PEER Reports

PEER Reports

Unbonded Pre-Tensioned Columns for Bridges in Seismic Regions, PEER Report 2012-04

Phillip M. Davis
Todd M. Janes
Marc O. Eberhard
John F. Stanton
2012

The severe traffic delays caused by traditional cast-in-place bridge construction can be reduced by precasting components off site and assembling them rapidly on site. In seismic regions, connecting precast concrete columns and beams creates difficulties because the connections often occur at the locations of large, inelastic moment reversals. Previous researchers have addressed this challenge through the development of a “Large-Bar, Large Duct” [Pang et al. 2008] and a “Socket” connection [Haraldsson et al. 2011]. Both connections are easy to construct and robust under simulated seismic...

Development of Simplified Analysis Procedure for Piles in Laterally Spreading Layered Soils, PEER Report 2012-05

Christopher R. McGann
Pedro Arduino
Peter Mackenzie-Helnwein
2012

This work presents the development of a simplified procedure for the analysis of liquefaction–induced lateral spreading using a beam on nonlinear Winkler foundation approach. A three-dimensional finite element model, considering a single pile in a soil continuum, is used to simulate lateral spreading and two alternative lateral load cases. Sets of p – y curves representative of the soil response in the 3D model are computed for various soil–pile systems. The affects of pile kinematics on these curves are evaluated and a computational procedure for p – y curves is proposed...

Fragilities for Precarious Rocks at Yucca Mountain, PEER Report 2012-06

Matthew D. Purvance
Rasool Anooshehpoor
James N. Brune
2012

Geomorphic features easily damaged by ground shaking can be used to constrain unexceeded ground motions during the feature residence times. Such features, in the form of precariously balanced rocks and fragile rock stacks, exist on the western flanks of Yucca Mountain, Nevada, the proposed site of the nation's first high-level radioactive nuclear waste repository. A set of the most fragile geological features found to date are detailed and digital representations are developed in this report. Their fragilities when shaken by representative ground motions are determined via three-...

Earthquake Engineering for Resilient Communities: 2012 PEER Internship Program Research Report Collection, PEER Report 2012-07

Heidi Tremayne
Stephen A. Mahin
Collin Anderson
Dustin Cook
Michael Erceg
Carlos Esparza
Jose Jimenez
Dorian Krausz
Andrew Lo
Stephanie Lopez
Nicole McCurdy
Paul Shipman
Alexander Strum
Eduardo Vega
2012

Recent earthquakes in the United States and around the world have repeatedly shown that earthquake resilience is essential to building and sustaining urban communities. Earthquake resilience will play an increasingly important role in the professions associated with earthquake hazard mitigation, thus there is a need to educate the next generation of these professionals. To address this need, the Pacific Earthquake Engineering Research Center (PEER) coordinates a summer internship program for undergraduate students that focuses on the theme of earthquake- resilient communities. With funding...

Guidelines for Estimation of Shear Wave Velocity, PEER Report 2012-08

Bernard R. Wair
Jason T. DeJong
Thomas Shantz
2012

Characterization of the small-strain shear modulus and the shear wave velocity of soils and rocks is an integral component of various seismic analyses, including site classification, hazard analysis, site response analysis, and soil–struct ure interaction. The Next Generation Attenuation ground motion prediction equations use the shear wave velocity of the top 30 m of the subsurface profile (VS30 ) as the primary parameter for characterizing the effects of sediment stiffness on ground motions. This report presents guidelines for estimating the shear wave velocity profiles in the...

PEER NGA-West2 Database, PEER Report 2013-03

Timothy D. Ancheta
Robert B. Darragh
Jonathan P. Stewart
Emel Seyhan
Walter J. Silva
Brian S.J. Chiou
Katie E. Wooddell
Robert W. Graves
Albert R. Kottke
David M. Boore
Tadahiro Kishida
Jennifer L. Donahue
2013

The NGA-West2 project database expands on the current PEER NGA ground-motion database to include worldwide ground-motion data recorded from shallow crustal earthquakes in active tectonic regimes post 2003. Since 2003, numerous well-recorded events have occurred worldwide, including the 2003 M6.6 Bam (Iran), 2004 M6 Parkfield (California), 2008 M7.9 Wenchuan (China), 2009 M6.3 L’Aquila (Italy), 2010 M7.2 El Mayor-Cucupah (California and Mexico), 2010 M7 Darfield (New Zealand), 2011 ...

Update of the AS08 Ground-Motion Prediction Equations Based on the NGA-West2 Data Set, PEER Report 2013-04

Norman A. Abrahamson
Walter J. Silva
Ronnie Kamai
2013

Empirical ground-motion models for the average horizontal component from shallow crustal earthquakes in active tectonic regions are derived using the PEER NGA-West2 database. The model is applicable to magnitudes 3.0—8.5, distances 0—300 km, and spectral periods of 0—10 sec. The model input parameters are the same as used by Abrahamson and Silva (2008) with the following exceptions: the loading level for nonlinear effects is based on the spectral acceleration at the period of interest rather than the PGA; the distance scaling for HW effects off the ends of the rupture includes a dependence...

Final Report of the NGA-West2 Directivity Working Group, PEER Report 2013-09

Paul Spudich
Jeffrey R. Bayless
Jack W. Baker
Brian S.J. Chiou
Badie Rowshandel
Shrey K. Shahi
Paul Somerville
2013

The 2008 Next Generation Attenuation (NGA-West1) ground motion prediction equations (GMPEs) did not include directivity; it was implemented as a post-facto correction without guidance for its application. The NGA-West2 GMPEs may be developed including the effects of directivity. Four directivity models (DMs) have been developed based on data from the NGA- West2 database and based on numerical simulations of large strike-slip and reverse-slip earthquake. All DMs avoid the use of normalized fault dimension, enabling them to scale up to the largest earthquakes sensibly. Models by Shahi and...

Nonlinear Horizontal Site Response for the NGA-West2 Project, PEER Report 2013-12

Ronnie Kamai
Norman A. Abrahamson
Walter J. Silva
2013

The nonlinear soil amplification models developed by Walling et al. (2008) are revisited for two main reasons: (a) the simulation database on which the models were developed has been updated and extended, with additional magnitudes and soil profiles, and (b) two alternatives for the input shaking parameter are explored – the Peak Ground Acceleration (PGA) and the spectral acceleration for each period, (Sa(T)). The benefits and limitations of each alternative are discussed.

The model is based on site amplification factors, relative to a VS30 =1170 m/sec site, computed for...

Effect of Hoop Reinforcement Spacing on the Cyclic Response of Large Reinforced Concrete Special Moment Frame Beams, PEER Report 2013-16

Marios Panagiotou
Tea Visnjic
Grigorios Antonellis
Panagiotis Galanis
Jack P. Moehle
2013

Recent developments in the construction of high-rise buildings in the highly seismic regions of the United States have resulted in construction of reinforced concrete special moment frame beams that are larger compared to those used previously. Governing building code requirements (ACI 318-08) for these beams were introduced in ACI 318-83 and are based on prevailing practices and technical knowledge from that period. When the existing provisions are applied to the larger beams that are now prevalent, hoop spacing can be as large as 305 mm (12 in.) in the beam plastic-hinge zone. An...