bluuebunny/crossref_metadata_2025 huggingface dataset:
Behaviour of Tendons for Cryogenic Applications
Authors: Gläser Christian , Zilch Konrad
Published: October 2011

When designing LNG tanks also accidental load situations like overfilling the tank beyond the specified limit have to be considered. In conjunction with overfilling leakage of the inner tank or total failure of the inner tank the surrounding members will be subjected to a thermal shock.

Therefore, among other things special investigations on the tendons are necessary. Sufficient resistance against static load at cryogenic conditions can be guaranteed by tests on the prestressing elements and by single tests with anchorages and tendons. Especially the single tests at cryogenic conditions shall be repeated for every LNG tank to guarantee similar behaviour of the strands and wedges used in the specific project. By requiring ductility criteria for the strands without anchorage as well as for the anchored strands brittle failures can be avoided.
Recent Innovations for Enhancing Durability of Post-Tensioning Systems in the USA
Authors: Aigner Erich
Published: October 2011

After more then 50 years of post-tensioned bridge construction, several recent failures in the UK and Florida alerted both government agencies and the construction industry to improve the design, fabrication, installation and testing of post-tensioning tendons. The largest supplier of post-tensioning materials in the USA, Dywidag Systems International (DSI), redesigned its hardware and revised installation procedures to protect tendons for years to come. Improved grout mixtures were developed using new methods intended to minimize voids and ensure adequate corrosion protection.
Short–Span Bridges – Leading Australian Innovations
Authors: Rapattoni Frank
Published: October 2011

Australia has one of the most extensive road networks in the world with some 37,000 bridges. The bridges have relatively short spans by comparison with other continents.

Bridge engineering has undergone a significant evolution in the past decade. New developments have led to reduction in costs, improvements in safety and lower environmental impact. The development of the prestressed concrete Super T-beam system has made the greatest impact capturing a large market share in a short time. Advances in the design and construction of steel bridges have also made these more competitive. Perhaps the most significant innovation is the “pier-redundant” bridge, a concept with unmatched safety in the event of pier collapse. These developments have potential application in the USA and around the world.
Shrinkage Effect at Concrete Interfaces in Rigid-frame Bridges
Authors: Shi Xue-fei , Li Xiaoxiang , Ruan Xin
Published: October 2011

Cracking problems at interfaces between concrete with different ages are getting serious, and shrinkage characteristic difference is considered as the main reason. Stress distribution due to shrinkage at typical interface parts was analyzed based on Chinese and American standards. Reasons for large difference between results under the two standards were also discussed. Results show that shrinkage stress level calculated under AASHTO standard is more reasonable than that under Chinese standard (JTG D62-2004) in concrete members with large thickness. Concrete at interface parts is easy to crack when casting time interval is long. According to JTG D62-2004, stress at interfaces is still small under different casting time intervals, while stress at position with mutation section is more obvious. It is necessary to set an upper limit value to theoretical thickness in Chinese standard, and 300mm is recommended. Finally, some design and construction countermeasures are put forward.
Stress Limitation of External Prestressing Tendons in Serviceability Limit State
Authors: Liu Chao , Xu Dong , Sun Yuan , Wu Zhenrong
Published: October 2011

The ultimate stress of external tendons sometimes controls the prestress design of a bridge. The ultimate stress of an external tendon can be expressed as the addition of the effective stress of the tendon and a stress increment in Ultimate Limit State. The effective stress is closely related to the stress limitation of the tendon in Serviceability Limit State. Theoretical research and experimental investigation were made at the Department of Bridge Engineering of Tongji University in order to get reasonable stress limitation of external tendons and make recommendation for bridge designers.
Effect of Long Carbon Fibers on Deflection of One-way Members
Authors: Lee Je Ii , Musselman Eric , Scanlon Andrew , Schokker Andrea
Published: October 2011

