The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
D S Weaver - One of the best experts on this subject based on the ideXlab platform.
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transverse natural frequencies and flow induced vibrations of double bellows Expansion Joints
Journal of Fluids and Structures, 1999Co-Authors: V F Jakubauskas, D S WeaverAbstract:This paper considers the transverse vibrations of fluid-filled double-bellows Expansion Joints. The bellows are modelled as a Timoshenko beam, and the fluid added mass includes rotary inertia and bellows convolution distortion effects. The natural frequencies are given in terms of a Rayleigh quotient, and both lateral and rocking modes of the pipe connecting the bellows units are considered. The theoretical predictions for the first six modes are compared with experiments in still air and water and the agreement is found to be very good. The flow-induced vibrations of the double bellows are then studied with the bellows downstream of a straight section of pipe and a 90° elbow. Strouhal numbers are computed for each of the flow-excited mode resonances. The bellows natural frequencies are not affected by the flowing fluid but the presence of an immediate upstream elbow substantially reduces the flow velocity required to excite resonance.
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transverse vibrations of bellows Expansion Joints part i fluid added mass
Journal of Fluids and Structures, 1998Co-Authors: V F Jakubauskas, D S WeaverAbstract:This paper presents the results of an analysis of the fluid-added mass in bellows Expansion Joints during bending vibrations. The added mass is shown to consist of two parts, one due to transverse rigid-body motion and the other due to distortion of the convolutions during bending. The latter component, neglected in previous analyses, is shown to be important for relatively short bellows, as are commonly used for Expansion Joints, and to become increasingly important for higher vibration modes. The distortion component has been determined using finite element analysis, and the results are presented in a graphical form for a typical range of bellows geometries. The total added mass is given in a form suitable for hand calculations.
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transverse vibrations of bellows Expansion Joints part ii beam model development and experimental verification
Journal of Fluids and Structures, 1998Co-Authors: V F Jakubauskas, D S WeaverAbstract:A theoretical model is developed for the transverse vibrations of bellows Expansion Joints. The model is based on Timoshenko beam theory and includes the added mass effect of an internal fluid. An analytical expression for bellows natural frequencies is developed in the form of a Rayleigh quotient and is presented in a way which is suitable for hand calculations. The results for the first four transverse modes are compared with experiments as well as the predictions of the simplified analysis of the Expansion Joint Manufacturers Association (EJMA). While the present analysis agrees well with experiments, the EJMA approach can be substantially in error due to its neglect of rotary inertia and the convolution distortion component of fluid added mass.
Montgomery T Shaw - One of the best experts on this subject based on the ideXlab platform.
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laboratory evaluation of a silicone foam sealant bonded to various header materials used in bridge Expansion Joints
Construction and Building Materials, 2011Co-Authors: Ramesh B Malla, Brian J Swanson, Montgomery T ShawAbstract:Abstract A silicone foam sealant was developed to provide an easy-to-use and economical joint sealant for small-movement bridge Expansion Joints. In studies reported previously, various laboratory tests were conducted to evaluate the performance of the sealant using concrete as the bonding substrate. In the present study, laboratory tests on the sealant were conducted using other substrates found in practice, including steel, asphalt, and polymer concrete. Some of the tests conducted included a tension test, repair test, oven-aged bonding test, salt water immersion test, and a cure (modulus over time) test that evaluated the mechanical properties of the sealant as it developed its final state of cure. Through the laboratory tests, it has been observed that the silicone foam has the ability to bond to various substrate materials and can easily accommodate deformation typical of small-movement Expansion Joints in bridges.
