International Journal of Structural Engineering http://www.inderscience.com/browse/index.php?journalID=336&year=2012&vol=3&issue=1/2 Inderscience Publishers Ltd en-uk International Journal of Structural Engineering 1758-7328 1758-7336 © 2012 Inderscience Publishers Ltd editor@inderscience.com https://www.inderscience.com/images/files/coverImgs/ijstructe_scoverijstructe.jpg http://www.inderscience.com/browse/index.php?journalID=336&year=2012&vol=3&issue=1/2 http://www.inderscience.com/link.php?id=45039 A three-story frame was designed for earthquake resistance by using post-tensioned (PT) columns and beams. Two interior connections, representing the first floor column and beam sizes, were tested under cyclic loading to evaluate the effects of energy dissipation and PT load and on the seismic behaviour. A full-scale one-story two-bay specimen frame, which was a substructure of the three-story PT building, was then built and tested. This paper presents experimental results of the connections and the frame and analytical simulations for the frame subassembly. Time-history analyses of the three-story PT building subjected to the design basis earthquake (DBE) and the maximum considered earthquake (MCE) were conducted to investigate seismic demands of the proposed frame. These tests confirmed the self-centring responses of the connections and the frame. Inelastic time history analyses of the three-story prototype building showed that the proposed frame system can achieve seismic demands under MCE level ground motions. Development of post-tensioned self-centring structures for earthquake resistance
Chung-Che Chou; Jun-Hen Chen
International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 4 - 17
A three-story frame was designed for earthquake resistance by using post-tensioned (PT) columns and beams. Two interior connections, representing the first floor column and beam sizes, were tested under cyclic loading to evaluate the effects of energy dissipation and PT load and on the seismic behaviour. A full-scale one-story two-bay specimen frame, which was a substructure of the three-story PT building, was then built and tested. This paper presents experimental results of the connections and the frame and analytical simulations for the frame subassembly. Time-history analyses of the three-story PT building subjected to the design basis earthquake (DBE) and the maximum considered earthquake (MCE) were conducted to investigate seismic demands of the proposed frame. These tests confirmed the self-centring responses of the connections and the frame. Inelastic time history analyses of the three-story prototype building showed that the proposed frame system can achieve seismic demands under MCE level ground motions.

]]> 10.1504/IJSTRUCTE.2012.045039 International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 4 - 17 Chung-Che Chou; Jun-Hen Chen Civil Engineering Department, National Taiwan University, 1, Sec. 4, Roosevelt Rd., Taipei 10617, Taiwan. ' Federal Engineering Consultant Inc., 12F-2, 41, Sec. 2, Hsin-Hai Rd., Taipei 10617, Taiwan post-tensioned structures earthquake resistance self-centring frames cyclic loading tests inelastic dynamic analysis energy dissipation simulation seismic demands three-story buildings ground motions earthquakes structural engineering. 2012-01-22T23:20:50-05:00 3 1/2 4 17 2012-01-22T23:20:50-05:00 http://www.inderscience.com/link.php?id=45040 A numerical model for first order elasto-plastic limit analysis of structural plane frame subjected to combined bending moment and axial force actions is presented. The model takes into account the influence of axial forces on the ultimate load carrying capacity of the structure. It also allows for reversal of plastic hinge formation. The applicability of the model has been demonstrated through elastic-plastic analysis of rectangular frames. The numerical solutions of the frames are compared to those obtained in the traditional simple elasto-plastic analysis which neglects the effects of axial forces on the ultimate load carrying capacity of the structure. The numerical solutions obtained in the frame showed that when the amount of axial force in the elements of a frame exceed 15% of the respective element plastic axial force, the conventional first order elasto-plastic limit analysis method over estimates the load carrying capacity of structures. Further, the new technique increased the rate of structure stiffness degradation. First-order elastic-plastic analysis of multi-story building frames by numerical modelling
Wanjala Ramadhan Salim
International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 18 - 26
A numerical model for first order elasto-plastic limit analysis of structural plane frame subjected to combined bending moment and axial force actions is presented. The model takes into account the influence of axial forces on the ultimate load carrying capacity of the structure. It also allows for reversal of plastic hinge formation. The applicability of the model has been demonstrated through elastic-plastic analysis of rectangular frames. The numerical solutions of the frames are compared to those obtained in the traditional simple elasto-plastic analysis which neglects the effects of axial forces on the ultimate load carrying capacity of the structure. The numerical solutions obtained in the frame showed that when the amount of axial force in the elements of a frame exceed 15% of the respective element plastic axial force, the conventional first order elasto-plastic limit analysis method over estimates the load carrying capacity of structures. Further, the new technique increased the rate of structure stiffness degradation.