This paper describes laboratory tests on simply supported one-way members containing steel reinforcing bars and long (75mm) coated carbon fibers. Carbon fiber yarn is coated to provide 75mm long stiff fiber tape that readily disperses in the concrete matrix. The tests were conducted to compare response to immediate and sustained loads, of members containing carbon fibers, with the response of companion beams without fibers. The specimens are 3.66 m long supported on an 3.35 m span, 300 mm wide, and 125 mm deep with two #3 bars at an effective depth of 100 mm. Two specimens containing 1.5% long carbon fiber by volume were loaded with concentrated loads at mid-span to simulate live load. Applied load and mid-span deflections were recorded. The applied loads were then removed and the beams were monitored for approximately one year to determine deflection response under sustained dead load. Immediate and time dependent responses of the fiber reinforced beams are compared with response of the companion beams containing regular reinforcing bars only. The tests clearly demonstrate the enhanced stiffness provided by carbon fiber under immediate and sustained loads.
Structural Design of Aluminium Bridge Decks for Existing Traffic Bridges
Authors: Maljaars Johan , Soetens Frans , De Kluyver Dick
Published: October 2011

Between 1930 and 1990, many traffic bridges are constructed consisting of a hardwood deck supported by a steel structure. The hardwood decks have to be replaced regularly. This paper discusses using extruded aluminium bridge decks as an alternative for timber decks for renovation of these bridges. Special attention is paid on fatigue design and connections between steel and aluminium structures.
Experiment on Seismic Behaviour of Damaged Cable-Suspended Structure
Authors: Ding Yang , Wang Jinguo , Qi Lin
Published: October 2011

Three damage modes of cable-suspended structures are summed up on the basis of experiences. A model scaled to be one eighth of a real cable-suspended bridge is established. The dynamic tests of the model in non-damage mode and the three damage modes are carried out respectively by applying white-noise and El Centro waves of different intensities to the model. The structural systems keep stable and the members of the model are not damaged, even though the maximum longitudinal and transverse accelerations applied exceed an equivalent of 0.4gfor a real structure. It means that the cable-suspended structures of pipelines, even in the three damage modes, have a good seismic resistant capacity in earthquake of intensity IX in China.
Dynamic analysis and optimisation using morphological indicators
Authors: Vandenbergh Thomas , De Wilde Willy Patrick , Latteur Pierre
Published: October 2011

This paper presents a basic analysis methodology to predict if a structure meets the design requirements concerning dynamic behaviour at conceptual design stage, combining a single degree of freedom model and morphological indicators (MI). MI are dimensionless numbers allowing to represent a structural property (volume, displacement, eigenfrequency,…) with a limited numbers of variables. The theory of MI is based on the use of a fully stressed design and optimisation from the point of view of resistance (Ultimate Limit State). Achieving satisfying vibration behaviour of a structure is a serviceability constraint (Serviceability Limit State) and is therefore not necessarily met by ULS-optimised solutions, especially in lightweight design. If the vibration behaviour is not acceptable the possibilities offered by a tuned mass damper, topology modification and stress level reduction are discussed. In this case, the use of MI as a design tool is no longer advantageous.
Research and Practice with Composite Polymer Bridges in Poland
Authors: Zobel Henryk
Published: October 2011

The paper consists of three topics. First part presents results of investigation of 8 years old FRP truss footbridge working under static and dynamic loads. Second topic is devoted to ongoing research on joints of FRP pultruded profiles in bridge structure. Some kinds of mechanical and glued-mechanical connectors were tested in the laboratory and on real pedestrian bridge. The FEM models for verification are also presented. In the third part of paper, new build inclined steel arch footbridge with composite polymer curved in plane deck is shown. Main girder is filed partly with self-compacted concrete to fulfill dynamic comfort criteria for pedestrian bridges. Special attention is paid to dynamic analysis of the structure with taking into account the simulation of aerodynamic impact from lorries traveling under the bridge. Generally, the paper gives current state of art in design, construction and maintenance of FRP bridges in Poland.
The Christopher S. Bond Bridge – An Icon for Kansas City, Missouri
Authors: Cassity Patrick
Published: October 2011

