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C.b. Barrass - One of the best experts on this subject based on the ideXlab platform.
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IMO Grain Rules for the safe carriage of grain in bulk
Ship Stability for Masters and Mates, 2012Co-Authors: C.b. Barrass, D.r. DerrettAbstract:This chapter discussesthe grain rules proposed by international maritime organization (IMO) for the safe carriage of grain in bulk. The intact stability characteristics of any ship carrying bulk grain must be shown to meet, throughout the voyage, three criteria relating to the moments due to grain shift: (1) the angle of heel due to the shift of grain shall not be greater than 12° or—in the case of ships constructed on or after 1 January 1994—the angle at which the Deck Edge is immersed, whichever is the lesser; (2) in the statical stability diagram, the net or residual area between the heeling arm curve and the righting arm curve up to the angle of heel of maximum difference between the ordinates of the two curves, or 40° or the angle of flooding, whichever is the least, shall be not less than 0.075 metre-radians in all conditions of loading; and (3) the initial metacentric height, after correction for free surface effects of liquids in tanks, shall not be less than 0.30 m. Before loading bulk grain, the master shall, if so required by the contracting government of the country of the port of loading, demonstrate the ability of the ship at all stages of any voyage to comply with the required stability criteria. After loading, the master shall ensure that the ship is upright before proceeding to sea.
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Effects of Beam and Freeboard on Stability
Ship Stability for Masters and Mates, 2012Co-Authors: C.b. Barrass, D.r. DerrettAbstract:This chapter discusses the effect of increasing the beam and freeboard on stability curve of a vessel. To investigate the effect of beam and freeboard on stability, it is necessary to assume the stability curve for a particular vessel in a particular condition of loading. The chapter concludes that with increased beam metacentric height (GM T ) and righting lever (GZ) increase, range of stability increases, Deck Edge immerses earlier, and moment about the keel (KB) remains similar. With increased freeboard GM T and GZ increase, range of stability increases, Deck Edge immerses later at greater θ, and KB decreases.
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Load Lines and Freeboard Marks
Ship Stability for Masters and Mates, 2012Co-Authors: C.b. Barrass, D.r. DerrettAbstract:Freeboard and stability curves are inextricably linked. With an increase in the freeboard, righting levers (GZ) increase, metacentric height (GM T ) increases, range of stability increases, Deck Edge immerses at greater angle of heel, dynamical stability increases, displacement decreases, and moment about the keel (KB) decreases. The chapter defines four types of vessels type A, type B, type (B-60), and type (B-100). The chapter discusses freeboards of oil tankers and general cargo ships. It further discusses tabulated freeboard values. When the freeboard for vessel is being assigned, the procedure is to compare a basic department for transport (DfT) standard ship with the new design about to enter service. If the new design has hull form and structures that would increase the danger of operation, then the tabular freeboard is increased by pre-arranged regulations and formulae. The chapter closes with a discussion on six correction methods: depth correction, block coefficient (C b ) correction, bow height correction, superstructure correction, sheer correction, and strength correction.
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Chapter 30 – IMO Grain Rules for the safe carriage of grain in bulk
Ship Stability for Masters and Mates, 2006Co-Authors: C.b. BarrassAbstract:Publisher Summary This chapter discussesthe grain rules proposed by international maritime organization (IMO) for the safe carriage of grain in bulk. The intact stability characteristics of any ship carrying bulk grain must be shown to meet, throughout the voyage, three criteria relating to the moments due to grain shift: (1) the angle of heel due to the shift of grain shall not be greater than 12° or—in the case of ships constructed on or after 1 January 1994—the angle at which the Deck Edge is immersed, whichever is the lesser; (2) in the statical stability diagram, the net or residual area between the heeling arm curve and the righting arm curve up to the angle of heel of maximum difference between the ordinates of the two curves, or 40° or the angle of flooding, whichever is the least, shall be not less than 0.075 metre-radians in all conditions of loading; and (3) the initial metacentric height, after correction for free surface effects of liquids in tanks, shall not be less than 0.30 m. Before loading bulk grain, the master shall, if so required by the contracting government of the country of the port of loading, demonstrate the ability of the ship at all stages of any voyage to comply with the required stability criteria. After loading, the master shall ensure that the ship is upright before proceeding to sea.
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Chapter 24 – Effect of beam and freeboard on stability
Ship Stability for Masters and Mates, 2006Co-Authors: C.b. BarrassAbstract:Publisher Summary This chapter discusses the effect of increasing the beam and freeboard on stability curve of a vessel. To investigate the effect of beam and freeboard on stability, it is necessary to assume the stability curve for a particular vessel in a particular condition of loading. The chapter concludes that with increased beam metacentric height (GMT) and righting lever (GZ) increase, range of stability increases, Deck Edge immerses earlier, and moment about the keel (KB) remains similar. With increased freeboard GMT and GZ increase, range of stability increases, Deck Edge immerses later at greater θ, and KB decreases.