]]> 10.1504/IJSTRUCTE.2012.045040 International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 18 - 26 Wanjala Ramadhan Salim Department of Civil Engineering and Building, Vaal University of Technology, Andries Potgieter Boulvard, Vanderbijlpark, Private Bag X021, Vanderbijlpark 1900, Republic of South Africa elasto-plastic analysis frames ultimate loading load carrying capacity structural engineering multi-story buildings building frames numerical modelling bending moment axial force plastic hinge formation rectangular frames stiffness degradation. 2012-01-22T23:20:50-05:00 3 1/2 18 26 2012-01-22T23:20:50-05:00 http://www.inderscience.com/link.php?id=45041 Earthquakes are among the most important natural hazards confronting engineers, regulatory authorities, and the public at large. The assessment of structural seismic vulnerability has become the subject of intensive research. In this paper, a mathematical framework for seismic vulnerability assessment of building structures is presented, and the concept of vulnerability function is introduced and mathematically described, which is integrally related to the fragility assessment and reflects the susceptibility of a system to serious consequences. The limit state of a building structure is stated as the structural demand exceeding the structural capacity, so the methodology is developed based on a systematic treatment of uncertainties in seismic hazard, structural demands due to seismic hazard, and capacities of building structures in resisting limit states. The methods and assessment procedures are illustrated through a steel building frame, showing the presented methodology is an efficient tool in support of seismic vulnerability assessment. The explicit consideration of uncertainty is an integral part of the engineering risk management and decision process, and the methodology can also be applied to other buildings, bridges or civil infrastructure systems. Seismic vulnerability assessment through explicit consideration of uncertainties in structural capacities and structural demands
Quanwang Li; Jiankang Sun; Jiansheng Fan
International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 27 - 36
Earthquakes are among the most important natural hazards confronting engineers, regulatory authorities, and the public at large. The assessment of structural seismic vulnerability has become the subject of intensive research. In this paper, a mathematical framework for seismic vulnerability assessment of building structures is presented, and the concept of vulnerability function is introduced and mathematically described, which is integrally related to the fragility assessment and reflects the susceptibility of a system to serious consequences. The limit state of a building structure is stated as the structural demand exceeding the structural capacity, so the methodology is developed based on a systematic treatment of uncertainties in seismic hazard, structural demands due to seismic hazard, and capacities of building structures in resisting limit states. The methods and assessment procedures are illustrated through a steel building frame, showing the presented methodology is an efficient tool in support of seismic vulnerability assessment. The explicit consideration of uncertainty is an integral part of the engineering risk management and decision process, and the methodology can also be applied to other buildings, bridges or civil infrastructure systems.

