Author: Gayle E. Albritton
Publisher:
ISBN:
Category : Materials
Languages : en
Pages : 216
Book Description
The general objective of the investigation was to study experimentally the behavior to failure of flexible, horizontally oriented cylinders buried at various depths in dense, dry sand and subjected to either static or dynamic surface overpressures. Static and dynamic tests were conducted on 33 different cylinders, fabricated of high-yield-strength aluminum. Results indicated that collapse of the cylinders occurred while the strains in the cylinder walls were still in the elastic range. The cylinders buried at the shallow depths (zero to one-half cylinder diameter above the crown) collapsed by a catastrophic snap-through or caving of the crown. For the cylinders buried at depths of three-quarters to two cylinder diameters above the crown, the mode of collapse was an instantaneous elastic buckle that occurred at the spring line or invert of the cylinder. The collapse mode of the cylinders under dynamic overpressure was similar to that of the cylinders collapsing under static overpressure. The results of the investigation verified the applicability of an equation for predicting the static collapse overpressure for smooth-walled, horizontally oriented, buried cylindrical structures and entranceways. The hoop-compression theory was found to be applicable for analyzing the structural design to determine if the cylinder would collapse in the elastic range. (Author).
Behavior of Flexible Cylinders Buried in Sand Under Static and Dynamic Loading
Author: Gayle E. Albritton
Publisher:
ISBN:
Category : Materials
Languages : en
Pages : 216
Book Description
The general objective of the investigation was to study experimentally the behavior to failure of flexible, horizontally oriented cylinders buried at various depths in dense, dry sand and subjected to either static or dynamic surface overpressures. Static and dynamic tests were conducted on 33 different cylinders, fabricated of high-yield-strength aluminum. Results indicated that collapse of the cylinders occurred while the strains in the cylinder walls were still in the elastic range. The cylinders buried at the shallow depths (zero to one-half cylinder diameter above the crown) collapsed by a catastrophic snap-through or caving of the crown. For the cylinders buried at depths of three-quarters to two cylinder diameters above the crown, the mode of collapse was an instantaneous elastic buckle that occurred at the spring line or invert of the cylinder. The collapse mode of the cylinders under dynamic overpressure was similar to that of the cylinders collapsing under static overpressure. The results of the investigation verified the applicability of an equation for predicting the static collapse overpressure for smooth-walled, horizontally oriented, buried cylindrical structures and entranceways. The hoop-compression theory was found to be applicable for analyzing the structural design to determine if the cylinder would collapse in the elastic range. (Author).
Publisher:
ISBN:
Category : Materials
Languages : en
Pages : 216
Book Description
The general objective of the investigation was to study experimentally the behavior to failure of flexible, horizontally oriented cylinders buried at various depths in dense, dry sand and subjected to either static or dynamic surface overpressures. Static and dynamic tests were conducted on 33 different cylinders, fabricated of high-yield-strength aluminum. Results indicated that collapse of the cylinders occurred while the strains in the cylinder walls were still in the elastic range. The cylinders buried at the shallow depths (zero to one-half cylinder diameter above the crown) collapsed by a catastrophic snap-through or caving of the crown. For the cylinders buried at depths of three-quarters to two cylinder diameters above the crown, the mode of collapse was an instantaneous elastic buckle that occurred at the spring line or invert of the cylinder. The collapse mode of the cylinders under dynamic overpressure was similar to that of the cylinders collapsing under static overpressure. The results of the investigation verified the applicability of an equation for predicting the static collapse overpressure for smooth-walled, horizontally oriented, buried cylindrical structures and entranceways. The hoop-compression theory was found to be applicable for analyzing the structural design to determine if the cylinder would collapse in the elastic range. (Author).