The US$232 million kcICON Design-Build Project includes the design and construction of a landmark bridge over the Missouri River and reconstruction of over six kilometers of Interstate- 29/35 in Kansas City, Missouri. The new bridge is almost 42 meters wide and approximately 518 meters long including approach spans. The suspended portion of the bridge consists of a composite steel and concrete, asymmetrical cable-stayed system with a main span of 168 meters and a side span of 138 meters. The striking, diamond-shaped pylon rises over 91 meters off the water and creates a natural gateway between the communities of North Kansas City and Kansas City. The aesthetic lighting features a kinetic lighting system with diode panels mounted to the edge girders to allow an infinite number of lighting shows across the length of the bridge, from simple one-color panels to complex color changing events.
Design of the Long-Span Roof of the O2 World in Berlin, Germany
Authors: Svensson Nils
Published: October 2011

In September 2008 the O2World, owned and operated by the internationally renowned Anschutz Entertainment Group (AEG), will be opened in Berlin. It is an indoor-arena, which has an ice-rink and seats up to 17,000 spectators. This report covers the design, analysis, optimisation and construction of the long-span roof structure of this arena
Cable stayed bridge with two decks and a single tower
Authors: Ribeiro Catão , Stucchi Fernando , Nogueira Heitor , Hernando Cândido
Published: October 2011

The objective of this paper is to describe the cable stayed bridge situated in Real Parque Complex, in the city of São Paulo, Brazil. This structure is important to connect the Jornalista Roberto Marinho Avenue with the Marginal do Rio Pinheiros Avenue, important city thoroughfares.

Due to existing traffic lanes and many public services companies interferences, these cable stayed bridges have a lot of particularities that make it unique great architectural and structural appeal (two overlapped decks with a constant curvature, the single “X” shape tower supporting both decks and the geometry of the cables are some of the exclusive characteristics of this project).
Seismic evaluation of Garcia Cadena Bridge (Colombia)
Authors: Maldonado Esperanza , Chio Gustavo , Villamizar Rodolfo
Published: October 2011

In this paper a dynamical behaviour evaluation of the Garcia Cadena Bridge is presented. This bridge is the most important in Bucaramanga (Colombia). It was built in 1970, and enlarged and reinforced in 1995. It consists of eight spans and a total length of 261 m, while its superstructure contains twelve prestressed concrete girders supported on seven reinforced concrete piers and two abutments.

The evaluation includes ambiental vibration measurements, finite element (FEM) modelling, visual inspection, numerical seismic evaluation by using earthquake data and damage evaluation of the bridge.
Design & Construction of WanZhou Yangtze River Railway Bridge
Authors: Duan Xuewei , Liao Mujie
Published: October 2011

The main bridge of Wanzhou Yangtze River Railway Bridge is a (168+360+168)m tied arch bridge with continuous steel truss, adopting self-balanced structural system; that is the push force tranfered from arch rib will be balanced by pull force of tied bar, no exterior push force exists. The suspenders adopt “H” shaped steel members, and anti-vibration holes setting of suspenders can prevent wind vibration. The anti-corrosion coating system for steel structure adopts fluorin-carbon dope as the finishing coat. The brdige structural type and anti-corrosion coating system are first adopted in China.The side span was installed by semi-cantilever method supported on temporary pier, while the mid span adopted balanced-cantilever method using sling tower frame, the bridge was closed at midspan.
SEI Pre-Standard and Commentary on Disproportionate Collapse (Part II)
Authors: Marchand Kirk , Stevens David , McKay Aldo
Published: October 2011

