Comparison of multiple support excitation solution techniques for piping systems

Although post-earthquake observations identified spatial variation of ground motion (i.e., multiple-support excitation) as a frequent cause of the unfavorable response of long-span bridges, this phenomenon is often not taken into account in seismic design to simplify the calculation procedure. This study investigates the influence of multiple-support excitation accounting for coherency loss and wave-passage effects on the seismic response of reinforced concrete deck arch bridges of long spans founded on rock sites. Parametric numerical study was conducted using the time-history method, the response spectrum method, and a simplified procedure according to the European seismic standards. Results showed that multiple-support excitation had a detrimental influence on response of almost all analyzed bridges regardless of considered arch span. Both considered spatial variation effects, acting separately or simultaneously, proved to be very important, with their relative significance depending on the response values and arch locations analyzed and seismic records used. Therefore, it is suggested that all spatially variable ground-motion effects are taken into account in seismic analysis of similar bridges.

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Comparison of seismic responses of a reticulated dome under stochastic uniform and spatially correlated and coherent multiple-support excitation for a scenario seismic event

International Journal of Space Structures ◽

10.1177/0956059920931012 ◽

2020 ◽

Vol 35 (4) ◽

pp. 113-125

Author(s):

YG Li ◽

TJ Liu ◽

F Fan ◽

HP Hong

Keyword(s):

Spatial Correlation ◽

Seismic Event ◽

Amplitude Spectrum ◽

Spatial Coherence ◽

Single Layer ◽

Seismic Load ◽

Seismic Responses ◽

Spatially Correlated ◽

Multiple Support ◽

Support Excitation

Structures with multiple supports can be sensitive to spatial coherence and spatial correlation. Since the historical recordings are insufficient for selecting records that match predefined inter-support distances of a structure, desired seismic magnitude (or intensity) and site to seismic source distance for structural analysis, such records need to be simulated. In this study, we use a procedure that is extended based on the stochastic point-source method to simulate records for scenario events. The application of the simulated records to a single-layer reticulated dome with multiple supports is presented. The application is aimed at investigating the differences between the responses subjected to spatially uniform excitation and to spatially correlated and coherent multiple-support excitation for a scenario seismic event, assessing the relative importance of the spatial coherence and spatial correlation on the responses, and evaluating the effect of the uncertainty in the spatially correlated and coherent records for a scenario event on the statistics of the seismic responses. The analysis results indicate that the spatial correlation of the Fourier amplitude spectrum has a predominant influence on the linear/nonlinear responses, and the consideration of spatially correlated and coherent excitation at multiple supports is very important. The consideration of uniform excitation severely underestimates the seismic load effects as compared to those obtained under spatially correlated and coherent multiple-support excitation.

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Efficient Estimation of Seismic Response of Large-Span Structures Considering the Effect of Multiple-Support Excitation

Journal of Engineering Mechanics ◽

10.1061/(asce)em.1943-7889.0001667 ◽

2019 ◽

Vol 145 (12) ◽

pp. 04019096 ◽

Cited By ~ 1

Author(s):

Han Qin ◽

Luyu Li ◽

Billie F. Spencer

Keyword(s):

Seismic Response ◽

Efficient Estimation ◽

Large Span ◽

Multiple Support ◽

Support Excitation

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A Test and Analysis of the Multiple Support Piping Systems

Journal of Pressure Vessel Technology ◽

10.1115/1.3265677 ◽

1989 ◽

Vol 111 (3) ◽

pp. 291-299 ◽

Cited By ~ 2

Author(s):

T. Chiba ◽

R. Koyanagi ◽

N. Ogawa ◽

C. Minowa

Keyword(s):

Large Scale ◽

Response Spectrum ◽

Steel Structures ◽

Response Spectra ◽

Piping System ◽

Multiple Response ◽

Actual Behavior ◽

Test Results ◽

Piping Systems ◽

Multiple Support

One of the current topics in the seismic design of piping systems is the overall reliability of them in earthquake events. Actual piping systems are generally supported by independent structures such as vessels and steel structures. So, it is very important to clarify the behavior of actual piping systems during the seismic events. For this purpose, the analytical method of multiple excitation problems is a preferable approach to not only evaluate the actual behavior of the piping systems, but also improve the reliability of piping systems. To clarify the dynamic characteristics of the piping systems and to assess the computational methods in the linear system subjected to multiple support excitations, an experimental study using a realistic large-scale piping model has been conducted. The equations for the multiple excitation problem have been validated and the adequacy of the multiple response spectra method has been confirmed by the comparison of the test results with the analytical one. This paper reports the results focusing on the analytical methods of the multiple support piping system. It is noted that the multiple response spectrum method is efficient for the multiple excitation problems.

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A Load Combination Method for Seismic Design of Multi-Degree-of-Freedom Piping Systems With Friction Characteristics and Multiple Support Systems

Volume 8: Seismic Engineering ◽

10.1115/pvp2014-28132 ◽

2014 ◽

Cited By ~ 1

Author(s):

Akira Sone ◽

Tatsuya Yamauchi ◽

Arata Masuda

Keyword(s):

Degree Of Freedom ◽

Combination Method ◽

Piping System ◽

Theory Approach ◽

Maximum Acceleration ◽

Friction Characteristics ◽

Load Combination ◽

Combination Scheme ◽

Piping Systems ◽

Multiple Support

A load combination scheme for seismic response calculation of multi-degree-of-freedom (MDOF) piping systems with friction characteristics to multiple support excitations is presented. This scheme has an advantage, such that the “response reduction factor” due to friction is taken into account by use of a stationary random vibration theory approach. Using a simple and analytical 5DOF piping system with friction characteristics to two support excitations, combination law is supplied to various friction characteristics and the maximum responses of piping is calculated. From these calculation results, it is clear that the maximum acceleration responses of piping systems calculated by the proposed scheme are reasonable compared with those by the numerical simulations.

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Stochastic Response of Piping Systems With Flexible Supports

Journal of Pressure Vessel Technology ◽

10.1115/1.2842152 ◽

1996 ◽

Vol 118 (1) ◽

pp. 109-114 ◽

Cited By ~ 1

Author(s):

H. O. Soliman ◽

T. K. Datta

Keyword(s):

Frequency Domain ◽

Cross Sections ◽

Equations Of Motion ◽

Response Analysis ◽

Piping System ◽

Dynamic Stresses ◽

Support Points ◽

Flexible Supports ◽

Piping Systems ◽

Support Excitation

A frequency domain spectral analysis of piping systems with flexible supports is presented for uniformly modulated nonstationary support excitations. The support points are idealized by spring-dashpot arrangements. The equations of motion of the resulting nonclassically damped, multipoint excitation system are written and solved in terms of the absolute displacements of the dynamic DOF. This facilitates a direct computation of the dynamic stresses induced at various cross sections of the pipe segments. The method of analysis provides a quasi-stationary response based on the assumption that the modulating function varies slowly with time; the exact response analysis in frequency domain for such systems with nonstationary support excitation is difficult to determine. Using the method of analysis presented, the response of a piping system is obtained for a set of important parametric variations related to the flexibility, damping, and excitation of the supports.

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