- Design for efficient structures using mechanics concepts, Biodynamic properties of human whole-body, Vibration measurement, Grandstands and long-span floors, Loads induced by human movements, Improving balance of elderly people, and 2 moreStructural vibration induced by rhythmic crowd loads and Human-structure interactionedit
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This paper investigates the action of an individual bouncing on a structure, including the load generated and the effect on the dynamic behavior of the structure. A simply supported beam at The University of Manchester is used as a... more
This paper investigates the action of an individual bouncing on a structure, including the load generated and the effect on the dynamic behavior of the structure. A simply supported beam at The University of Manchester is used as a supporting structure for an individual bouncing and its responses to bouncing are recorded. Four hundred thirty three tests were conducted ranging bouncing frequency from 0.4 to 3.2 Hz for determining the load factors of individual bouncing loads. Over 7,300 bouncing frequencies are identified from the tests ...
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ABSTRACT: This paper describes an experimental investigation to determine the dynamic loads produced by groups of people jumping and focuses on the changes in the characteristics of the load with increasing group size. Two floors were... more
ABSTRACT: This paper describes an experimental investigation to determine the dynamic loads produced by groups of people jumping and focuses on the changes in the characteristics of the load with increasing group size. Two floors were selected and subjected to forced vibration tests to determine their dynamic characteristics. The floors' responses were monitored as groups of up to 64 people jumped in time to a musical beat. The recorded responses were then analysed to determine peak accelerations and ...
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Synopsis This paper is concerned with the dynamic behaviour of an eightstorey steel-framed building. The building construction was undertaken in discrete stages, five of which are described. At each stage the natural frequencies of the... more
Synopsis This paper is concerned with the dynamic behaviour of an eightstorey steel-framed building. The building construction was undertaken in discrete stages, five of which are described. At each stage the natural frequencies of the building were measured using a laser system. A comprehensive forced vibration test was also performed when the building was complete to determine all of the characteristics of the fundamental modes of vibration. Both types of test are described, and the results that were obtained are presented. In ...
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Although grandstands are built for sports events they may also be used for pop concerts. The dynamic loads induced by crowds at these events can be significant and should be considered in design. This paper summarises some research work... more
Although grandstands are built for sports events they may also be used for pop concerts. The dynamic loads induced by crowds at these events can be significant and should be considered in design. This paper summarises some research work in the UK on dynamics problems in the design of grandstands. Theoretical and experimental investigations have been conducted on rhythmic crowd loading, on the dynamic behaviour of temporary and permanent grandstands and on grandstand response to crowd loading. Areas are ...
This paper is concerned with the structural mechanics of pin-jointed structures and temporary grandstands. Particular attention is paid to horizontal stiffness which is one of the principal design checks for such structures. It is... more
This paper is concerned with the structural mechanics of pin-jointed structures and temporary grandstands. Particular attention is paid to horizontal stiffness which is one of the principal design checks for such structures. It is demonstrated that the stiffness of a pin-jointed structure can be increased by providing shorter or direct load paths between the loads and the supports and also by providing a uniform inner force distribution. Following these concepts, 5 simple criteria for arranging bracing members of temporary grandstands ...
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Synopsis This paper is concerned with modelling the loads generated by groups of people jumping rhythmically. The principal objective is to replicate the results that were obtained in an earlier experimental study in which measurements... more
Synopsis This paper is concerned with modelling the loads generated by groups of people jumping rhythmically. The principal objective is to replicate the results that were obtained in an earlier experimental study in which measurements were made with groups of up to 64 people. The experiments showed how the Fourier components of the loads attenuate with increasing group size and this defines a load model which can be used to calculate structural response. The measurements also showed the variations that can occur for ...
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Human–structure interaction is a topical issue in the analysis and design of structures subjected to dynamic human loading. However, it is not clear how the human body should be modelled. This paper provides qualitatively accurate models... more
Human–structure interaction is a topical issue in the analysis and design of structures subjected to dynamic human loading. However, it is not clear how the human body should be modelled. This paper provides qualitatively accurate models for a standing human body in vertical vibration. These models are derived from a study of human–structure interaction. The derivation is obtained by placing a continuous model of a standing human body on a vibrating structure; this is in contrast to existing body models, which are obtained with a ...
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The unexpected swaying and torsional movements of the London Millennium Bridge brought a mechanics problem, the equilibrium of a cable and rigid-body system, for investigation. This article studies the static characteristics of a cable... more
The unexpected swaying and torsional movements of the London Millennium Bridge brought a mechanics problem, the equilibrium of a cable and rigid-body system, for investigation. This article studies the static characteristics of a cable and rigid-body system, which may explain what was the first push to cause the vibrations of the bridge. As the bridge system allows geometrical movements in the horizontal and rotational directions when it is subjected to asymmetrically distributed vertical loads, the pedestrian loading ...