At lower levels of risk, prescribed levels of appropriate robustness could be incorporated into the structural elements and system, even in the absence of specified threat or probability of occurrence. As a minimum, robustness can be added to an element or system through the prescription of integrity requirements such as element to element connectivity, balanced minimum requirements for multiple response mechanisms, and enhanced stability requirements (assumption of increased unsupported lengths, etc.) At higher risk levels, robustness requirements might include so-called “tying” requirements, “bridging” techniques, prescriptive key element hardening, or, for certain form factor buildings, compartmentalization.
Fatigue behavior of welded pipe intersections in bridges
Authors: Romen Norbert , Mangerig Ingbert
Published: October 2011

In the design of tubular truss-girder bridges, the critical aspect is represented by the welded pipe intersections in the structural analysis due to their limited fatigue behavior. In the case under consideration, economical reasons led to the decision to weld the joints instead of using cast steel nodes. Considering the span length of nearly 100 meters, the static design required diameters up to 800 mm and wall thicknesses up to 50 mm. As fatigue problems are covered by the current codes only for smaller dimensions, it was decided to conduct large-scale tests to investigate the fatigue behavior of the welded pipe intersections. Comparative tests comprising specimens with partially UIT-treated welding seams were performed in order to verify the efficacy for this post-weld treatment method. Furthermore a repair technique for existing fatigue cracks was investigated. For this purpose the entire fatigue crack of an already damaged specimen was grinded and rewelded.
Dynamic response of water networks in seismic areas
Authors: Corrado Virginia , D'Acunto Berardino , Fontana Nicola , Giugni Maurizio
Published: October 2011

This study aimed at evaluating the dynamic response of continuous buried pipeline. Under the hypothesis that the soil is a Winkler elastic medium and the pipe can be held to be continuous (welded joints), a numerical model is presented. The model makes it possible to evaluate, with reference to specific boundary conditions and at a generic abscissa, the trend over time of the pipe’s axial and transverse displacements. These can then be used to define the corresponding trends over time of the strains and, hence, the stresses acting on the pipe.

In this paper emphasis has been placed on the analysis of axial displacements and strains with reference to steel pipes. The effects of the surrounding soil and the pipe length on the seismic behavior of pipelines are also discussed. Numerical results show that the characteristics of soil as well as the pipe length have a remarkable influence on the pipe seismic response.
Exploration of a New Rigid-Frame Arch Bridge Constructed by Vertical Downrotation
Authors: Zhixiang Zhou , Guowen Yao , Haijun Wu , Yong Xu
Published: October 2011

Techno-economic analysis of the conventional concrete arch bridge and continuous rigid frame bridge was performed. A new rigid-frame arch bridge structure spanning over deep valley and river in mountainous areas was proposed based on the advantages of both above. Then its structural characteristics, downrotating vertically construction technology and techno-economic benefits were analyzed. For the rigid-frame arch bridge, half the arch rib is constructed in pillar on two banks respectively at first, and then two halves are rotated down vertically, close up and form a whole arch rib. The rigid-frame arch structure has been successfully applied in Gulu Middle School Overpass Bridge over Chongqing Yulin highway. The researches and engineering application show that the rigid-frame arch bridge is simple, safe and efficient in construction without broad constructing yards, and behaves good mechanical properties, structural integrity and aseismatic ductility. Its downrotating vertically construction method can be extended to large and medium span bridges constructed rapidly without scaffolding.
A Complete Guide to Blast-Resistant Design of Low Rise Reinforced Concrete Buildings
Authors: Smith Steven , Bilow David , McCann Dennis , Kamara Mahmoud
Published: October 2011

The Portland Cement Association’s Blast Resistant Design Guide for Reinforced Concrete Structures provides a practical treatment of the design of cast-in-place low rise concrete structures to resist the effects of blast loads. The Guide is a self-contained reference document that contains chapters on basic security design principles, blast pressures and building loads, analysis and element design, detailing and progressive collapse. Numerous examples based on a hypothetical office building and multiple explosion scenarios are provided to illustrate key concepts associated with blast-resistant design.
Design and Erection of two recent urban Cable-stayed Bridges in Spain
Authors: Jose Arenas Juan , Capellán Guillermo , Sacristán Miguel
Published: October 2011

