PEER Reports

PEER Reports

Shear Wave Velocity as a Statistical Function of Standard Penetration Test Resistance and Vertical Effective Stress at Caltrans Bridge Sites, PEER Report 2010-03

Scott J. Brandenberg
Naresh Bellana
Thomas Shantz
2010

Shear wave velocity, Vs, is defined as a statistical function of SPT blow count, N60, and vertical effective stress, σv', using a data set collected at various California bridge sites. At each site, Vs measurements were recorded by suspension logging in the same borehole in which N60 was measured. Regression analysis was used to derive statistical relations for sand, silt, and clay soil types. The relation between Vs and N60 is shown to depend strongly on σv', since Vs and N60 normalize differently with...

In-Situ Monitoring of the Force Output of Fluid Dampers: Experimental Investigation, PEER Report 2011-103

Dimitrios Konstantinidis
James M. Kelly
Nicos Makris
2011

An alarming problem of leaking dampers has emerged in recent years in some California bridges, such as the west span of the San Francisco–Oakland Bay Bridge and the Vincent Thomas Bridge crossing the Los Angeles Harbor. This reports presents the results of an experimental testing program that was undertaken to develop and validate a simple and reliable way to monitor the force output of viscous fluid dampers in bridges.

The research includes indoor and outdoor experiments on two medium-size (250 kips at 42 in/sec piston velocity, ±8.0 in. stroke capacity) and two...

Design and Instrumentation of the 2010 E-Defense Four-Story Reinforced Concrete and Post-Tensioned Concrete Buildings, PEER Report 2011-104

Takuya Nagae
Kenichi Tahara
Taizo Matsumori
Hitoshi Shiohara
Susumu Kono
Minehiro Nishiyama
John Wallace
Wassim Ghannoum
Jack Moehle
Richard Sause
Wesley Keller
Zeynep Tuna
2011

This study reports on a collaborative research on the design, instrumentation, and preliminary analytical studies of two, full-scale, four-story buildings tested simultaneously on the NIED E-Defense shake table in December 2010. The two buildings are similar, with the same height and floor plan; one building utilized a conventional reinforced concrete (RC) structural system with shear walls and moment frames, whereas the other utilized the same systems constructed with post-tensioned (PT) members. The buildings were subjected to increasing intensity shaking using the JMA-Kobe record until...

Self Compacting Hybrid Fiber Reinforced Concrete Composites for Bridge Columns, PEER Report 2011-106

Pardeep Kumar
Gabriel Jen
William Trono
Marios Panagiotou
Claudia P. Ostertag
2011

Although fiber-reinforced composites have the potential to enhance the seismic performance of bridge columns, their use has been hampered by their poor workability and inadequate compaction for cast-in-place applications. To address this issue, this study developed a self-compacting hybrid fiber reinforced concrete (SC- HyFRC) composite. Optimized specifically for bridge columns, this composite flows under its own weight, completely filling the formwork and achieving full compaction without internal or external vibration. In addition, this SC-HyFRC provides enhanced ductility, shear...

Nonlinear Site Response and Seismic Compression at Vertical Array Strongly Shaken by 2007 Niigata-ken Chuetsu-oki Earthquake, PEER Report 2011-107

Eric Yee
Jonathan P. Stewart
Kohji Tokimatsu
2011

Strong ground motions from the Mw 6.6 2007 Niigata-ken Chuetsu-oki earthquake were recorded by a free-field downhole array installed near the Service Hall at the Kashiwazaki-Kariwa nuclear power plant. Site conditions at the array consist of about 70 m of medium-dense sands overlying clayey bedrock, with ground water located at 45 m. Ground shaking at the bedrock level had geometric mean peak accelerations of 0.55 g, which reduced to 0.4 g at the ground surface, indicating nonlinear site response. Ground settlements of approximately 15±5 cm occurred at the site. A site...

A Bayesian Network Methodology for Infrastructure Seismic Risk Assessment and Decision Support, PEER Report 2011-02

Michelle T. Bensi
Armen Der Kiureghian
Daniel Straub
2011

A Bayesian Network (BN) methodology is developed for performing infrastructure seismic risk assessment and providing decision support with an emphasis on immediate post-earthquake applications. A BN is a probabilistic graphical model that represents a set of random variables and their probabilistic dependencies. The variables may represent demand or capacity values, or the states of components and systems. Decision and utility nodes may be added that encode various decision alternatives and associated costs, thus facilitating support for decision-making under uncertainty.

BNs have...

New Ground Motion Selection Procedures and Selected Motions for the PEER Transportation Research Program, PEER Report 2011-03

Jack W. Baker
Ting Lin
Shrey K. Shahi
Nirmal Jayaram
2011

The primary goal of this project was to develop strategies for selecting standardized sets of ground motions for use by the Pacific Earthquake Engineering Research Center’s Transportation Research Program. The broad research activities of the Transportation Research Program require ground motions for use in a variety of applications, including analysis of structural and geotechnical systems at locations throughout California (or other active areas where seismic hazard is dominated by mid- to large-magnitude crustal earthquakes at near to moderate distances). The systems of interest may be...

Recommended Design Practice for Pile Foundations in Laterally Spreading Ground, PEER Report 2011-04

Scott A. Ashford
Ross W. Boulanger
Scott J. Brandenberg
2011

This report presents recommended procedures and practices for the design and performance evaluation of pile foundations for bridges in areas subject to lateral spreading hazards. The past decade of research has produced numerous insights into the behavior and performance of pile foundations and bridges impacted by liquefaction and lateral spreading. The purpose of this report is to develop a set of recommended procedures and practices for analysis and design that are based on a synthesis of research findings when supporting research is available, and on the professional opinions of the...

Calibration of Semi-Stochastic Procedure for Simulating High-Frequency Ground Motions, PEER Report 2011-09

Jonathan P. Stewart
Emel Seyhan
Robert W. Graves
2011

Broadband ground motion simulation procedures typically utilize physics-based modeling of source and path effects at low frequencies coupled with semi-stochastic procedures at high frequencies. The high-frequency procedure considered here combines a deterministic Fourier amplitude spectrum that is a function of closed-form source, path, and site models with a random phase. Previous analysis of the simulation procedure in the ShakeOut exercise demonstrated faster distance attenuation and lower intra-event dispersion of high-frequency ground motions than in empirical ground motion equations...

Spectral Damping Scaling Factors for Shallow Crustal Earthquakes in Active Tectonic Regions, PEER Report 2012-01

Sanaz Rezaeian
Yousef Bozorgnia
I.M. Idriss
Kenneth Campbell
Norman Abrahamson
Walter Silva
2012

Ground motion prediction equations (GMPEs) for el astic response spectra, including the Next Generation Attenuation (NGA) models, are typically developed at a 5% viscous damping ratio. In reality, however, structural and non-structural systems can have damping ratios other than 5%, depending on various factors such as structural types, construction materials, level of ground motion excitations, among others. This report provides the findings of a comprehensive study to develop a new model for a Damping Scaling Factor ( DSF) that can be used to adjust the 5% damped spectral...