BIOMECHANICAL CHARACTERIZATION OF SLIPPING ON PERVIOUS AND TRADITIONAL ...

60 Pages·2012·2.08 MB·English

BIOMECHANICAL CHARACTERIZATION OF SLIPPING ON
PERVIOUS AND TRADITIONAL CONCRETE
WALKING SURFACES

A THESIS IN
Mechanical Engineering

Presented to the Faculty of the University
of Missouri-Kansas City in partial fulfillment of
the requirements for the degree

MASTER OF SCIENCE

by
ADAM PATRICK BRUETSCH

B.S., University of Missouri-Kansas City, 2010

Kansas City, Missouri
2012
© 2012
ADAM PATRICK BRUETSCH
ALL RIGHTS RESERVED
BIOMECHANICAL CHARACTERIZATION OF SLIPPING ON
PERVIOUS AND TRADITIONAL CONCRETE
WALKING SURFACES

Adam Patrick Bruetsch, Candidate for the Master of Science Degree
University of Missouri-Kansas City, 2012

ABSTRACT

Pervious concrete is a porous material that may provide superior slip resistance due to its
ability to exfiltrate melted ice and other slippery surface contaminants. The purpose of
this study was to analyze slip-related biomechanical characteristics during gait on
pervious and traditional concrete in dry and icy conditions. The hypothesis tested was
that pervious concrete, compared to traditional, would exhibit improved frictional
characteristics that are less likely to cause slipping events. Both pervious and traditional
concrete slabs were manufactured, and misted water was frozen on the surface of the icy
slabs. Ten participants completed walking trials across traditional and pervious concrete
in both dry and icy conditions. Ground reaction forces were captured by a force platform
beneath each concrete surface and used to determine friction usage, which was defined as
the ratio of peak utilized shear to normal force normalized to static coefficient of friction.
An analyses of variance (ANOVA) was performed on the resulting data. A statistically
significant decrease in friction usage was found for pervious concrete compared to
traditional. Pervious concrete exhibited significantly smaller levels of friction usage for
icy conditions, suggesting its potential utility in reducing slipping events.
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The faculty listed below, appointed by the Dean of School of Computing and
Engineering, have examined the thesis titled “Biomechanical Characterization of Slipping
on Pervious and Traditional Concrete Walking Surfaces,” presented by Adam Patrick
Bruetsch, candidate for the Master of Science degree, and certify that in their opinion it is
worthy of acceptance.

Supervisory Committee
Gregory W. King, Ph.D, Committee Co-Chairperson
Department of Civil and Mechanical Engineering

John T. Kevern, Ph.D, Committee Co-Chairperson
Department of Civil and Mechanical Engineering

Trent M. Guess, Ph.D
Department of Civil and Mechanical Engineering

Amber R. Stern, Ph.D
Department of Civil and Mechanical Engineering
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CONTENTS
ABSTRACT........................................................................................................................ iii
TABLES............................................................................................................................. vii
ILLUSTRATIONS.............................................................................................................viii
EQUATIONS...................................................................................................................... ix
ACKNOWLEDGEMENTS ................................................................................................. x
Chapter
1. INTRODUCTION .....................................................................................................1
2. BACKGROUND .......................................................................................................3
2.1 – Significance of Slips and Falls....................................................................... 3
2.2 – Muscle Response Characteristics of Slips and Falls ...................................... 4
2.3 – Foot Kinematic Characteristics of Slips and Falls ......................................... 5
2.4 – Surface Characteristics of Slips and Falls...................................................... 6
2.5 – Pervious Concrete .......................................................................................... 8
3. METHODS ..............................................................................................................10
3.1 – Hardware and Software Configuration ........................................................ 10
3.2 – Materials Preparation ................................................................................... 12
3.3 – Subject Preparation ...................................................................................... 19
3.4 – Experimental Procedure ............................................................................... 20
3.5 – Data Preparation........................................................................................... 22
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3.6 – Statistical Analysis Preparation ................................................................... 23
4. RESULTS ................................................................................................................26
4.1 – Friction Usage Results ................................................................................. 26
4.2 – Statistical Analysis Theory & Verification .................................................. 28
4.3 – Regression Analysis Results ........................................................................ 30
4.4 – ANOVA Results .......................................................................................... 31
4.5 – Preliminary EMG and Motion Results ........................................................ 34
5. DISCUSSION ..........................................................................................................37
5.1 – Interpretation of Results............................................................................... 37
5.2 – Comparison to Previous Studies .................................................................. 38
5.3 – Implications of Results ................................................................................ 39
5.4 – Limitations of the Experiment & Future Work............................................ 39
5.5 – Conclusion ................................................................................................... 41
APPENDIX ........................................................................................................................43
REFERENCES ..................................................................................................................46
VITA ..................................................................................................................................50
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TABLES
Table Page
Table 1: Pervious concrete material testing results........................................................... 14
Table 2: Shoe contact characteristics ................................................................................ 17
Table 3: Material COF values for utilized friction ........................................................... 19
Table 4: Subject demographics ......................................................................................... 20
Table 5: Coded demographic factors ................................................................................ 24
Table 6: Coded factors for factorial design....................................................................... 25
Table 7: Regression analysis results ................................................................................. 30
Table 8: ANOVA results................................................................................................... 31
Table 9: Mean and standard deviation of EMG and motion data ..................................... 36