Two urban cable stayed bridges designed by Arenas & Asociados have finished its construction in 2007. “Las Rozas” Bridge, in the outskirts of Madrid, with 102 m span, and the Science and Technology Park of Cantabria Bridge (PCTCAN), in Santander, with 72 m span. They are both Asymmetrical cable stayed bridges with central plans of stays and decks over 20 m wide, and they are both meant to become iconic gates of entrance to the city of Las Rozas and to the new Technology Park in Santander, because of its conceptual design.
Design of Heavy Movable Structures using Advanced Modelling and Visualizations
Authors: Griesing Keith
Published: October 2011

The Heavy Movable Structures (HMS) industry, which includes movable bridges, kinetic architecture, and stadium roofs, in general, has not implemented building information modelling (BIM) to the same extent as other sectors of the Architecture/Engineering/Construction industry. The use of the solid modelling and visualization concepts inherent in BIM can be beneficial to the design and construction of HMS. HMS are typically complex, dynamic mechanisms that require coordination of multiple disciplines of design professionals, such as structural engineers, architects, mechanical engineers, and electrical engineers. The development and advancement of computer aided design and three-dimensional modelling tools permit close coordination amongst these groups and overall project quality to be increased.
Fluoropolymer Coatings for Buildings, Bridges, and Infrastructure
Authors: Darden Winn , Takayanagi Takashiu
Published: October 2011

Damage to buildings, bridges, and infrastructure by corrosion and other environmental processes costs billions of dollars per year. Paints and coatings can be used to protect existing and new infrastructure from degradation by the elements. Coatings based on fluoropolymer resins have lifetimes exceeding 30 years, leading to substantially lower life cycle costs compared to conventional coatings. Fluoropolymer coatings have been successfully used on over 150,000 structures worldwide.
Two Examples for the Design of Load Bearing Structures with Steel Fibre Reinforced Concrete
Authors: Kasper Thomas , Edvardsen Carola , Sørensen Carsten S.
Published: October 2011

A major part of the foundation slab of a high bay warehouse at the Carlsberg brewery in Fredericia, Denmark, and the segmental tunnel lining of the district heating tunnel in Copenhagen, Denmark, have been designed with steel fibre reinforced concrete (SFRC) without traditional rebar reinforcement. The two examples are chosen to demonstrate the application of SFRC as an innovative material for a foundation slab of a tall building and for the construction of a major infrastructure project. The paper presents and discusses the design methods, advantages, special aspects, limitations and risks of steel fibre reinforced concrete for these load bearing structures.
Warta River crossing 130 m of ready construction per week with a crowing achievement – extradosed bridge
Authors: Berger Andrzej , Lewandowski Marcin , Nadolny Adam , Onysyk Jerzy , Sadowski Krzysztof , Hawryszków Paweł
Published: October 2011

The Warta is a medium size river in central Poland. The project of the Warta river crossing was connected with the project of the town ring road of Konin. The crossing was divided into four independent structures: three flyovers E5, E7, E8 and the main bridge. All structures were designed for two roads.
Widening and Rehabilitation of some bridges in Indiana Toll Road
Authors: Fadón Santiago , Herrero J. E. , Leon Javier , Gonzalez Jesus
Published: October 2011

This paper shows a new approach to the problem of rehabilitation and widening of bridges. Some unique factors are being employed to improve the Indiana Toll Road. The first requirement for the design was to keep two lanes in each direction during the whole construction process minimizing the traffic impediments so the complete demolition of structures was not an option. Therefore a very important engineering effort has been done. After a careful identification of the pre-existing damages, the right treatment was implemented in each element taking into account a life expectancy of 50 years. A special treatment against damages produced by de-icing salts has been designed using cathodic protection to avoid cell effect. Each stage of the construction process for the widening has been analyzed coordinating geometrical and structural conditions with traffic management.
Light curing acrylates in glass structures
Authors: Weller Bernhard , Tasche Silke
Published: October 2011

