Precast concrete facilitates a construction method using durable and rapidly erectable prefabricated members to create costeffective and high-quality structures. In this method, the connections between the precast members as well as between the members and the foundation require special attention to ensure good seismic performance. Extensive research conducted since the 1980s has led to new precast concrete structural systems, designs, details, and techniques that are particularly suited for use in regions of high seismic hazard. This paper reviews the state of the art of these advances, including code developments and practical applications, related to four different systems: (1) moment frames; (2) structural walls; (3) floor diaphragms; and (4) bridges. It is concluded from this review that the widespread use of precast concrete in seismic regions is feasible today and that the jointed connection innovation introduced through precast research leads to improved seismic performance of building and bridge structures.dividual papers. This paper is part of the Journal of Structural Engineering, © ASCE, ISSN 0733-9445. © ASCE 03118001-1 J. Struct. Eng. J. Struct. Eng., 2018, 144(4): 03118001 Downloaded from ascelibrary.org by University of Notre Dame on 01/17/18. Copyright ASCE. For personal use only; all rights reserved. © ASCE 03118001-2 J. Struct. Eng. J. Struct. Eng., 2018, 144(4): 03118001 Downloaded from ascelibrary.org by University of Notre Dame on 01/17/18. Copyright ASCE. For personal use only; all rights reserved. © ASCE 03118001-3 J. Struct. Eng. J. Struct. Eng., 2018, 144(4): 03118001 Downloaded from ascelibrary.org by University of Notre Dame on 01/17/18. Copyright ASCE. For personal use only; all rights reserved. © ASCE 03118001-4 J. Struct. Eng. J. Struct. Eng., 2018, 144(4): 03118001 Downloaded from ascelibrary.org by University of Notre Dame on 01/17/18. Copyright ASCE. For personal use only; all rights reserved. © ASCE 03118001-5 J. Struct. Eng. © ASCE 03118001-10 J. Struct. Eng. J. Struct. Eng., 2018, 144(4): 03118001 Downloaded from ascelibrary.org by University of Notre Dame on 01/17/18. Copyright ASCE. For personal use only; all rights reserved. © ASCE 03118001-11 J. Struct. Eng. J. Struct. Eng., 2018, 144(4): 03118001 Downloaded from ascelibrary.org by University of Notre Dame on 01/17/18. Copyright ASCE. For personal use only; all rights reserved. © ASCE 03118001-18 J. Struct. Eng. J. Struct. Eng., 2018, 144(4): 03118001 Downloaded from ascelibrary.org by University of Notre Dame on 01/17/18.

Summary: This paper presents the development of a deformable connection that is used to connect each floor system of the flexible gravity load resisting system (GLRS) with the stiff lateral force resisting system (LFRS) of an earthquake-resistant building. It is shown that the deformable connection acts as a seismic response modification device, which limits the lateral forces transferred from each floor to the LFRS and allows relative motion between the GLRS and LFRS. In addition, the floor accelerations and the LFRS story shears related to the highermode responses are reduced. The dispersion of peak responses is also significantly reduced. Numerical simulations of the earthquake response of a 12-story reinforced concrete shear wall example building with deformable connections are used to define an approximate feasible design space for the deformable connection. The responses of the example building model with deformable connections and the example building model with rigid-elastic connections are compared. Two configurations of the deformable connection are studied. In one configuration, a buckling restrained brace is used as the limited-strength load-carrying hysteretic component of the deformable connection, and in the other configuration, a friction device is used. Low damping laminated rubber bearings are used in both configurations to ensure the out-of-plane stability of the LFRS and to provide post-elastic stiffness to the deformable connection. Important experimental results from full-scale tests of the deformable connections are presented and used to calibrate numerical models of the connections.Original language English

His research activities include the seismic design and retrofit of precast and reinforced concrete bridges and buildings.

No abstract

Building structures are typically designed using the assumption that the oor systems serve as a rigid diaphragm between the vertical elements of the lateral load-resisting system. However, long-oor span structures with perimeter lateral load-resisting systems possess diaphragms which behave quite exibly. The dynamic behaviour of such structures is dissimilar to the behavior expected of typical structures. This di erence can lead to unexpected force and drift patterns. If force levels are su ciently underestimated, inelastic diaphragm behaviour can occur, exacerbating the e ects of diaphragm exibility. Such response may lead to a non-ductile diaphragm failure or structural instability due to high drift demands in the gravity system.Analytical models were developed which capture the diaphragm exibility of structures with long-oor spans and perimeter lateral-systems. Modal examination and time-history analyses were performed to determine the e ect of diaphragm exibility and diaphragm inelastic behaviour on the dynamic behaviour of these structures.

Summary This paper presents experimental and numerical studies of a full‐scale deformable connection used to connect the floor system of the flexible gravity load resisting system to the stiff lateral force resisting system (LFRS) of an earthquake‐resistant building. The purpose of the deformable connection is to limit the earthquake‐induced horizontal inertia force transferred from the floor system to the LFRS and thereby to reduce the horizontal floor accelerations and the forces in the LFRS. The deformable connection that was studied consists of a friction device (FD) and carbon fiber‐reinforced laminated low‐damping rubber bearings (RB), denoted as the FD + RB connection. The test results show that the force‐deformation responses of the FD + RB connection are stable under quasi‐static sinusoidal and earthquake loading histories and dynamic sinusoidal loading histories. The FD + RB connection force‐deformation response is approximated with a bilinear elastic‐plastic force‐deformation response with kinematic hardening. The FD is axially stiff, compact, easy‐to‐assemble, and able to accommodate the FD + RB connection kinematic requirements. The FD elastic stiffness controls the FD + RB connection elastic stiffness. The FD friction force controls the force when the FD + RB connection force‐deformation response transitions from elastic to post elastic. The RB provide predictable and reliable post‐elastic stiffness to the FD + RB connection. The machining tolerances for the FD components, the “break‐in” effect, the sliding history, and the dwell time affect the FD friction force. Numerical simulation results for a 12‐story reinforced concrete wall building with FD + RB connections under seismic loading show that a reduction of the FD friction force increases the FD + RB connection deformation demand.

Building structures are typically designed using the assumption that the floor systems serve as a rigid diaphragm between the vertical elements of the lateral force-resisting system (lateral system). However, perimeter lateralsystem structures with long floor spans possess diaphragms that behave quite flexibly. Difficulty can exist in predicting diaphragm force demand in these structures. Thus, current design may provide insufficient strength to maintain elastic diaphragm response. Inelastic diaphragm response exacerbates the effects of diaphragm flexibility. Such response may lead to poor seismic performance, including nonductile diaphragm failure or structural instability due to high drift demands in the gravity system. An analytical study was performed to determine the effect of diaphragm flexibility and strength on the seismic performance of perimeter lateral-system structures with highly flexible diaphragms. Nonlinear transient analyses were performed using ground motions suites corresponding to multiple levels of hazard for high seismic zones. Design recommendations for flexible diaphragms are presented.

No abstract