]]> 10.1504/IJSTRUCTE.2012.045041 International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 27 - 36 Quanwang Li; Jiankang Sun; Jiansheng Fan Civil Engineering Department, Tsinghua University, Beijing 100084, China. ' Department of Transportation, Baodi District, Tianjin, 301800 China. ' Civil Engineering Department, Tsinghua University, Beijing 100084, China seismic vulnerability vulnerability assessment uncertainty structural engineering structural demands structural capacity earthquakes building structures engineering risk management. 2012-01-22T23:20:50-05:00 3 1/2 27 36 2012-01-22T23:20:50-05:00 http://www.inderscience.com/link.php?id=45042 The author has developed a method of three-dimensional seismic tomography on concrete structures. This method is based on ray-trace and identification technique, and the distribution of slowness or energy dissipation is identified based on simultaneously iterative reconstruction technique (SIRT) or the other kind of statistical identification technique. This kind of technique was originally developed for investigation of underground that is called geotomography, however, this technique was difficult to apply to concrete structures because the structures generally have irregular shape. A hexahedral element was implemented by the author to overcome this difficulty based on the idea of isoparametric mapping of hexahedral element on finite element analysis, however, it is still difficult to apply the method to the structures that have highly irregular shape. In this respect, an implementation of tetrahedral element is proposed for the three-dimensional seismic tomography on concrete structures to solve the difficulty in this paper. This implementation is based on the idea of isoparametric mapping as well as the case of hexahedral element and it enables to apply the method to structures of complex shape that is insufficient to represent by hexahedral elements. The validity of the proposed method is checked by some numerical example. Three-dimensional seismic tomography with tetrahedra element on isoparametric mapping
Yoshikazu Kobayashi
International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 37 - 47
The author has developed a method of three-dimensional seismic tomography on concrete structures. This method is based on ray-trace and identification technique, and the distribution of slowness or energy dissipation is identified based on simultaneously iterative reconstruction technique (SIRT) or the other kind of statistical identification technique. This kind of technique was originally developed for investigation of underground that is called geotomography, however, this technique was difficult to apply to concrete structures because the structures generally have irregular shape. A hexahedral element was implemented by the author to overcome this difficulty based on the idea of isoparametric mapping of hexahedral element on finite element analysis, however, it is still difficult to apply the method to the structures that have highly irregular shape. In this respect, an implementation of tetrahedral element is proposed for the three-dimensional seismic tomography on concrete structures to solve the difficulty in this paper. This implementation is based on the idea of isoparametric mapping as well as the case of hexahedral element and it enables to apply the method to structures of complex shape that is insufficient to represent by hexahedral elements. The validity of the proposed method is checked by some numerical example.

]]> 10.1504/IJSTRUCTE.2012.045042 International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 37 - 47 Yoshikazu Kobayashi Department of Civil Engineering, College of Science and Technology, Nihon University, 1-8-14, Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-8308, Japan 3D seismic tomography tetrahedral elements ray trace algorithms statistical identification isoparametric mapping irregular shapes structural engineering earthquakes concrete structures energy dissipation geotomography finite element analysis FEA hexahedral elements. 2012-01-22T23:20:50-05:00 3 1/2 37 47 2012-01-22T23:20:50-05:00 http://www.inderscience.com/link.php?id=45043 During the last several decades, considerable efforts have been devoted to high-speed impact tests to investigate dynamic properties of materials, such as metal, alloy, ceramic, polymer, rock, concrete, brick, mortar etc. The purpose of impact or shock test is to study the crash-relevant or blast-relevant behaviour of engineering materials under high strain rates. According to different test purposes, sometimes the strain rate could be extremely high, i.e., up to 10,000 unit strain per second. In the School of Civil and Resource Engineering at the University of Western Australia, some impact tests on steel material and concrete material have been carried out recently, to calibrate the impact loading ability of an innovative blast simulator device. From the test results, some special phenomena about measured strain signals were observed and reported, which may have an unavoidable influence on properly describing material dynamic properties. In order to avoid misleading the consequent analysis on acquiring the genuine dynamic behaviour of material or specimen from high-speed impact tests, some important factors, from the point view of experimental technique are discussed in the current paper. Some special phenomena and preliminary interpretations about measured strain signals from high-speed impact tests
Chunwei Zhang; Hong Hao; Boris Tarasov; Xinqun Zhu
International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 48 - 60
During the last several decades, considerable efforts have been devoted to high-speed impact tests to investigate dynamic properties of materials, such as metal, alloy, ceramic, polymer, rock, concrete, brick, mortar etc. The purpose of impact or shock test is to study the crash-relevant or blast-relevant behaviour of engineering materials under high strain rates. According to different test purposes, sometimes the strain rate could be extremely high, i.e., up to 10,000 unit strain per second. In the School of Civil and Resource Engineering at the University of Western Australia, some impact tests on steel material and concrete material have been carried out recently, to calibrate the impact loading ability of an innovative blast simulator device. From the test results, some special phenomena about measured strain signals were observed and reported, which may have an unavoidable influence on properly describing material dynamic properties. In order to avoid misleading the consequent analysis on acquiring the genuine dynamic behaviour of material or specimen from high-speed impact tests, some important factors, from the point view of experimental technique are discussed in the current paper.