Adhesive joints in glass construction have been carried out by using single - and double-component silicones for more than twenty years. The use of UV- and light-curing acrylates in glass constructions, however, offer further design potential due to their inherent transparency, advantages in the production process and increased material strength. Aging performance of these adhesives was, therefore, comprehensively tested on bonded joints of float glass and metal. Additional tests were conducted on full-scale samples for various glass applications. Now, for the first time it has been proofed that UV- and light-curing acrylates are suitable in principle to be used for certain applications in glass construction.
Construction process simulation based on significant day-to-day data
Authors: Ailland Karin , Bargstaedt Hans-Joachim
Published: October 2011

This paper presents developments to improve the controlling of construction progress in complex building projects by using simulation. Thus it points out the great potential of simulation that arises from identifying long-term consequences at earlier stages. Therewith the controlling and flexibility in case of changed conditions will increase enormously. As basis for simulation models the real- time state of construction has to be captured. In consequence the paper discusses how to combine different controlling tools for gathering construction performance and for deriving on the real on- site status.

The approach is structured into three parts. The definition of data, which are actually needed for evaluating a current on-site status, the instruments that can effectively be used for the data evaluation, and the creation of a structured process model based on the aforementioned aspects. Finally future lines of development of the real time based simulation are discussed.
Geotechnical Engineering of the 600 m Chicago Spire
Authors: Walton William , Diehm Darren , Burns Joseph , Sarabia Fernando , Browne Garret , Provanzana Suzanne
Published: October 2011

The 600 meter high Chicago Spire, being developed by Shelbourne Development, is now under construction. Santiago Calatrava provided the architectural and engineering design, Thornton Tomasetti is the structural engineer of record, and STS is the geotechnical engineer of record for the project. The Chicago Spire has a very innovative structural system that is a true integration of architecture and engineering. While the project will be very well known as the tallest building in North America, it will also have the deepest basement in Chicago. The top-down method of construction will enable the tower construction to commence much earlier than the conventional bottom-up method. Because of the depth of the excavation and the proximity of adjacent structures, a significant analytical effort to predict and monitor ground movements is being conducted in concert with the construction.
Earthquake Tests of Glass Structures
Authors: Siebert Geralt
Published: October 2011

Worldwide investigations to protect people in case of earthquakes in seismic active regions like e.g. Japan or part of the United States are done. Earthquake engineering develops differnet methods for design of building or bridges with minimised risk of collapse due to earthquake. But there is an – often underestimated – risk for the health of people outside the buildings (e.g. on pavements) in case of an earthquake caused by falling parts of facades or canopies.

In this paper basics of glass structures (different applications and bearing situations, different kinds of glass) and an overview about their design is given briefly. The main part is testing of glass elements with a special focus on earthquake tests which are done in laboratory of the Universität der Bundeswehr München at present. Research work will be continued with different bearing situations and other common applications like facades.
Analysis for Initial Equilibrium Condition and Erection Stages of Sorok (Self-Anchored Suspension) Bridge
Authors: Son Yunki , Yoo Dongho , Jeong Seungwook , Yoon Teaseop
Published: October 2011

This paper presents analysis and construction method of the Sorok (self-anchored suspension) bridge that is currently under construction in the Sorok Island, CheonllaNamdo, Korea and expected to be completed in 2008. To find the optimum initial equilibrium condition of self- anchored suspension bridge, the force of main cable and hanger are developed together with minimizing vertical camber of stiffening girder. Erection stage analyses are carried out for both hanger-pulling method and girder jack-down method to find out the more effective one which ensure the erection stability and cost efficiency. Hanger-pulling method is adopted as the erection scheme of suspension system as a result of the study. Various measurement results at site show that analysis results are well matched up with bridge deformation and girder profile during construction and at ist final stage and have a good correspondence with the original design profile
Post-Weld Treatments for the Service Life Extension of Existing Steel Bridges
Authors: Walbridge Scott
Published: October 2011