Dibu Dave Mbako - One of the best experts on this subject based on the ideXlab platform.
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experimental study on fatigue failure of rib to Deck welded connections in orthotropic steel bridge Decks
International Journal of Fatigue, 2017Co-Authors: Bin Cheng, Xinghan Ye, Dibu Dave MbakoAbstract:Abstract The rib-to-Deck (RD) welded connections are the most sensitive locations to encounter the fatigue failure in orthotropic steel Decks (OSDs), and numbers of fatigue cracks arising from these areas have been found in existing OSD bridges. This research focus on the fatigue cracking process, fatigue characteristics as well as failure mechanics of RD connections under cyclic loading. Six full-scale RD welded joints were fabricated, and two load cases of centric and eccentric loading were considered. Static loading was first conducted with aims of measuring elastic strain distributions at potential hot spots. Structural hot spot stresses at weld toes as well as stress concentration factors (SCFs) were linearly extrapolated by using the recorded strains, based on which critical locations were identified. High-cycle repeated loading was subsequently implemented, from which the fatigue crack initiation and propagation process, fatigue failure mode, characteristic fatigue life, as well as degradation of vertical rigidity, were obtained. Four stages of crack propagation were mainly observed, and the remaining fatigue lives after the crack reached the Deck Edge were short to be neglected. Variations of crack dimensions including the longitudinal length and the depth in the plate thickness were also revealed. Comparison between experimental numbers of cycles and standard S-N formulae indicates that the FAT 100 curve provided in the IIW fatigue recommendation could be conservatively used to estimate the fatigue resistance of such rib-to-Deck welded connections composed of 16 mm thick Deck plates and 80% PJP welds.
Bin Cheng - One of the best experts on this subject based on the ideXlab platform.
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fatigue tests of welded connections between longitudinal stringer and Deck plate in railway bridge orthotropic steel Decks
Engineering Structures, 2017Co-Authors: Bin Cheng, Xinger Cao, Yishan CaoAbstract:Abstract This research presented the fatigue tests of longitudinal stringer-to-Deck (SD) welded connections, which have been identified as the locations most sensitive to fatigue damage in the orthotropic steel Decks (OSDs) of railway bridges. Four full-scale SD connections were fabricated, and two loading patches were considered. Static loading was first carried out to obtain the structural hot spot stresses at weld toes as well as stress concentration factors (SCFs), by which the hot spots providing the highest stresses were identified. Cyclic loading was then implemented next to the static loading, and the behaviors including fatigue crack initiation and propagation process, fatigue failure mode, characteristic fatigue life, as well as degradation of vertical rigidity, were all obtained from the test. The crack growing process can be totally divided into four stages, and the fatigue lives after the crack arrived at the Deck Edge were very short. Variations of crack dimensions were also obtained, and the simplified formulae of crack growth rate were numerically fitted so that the crack propagation lives can be predicted by using the crack dimensions. Comparisons also show that the FAT 100 curve in IIW fatigue design recommendation could overestimate the fatigue resistance of such connections where double-sided fillet welds were used to connect the stringer web and the Deck plate, and therefore double-sided groove welds with partial or full penetrations are recommended for the stringer-to-Deck connections in railway bridge Decks.
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experimental study on fatigue failure of rib to Deck welded connections in orthotropic steel bridge Decks
International Journal of Fatigue, 2017Co-Authors: Bin Cheng, Xinghan Ye, Dibu Dave MbakoAbstract:Abstract The rib-to-Deck (RD) welded connections are the most sensitive locations to encounter the fatigue failure in orthotropic steel Decks (OSDs), and numbers of fatigue cracks arising from these areas have been found in existing OSD bridges. This research focus on the fatigue cracking process, fatigue characteristics as well as failure mechanics of RD connections under cyclic loading. Six full-scale RD welded joints were fabricated, and two load cases of centric and eccentric loading were considered. Static loading was first conducted with aims of measuring elastic strain distributions at potential hot spots. Structural hot spot stresses at weld toes as well as stress concentration factors (SCFs) were linearly extrapolated by using the recorded strains, based on which critical locations were identified. High-cycle repeated loading was subsequently implemented, from which the fatigue crack initiation and propagation process, fatigue failure mode, characteristic fatigue life, as well as degradation of vertical rigidity, were obtained. Four stages of crack propagation were mainly observed, and the remaining fatigue lives after the crack reached the Deck Edge were short to be neglected. Variations of crack dimensions including the longitudinal length and the depth in the plate thickness were also revealed. Comparison between experimental numbers of cycles and standard S-N formulae indicates that the FAT 100 curve provided in the IIW fatigue recommendation could be conservatively used to estimate the fatigue resistance of such rib-to-Deck welded connections composed of 16 mm thick Deck plates and 80% PJP welds.
