ABSTRACT: Presently, there is no clear method for determining the optimal railway bridge design f... more ABSTRACT: Presently, there is no clear method for determining the optimal railway bridge design for a particular ground type and expected seismic intensity. Four main types of RC bridge dominate the current multi-span railway bridge design trends–the Simply Supported Beam, Continuous Box-Girder (CBG), CBG with Lead Rubber Bearing (LRB) supports and the laterally fixed continuous deck (CRB) with LRBs. In this paper, the seismic performance of these four types is examined for varying ground types and seismic intensities.
It is well known that hardware and software time delays reduce the effectiveness of semi-active c... more It is well known that hardware and software time delays reduce the effectiveness of semi-active control and make the experimental response of controlled structures differ significantly from that theoretically expected. In this paper, two response prediction methods, both based on matching the immediate future response of the generic instrumented point of the structure to an half period sine wave, are presented.
Polymer reinforced Compact Reinforced Composite, PCRC, is a Fiber reinforced Densified Small Part... more Polymer reinforced Compact Reinforced Composite, PCRC, is a Fiber reinforced Densified Small Particle system, FDSP, combined with a high strength longitudinal flexural rebar arrangement laced together with polymer lacing to avoid shock initiated disintegration of ...
... (4) Compatibility equation: (4) where are strain rate tensors. (5) Incompressibility conditio... more ... (4) Compatibility equation: (4) where are strain rate tensors. (5) Incompressibility condition: (5). (6) Flow stress: (6) Eq. (6)is the work-hardening law of Swift, where C, ε 0 and n are material parameters. 2.2. Weak form of the boundary-value problem. ...
Page 1. DTU Civil Engineering Report R-235 (UK) March 2011 Henrik Gjelstrup PhD Thesis Department... more Page 1. DTU Civil Engineering Report R-235 (UK) March 2011 Henrik Gjelstrup PhD Thesis Department of Civil Engineering 2011 Understanding and simulating windinduced vibrations of iced vertical cables Theoretical modelling and experimental studies
The dissertation investigates the phenomenon of excessive pedestrian-induced lateral vibrations a... more The dissertation investigates the phenomenon of excessive pedestrian-induced lateral vibrations as observed on several high-profile footbridges. In particular, the temporary closures of both Paris' Solferino Bridge (1999) and the London Millennium Bridge (2000) have led to an understanding on the part of engineers and architects of the need to evaluate the potential for footbridge vibrations that can be attributed to pedestrians. Within the scientific community, the closures have also led to the initiation of a new tract of research, ...
This paper investigates the phenomenon of excessive pedestrian-induced lateral vibrations as obse... more This paper investigates the phenomenon of excessive pedestrian-induced lateral vibrations as observed on several high-profile footbridges. The vibrations are a consequence of human-structure interaction, in which the forces generated by the pedestrians depend strongly on the vibration of the underlying pavement. An extensive experimental analysis has been carried out to determine the lateral forces generated by pedestrians when walking on a laterally moving treadmill. Two different conditions are investigated; initially the ...
In recent years, several high-profile footbridges have suffered from unexpected excessive pedestr... more In recent years, several high-profile footbridges have suffered from unexpected excessive pedestrian-induced lateral vibrations. There is a commonly accepted view that the synchronisation of pedestrians to the lateral movement of a structure is necessary for the onset of a form of instability which may lead to large lateral responses. Several recently published load models are based on this assumption. Yet, few experimental studies exist to support this hypothesis. Therefore, an extensive experimental campaign, involving 71 test ...
Abstract: Different patterns of pedestrian loading of footbridges exist, whose occurrence depends... more Abstract: Different patterns of pedestrian loading of footbridges exist, whose occurrence depends on a number of parameters, such as the bridge span, frequency, damping and mass, and the pedestrian density and activity. In this paper analytical models for the transient action of one walker and for the stationary action of an incoherent crowd of walkers will be presented, whose parameters have to be calibrated based on experimental tests. Results will be summarised of tests aimed at a statistical characterisation of the walking ...
An improved and codifiable footbridge response evaluation is presented herewith, in which peak ve... more An improved and codifiable footbridge response evaluation is presented herewith, in which peak vertical accelerations are provided as a function of load return period in the form of response spectra. To achieve this, a series of Monte Carlo simulations are employed to generate vertical loads induced by a" random" crowd that are subsequently used in linear timehistory analyses of the response of bridges with varying fundamental frequencies. The peak accelerations are presented as a function of return period and it is shown that the ...