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temperature aging compression recovery creep and weathering of a foam silicone sealant for bridge Expansion Joints
Journal of Materials in Civil Engineering, 2011Co-Authors: Ramesh B Malla, Montgomery T Shaw, Matu R Shrestha, Smita BrijmohanAbstract:Silicone foam was investigated as a sealant for small movement Expansion Joints in bridge decks. This paper presents results from the laboratory assessment of a model foam sealant subjected to thermal aging (exposure to high and low temperatures and temperature cycling), fatigue conditions, and outdoor weathering. Parallel tests were performed on a commercial solid-silicone bridge-joint sealant. Test results showed that the solid sealant recovered faster than the foam sealant after being subjected to prolonged compression at elevated temperature. When subjected to a constant tensile force, both the foam and solid sealants exhibited high initial creep rates (rate of elongation), but appeared to reach an equilibrium level of elongation at longer times. The foam sealant creeps at a slower rate and takes more time to get to the equilibrium elongation, whereas the solid sealant creeps much faster initially and reaches equilibrium faster. Thermal aging was found to have significant effects on the sealant modulus (increases with temperature); however, the effects on ultimate stress and strain were not apparent for both types of sealants. Temperature cycling between 24 and -29°C was observed to diminish the ultimate stress and strain of both the sealants by roughly 25%; however, no significant changes in modulus were found. Results from the tests on a limited number of outdoor-weathered sealant specimens showed that weathering appeared to produce an increase in sealant tensile and shear moduli (i.e., hardening effects because of weathering) and a decrease in ultimate strain. The weathered samples show tension loading-unloading behavior similar to the unaged samples. The tensile stress relaxation rate of the outdoor-weathered sealants could not be distinguished from those laboratory-cured (unweathered) counterparts.
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laboratory evaluation of a silicone foam sealant for field application on bridge Expansion Joints
2011Co-Authors: Ramesh B Malla, Brian J Swanson, Montgomery T ShawAbstract:A silicone foam sealant was developed to provide an alternative small-bridge joint sealant that was effective, easy-to-use, and economical. In the previous study various laboratory tests including tension, bonding, compression, shear, stress relaxation, and other were conducted to determine the engineering characteristics of the sealant. All these tests were limited to the concrete as the substrate to which the sealant was bonded to. In the present study, laboratory tests on the sealant were conducted using other substrates found in practice, including steel, asphalt and polymeric concrete. Some of the tests conducted included tension (pull to failure) test, oven-aged bonding test, salt water immersion test, and a performance-during-curing test that evaluated the strength and strain of the sealant.. Through the laboratory tests, it has been observed that the silicone foam can exhibits good bonding to various substrate materials and can easily accommodate small movement bridge Expansion Joints. In addition to these tests in small specimen, a procedure to produce larger quantity of sealant and apply it to an actual bridge Expansion joint was developed using a simulated joint built in the laboratory. Through the development of this procedure and the eventual application of the sealant into various bridge Expansion Joints, it can be determined that the silicone foam presents an alternative sealant that is east-to-use and allows for quick installation.
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development and laboratory analysis of silicone foam sealant for bridge Expansion Joints
Journal of Bridge Engineering, 2007Co-Authors: Ramesh B Malla, Montgomery T Shaw, Matu R Shrestha, Smita BrijmohanAbstract:Sealing of bridge Expansion joint systems is important to protect the structural components below the joint. An elastomeric foam-type joint sealant has been developed for sealing small-movement bridge Expansion Joints. Laboratory tests including tension, compression, shear, bonding, stress relaxation, cure rate, tack-free time, and water tightness were performed on this sealant. In addition, loading-unloading behavior in tension and compression and effects of immersion in saturated saltwater solution on its engineering properties were investigated. The silicone foam sealant showed an increase in volume of ~70% on curing and attained approximately 80% of the 21-day curing strength in the first 7 days. Tack-free time for the foam sealant was below 1.5 h and comparable to that for the solid sealant. The mechanical test results indicated lower stiffness, greater extensibility, and better bonding associated with the foam sealant compared to the solid (unfoamed) sealant. The foam sealant exhibited smaller loss in extensibility at failure due to saltwater immersion compared to the solid sealant. While in tension both sealants exhibited similar rates of stress decay, in compression the foam sealant was found to relax faster than the solid. Neither sealants exhibited any water leakage during a 96-h test period.
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sealing of small movement bridge Expansion Joints
2006Co-Authors: Ramesh B Malla, Montgomery T Shaw, Matu R Shrestha, Smita BoobAbstract:Sealing of bridge Expansion joint systems is important to protect the structural components below the joint from damage due to water, salt, and other roadway debris. A new elastomeric foam-type joint sealant has been developed for sealing small-movement bridge Expansion Joints. Laboratory tests including tension, compression, shear, binding, salt water immersion, temperature sensitivity, compression recovery, creep, stress relaxation, cure rate, tack time, and watertightness were performed on this newly developed sealant to assess its mechanical and material characteristics. In addition, loading-unloading behavior in tension and compression and effects of exposure to outdoor condition for 6.5 months period on its engineering properties were investigated. Similar tests were also performed on a currently available commercial bridge joint sealant material for comparison purposes. The new silicone foam sealant showed an increase in volume by about 70% after the mixing of sealant components. The test results indicated lower stiffness, greater extensibility, and better bonding associated with the foam sealant compared to the commercial sealant. Foam sealant showed more resistant to fatigue with tensile deformation cycles and its stress relaxation rate was greater than that of commercial sealant. The tack and cure time for foam sealant were small and no leakage was observed through the sealant and joint interface. The sealant also did not exhibit any physical deterioration during prolonged exposure to natural weathering elements; however, it appeared to stiffen which might be due to oxidation and continuous sealant cure.