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SUSP, an analysis program for geometrically non-linear problems, is used for cable-nets with arbitrary shape and structures consisting of a combination of cables and trusses. The efficiency of the program is enhanced by means of three... more
SUSP, an analysis program for geometrically non-linear problems, is used for cable-nets with arbitrary shape and structures consisting of a combination of cables and trusses. The efficiency of the program is enhanced by means of three measures which are 1. Parallel consideration of design requirements and computational features; 2. Providing rational design parameters; 3. Ensuring correctly computed results. The design procedures for two practical structures, a transversely stiffened single curvature cable-suspended roof for ...
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The low impact forces of Tai Chi push-hand exercises may be particularly suited for older people and for those with arthritis; however, the biomechanics of push-hand exercises have not previously been reported. This paper examines the... more
The low impact forces of Tai Chi push-hand exercises may be particularly suited for older people and for those with arthritis; however, the biomechanics of push-hand exercises have not previously been reported. This paper examines the ground reaction forces (GRFs) and plantar force distributions during Tai Chi push-hand exercises in a stationary stance with and without an opponent. Ten male Tai Chi practitioners participated in the study. The GRFs of each foot were measured in three perpendicular directions using two force plates (Kistler). The plantar force distribution of each foot was measured concurrently using an insole sensor system (Novel). The results showed that the average maximum vertical GRF of each foot was not more than 88% ± 6.1% of the body weight and the sum of the vertical forces (103% ± 1.4%) generated by the two feet approximately equals the body weight at any one time. The horizontal GRFs generated by the two feet were in the opposite directions and the measured...
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Résumé/Abstract This paper investigates the dynamic behaviour of a cantilever grandstand using two-dimensional (2D) frame, three-dimensional (3D) open-ended and 3D enclosed finite-element models. The effects of bracing systems, stiffness... more
Résumé/Abstract This paper investigates the dynamic behaviour of a cantilever grandstand using two-dimensional (2D) frame, three-dimensional (3D) open-ended and 3D enclosed finite-element models. The effects of bracing systems, stiffness of seating decks and eccentricity of connections are examined. This comparative study also considers the relative advantages of the typical 2D and 3D models used in the study of dynamic behaviour and the response of grandstands to human loads. It is concluded that a 2D frame model is ...
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Résumé/Abstract This paper considers the significance of vertical loads that can produce horizontal movements of frame structures. It is shown that, with a small number of exceptions, vertical loads can induce horizontal movements of... more
Résumé/Abstract This paper considers the significance of vertical loads that can produce horizontal movements of frame structures. It is shown that, with a small number of exceptions, vertical loads can induce horizontal movements of symmetric, antisymmetric and asymmetric frames, which represent a wide range of engineering structures. The magnitudes of the horizontal movements depend on both the structural form and the location of the vertical loading. When vertical loads are applied dynamically, the movements of a ...
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This paper provides an approximate method to determine the stiffness and the fundamental frequency of a cracked beam. The cracked beam is first represented as an un-cracked beam with equivalent reduced sections around the cracks. The... more
This paper provides an approximate method to determine the stiffness and the fundamental frequency of a cracked beam. The cracked beam is first represented as an un-cracked beam with equivalent reduced sections around the cracks. The effect of the cracks is explained, visualised and quantified using the equivalence concept developed for stepped beams with periodically variable cross-sections. Then an alternative expression of the improved Rayleigh method is provided to calculate the natural frequencies of a beam with a variable ...
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ABSTRACT This paper considers appropriate human whole-body models for evaluating structural vibration. A new phenomenon of human-structure interaction was identified from observations of a grandstand when it was empty and when it was full... more
ABSTRACT This paper considers appropriate human whole-body models for evaluating structural vibration. A new phenomenon of human-structure interaction was identified from observations of a grandstand when it was empty and when it was full of spectators. A series of laboratory tests were conducted to identify the human whole-body models for stationary and in-motion situations. It was found that a person acts solely as a load when he moves, such as jumping and stamping, and as a mass-spring-damper when he is stationary, such as sitting and standing. The laboratory study relates to individuals while the site measurements concerns crowds. Finally, several applications based on the new findings are described. Introduction For many years the human whole-body has been incorrectly considered solely as a mass in structural vibration whether the person is stationary or moving. For example, the Canadian code [National Research Council of Canada, 1985] considered the human mass in the design of dance flo...