The problem of fatigue cracking in existing steel bridges is becoming an increasingly important one due to the natural aging of these structures, as well as the increasing traffic loads and volumes to which they are being subjected. One possible method of rehabilitating structures such as these that has received recent attention is the use of residual stress-based post-weld treatments, such as needle, hammer, or ultrasonic peening. Herein, a strain-based fracture mechanics model for predicting the effects of these treatments is presented and validated using the results of a test-based study. This model is thought to be particularly well suited for predicting the effectiveness of these treatments under realistic service loading conditions. The validated model is used to study the effects of the constant amplitude loading parameters, compressive overload magnitude, and treatment timing

(i.e. before or after dead load introduction) on the treatment benefit.
Competition between grain growth and grain-size reduction in polar ice
Authors: Roessiger Jens , Bons Paul D. , Griera Albert , Jessell Mark W. , Evans Lynn , Montagnat Maurine , Kipfstuhl Sepp , Faria Sérgio H. , Weikusat Ilka
Published: October 2011

Static (or ‘normal’) grain growth, i.e. grain boundary migration driven solely by grain boundary energy, is considered to be an important process in polar ice. Many ice-core studies report a continual increase in average grain size with depth in the upper hundreds of metres of ice sheets, while at deeper levels grain size appears to reach a steady state as a consequence of a balance between grain growth and grain-size reduction by dynamic recrystallization. The growth factorkin the normal grain growth law is important for any process where grain growth plays a role, and it is normally assumed to be a temperature-dependent material property. Here we show, using numerical simulations with the program Elle, that the factorkalso incorporates the effect of the microstructure on grain growth. For example, a change in grain-size distribution from normal to log-normal in a thin section is found to correspond to an increase inkby a factor of 3.5.
Glacimarine sedimentation processes at Kronebreen and Kongsvegen, Svalbard
Authors: Kehrl Laura M. , Hawley Robert L. , Powell Ross D. , Brigham-Grette Julie
Published: October 2011

Tidewater glaciers deposit sediment at their terminus, thereby reducing the relative water depth. Reduced water depth can lead to increased glacier stability through decreased rates of iceberg calving, glacier thinning and submarine melting. Here we investigate sedimentation processes at the termini of Kronebreen and Kongsvegen, Svalbard. We mapped the fjord floor bathymetry in August 2009 and calculate sedimentation rates based on our bathymetry and that from a similar study in 2005. A grounding-line fan is developing near the current position of the subglacial stream. An older, abandoned grounding-line fan that likely formed between ∼1987 and 2001 is degrading near the middle of the ice front. Our findings indicate that sediment gravity flows reduce the height of the sediment mound forming at the glacier terminus. The future impact of glacimarine sedimentation processes on glacier stability will depend on the net balance between the observed gravity flows and sediment deposition.
High basal melting rates within high-precipitation temperate glaciers
Authors: Alexander David , Shulmeister James , Davies Tim
Published: October 2011

The role of basal melting within high-precipitation temperate glaciers represents a significant gap in understanding glacier melting processes. We use a basal melt equation to calculate geothermal and frictional heat-induced basal melt and develop an equation to calculate the rainfall-induced basal melt for Franz Josef Glacier, New Zealand, a high-precipitation, temperate glacier. Additionally, we calculate basal melt due to heat dissipation within water and ice. Data collated from published information on glacier dynamics and climate station readings show that total basal melt contributes on average ∼2.50 m a−1 over the lower to mid-ablation zone (300–1500 m a.s.l.), which is equivalent to >10% of the total ablation for the glacier. This indicates that basal melting is an important component of mass balance for high-precipitation, temperate glaciers.
Analysis of ice plains of the Filchner–Ronne Ice Shelf, Antarctica, using ICESat laser altimetry
Authors: Brunt Kelly M. , Fricker Helen A. , Padman Laurie
Published: October 2011