Ramesh B Malla - One of the best experts on this subject based on the ideXlab platform.
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laboratory evaluation of a silicone foam sealant bonded to various header materials used in bridge Expansion Joints
Construction and Building Materials, 2011Co-Authors: Ramesh B Malla, Brian J Swanson, Montgomery T ShawAbstract:Abstract A silicone foam sealant was developed to provide an easy-to-use and economical joint sealant for small-movement bridge Expansion Joints. In studies reported previously, various laboratory tests were conducted to evaluate the performance of the sealant using concrete as the bonding substrate. In the present study, laboratory tests on the sealant were conducted using other substrates found in practice, including steel, asphalt, and polymer concrete. Some of the tests conducted included a tension test, repair test, oven-aged bonding test, salt water immersion test, and a cure (modulus over time) test that evaluated the mechanical properties of the sealant as it developed its final state of cure. Through the laboratory tests, it has been observed that the silicone foam has the ability to bond to various substrate materials and can easily accommodate deformation typical of small-movement Expansion Joints in bridges.
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temperature aging compression recovery creep and weathering of a foam silicone sealant for bridge Expansion Joints
Journal of Materials in Civil Engineering, 2011Co-Authors: Ramesh B Malla, Montgomery T Shaw, Matu R Shrestha, Smita BrijmohanAbstract:Silicone foam was investigated as a sealant for small movement Expansion Joints in bridge decks. This paper presents results from the laboratory assessment of a model foam sealant subjected to thermal aging (exposure to high and low temperatures and temperature cycling), fatigue conditions, and outdoor weathering. Parallel tests were performed on a commercial solid-silicone bridge-joint sealant. Test results showed that the solid sealant recovered faster than the foam sealant after being subjected to prolonged compression at elevated temperature. When subjected to a constant tensile force, both the foam and solid sealants exhibited high initial creep rates (rate of elongation), but appeared to reach an equilibrium level of elongation at longer times. The foam sealant creeps at a slower rate and takes more time to get to the equilibrium elongation, whereas the solid sealant creeps much faster initially and reaches equilibrium faster. Thermal aging was found to have significant effects on the sealant modulus (increases with temperature); however, the effects on ultimate stress and strain were not apparent for both types of sealants. Temperature cycling between 24 and -29°C was observed to diminish the ultimate stress and strain of both the sealants by roughly 25%; however, no significant changes in modulus were found. Results from the tests on a limited number of outdoor-weathered sealant specimens showed that weathering appeared to produce an increase in sealant tensile and shear moduli (i.e., hardening effects because of weathering) and a decrease in ultimate strain. The weathered samples show tension loading-unloading behavior similar to the unaged samples. The tensile stress relaxation rate of the outdoor-weathered sealants could not be distinguished from those laboratory-cured (unweathered) counterparts.
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laboratory evaluation of a silicone foam sealant for field application on bridge Expansion Joints
2011Co-Authors: Ramesh B Malla, Brian J Swanson, Montgomery T ShawAbstract:A silicone foam sealant was developed to provide an alternative small-bridge joint sealant that was effective, easy-to-use, and economical. In the previous study various laboratory tests including tension, bonding, compression, shear, stress relaxation, and other were conducted to determine the engineering characteristics of the sealant. All these tests were limited to the concrete as the substrate to which the sealant was bonded to. In the present study, laboratory tests on the sealant were conducted using other substrates found in practice, including steel, asphalt and polymeric concrete. Some of the tests conducted included tension (pull to failure) test, oven-aged bonding test, salt water immersion test, and a performance-during-curing test that evaluated the strength and strain of the sealant.. Through the laboratory tests, it has been observed that the silicone foam can exhibits good bonding to various substrate materials and can easily accommodate small movement bridge Expansion Joints. In addition to these tests in small specimen, a procedure to produce larger quantity of sealant and apply it to an actual bridge Expansion joint was developed using a simulated joint built in the laboratory. Through the development of this procedure and the eventual application of the sealant into various bridge Expansion Joints, it can be determined that the silicone foam presents an alternative sealant that is east-to-use and allows for quick installation.