]]> 10.1504/IJSTRUCTE.2012.045043 International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 48 - 60 Chunwei Zhang; Hong Hao; Boris Tarasov; Xinqun Zhu Civionics Research Centre, University of Western Sydney, Penrith, NSW 2751, Australia. ' School of Civil and Resource Engineering, The University of Western Australia, Crawley, WA 6009, Australia. ' School of Civil and Resource Engineering, The University of Western Australia, Crawley, WA 6009, Australia. ' School of Engineering, University of Western Sydney, Penrith, NSW 2751, Australia high speed impact testing dynamic behaviour material behaviour stress wave propagation amplifier bandwidth strain rate blast simulator shock tests engineering materials steel concrete blast simulation structural engineering. 2012-01-22T23:20:50-05:00 3 1/2 48 60 2012-01-22T23:20:50-05:00 http://www.inderscience.com/link.php?id=45044 Vertical vibration serviceability of an as-built concrete floor, whose 41.55 m span is currently the longest in China, are investigated in this paper by field measurements and numerical analysis. A vibration monitoring system were designed and installed on the floor. Different types of human-induced excitation are simulated such as single person walking, multi-person walking at the same pace rate, multi-person jumping and multi-person randomly walking. The dynamic properties and responses of the floor are also computed using finite element method. It is found in this paper that the acceleration vibration amplitudes of the floor under different excitations are lower than the limitation. The amplitudes of floor response are quite different for different types of excitation. The response of wooden floor is much higher than the structure floor at the same location therefore, cannot be directly adopted for serviceability assessment. The fundamental frequency of the floor can be accurately predicted if the mass properties and boundary conditions are properly modelled. Finally, it is suggested that the vibration amplitude control is much more important than frequency control for vibration serviceability design of long-span concrete floor. Field measurements and assessment of vibration serviceability of as-built long-span concrete floor
Jun Chen; Qinsheng Liu; Xiongxion She
International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 61 - 74
Vertical vibration serviceability of an as-built concrete floor, whose 41.55 m span is currently the longest in China, are investigated in this paper by field measurements and numerical analysis. A vibration monitoring system were designed and installed on the floor. Different types of human-induced excitation are simulated such as single person walking, multi-person walking at the same pace rate, multi-person jumping and multi-person randomly walking. The dynamic properties and responses of the floor are also computed using finite element method. It is found in this paper that the acceleration vibration amplitudes of the floor under different excitations are lower than the limitation. The amplitudes of floor response are quite different for different types of excitation. The response of wooden floor is much higher than the structure floor at the same location therefore, cannot be directly adopted for serviceability assessment. The fundamental frequency of the floor can be accurately predicted if the mass properties and boundary conditions are properly modelled. Finally, it is suggested that the vibration amplitude control is much more important than frequency control for vibration serviceability design of long-span concrete floor.

