A BRIEF OF MY RESEARCH
My research in structural dynamics and structural engineering has focused on such structural problems that are there and to be solved and require significant knowledge in mechanics, and such mechanics problems that have potential applications in engineering practice. Human-structure interaction, structural response induced by human movements, modelling of structural dynamic behaviour and the use of structural concepts in engineering practice are the priorities in my current and further research
Human-structure
interaction
I have been working to establish a new topic, if it is
not large enough to be a new subject, human-structure interaction, which treats
a group of people and a structure as a whole and studies structural vibration
when people are involved and human response to structural vibration. The study
requires the knowledge of biodynamcs of human body
and of structural dynamics and needs both experimental and theoretical
investigations. Dr Brian Ellis and I were the first to identify and report the
phenomenon of human-structure interaction in 1997. Major progress in the research
has been made since a three-year research project, human-structure interaction – applying body biodynamics
into structural dynamics, was award by the Leverhulme
Trust and started from April 2003. The main outcome from the study includes: a)
qualitatively exact human body models are established based on a vibrating
environment and b) the effects of human body when standing, bouncing and
walking on vertical and lateral structural vibration are experimentally and
qualitatively identified.
The key publications and further information are given
as follows:
1. Ji, T., (1995), A
continuous model of the vertical vibration of the human body in a standing
position, UK Informal Group Meeting on Human Response to Vibration, Silsoe, 18-20 September 1995.
2. Ellis, B. R. and Ji, T.,(1997), Human-structure interaction
in vertical vibrations, Structures and Buildings, the Proceedings of Civil
Engineers, Vol. 122, No.1, pp.1-9.
3. Ji, T., (2003), Understanding the interactions between
people and structures, The Structural Engineers, Vol.81, No.14, pp.12-13
4. Zhou, D and Ji, T, (2006), Dynamic characteristics of
a beam and distributed spring-mass system, International
Journal of Solids and Structures, Vol.43, No.18-19, 5555-5569
5. Zhou,
D and Ji, T, (2006), Free vibration of
rectangular plates with distributed spring-mass, International Journal of Solids
and Structures, Vol.43, No.21, 6502-6520.
6. Wang, D and Ji, T., Frequency characteristics of a
highly damped two degrees-of-freedom system, submitted to the Journal of Sound
and Vibration.
7. http://personalpages.manchester.ac.uk/staff/tianjian.ji/research/hulme/human.htm
Structural
vibration induced by human movements
I have been investigated structural vibration induced
by human movements since May 1992 when a temporary grandstand was collapsed in
The key publications include:
1. Ji, T. and Ellis, B. R., (1994), Floor vibrations induced by dance type loads
-- theory, The Structural Engineer, Vol.72, No.3, pp.37-44. (The paper was
awarded the Henry Adams Award Diploma by the Institution of Structural
Engineers, 1993/1994 session).
2. Ellis, B. R. and Ji, T., (1994), Floor vibrations induced by dance type
loads -- verification, The Structural Engineer, Vol.72, No.3, pp.45-50
3. Ellis, B. R., Ji, T. and Littler, J., (2000), The response of
grandstands to dynamic crowd loads, Structures and Buildings, Vol.140,
No.4, pp.355-365, The Proceedings of the Institution of Civil Engineers,
4. Ellis, B. R. and Ji, T., (1997, 2004), BRE Digest 426:
The Response of Structures to
Dynamic Crowd Loads, ISBN 1 86081 1744, October 1997 and the second edition
August 2004.
5. Ellis, B R and Ji, T, (2004), Loads generated by jumping crowds: numerical
modelling, The Structural Engineer, Vol.82,
No.17, pp35-40.
6. Ernesto, E and Ji, T, (2009), The action of individual
bouncing on structures, ASCE Journal of Structural Engineering, 135(7), pp. 818-827.
7. http://personalpages.manchester.ac.uk/staff/tianjian.ji/research/floorwalking/floormain.htm
Modelling of
structural dynamic behaviour
I am a Registered Analyst of NAFEMS. In order to
predict structural response to human loads, we need to be able to model
structures correctly. We have modelled grandstands, multi-panel floors and
buildings and provided consultancy on vibrations of grandstands and floors in
the past years. The measurements of natural frequencies of structures are often
used to improve FE models where possible. We have proposed appropriate FE model
to deal with typical types of floor structures. We will investigate the
modelling of complex structures on improving computation efficiency by incorporating
analytical solutions and on improving prediction accuracies by using experiment
measurements and conceptual understanding.
The key publications include:
1. Ellis, B. R. and Ji, T., (1996), Dynamic testing and numerical
modelling of the Cardington steel framed building from construction to
completion, The Structural Engineer, Vol.74, No.11, pp.186-192.
2. Ji, T. and Ellis, B. R., (1996), Applications of
finite element modelling in structural dynamics, Benchmark, October 1996,
pp.25-28.
3. El-Dadiry, E., Wahyuni, E., Ji, T. and Ellis, B. R., (2002), Improving FE models of a long-span flat
concrete floor using frequency measurements, Computers and Structures,
Vol.80, pp.2145-2156.
4. Mandal, P and Ji, T, (2004), Modelling dynamic behaviour of a
cantilever grandstand, Structures and Buildings, The Proceedings of the
Institution of Civil Engineers, 157(3) p.173-184.
5. El-Dardiry, E and Ji, T,
(2006), Modelling of the
dynamic behaviour of profiled composite floors, Engineering Structures,
Vol.28, No.4, pp567-579.
6. El-Dardiry, E and Ji, T., (2007),
The effect of eccentricity on free vibration of composite floors, submitted to
Computers and Structures, Vol. 85. No. 21. pp 1647-1660
Structural
concepts and their applications in engineering
I am interested in identifying new structural concepts
from engineering practice, developing new understanding from existing
structural concepts and applying structural concepts to solving engineering
problems. Some concepts developed are very useful for engineering design, such
as the smaller the internal forces, the
stiffer the structure; lateral
resonance of a structure can be induced by vertical dynamic loading. The
bracing systems developed through using structural concepts have been used by
consulting firms. For helping students to understanding structural concepts,
lecturers to teaching structural concepts and engineers to use structural
concepts, I and Dr Bell have developed a website, Seeing and Touching Concepts,
through using physical models and examples from everyday life and engineering
practice. The website contains over 100 sets of model and example.
The key publications include:
1. Ji, T, Ellis, B R and
2. Ji, T, (2003), Concepts
for designing stiffer structures, The Structural Engineer, Vol.81, No.21,
p.36-42.
3. Ji, T and
4. Ji, T and