Behavior of Stiff Cylinders Buried in Sand Under Static Loading
Author: Charles D. Norman
Publisher:
ISBN:
Category : Cylinders
Languages : en
Pages : 114
Book Description
Publisher:
ISBN:
Category : Cylinders
Languages : en
Pages : 114
Book Description
Behavior of Circular Tubes Buried in Sand Under Dynamic Loading
Author: Algirdas G. Leskys
Publisher:
ISBN:
Category : Materials
Languages : en
Pages : 86
Book Description
The general objective of this investigation was to study experimentally the behavior to failure of flexible, horizontally oriented circular tubes buried at various depths in dense, dry sand and subjected to dynamic surface overpressures. Dynamic tests were conducted on ten brass tubes in the Small Blast Load Generator. The tubes had a wall thickness of 0.005 inch, an outside diameter of 4 inches, and a specially isolated 5.75-inch-long test section. The tubes were flexible and had a stiffness EI/R3 of 0.018 psi. To examine the effect of depth of burial, tests were conducted in dense, dry sand at depths ranging from 1 to 16 inches, or four tube diameters above the crown. The dynamic tests were conducted at overpressures ranging from 6.2 to 34.9 psi. Measurements were made of the applied overpressure, and the tube deflection was recorded by means of a high-speed camera linked to the pressure-time base. Results indicate that collapse of the tubes was initiated by a buckle that occurred along a longitudinal seam where the tubes were spliced. The dynamic collapse overpressure increased greatly with increased depth of burial down to a depth of one tube diameter; subsequently, the increase in collapse overpressure with increase of burial depth to four tube diameters was insignificant. The dynamic collapse overpressure was approximately the same as the static collapse overpressure as determined from correlation with previously reported results. The results of this investigation have verified the applicability of an equation for predicting the dynamic collapse overpressure of very flexible tubes. (Author).
Publisher:
ISBN:
Category : Materials
Languages : en
Pages : 86
Book Description
The general objective of this investigation was to study experimentally the behavior to failure of flexible, horizontally oriented circular tubes buried at various depths in dense, dry sand and subjected to dynamic surface overpressures. Dynamic tests were conducted on ten brass tubes in the Small Blast Load Generator. The tubes had a wall thickness of 0.005 inch, an outside diameter of 4 inches, and a specially isolated 5.75-inch-long test section. The tubes were flexible and had a stiffness EI/R3 of 0.018 psi. To examine the effect of depth of burial, tests were conducted in dense, dry sand at depths ranging from 1 to 16 inches, or four tube diameters above the crown. The dynamic tests were conducted at overpressures ranging from 6.2 to 34.9 psi. Measurements were made of the applied overpressure, and the tube deflection was recorded by means of a high-speed camera linked to the pressure-time base. Results indicate that collapse of the tubes was initiated by a buckle that occurred along a longitudinal seam where the tubes were spliced. The dynamic collapse overpressure increased greatly with increased depth of burial down to a depth of one tube diameter; subsequently, the increase in collapse overpressure with increase of burial depth to four tube diameters was insignificant. The dynamic collapse overpressure was approximately the same as the static collapse overpressure as determined from correlation with previously reported results. The results of this investigation have verified the applicability of an equation for predicting the dynamic collapse overpressure of very flexible tubes. (Author).
Alternatives in Energy Conservation
List of Publications of the U.S. Army Engineer Waterways Experiment Station
Author: U.S. Army Engineer Waterways Experiment Station
Publisher:
ISBN:
Category : Hydraulic engineering
Languages : en
Pages : 430
Book Description
Publisher:
ISBN:
Category : Hydraulic engineering
Languages : en
Pages : 430
Book Description
Failure of Footing-supported Buried Steel Arches Loaded Statically
Author: John F. Munn
Publisher:
ISBN:
Category : Concrete footings
Languages : en
Pages : 90
Book Description
The objective of this investigation was to study the failure of statically loaded steel circular arches buried in sand as affected by three variables; footing width, arch flexibility, and depth of burial. Static tests were performed on 16 arches with 18-inch outside diameters. The parameters varied were wall thickness, depth of burial, and footing area. The maximum static overpressure available was 100 psi. Strain measurements were made at various locations on the arch so that thrusts and moments could be computed. (The computer program developed for these computations is described in Appendix B.) Measurements of crown deflection and footing settlement were also made. Three modes of failure were observed in the various tests. Buckling of the crown of the arch and punching of the footings into the supporting soil were the two dominant failure modes, but buckling of the arch haunches also occurred in the case of the thin arch with large footings. Generally, it was observed that the thin arches with large footings exhibited arch failure while the thick arches with small footings exhibited footing failure. Based on the test results, a method was proposed for predicting the type of failure occurring for arches with various footing and arch stiffness configuration combinations. Support investigations were conducted to determine the properties of the sand and steel used in the test. Sand properties are described in Appendix A. (Author).