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development and laboratory analysis of silicone foam sealant for bridge Expansion Joints
Journal of Bridge Engineering, 2007Co-Authors: Ramesh B Malla, Montgomery T Shaw, Matu R Shrestha, Smita BrijmohanAbstract:Sealing of bridge Expansion joint systems is important to protect the structural components below the joint. An elastomeric foam-type joint sealant has been developed for sealing small-movement bridge Expansion Joints. Laboratory tests including tension, compression, shear, bonding, stress relaxation, cure rate, tack-free time, and water tightness were performed on this sealant. In addition, loading-unloading behavior in tension and compression and effects of immersion in saturated saltwater solution on its engineering properties were investigated. The silicone foam sealant showed an increase in volume of ~70% on curing and attained approximately 80% of the 21-day curing strength in the first 7 days. Tack-free time for the foam sealant was below 1.5 h and comparable to that for the solid sealant. The mechanical test results indicated lower stiffness, greater extensibility, and better bonding associated with the foam sealant compared to the solid (unfoamed) sealant. The foam sealant exhibited smaller loss in extensibility at failure due to saltwater immersion compared to the solid sealant. While in tension both sealants exhibited similar rates of stress decay, in compression the foam sealant was found to relax faster than the solid. Neither sealants exhibited any water leakage during a 96-h test period.
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sealing of small movement bridge Expansion Joints
2006Co-Authors: Ramesh B Malla, Montgomery T Shaw, Matu R Shrestha, Smita BoobAbstract:Sealing of bridge Expansion joint systems is important to protect the structural components below the joint from damage due to water, salt, and other roadway debris. A new elastomeric foam-type joint sealant has been developed for sealing small-movement bridge Expansion Joints. Laboratory tests including tension, compression, shear, binding, salt water immersion, temperature sensitivity, compression recovery, creep, stress relaxation, cure rate, tack time, and watertightness were performed on this newly developed sealant to assess its mechanical and material characteristics. In addition, loading-unloading behavior in tension and compression and effects of exposure to outdoor condition for 6.5 months period on its engineering properties were investigated. Similar tests were also performed on a currently available commercial bridge joint sealant material for comparison purposes. The new silicone foam sealant showed an increase in volume by about 70% after the mixing of sealant components. The test results indicated lower stiffness, greater extensibility, and better bonding associated with the foam sealant compared to the commercial sealant. Foam sealant showed more resistant to fatigue with tensile deformation cycles and its stress relaxation rate was greater than that of commercial sealant. The tack and cure time for foam sealant were small and no leakage was observed through the sealant and joint interface. The sealant also did not exhibit any physical deterioration during prolonged exposure to natural weathering elements; however, it appeared to stiffen which might be due to oxidation and continuous sealant cure.
V F Jakubauskas - One of the best experts on this subject based on the ideXlab platform.
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added fluid mass for bellows Expansion Joints in axial vibrations
Journal of Pressure Vessel Technology-transactions of The Asme, 1999Co-Authors: V F JakubauskasAbstract:This paper presents the results of an analysis of fluid added mass in bellows Expansion Joints during bending vibrations. The added mass is shown to consist of two parts, one due to transverse rigid body motion and the other due to distortion of the convolution during bending. The latter component, neglected in previous analyses, is shown to be important for relatively short bellows, as are commonly used for Expansion Joints, and to become increasingly important for higher vibration modes. The distortion component has been determined using finite element analysis and the results are presented in graphical form for a typical range of bellows geometries. The total added mass is given in a form suitable for hand calculations.