]]> 10.1504/IJSTRUCTE.2012.045044 International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 61 - 74 Jun Chen; Qinsheng Liu; Xiongxion She State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University, Siping Road 1239, Shanghai, China. ' Qingdao International Expo Center, Tongan Road 870, Qingdao, China. ' Department of Building Engineering, Tongji University, Siping Road 1239, Shanghai, China vibration serviceability post-tensioned concrete floors vibration monitoring CCIP-016 China long-span concrete floors human-induced excitation walking jumping finite element method FEM floor response modelling. 2012-01-22T23:20:50-05:00 3 1/2 61 74 2012-01-22T23:20:50-05:00 http://www.inderscience.com/link.php?id=45045 Active control of building structure using lattice probabilistic neural network (LPNN) employing the gradient descent method (GDM) for learning to increase control capability is proposed. With the lattice pattern of the state vector used as the training data, LPNN calculates the control force using only the adjacent information of input, thus, response is greatly faster. Three story building under El Centro earthquake is used to train the LPNN. Northridge earthquake is used to verify the proposed method. In the numerical simulation of the building structure control, the control results of the LPNN are compared with the uncontrolled results. The proposed LPNN algorithm can effectively reduce the response of the building structure under earthquakes. Active control of building structure using lattice probabilistic neural network based on learning algorithm
Seongkyu Chang; Dookie Kim
International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 75 - 82
Active control of building structure using lattice probabilistic neural network (LPNN) employing the gradient descent method (GDM) for learning to increase control capability is proposed. With the lattice pattern of the state vector used as the training data, LPNN calculates the control force using only the adjacent information of input, thus, response is greatly faster. Three story building under El Centro earthquake is used to train the LPNN. Northridge earthquake is used to verify the proposed method. In the numerical simulation of the building structure control, the control results of the LPNN are compared with the uncontrolled results. The proposed LPNN algorithm can effectively reduce the response of the building structure under earthquakes.

]]> 10.1504/IJSTRUCTE.2012.045045 International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 75 - 82 Seongkyu Chang; Dookie Kim Department of Civil and Environmental Engineering, Kunsan National University, Kunsan, Jeonbuk 573-701, Korea. ' Department of Civil and Environmental Engineering, Kunsan National University, Kunsan, Jeonbuk 573-701, Korea lattice probabilistic neural networks LPNN learning algorithms active control earthquakes building structures structural engineering gradient descent method three story buildings seismic demands. 2012-01-22T23:20:50-05:00 3 1/2 75 82 2012-01-22T23:20:50-05:00 http://www.inderscience.com/link.php?id=45046 Earthquake response of benchmark highway bridge, isolated with variable frequency pendulum isolator (VFPI) is investigated under six earthquakes, using a simplified lumped mass finite element model. The isolators are installed between deck-ends and abutments. Seismic response of the bridge with VFPI is compared with that of the bridge with the friction pendulum system (FPS). Parametric studies are carried to find the optimum values of coefficient of friction and isolation period of the FPS, and frequency variation factor, initial time period and coefficient of friction of VFPI. The response of the bridge with VFPI is compared with the uncontrolled case, with FPS, and that controlled by alternate sample control strategies. Significant reductions in base shear, base moment, deck displacements and bearing displacements are observed using FPS and VFPI. It is concluded that these isolators are quite effective in substantially reducing peak response quantities of the bridge, comparable to that of the sample controllers. Control of seismically excited benchmark highway bridge with variable frequency pendulum isolator
Suhasini N. Madhekar; R.S. Jangid
International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 83 - 117
Earthquake response of benchmark highway bridge, isolated with variable frequency pendulum isolator (VFPI) is investigated under six earthquakes, using a simplified lumped mass finite element model. The isolators are installed between deck-ends and abutments. Seismic response of the bridge with VFPI is compared with that of the bridge with the friction pendulum system (FPS). Parametric studies are carried to find the optimum values of coefficient of friction and isolation period of the FPS, and frequency variation factor, initial time period and coefficient of friction of VFPI. The response of the bridge with VFPI is compared with the uncontrolled case, with FPS, and that controlled by alternate sample control strategies. Significant reductions in base shear, base moment, deck displacements and bearing displacements are observed using FPS and VFPI. It is concluded that these isolators are quite effective in substantially reducing peak response quantities of the bridge, comparable to that of the sample controllers.

