The use of lightweight and high strength materials in building construction have resulted in larg... more The use of lightweight and high strength materials in building construction have resulted in larger bays and longer spans in floor systems. Lighter materials in addition to the trend towards a “paperless” office decreases damping and the amount of live load on the floors. As a result, floors have become more vulnerable to annoying vibrations induced by human occupancy. The number of complaints by occupants has increased in recent years and floor vibrations have become an area of serviceability concern. Activities like walking, dancing, running, jumping, aerobics, etc. generate floor vibrations and humans have different tolerance levels for these vibrations. Because humans are both the source and the sensor, human-induced vibration can not be isolated from the structure; vibration must be controlled by the floor system. Extensive research has been conducted on human perceptibility of floor vibrations and dynamic behavior of floor systems. The procedures in the AISC/CISC Design Guide 11- Floor Vibrations Due to Human Activity (Murray et al. 1997) are available for designers to determine acceptable acceleration levels and minimize excessive floor vibrations. The best approach is to design floors that do not allow annoying vibrations, as remedies for floors susceptible to excessive floor vibrations are very expensive. Possible modifications of existing problem floors include adding mass, increasing damping (using partitions, damping posts or tuned mass dampers) and increasing structural stiffness of the floor systems. Open web steel joists are very popular in steel building construction. The open web allows the duct work to be run through the web and maintenance can be done easily after the construction is completed. This makes open web steel joists very feasible and economical; however, vibrations of joist supported floor systems, and in particular, the effect of extended bottom chords, are still not very well understood. Extending joist bottom chords in an attempt to improve problem floors has been reported but without success. However, these retrofits were done after fit-out of the buildings and without introducing a preload into the extensions. The purpose of this study is to examine the effect of bottom chord extensions on deflections and vibration characteristics of joist supported floor systems when joist bottom chord extensions are installed (a) before the concrete was placed, (b) after the fit-out with jacking for a single span footbridge, and (c) after the fit-out without jacking for a three span footbridge. Extensive analytical and experimental studies are performed on two laboratory footbridges with different bottom chord extension configurations to understand the effect of extended bottom chords on deflection, natural frequency, damping, mode shape and effective mass. Finite element computer models are created to simulate and compare the results of stiffness and vibration tests.
... Show full item record. Title: Effects of Bottom Chord Extensions on the Performance of Stee... more ... Show full item record. Title: Effects of Bottom Chord Extensions on the Performance of Steel Joist Supported Floors. Author: Onur AVCI. URI: http://hdl.handle.net/123456789/140840. Date: 2011-06-02. Files in this item. Files, Size, Format, View. Effects of Bott ... ...
Progress in Structural Engineering and Materials, 2000
In this article, the factors in the cost of steel construction are discussed with emphasis on the... more In this article, the factors in the cost of steel construction are discussed with emphasis on the dominant components of the total cost. Basic suggestions are given for improving the economy of steel building construction. Subsequently, several recent developments are ...
Progress in Structural Engineering and Materials, 2000
In this article, the factors in the cost of steel construction are discussed with emphasis on the... more In this article, the factors in the cost of steel construction are discussed with emphasis on the dominant components of the total cost. Basic suggestions are given for improving the economy of steel building construction. Subsequently, several recent developments are ...
... provides equations for the required plate thickness, based on strength and stiffness, and the... more ... provides equations for the required plate thickness, based on strength and stiffness, and thedetermination of bolt ... For beam-to-column end-plate connections with a composite slab, the slab and shear studs should be detailed to ensure that the composite shear connection ...
The use of lightweight and high strength materials in building construction have resulted in larg... more The use of lightweight and high strength materials in building construction have resulted in larger bays and longer spans in floor systems. Lighter materials in addition to the trend towards a “paperless” office decreases damping and the amount of live load on the floors. As a result, floors have become more vulnerable to annoying vibrations induced by human occupancy. The number of complaints by occupants has increased in recent years and floor vibrations have become an area of serviceability concern. Activities like walking, dancing, running, jumping, aerobics, etc. generate floor vibrations and humans have different tolerance levels for these vibrations. Because humans are both the source and the sensor, human-induced vibration can not be isolated from the structure; vibration must be controlled by the floor system. Extensive research has been conducted on human perceptibility of floor vibrations and dynamic behavior of floor systems. The procedures in the AISC/CISC Design Guide 11- Floor Vibrations Due to Human Activity (Murray et al. 1997) are available for designers to determine acceptable acceleration levels and minimize excessive floor vibrations. The best approach is to design floors that do not allow annoying vibrations, as remedies for floors susceptible to excessive floor vibrations are very expensive. Possible modifications of existing problem floors include adding mass, increasing damping (using partitions, damping posts or tuned mass dampers) and increasing structural stiffness of the floor systems. Open web steel joists are very popular in steel building construction. The open web allows the duct work to be run through the web and maintenance can be done easily after the construction is completed. This makes open web steel joists very feasible and economical; however, vibrations of joist supported floor systems, and in particular, the effect of extended bottom chords, are still not very well understood. Extending joist bottom chords in an attempt to improve problem floors has been reported but without success. However, these retrofits were done after fit-out of the buildings and without introducing a preload into the extensions. The purpose of this study is to examine the effect of bottom chord extensions on deflections and vibration characteristics of joist supported floor systems when joist bottom chord extensions are installed (a) before the concrete was placed, (b) after the fit-out with jacking for a single span footbridge, and (c) after the fit-out without jacking for a three span footbridge. Extensive analytical and experimental studies are performed on two laboratory footbridges with different bottom chord extension configurations to understand the effect of extended bottom chords on deflection, natural frequency, damping, mode shape and effective mass. Finite element computer models are created to simulate and compare the results of stiffness and vibration tests.
