New PEER Reports

 The following reports are available from the National Information Service for Earthquake Engineering (NISEE). To order, please contact the Pacific Earthquake Engineering Research Center, 1301 South 46th Street, Richmond, California 94804-4698. Tel.: (510) 231-9468; Fax: (510) 231-9461;

PEER 2001/03 A Modal Pushover Analysis Procedure to Estimate Seismic Demands for Buildings: Theory and Preliminary Evaluation. Anil K. Chopra and Rakesh K. Goel.

The principal objective of this investigation is to develop a pushover analysis procedure based on structural dynamics theory, which retains the conceptual simplicity and computational attractiveness of current procedures with invariant force distribution, but provides superior accuracy in estimating seismic demands on buildings. The standard response spectrum analysis (RSA) for elastic buildings is reformulated as a Modal Pushover Analysis. The MPA procedure is extended to estimate the seismic demands for inelastic systems.

PEER 2000/07 Cover-Plate and Flange-Plate Reinforced Steel Moment-Resisting Connections. Taejin Kim, Andrew S. Whittaker, Amir S. Gilani, Vitelmo V. Bertero, and Shakhzod M. Takhirov.

Five cover-plate and five flange-plate-reinforced steel moment-resisting connections were studied by analysis and experimentation. All ten were single-sided steel beam-column assemblies that are representative of exterior beam-column connections, and all ten were composed of W14x176 Grade 50 columns and S30x99 Grade 50 beams. The reinforcing plates were fabricated from Grade 50 steel. A solid-element model of each connection was prepared and analyzed before the fabrication of the test specimens. Following completion of the testing program, solid-element and shell-element models of selected connections were prepared using measured material properties and were analyzed for the purpose of augmenting the experimental observations.

PEER 2000/05 Performance-Based Evaluation of Exterior Reinforced Concrete Building Joints for Seismic Excitation. Chandra Clyde, Chris P. Pantelides, and Lawrence D. Reaveley.

Reinforced concrete (RC) buildings that were built in the 1960s behave in a nonductile manner and do not meet current seismic design criteria. In this report, beam-column joints of such nonductile buildings were investigated using several performance-based criteria. Four half-scale RC exterior joints were tested to investigate their behavior in a shear-critical mode. The joints were subjected to quasi-static cyclic loading, and their performance was examined in terms of lateral load capacity, drift, axial load reduction in the column at high levels of drift, joint shear strength, ductility, shear angle, residual strength, and other PEER-established performance criteria. Two levels of axial compression load in the columns were investigated, and their influence on the performance of the joint is discussed.

PEER 2000/04 An Evaluation of Seismic Energy Demand: An Attenuation Approach. Chung-Che Chou and Chia-Ming Uang.

As a first step for the development of an energy-based procedure for seismic design and verification, establishing seismic demand in the form of absorbed energy spectra for an inelastic single-degree-of-freedom system was the main objective of this research. The absorbed energy (Ea), not the input energy or hysteresis energy, was selected as the key demand parameter because it is not only related to the yield strength but is also directly attributed to the damage to the structure. Furthermore, expressing Ea in its equivalent velocity form ( where m = mass), Va converges to pseudo-velocity (V) in the special case when the structure responds elastically. Thus the proposed Va parameter bridges the seismic demands for both the energy-based and force-based design methods. Based on 273 strong ground motion records from 15 earthquakes in California, an attenuation relationship was used to relate Va to the earthquake magnitude, source-to-site distance, and site class. Va , which represents the equivalent velocity of the geometric mean of Ea values for two randomly oriented components of each record, was computed at 27 periods (0.1 sec to 3.0 sec) for 3 ductility levels (2, 4, and 6).

PEER 1999/12 Rehabilitation of Nonductile RC Frame Building Using Encasement Plates and Energy-Dissipating Devices. Mehrdad Sasani, Vitelmo V. Bertero, James C. Anderson.

A general seismic rehabilitation and upgrade approach is developed for existing nonductile reinforced concrete (RC) moment frame buildings. A review of the design and as-built drawings of such existing buildings reveals that one of the main weaknesses is the lack of transverse (shear) reinforcement in the beam-column joints. An upgrade approach is conducted centered on the use of a steel jacket placed around each of these joints. The study was conducted on an existing instrumented building that had already been subjected to at least moderate earthquake ground motions in order to calibrate the analytical models and computations involved in the analyses of its response and degree of damage.