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Microcomputer implementation of digital control strategies for structural response reduction
I
6
SURFACE STRUCTURES:DYNAMIC
Influence
of dynamic loads
955294 Microcomputer implementation of digital control strategies for structural response reduction P. Quast, M. K. Sam, B. F. Spencer Jr & S. J. Dyke, Microcomputers in Civil Engineering, 10(l), 1995, pp 13-25. Recently developed hardware based on dedicated digital signal processing chips has offered new possibilities for control algorithm implementation. This paper discusses digital control system concepts and specific practical aspects of digital control implementation, including the use of supervision. Details regarding active structural control using the Texas Instruments TMS32OC30 DSP chip and experimental verification of the hardware performance are given. (Authors)
955297
An optimized implementation of the Newmark/NewtonRaphson algorithm for the time integration of non-linear problems B. Pinheiro Jacob & N. F. Favilla Ebecken, Communications in Numerical Methods in Engineering, 10(12), 1994, pp 983992. The paper describes an optimized computational implementation of a basic ‘building block’ for non-linear structural dynamic analysis programs. The objective of this implementation is to attain improved computational efficiency, regarding both CPU time and memory requirements. The basic formulation and derivation are presented, along with the implementation details; the positive aspects related to the computational optimization are highlighted. (Authors)
955298 Six-degree-of-freedom ground-motion measurement R. L. Nigbor, Bulletin - Seismological Society of America, 84(S), 1994, pp 1665-1669. True six-degree-of-freedom (6DOF) measurement of freefield strong ground motion has been accomplished using a prototype 6DQF accelerograph system. This system consists of a traditional triaxial translational accelerometer, three new rotational velocity sensors, and a digital data logger. Rotational and translational ground motions at a single free-field location were measured successfully during the recent NPE event, a very large (1 kton) chemical explosion. (from Author)
955299 Wave dispersion and optimal mass modelling for onedimensional periodic structures N. Fukuwa & S. Matsushima, Earthquake Engineering & Structural Dynamics, 23(1 l), 1994, pp 1165-l 180. Discrete analysis methods are frequently used for the study of the structure and soil. However, the assumption of the displacement interpolation function makes the waves dispersive, which means numerical dispersion. The wave dispersion induced by discretixation depends on mass modelling. Also, the existence of added lumped masses makes waves dispersive even for continuum modelling. In order to examine these wave dispersions, a one-dimensional period structure is adopted as an analysis model and the dynamic transfer matrix method is applied. The optimal consistent mass ratio makes the wave velocity of the discrete model the same as that of the continuum model. (Authors)
LOADS
239A
955300 ISDP: Integrated approach to seismic design of reinforced concrete structures W. C. Stone & A. W. Taylor, Journal of Structural Engineering - AXE, 120(12), 1994, pp 3548-3566. An integrated seismic design procedure (ISDP) is proposed, the main features of which are: 1) The automatic selection and scaling of design ground motions given the earthquake magnitude, epicentral distance, and the type of overlying soil strata; 2) prediction of the inelastic behavior of reinforced concrete elements when subjected to random lateral loads up to and including failure; and 3) calculation of cumulative damage that is directly correlated to observed states of damage from laboratory tests of reinforced concrete elements. New seismic design criteria are proposed. The proposed approach is demonstrated by means of a practical example. (from Authors)
955301 Ductility and overstrengtb in seismic design of reinforced concrete structures D. Mitchell & P. Paultre, Canadian Journal of Civil Engineering, 21(6), 1994, pp 1049-1060. The paper first reviews the different approaches taken by codes of practice in their treatment of ductility demand by the use of force modification factors. The way in which structural overstrength affects structural response and the factors influencing overstrength are discussed. Nonlinear analyses of reinforced concrete structures, designed by the Canadian codes, demonstrate the significance of structural overstrength on the ability of the structures to resist lateral load without collapse. The manner in which structural overstrength can be accounted for in the design of reinforced concrete structures is presented. (Authors)
955302 Period-dependent effects in seismic torsional response of code systems A. M. Chandler, J. C. Correnxa & G. L. Hutchinson, Journal of Structural Engineering - ASCE, 120(12), 1994, pp 3418-3435. This paper demonstrates that when a reference model is adopted that adheres rigorously to the design regulations of codes, including provisions for so-called accidental torsional effects, significant period dependency of inelastic seismic torsional response behavior is revealed. To demonstrate this, a reevaluation of the equivalent static torsional design procedures of codes is presented. (from Authors)
955303 Seismic storey drift estimation T. J. Zhu, Canadian Journal of Civil Engineering, 21(6), 1994, pp 1081-1083. The seismic storey drift estimation procedure in the 1990 edition of the National Building Code of Canada is evaluated for ductile moment-resisting frame buildings located in different seismic regions. The evaluation is based on a comparison of the storey drifts estimated from the code procedure with those obtained from the inelastic dynamic analysis of the buildings. The results indicate that the code procedure underestimates storey drift for low-rise ductile moment-resisting frame buildings. It provides good estimates of storey drift for medium- and high-rise ductile momentresisting frame buildings. The code estimation tends to become conservative as the number of storeys increases. (Author)
