of the state’s new residents and businesses have never experienced a major earthquake. It is almost guaranteed that there will be a major damaging earthquake somewhere...

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....