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transverse natural frequencies and flow induced vibrations of double bellows Expansion Joints
Journal of Fluids and Structures, 1999Co-Authors: V F Jakubauskas, D S WeaverAbstract:This paper considers the transverse vibrations of fluid-filled double-bellows Expansion Joints. The bellows are modelled as a Timoshenko beam, and the fluid added mass includes rotary inertia and bellows convolution distortion effects. The natural frequencies are given in terms of a Rayleigh quotient, and both lateral and rocking modes of the pipe connecting the bellows units are considered. The theoretical predictions for the first six modes are compared with experiments in still air and water and the agreement is found to be very good. The flow-induced vibrations of the double bellows are then studied with the bellows downstream of a straight section of pipe and a 90° elbow. Strouhal numbers are computed for each of the flow-excited mode resonances. The bellows natural frequencies are not affected by the flowing fluid but the presence of an immediate upstream elbow substantially reduces the flow velocity required to excite resonance.
-
transverse vibrations of bellows Expansion Joints part i fluid added mass
Journal of Fluids and Structures, 1998Co-Authors: V F Jakubauskas, D S WeaverAbstract:This paper presents the results of an analysis of the fluid-added mass in bellows Expansion Joints during bending vibrations. The added mass is shown to consist of two parts, one due to transverse rigid-body motion and the other due to distortion of the convolutions during bending. The latter component, neglected in previous analyses, is shown to be important for relatively short bellows, as are commonly used for Expansion Joints, and to become increasingly important for higher vibration modes. The distortion component has been determined using finite element analysis, and the results are presented in a graphical form for a typical range of bellows geometries. The total added mass is given in a form suitable for hand calculations.
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transverse vibrations of bellows Expansion Joints part ii beam model development and experimental verification
Journal of Fluids and Structures, 1998Co-Authors: V F Jakubauskas, D S WeaverAbstract:A theoretical model is developed for the transverse vibrations of bellows Expansion Joints. The model is based on Timoshenko beam theory and includes the added mass effect of an internal fluid. An analytical expression for bellows natural frequencies is developed in the form of a Rayleigh quotient and is presented in a way which is suitable for hand calculations. The results for the first four transverse modes are compared with experiments as well as the predictions of the simplified analysis of the Expansion Joint Manufacturers Association (EJMA). While the present analysis agrees well with experiments, the EJMA approach can be substantially in error due to its neglect of rotary inertia and the convolution distortion component of fluid added mass.
Brian J Swanson - One of the best experts on this subject based on the ideXlab platform.
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laboratory evaluation of a silicone foam sealant bonded to various header materials used in bridge Expansion Joints
Construction and Building Materials, 2011Co-Authors: Ramesh B Malla, Brian J Swanson, Montgomery T ShawAbstract:Abstract A silicone foam sealant was developed to provide an easy-to-use and economical joint sealant for small-movement bridge Expansion Joints. In studies reported previously, various laboratory tests were conducted to evaluate the performance of the sealant using concrete as the bonding substrate. In the present study, laboratory tests on the sealant were conducted using other substrates found in practice, including steel, asphalt, and polymer concrete. Some of the tests conducted included a tension test, repair test, oven-aged bonding test, salt water immersion test, and a cure (modulus over time) test that evaluated the mechanical properties of the sealant as it developed its final state of cure. Through the laboratory tests, it has been observed that the silicone foam has the ability to bond to various substrate materials and can easily accommodate deformation typical of small-movement Expansion Joints in bridges.
-
laboratory evaluation of a silicone foam sealant for field application on bridge Expansion Joints
2011Co-Authors: Ramesh B Malla, Brian J Swanson, Montgomery T ShawAbstract:A silicone foam sealant was developed to provide an alternative small-bridge joint sealant that was effective, easy-to-use, and economical. In the previous study various laboratory tests including tension, bonding, compression, shear, stress relaxation, and other were conducted to determine the engineering characteristics of the sealant. All these tests were limited to the concrete as the substrate to which the sealant was bonded to. In the present study, laboratory tests on the sealant were conducted using other substrates found in practice, including steel, asphalt and polymeric concrete. Some of the tests conducted included tension (pull to failure) test, oven-aged bonding test, salt water immersion test, and a performance-during-curing test that evaluated the strength and strain of the sealant.. Through the laboratory tests, it has been observed that the silicone foam can exhibits good bonding to various substrate materials and can easily accommodate small movement bridge Expansion Joints. In addition to these tests in small specimen, a procedure to produce larger quantity of sealant and apply it to an actual bridge Expansion joint was developed using a simulated joint built in the laboratory. Through the development of this procedure and the eventual application of the sealant into various bridge Expansion Joints, it can be determined that the silicone foam presents an alternative sealant that is east-to-use and allows for quick installation.