6
SURFACE STRUCTURES:DYNAMIC
Influence
of dynamic loads
955294 Microcomputer implementation of digital control strategies for structural response reduction P. Quast, M. K. Sam, B. F. Spencer Jr & S. J. Dyke, Microcomputers in Civil Engineering, 10(l), 1995, pp 13-25. Recently developed hardware based on dedicated digital signal processing chips has offered new possibilities for control algorithm implementation. This paper discusses digital control system concepts and specific practical aspects of digital control implementation, including the use of supervision. Details regarding active structural control using the Texas Instruments TMS32OC30 DSP chip and experimental verification of the hardware performance are given. (Authors)
955297
An optimized implementation of the Newmark/NewtonRaphson algorithm for the time integration of non-linear problems B. Pinheiro Jacob & N. F. Favilla Ebecken, Communications in Numerical Methods in Engineering, 10(12), 1994, pp 983992. The paper describes an optimized computational implementation of a basic ‘building block’ for non-linear structural dynamic analysis programs. The objective of this implementation is to attain improved computational efficiency, regarding both CPU time and memory requirements. The basic formulation and derivation are presented, along with the implementation details; the positive aspects related to the computational optimization are highlighted. (Authors)
955298 Six-degree-of-freedom ground-motion measurement R. L. Nigbor, Bulletin - Seismological Society of America, 84(S), 1994, pp 1665-1669. True six-degree-of-freedom (6DOF) measurement of freefield strong ground motion has been accomplished using a prototype 6DQF accelerograph system. This system consists of a traditional triaxial translational accelerometer, three new rotational velocity sensors, and a digital data logger. Rotational and translational ground motions at a single free-field location were measured successfully during the recent NPE event, a very large (1 kton) chemical explosion. (from Author)
955299 Wave dispersion and optimal mass modelling for onedimensional periodic structures N. Fukuwa & S. Matsushima, Earthquake Engineering & Structural Dynamics, 23(1 l), 1994, pp 1165-l 180. Discrete analysis methods are frequently used for the study of the structure and soil. However, the assumption of the displacement interpolation function makes the waves dispersive, which means numerical dispersion. The wave dispersion induced by discretixation depends on mass modelling. Also, the existence of added lumped masses makes waves dispersive even for continuum modelling. In order to examine these wave dispersions, a one-dimensional period structure is adopted as an analysis model and the dynamic transfer matrix method is applied. The optimal consistent mass ratio makes the wave velocity of the discrete model the same as that of the continuum model. (Authors)
LOADS
239A
955300 ISDP: Integrated approach to seismic design of reinforced concrete structures W. C. Stone & A. W. Taylor, Journal of Structural Engineering - AXE, 120(12), 1994, pp 3548-3566. An integrated seismic design procedure (ISDP) is proposed, the main features of which are: 1) The automatic selection and scaling of design ground motions given the earthquake magnitude, epicentral distance, and the type of overlying soil strata; 2) prediction of the inelastic behavior of reinforced concrete elements when subjected to random lateral loads up to and including failure; and 3) calculation of cumulative damage that is directly correlated to observed states of damage from laboratory tests of reinforced concrete elements. New seismic design criteria are proposed. The proposed approach is demonstrated by means of a practical example. (from Authors)
955301 Ductility and overstrengtb in seismic design of reinforced concrete structures D. Mitchell & P. Paultre, Canadian Journal of Civil Engineering, 21(6), 1994, pp 1049-1060. The paper first reviews the different approaches taken by codes of practice in their treatment of ductility demand by the use of force modification factors. The way in which structural overstrength affects structural response and the factors influencing overstrength are discussed. Nonlinear analyses of reinforced concrete structures, designed by the Canadian codes, demonstrate the significance of structural overstrength on the ability of the structures to resist lateral load without collapse. The manner in which structural overstrength can be accounted for in the design of reinforced concrete structures is presented. (Authors)
955302 Period-dependent effects in seismic torsional response of code systems A. M. Chandler, J. C. Correnxa & G. L. Hutchinson, Journal of Structural Engineering - ASCE, 120(12), 1994, pp 3418-3435. This paper demonstrates that when a reference model is adopted that adheres rigorously to the design regulations of codes, including provisions for so-called accidental torsional effects, significant period dependency of inelastic seismic torsional response behavior is revealed. To demonstrate this, a reevaluation of the equivalent static torsional design procedures of codes is presented. (from Authors)
955303 Seismic storey drift estimation T. J. Zhu, Canadian Journal of Civil Engineering, 21(6), 1994, pp 1081-1083. The seismic storey drift estimation procedure in the 1990 edition of the National Building Code of Canada is evaluated for ductile moment-resisting frame buildings located in different seismic regions. The evaluation is based on a comparison of the storey drifts estimated from the code procedure with those obtained from the inelastic dynamic analysis of the buildings. The results indicate that the code procedure underestimates storey drift for low-rise ductile moment-resisting frame buildings. It provides good estimates of storey drift for medium- and high-rise ductile momentresisting frame buildings. The code estimation tends to become conservative as the number of storeys increases. (Author)