... Show full item record. Title: Effects of Bottom Chord Extensions on the Performance of Stee... more ... Show full item record. Title: Effects of Bottom Chord Extensions on the Performance of Steel Joist Supported Floors. Author: Onur AVCI. URI: http://hdl.handle.net/123456789/140840. Date: 2011-06-02. Files in this item. Files, Size, Format, View. Effects of Bott ... ...
Progress in Structural Engineering and Materials, 2000
In this article, the factors in the cost of steel construction are discussed with emphasis on the... more In this article, the factors in the cost of steel construction are discussed with emphasis on the dominant components of the total cost. Basic suggestions are given for improving the economy of steel building construction. Subsequently, several recent developments are ...
Progress in Structural Engineering and Materials, 2000
In this article, the factors in the cost of steel construction are discussed with emphasis on the... more In this article, the factors in the cost of steel construction are discussed with emphasis on the dominant components of the total cost. Basic suggestions are given for improving the economy of steel building construction. Subsequently, several recent developments are ...
... provides equations for the required plate thickness, based on strength and stiffness, and the... more ... provides equations for the required plate thickness, based on strength and stiffness, and thedetermination of bolt ... For beam-to-column end-plate connections with a composite slab, the slab and shear studs should be detailed to ensure that the composite shear connection ...
Uploads
Papers by Thomas. M. Murray
Activities like walking, dancing, running, jumping, aerobics, etc. generate floor vibrations and humans have different tolerance levels for these vibrations. Because humans are both the source and the sensor, human-induced vibration can not be isolated from the structure; vibration must be controlled by the floor system. Extensive research has been conducted on human perceptibility of floor vibrations and dynamic behavior of floor systems. The procedures in the AISC/CISC Design Guide 11- Floor Vibrations Due to Human Activity (Murray et al. 1997) are available for designers to determine acceptable acceleration levels and minimize excessive floor vibrations.
The best approach is to design floors that do not allow annoying vibrations, as remedies for floors susceptible to excessive floor vibrations are very expensive. Possible modifications of existing problem floors include adding mass, increasing damping (using partitions, damping posts or tuned mass dampers) and increasing structural stiffness of the floor systems.
Open web steel joists are very popular in steel building construction. The open web allows the duct work to be run through the web and maintenance can be done easily after the construction is completed. This makes open web steel joists very feasible and economical; however, vibrations of joist supported floor systems, and in particular, the effect of extended bottom chords, are still not very well understood. Extending joist bottom chords in an attempt to improve problem floors has been reported but without success. However, these retrofits were done after fit-out of the buildings and without introducing a preload into the extensions.
The purpose of this study is to examine the effect of bottom chord extensions on deflections and vibration characteristics of joist supported floor systems when joist bottom chord extensions are installed (a) before the concrete was placed, (b) after the fit-out with jacking for a single span footbridge, and (c) after the fit-out without jacking for a three span footbridge. Extensive analytical and experimental studies are performed on two laboratory footbridges with different bottom chord extension configurations to understand the effect of extended bottom chords on deflection, natural frequency, damping, mode shape and effective mass. Finite element computer models are created to simulate and compare the results of stiffness and vibration tests.
Activities like walking, dancing, running, jumping, aerobics, etc. generate floor vibrations and humans have different tolerance levels for these vibrations. Because humans are both the source and the sensor, human-induced vibration can not be isolated from the structure; vibration must be controlled by the floor system. Extensive research has been conducted on human perceptibility of floor vibrations and dynamic behavior of floor systems. The procedures in the AISC/CISC Design Guide 11- Floor Vibrations Due to Human Activity (Murray et al. 1997) are available for designers to determine acceptable acceleration levels and minimize excessive floor vibrations.
The best approach is to design floors that do not allow annoying vibrations, as remedies for floors susceptible to excessive floor vibrations are very expensive. Possible modifications of existing problem floors include adding mass, increasing damping (using partitions, damping posts or tuned mass dampers) and increasing structural stiffness of the floor systems.
Open web steel joists are very popular in steel building construction. The open web allows the duct work to be run through the web and maintenance can be done easily after the construction is completed. This makes open web steel joists very feasible and economical; however, vibrations of joist supported floor systems, and in particular, the effect of extended bottom chords, are still not very well understood. Extending joist bottom chords in an attempt to improve problem floors has been reported but without success. However, these retrofits were done after fit-out of the buildings and without introducing a preload into the extensions.
The purpose of this study is to examine the effect of bottom chord extensions on deflections and vibration characteristics of joist supported floor systems when joist bottom chord extensions are installed (a) before the concrete was placed, (b) after the fit-out with jacking for a single span footbridge, and (c) after the fit-out without jacking for a three span footbridge. Extensive analytical and experimental studies are performed on two laboratory footbridges with different bottom chord extension configurations to understand the effect of extended bottom chords on deflection, natural frequency, damping, mode shape and effective mass. Finite element computer models are created to simulate and compare the results of stiffness and vibration tests.