D.r. Derrett - One of the best experts on this subject based on the ideXlab platform.
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IMO Grain Rules for the safe carriage of grain in bulk
Ship Stability for Masters and Mates, 2012Co-Authors: C.b. Barrass, D.r. DerrettAbstract:This chapter discussesthe grain rules proposed by international maritime organization (IMO) for the safe carriage of grain in bulk. The intact stability characteristics of any ship carrying bulk grain must be shown to meet, throughout the voyage, three criteria relating to the moments due to grain shift: (1) the angle of heel due to the shift of grain shall not be greater than 12° or—in the case of ships constructed on or after 1 January 1994—the angle at which the Deck Edge is immersed, whichever is the lesser; (2) in the statical stability diagram, the net or residual area between the heeling arm curve and the righting arm curve up to the angle of heel of maximum difference between the ordinates of the two curves, or 40° or the angle of flooding, whichever is the least, shall be not less than 0.075 metre-radians in all conditions of loading; and (3) the initial metacentric height, after correction for free surface effects of liquids in tanks, shall not be less than 0.30 m. Before loading bulk grain, the master shall, if so required by the contracting government of the country of the port of loading, demonstrate the ability of the ship at all stages of any voyage to comply with the required stability criteria. After loading, the master shall ensure that the ship is upright before proceeding to sea.
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Effects of Beam and Freeboard on Stability
Ship Stability for Masters and Mates, 2012Co-Authors: C.b. Barrass, D.r. DerrettAbstract:This chapter discusses the effect of increasing the beam and freeboard on stability curve of a vessel. To investigate the effect of beam and freeboard on stability, it is necessary to assume the stability curve for a particular vessel in a particular condition of loading. The chapter concludes that with increased beam metacentric height (GM T ) and righting lever (GZ) increase, range of stability increases, Deck Edge immerses earlier, and moment about the keel (KB) remains similar. With increased freeboard GM T and GZ increase, range of stability increases, Deck Edge immerses later at greater θ, and KB decreases.
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Load Lines and Freeboard Marks
Ship Stability for Masters and Mates, 2012Co-Authors: C.b. Barrass, D.r. DerrettAbstract:Freeboard and stability curves are inextricably linked. With an increase in the freeboard, righting levers (GZ) increase, metacentric height (GM T ) increases, range of stability increases, Deck Edge immerses at greater angle of heel, dynamical stability increases, displacement decreases, and moment about the keel (KB) decreases. The chapter defines four types of vessels type A, type B, type (B-60), and type (B-100). The chapter discusses freeboards of oil tankers and general cargo ships. It further discusses tabulated freeboard values. When the freeboard for vessel is being assigned, the procedure is to compare a basic department for transport (DfT) standard ship with the new design about to enter service. If the new design has hull form and structures that would increase the danger of operation, then the tabular freeboard is increased by pre-arranged regulations and formulae. The chapter closes with a discussion on six correction methods: depth correction, block coefficient (C b ) correction, bow height correction, superstructure correction, sheer correction, and strength correction.
Bob W. Bielenberg - One of the best experts on this subject based on the ideXlab platform.
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Design and Testing of Tie-Down Systems for Temporary Barriers
Transportation Research Record: Journal of the Transportation Research Board, 2003Co-Authors: Bob W. Bielenberg, John R. Rohde, Ronald K Faller, John D. Reid, Dean L SickingAbstract:Two tie-down temporary barrier systems were developed and crash tested according to the safety performance criteria provided in NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features. Both tie-down systems were designed to reduce barrier displacements and to retain deflected barriers on the bridge Deck Edge. The first system consisted of a steel tie-down strap concept for use with the Iowa F-shape temporary concrete barrier. At each barrier joint, the trapezoidal-shaped strap retained the vertical pin and was attached to the concrete bridge Deck using two drop-in anchors. An acceptable fullscale vehicle crash test of the tie-down strap concept was conducted according to the Test Level 3 (TL-3) impact safety standards in NCHRP Report 350. The second tie-down system was developed for use with Iowa’s steel H-section temporary barrier. A new barrier connection was developed to simplify barrier attachment and to accommodate deviations in horizontal and vertical alignment. It consisted of two steel shear plates positioned within an opening on the adjacent barrier section and held in place with two steel drop pins. Four steel angle brackets were welded to the barrier’s base to allow for rigid attachment to the concrete bridge Deck with drop-in anchors. Two full-scale vehicle crash tests were conducted on the steel H-barrier system according to TL-3 impact safety standards found in NCHRP Report 350. After an unacceptable first test, the system was successfully tested with minor design modifications.