ABSTRACT: Presently, there is no clear method for determining the optimal railway bridge design f... more ABSTRACT: Presently, there is no clear method for determining the optimal railway bridge design for a particular ground type and expected seismic intensity. Four main types of RC bridge dominate the current multi-span railway bridge design trends–the Simply Supported Beam, Continuous Box-Girder (CBG), CBG with Lead Rubber Bearing (LRB) supports and the laterally fixed continuous deck (CRB) with LRBs. In this paper, the seismic performance of these four types is examined for varying ground types and seismic intensities.
It is well known that hardware and software time delays reduce the effectiveness of semi-active c... more It is well known that hardware and software time delays reduce the effectiveness of semi-active control and make the experimental response of controlled structures differ significantly from that theoretically expected. In this paper, two response prediction methods, both based on matching the immediate future response of the generic instrumented point of the structure to an half period sine wave, are presented.
Polymer reinforced Compact Reinforced Composite, PCRC, is a Fiber reinforced Densified Small Part... more Polymer reinforced Compact Reinforced Composite, PCRC, is a Fiber reinforced Densified Small Particle system, FDSP, combined with a high strength longitudinal flexural rebar arrangement laced together with polymer lacing to avoid shock initiated disintegration of ...
... (4) Compatibility equation: (4) where are strain rate tensors. (5) Incompressibility conditio... more ... (4) Compatibility equation: (4) where are strain rate tensors. (5) Incompressibility condition: (5). (6) Flow stress: (6) Eq. (6)is the work-hardening law of Swift, where C, ε 0 and n are material parameters. 2.2. Weak form of the boundary-value problem. ...
Page 1. DTU Civil Engineering Report R-235 (UK) March 2011 Henrik Gjelstrup PhD Thesis Department... more Page 1. DTU Civil Engineering Report R-235 (UK) March 2011 Henrik Gjelstrup PhD Thesis Department of Civil Engineering 2011 Understanding and simulating windinduced vibrations of iced vertical cables Theoretical modelling and experimental studies
The dissertation investigates the phenomenon of excessive pedestrian-induced lateral vibrations a... more The dissertation investigates the phenomenon of excessive pedestrian-induced lateral vibrations as observed on several high-profile footbridges. In particular, the temporary closures of both Paris' Solferino Bridge (1999) and the London Millennium Bridge (2000) have led to an understanding on the part of engineers and architects of the need to evaluate the potential for footbridge vibrations that can be attributed to pedestrians. Within the scientific community, the closures have also led to the initiation of a new tract of research, ...
This paper investigates the phenomenon of excessive pedestrian-induced lateral vibrations as obse... more This paper investigates the phenomenon of excessive pedestrian-induced lateral vibrations as observed on several high-profile footbridges. The vibrations are a consequence of human-structure interaction, in which the forces generated by the pedestrians depend strongly on the vibration of the underlying pavement. An extensive experimental analysis has been carried out to determine the lateral forces generated by pedestrians when walking on a laterally moving treadmill. Two different conditions are investigated; initially the ...
In recent years, several high-profile footbridges have suffered from unexpected excessive pedestr... more In recent years, several high-profile footbridges have suffered from unexpected excessive pedestrian-induced lateral vibrations. There is a commonly accepted view that the synchronisation of pedestrians to the lateral movement of a structure is necessary for the onset of a form of instability which may lead to large lateral responses. Several recently published load models are based on this assumption. Yet, few experimental studies exist to support this hypothesis. Therefore, an extensive experimental campaign, involving 71 test ...
Abstract: Different patterns of pedestrian loading of footbridges exist, whose occurrence depends... more Abstract: Different patterns of pedestrian loading of footbridges exist, whose occurrence depends on a number of parameters, such as the bridge span, frequency, damping and mass, and the pedestrian density and activity. In this paper analytical models for the transient action of one walker and for the stationary action of an incoherent crowd of walkers will be presented, whose parameters have to be calibrated based on experimental tests. Results will be summarised of tests aimed at a statistical characterisation of the walking ...
An improved and codifiable footbridge response evaluation is presented herewith, in which peak ve... more An improved and codifiable footbridge response evaluation is presented herewith, in which peak vertical accelerations are provided as a function of load return period in the form of response spectra. To achieve this, a series of Monte Carlo simulations are employed to generate vertical loads induced by a" random" crowd that are subsequently used in linear timehistory analyses of the response of bridges with varying fundamental frequencies. The peak accelerations are presented as a function of return period and it is shown that the ...
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