]]> 10.1504/IJSTRUCTE.2012.045046 International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 83 - 117 Suhasini N. Madhekar; R.S. Jangid Department of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India. ' Department of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India benchmark highway bridges seismic isolation structural control vibration control friction pendulum systems FPS friction coefficient frequency variation factor FVF variable frequency pendulum isolator VFPI earthquake response earthquakes base shear base moment deck displacement bearing displacement finite element method FEM modelling structural engineering. 2012-01-22T23:20:50-05:00 3 1/2 83 117 2012-01-22T23:20:50-05:00 http://www.inderscience.com/link.php?id=45047 As the traditional knowledge of optimal polynomial controls, the control effect of non-linear control strategy hinges on the order of the polynomial controllers either for linear systems or non-linear systems, In the present paper, a novel optimal polynomial control strategy against this knowledge, based on the framework of physical stochastic optimal control, for stochastic dynamical systems is proposed. The control criterion relies on the minimum of a performance function in an energy trade-off sense, as gauged by exceedance probability of system quantities of interest, involving an optimisation programme. For illustrative purposes, non-linear stochastic optimal controls of base-excited multi-degree-of-freedom linear and hysteretic structural systems are carried out, respectively. Numerical results reveal that the optimal polynomial control exhibits the order-independent behaviour that the linear control with the first-order controller suffices even for the hysteretic systems when the exceedance probability based control criterion is employed. This is practically meaningful since it bypasses the need to utilise non-linear controllers which might be associated with dynamical instabilities due to time delay and computational dynamics. It is noted, meanwhile, that the response performance of the controlled structural systems is improved significantly. Order-independent optimal polynomial control of stochastic dynamical systems
Yong-Bo Peng; Jie Li; Jian-Bing Chen
International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 118 - 136
As the traditional knowledge of optimal polynomial controls, the control effect of non-linear control strategy hinges on the order of the polynomial controllers either for linear systems or non-linear systems, In the present paper, a novel optimal polynomial control strategy against this knowledge, based on the framework of physical stochastic optimal control, for stochastic dynamical systems is proposed. The control criterion relies on the minimum of a performance function in an energy trade-off sense, as gauged by exceedance probability of system quantities of interest, involving an optimisation programme. For illustrative purposes, non-linear stochastic optimal controls of base-excited multi-degree-of-freedom linear and hysteretic structural systems are carried out, respectively. Numerical results reveal that the optimal polynomial control exhibits the order-independent behaviour that the linear control with the first-order controller suffices even for the hysteretic systems when the exceedance probability based control criterion is employed. This is practically meaningful since it bypasses the need to utilise non-linear controllers which might be associated with dynamical instabilities due to time delay and computational dynamics. It is noted, meanwhile, that the response performance of the controlled structural systems is improved significantly.

]]> 10.1504/IJSTRUCTE.2012.045047 International Journal of Structural Engineering, Vol. 3, No. 1/2 (2012) pp. 118 - 136 Yong-Bo Peng; Jie Li; Jian-Bing Chen State Key Laboratory of Disaster Reduction in Civil Engineering; Shanghai Institute of Disaster Prevention and Relief, Tongji University, Shanghai, 200092, China. ' State Key Laboratory of Disaster Reduction in Civil Engineering; School of Civil Engineering, Tongji University, Shanghai, 200092, China. ' State Key Laboratory of Disaster Reduction in Civil Engineering; School of Civil Engineering, Tongji University, Shanghai, 200092, China physical stochastic optimal control order-independent polynomial control exceedance probability nonlinear control hysteresis structural control structural engineering. 2012-01-22T23:20:50-05:00 3 1/2 118 136 2012-01-22T23:20:50-05:00