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duplication for publication or sale is strictly prohibited without prior written permission of the transportation research board design and testing of tie down systems for temporary barriers
2003Co-Authors: Bob W. Bielenberg, Ronald K Faller, John D. Reid, Walter Scott, John R. RohdeAbstract:ABSTRACT Two tie-down temporary barriers systems were developed and crash tested according to the safety performance criteria provided in the National Cooperative Highway Research Program (NCHRP) Report No. 350, Recommended Procedures for the Safety Performance Evaluation of Highway Features . Both tie-down systems were designed to reduce barrier displacements as well as to retain deflected barriers on the bridge Deck Edge. The first system consisted of a steel tie-down strap concept for use with the Iowa F-shape temporary concrete barrier. At each barrier joint, the trapezoidal-shaped strap retained the vertical pin and was attached to the concrete bridge Deck using two drop-in anchors. An acceptable full-scale vehicle crash test was conducted on the tie-down strap concept according to the TL-3 impact safety standards found in NCHRP Report No. 350. The second tie-down system was developed for use with Iowa’s steel H-section temporary barrier. A new barrier connection was developed to simplify barrier attachment as well as to accommodate deviations in horizontal and vertical alignment. It consisted of two steel shear plates positioned within an opening on the adjacent barrier section and held in place with two steel drop pins. Four steel angle brackets were welded to the each barrier’s base to allow for rigid attachment to the concrete bridge Deck using drop-in anchors. Two full-scale vehicle crash tests were conducted on the steel H-barrier system according to the TL-3 impact safety standards found in NCHRP Report No. 350. After an unsuccessful first test, the system was successfully tested with minor design modifications. Keywords: Crash Testing, Work-Zone Safety, Longitudinal Barrier, Construction Barrier, Temporary Barrier, and Tie-Down System
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DEVELOPMENT OF A TIE-DOWN SYSTEM FOR TEMPORARY CONCRETE BARRIERS
2002Co-Authors: Bob W. Bielenberg, Ronald K Faller, John R. Rohde, John D. Reid, J C Holloway, Dean L SickingAbstract:During construction of highways and bridges, it is common for temporary concrete barriers to be installed near the Edge of a roadway or bridge Deck during construction. Free-standing temporary barriers placed close to the bridge Deck Edge pose a major safety hazard to errant vehicles as there is a significant risk for the barrier segments to be propelled off of the bridge. Previous testing of temporary barriers has shown deflections of more than one meter. These large dynamic deflections, in combination with a narrow gap located behind the barriers, would prove sufficient to push the barriers as well as the impacting vehicle off of the bridge Deck. In 1998, researchers at the Midwest Roadside Safety Facility at the University of Nebraska, Lincoln were approached to develop a tie-down system for this type of installation. This report details the development and testing of an NCHRP Report 350 compliant tie-down system for use with F-shape temporary concrete barriers. Development of the tie-down system began with the creation and evaluation of several design concepts. Following the researchers' evaluation of the design prototypes, the steel strap tie-down concept was selected for further study. This concept consisted of a steel strap that connected to the barrier joints and then bolted to the concrete bridge Deck. The steel strap tie-down was analyzed and redesigned using LS-DYNA finite element computer simulation modeling. The strap tie-down is comprised of a 76-mm x 6.4-mm x 914-mm piece of ASTM A36 steel bent into a trapezoidal shape. Holes are punched in the plate to allow the connecting pin at the barrier joints to pass through the strap as well as allow the strap to be anchored to the bridge Deck at each end. Anchoring of the strap to the bridge Deck is done using two of 19-mm diameter drop-in anchors for each strap. The steel strap tie-down was bogie tested to evaluate its performance. One full-scale vehicle crash test, test no. ITD-1, was conducted according to Test Level 3 (TL-3) test no. 3-11 found in the NCHRP Report No. 350. The test consisted of a 2,012-kg pickup truck impacting the temporary barrier system at a speed of 97.6 km/h and at an angle of 24.3 deg. The impact occurred 1.2 meters upstream of the barrier joint. Results from the crash test showed that the system safely redirected the impacting pickup truck, and the test was judged to be successful according to the NCHRP Report No. 350 safety performance criteria. Based on the results of the NCHRP Report No. 350 compliance test, it is recommended that this design be approved for use on Federal-aid highways. Recommendations for proper application of the new design are also given.