An innovative method of both teaching and learning structural concepts for civil engineering students has been developed at the University of Manchester. For teaching purposes, structural concepts (and their eff ects) are demonstrated... more
An innovative method of both teaching
and learning structural concepts for civil
engineering students has been developed
at the University of Manchester. For
teaching purposes, structural concepts
(and their eff ects) are demonstrated using
physical models. The application of these
concepts are illustrated using appropriate
real examples from engineering practice
and everyday life. An associated website
(www.structuralconcepts.org)1 has been
created using teaching material developed
over many years and is now used both in
the UK and internationally. To aid learning,
coursework has been developed for
enhancing the understanding of structural
concepts and for solving real problems in
innovative ways. Our students are able to
learn/revise structural concepts at their own
pace using existing demonstration models
and practical examples, as well as producing
new models of their own. This article
describes the development of resources for
eff ective teaching and learning of structural
concepts at Manchester.
and learning structural concepts for civil
engineering students has been developed
at the University of Manchester. For
teaching purposes, structural concepts
(and their eff ects) are demonstrated using
physical models. The application of these
concepts are illustrated using appropriate
real examples from engineering practice
and everyday life. An associated website
(www.structuralconcepts.org)1 has been
created using teaching material developed
over many years and is now used both in
the UK and internationally. To aid learning,
coursework has been developed for
enhancing the understanding of structural
concepts and for solving real problems in
innovative ways. Our students are able to
learn/revise structural concepts at their own
pace using existing demonstration models
and practical examples, as well as producing
new models of their own. This article
describes the development of resources for
eff ective teaching and learning of structural
concepts at Manchester.
Research Interests:
Human–structure interaction is a topical issue in the analysis and design of structures subjected to dynamic human loading. However, it is not clear how the human body should be modelled. This paper provides qualitatively accurate models... more
Human–structure interaction is a topical issue in the analysis and design of structures subjected to dynamic human loading. However, it is not clear how the human body should be modelled. This paper provides qualitatively accurate models for a standing human body in vertical vibration. These models are derived from a study of human–structure interaction.
Synopsis This paper is concerned with modelling the loads generated by groups of people jumping rhythmically. The principal objective is to replicate the results that were obtained in an earlier experimental study in which measurements... more
Synopsis This paper is concerned with modelling the loads generated by groups of people jumping rhythmically. The principal objective is to replicate the results that were obtained in an earlier experimental study in which measurements were made with groups of up to 64 people. The experiments showed how the Fourier components of the loads attenuate with increasing group size and this defines a load model which can be used to calculate structural response.
The response of structures to dynamic loads induced by individuals or crowds is becoming increasingly important. Concern may range from serviceability aspects (eg people walking across a structure and producing noticeable vibrations) to... more
The response of structures to dynamic loads induced by individuals or crowds is becoming increasingly important. Concern may range from serviceability aspects (eg people walking across a structure and producing noticeable vibrations) to safety considerations (eg crowds of people jumping on floors or grandstands). 1 B esides generating loads people will interact with a structure, and this may be significant if the mass of the people is reasonably large in comparison with the mass of the structure.
& This paper provides an overview of the response of grandstands to dynamic crowd loading. It summarizes the guidance which is currently available in the UK and how it has been developed. The interaction between structures and crowds is... more
& This paper provides an overview of the response of grandstands to dynamic crowd loading. It summarizes the guidance which is currently available in the UK and how it has been developed. The interaction between structures and crowds is then considered for both jumping and stationary crowds. A model for jumping loads is given, and the frequency range for jumping and the dynamic crowd e ect are discussed.
Synopsis This paper is concerned with the response of floors to loading produced by dancing and aerobics, especially where the dancing involves jumping. Its purpose is to provide an analytical method for determining the response of floors... more
Synopsis This paper is concerned with the response of floors to loading produced by dancing and aerobics, especially where the dancing involves jumping. Its purpose is to provide an analytical method for determining the response of floors to these loads. The characteristics of the load time history are dealt with initially, and, for calculation purposes, the load is expressed in terms of Fourier series.
Synopsis This paper is concerned with the dynamic behaviour of an eightstorey steel-framed building. The building construction was undertaken in discrete stages, five of which are described. At each stage the natural frequencies of the... more
Synopsis This paper is concerned with the dynamic behaviour of an eightstorey steel-framed building. The building construction was undertaken in discrete stages, five of which are described. At each stage the natural frequencies of the building were measured using a laser system. A comprehensive forced vibration test was also performed when the building was complete to determine all of the characteristics of the fundamental modes of vibration. Both types of test are described, and the results that were obtained are presented.