Publisher:
ISBN:
Category : Concrete footings
Languages : en
Pages : 90
Book Description
The objective of this investigation was to study the failure of statically loaded steel circular arches buried in sand as affected by three variables; footing width, arch flexibility, and depth of burial. Static tests were performed on 16 arches with 18-inch outside diameters. The parameters varied were wall thickness, depth of burial, and footing area. The maximum static overpressure available was 100 psi. Strain measurements were made at various locations on the arch so that thrusts and moments could be computed. (The computer program developed for these computations is described in Appendix B.) Measurements of crown deflection and footing settlement were also made. Three modes of failure were observed in the various tests. Buckling of the crown of the arch and punching of the footings into the supporting soil were the two dominant failure modes, but buckling of the arch haunches also occurred in the case of the thin arch with large footings. Generally, it was observed that the thin arches with large footings exhibited arch failure while the thick arches with small footings exhibited footing failure. Based on the test results, a method was proposed for predicting the type of failure occurring for arches with various footing and arch stiffness configuration combinations. Support investigations were conducted to determine the properties of the sand and steel used in the test. Sand properties are described in Appendix A. (Author).
List of Publications of the U.S. Army Engineers Waterway Experiment Station
Author: United States. Army. Corps of Engineers
Publisher:
ISBN:
Category :
Languages : en
Pages : 438
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 438
Book Description
List of Publications of the U.S. Army Engineer Waterways Experiment Station
Author: Waterways Experiment Station (U.S.)
Publisher:
ISBN:
Category : Hydraulic engineering
Languages : en
Pages : 322
Book Description
Publisher:
ISBN:
Category : Hydraulic engineering
Languages : en
Pages : 322
Book Description
Report No. FHWA-RD.
Author: United States. Federal Highway Administration. Offices of Research and Development
Publisher:
ISBN:
Category :
Languages : en
Pages : 654
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 654
Book Description
Static Behavior of Buried Reinforced-concrete Model Cylinders
Author: Jay R. Allgood
Publisher:
ISBN:
Category :
Languages : en
Pages : 60
Book Description
Experimental results and empirical relations are given which define the behavior of reinforced-concrete model cylinders that are buried in dry sand with their longitudinal axis parallel to the surface. The model cylinders were 9 inches in outside diameter and had a single layer of reinforcement at midsection. Thickness, percent reinforcement, and depth of cover were varied. The 12 test cylinders cracked at uniform surface pressures of less than 60 psi and subsequently deformed in such a way that the ratio of the effective stiffness of the cylindrical inclusion to the stiffness of the soil in the vertical direction remained constant. Significant moments were induced that would preclude the design of buried cylindrical shelters on the basis of the pure compression mode. The magnitude of the induced moments increased with increasing wall thickness and increased at a decreasing rate with increasing load. Empirical relations which agree reasonably well with the test data are given for permitting estimates of horizontal expansion, arching, thrust, moment, and interface pressure. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 60
Book Description
Experimental results and empirical relations are given which define the behavior of reinforced-concrete model cylinders that are buried in dry sand with their longitudinal axis parallel to the surface. The model cylinders were 9 inches in outside diameter and had a single layer of reinforcement at midsection. Thickness, percent reinforcement, and depth of cover were varied. The 12 test cylinders cracked at uniform surface pressures of less than 60 psi and subsequently deformed in such a way that the ratio of the effective stiffness of the cylindrical inclusion to the stiffness of the soil in the vertical direction remained constant. Significant moments were induced that would preclude the design of buried cylindrical shelters on the basis of the pure compression mode. The magnitude of the induced moments increased with increasing wall thickness and increased at a decreasing rate with increasing load. Empirical relations which agree reasonably well with the test data are given for permitting estimates of horizontal expansion, arching, thrust, moment, and interface pressure. (Author).