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ILLUSTRATIONS
Figure Page
Figure 1: AMTI OR6-6 force platforms ........................................................................... 10
Figure 2: VICON MX-T40 motion capture camera ......................................................... 11
Figure 3: Motion capture marker ...................................................................................... 11
Figure 4: EMG system ...................................................................................................... 12
Figure 5: Pervious concrete slab covered with layer of ice atop force platform .............. 13
Figure 6: PC cylinders being prepared for permeability testing ....................................... 15
Figure 7: Permeability test ................................................................................................ 15
Figure 8: Pervious concrete contact area .......................................................................... 16
Figure 9: Material coefficient of friction test.................................................................... 18
Figure 10: Static and dynamic COF results for TC and PC.............................................. 18
Figure 11: Standardized soft-soled athletic shoes............................................................. 20
Figure 12: Normalized friction usage mean values for dry condition .............................. 26
Figure 13: Normalized friction usage mean values for icy condition............................... 27
Figure 14: Residual analysis of transformed data ............................................................. 29
Figure 15: Main effects plot.............................................................................................. 31
Figure 16: Interaction plot................................................................................................. 32
Figure 17: TC AP foot position/velocity and TA EMG ................................................... 35
Figure 18: PC AP foot position/velocity and TA EMG.................................................... 35

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EQUATIONS
Equation Page
Equation 1: Coefficient of friction calculation ................................................................. 23
Equation 2: Friction usage calculation.............................................................................. 23
Equation 3: Null hypothesis .............................................................................................. 28
Equation 4: Alternative hypothesis ................................................................................... 28
Equation 5: Second null hypothesis .................................................................................. 28
Equation 6: Second alternative hypothesis ....................................................................... 28
Equation 7: Third hypothesis ............................................................................................ 29
Equation 8: Regression equation ...................................................................................... 30

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ACKNOWLEDGEMENTS

There are many people to whom I am indebted for their assistance with this
project.
My graduate advisor, Dr. Greg King, has afforded me the opportunity to
participate in an enriching and stimulating research project. He has also consistently and
generously provided advice and assistance in every phase of this project.
I am equally grateful to Dr. John Kevern for providing access to the civil
engineering resources and facilities in this collaborative endeavor. This was the first time
I had worked outside of my own specific discipline of mechanical engineering and Dr.
Kevern made this a painless process.
I would also like to thank all those that worked to provide funding for the project.
Firstly, thanks to the National Science Foundation for providing the funding to conduct
this study. Thanks again to Drs. King and Kevern who worked hard to ensure the project
remained funded throughout its entirety. Dr. Mark McClernon also went out of his way to
help provide funding for the project.
Thank you to the other supervisory committee members, Dr. Trent Guess and Dr.
Amber Stern, for taking the time to review my work, Kyle Dunning for volunteering as a
test subject during the pilot testing phase, and my family and friends for their continued
support throughout the completion of this endeavor.

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