We use repeat-track laser altimeter data from the Ice, Cloud and land Elevation Satellite (ICESat) to map the grounding zone (GZ) of the Filchner–Ronne Ice Shelf, Antarctica. Ice flexure in the GZ occurs as the ice shelf responds to ocean-height changes due primarily to tides. We have identified three ‘ice plains’, regions of low surface slope near the GZ where the ice is close to hydrostatic equilibrium: one on Institute Ice Stream; another to its east; and another west of Foundation Ice Stream. The vertical information from repeated ICESat tracks enables us to study the topography, state of flotation and flexure characteristics across these features. In regions of ephemeral grounding, tidal migration of the grounding line allows us to estimate bed slope (∼1–2 × 10−3). From these studies we develop a classification scheme for ice plains, expressed in terms of the evolution, or ‘life cycle’, of these features. A lightly grounded ice plain progresses to a state of ephemeral grounding as the ice sheet thins near the GZ. Once sufficient thinning has occurred, the ice plain becomes a fully floating, relict ice plain with an undulated surface topography similar to that of lightly grounded ice; we expect viscous relaxation to a smooth ice-shelf surface to occur over a timescale of decades. Our improved insight into ice-plain evolution suggests added complexity in modeling ice in the vicinity of the GZ, and a role for ice-plain observations as a guide to relatively rapid changes in ice-sheet mass balance.
Tomography-based determination of permeability and Dupuit–Forchheimer coefficient of characteristic snow samples
Authors: Zermatten Emilie , Haussener Sophia , Schneebeli Martin , Steinfeld Aldo
Published: October 2011

A tomography-based methodology for the mass transport characterization of snow is presented. Five samples, characteristic for a wide range of seasonal snow, are considered. Their three-dimensional (3-D) geometrical representations are obtained by micro-computed tomography and used in direct pore-level simulations to numerically solve the governing mass and momentum conservation equations, allowing for the determination of their effective permeability and Dupuit–Forchheimer coefficient. The extension to the Dupuit–coefficient is useful near the snow surface, where Reynolds numbers higher than unity can appear. Simplified semi-empirical models of porous media are also examined. The methodology presented allows for the determination of snow’s effective mass transport properties, which are strongly dependent on the snow microstructure and morphology. These effective properties can, in turn, readily be used in snowpack volume-averaged (continuum) models such as strongly layered samples with macroscopically anisotropic properties.
Advanced microstructural characterization of four East Antarctic firn/ice cores
Authors: Spaulding N.E. , Meese D.A. , Baker I.
Published: October 2011

The microstructures and microchemistry of four US International Trans-Antarctic Scientific Expedition ice cores were examined, at three depths (30, 60, 90 m) each, using scanning electron microscopy, including electron backscattered patterns and energy-dispersive spectroscopy (EDS), in order to assess the relationship between chemical and physical properties. The physical characteristics (grain size, porosity, density, internal surface volume, and crystallographic orientation) at the four sites were inhomogeneous, as expected on the basis of differences in the moisture content of deposited snow and the accumulation rate at their respective locations. Evidence of shallow subgrain boundary formation and trends in internal surface volume, having implications for the study of firn densification and ice-sheet modeling, were also found. Chemical characterization revealed that site-specific variations in particulate concentration and source could accurately be determined using EDS analysis. It was also found that the combination of elements predominant within the sample controls the morphology and microstructural location of the impurities.
Snapshots of the Greenland ice sheet configuration in the Pliocene to early Pleistocene
Authors: Solgaard Anne M. , Reeh Niels , Japsen Peter , Nielsen Tove
Published: October 2011

The geometry of the ice sheets during the Pliocene to early Pleistocene is not well constrained. Here we apply an ice-flow model in the study of the Greenland ice sheet (GIS) during three extreme intervals of this period constrained by geological observations and climate reconstructions. We study the extent of the GIS during the Mid-Pliocene Warmth (3.3–3.0 Ma), its advance across the continental shelf during the late Pliocene to early Pleistocene glaciations (3.0–2.4 Ma) as implied by offshore geological studies, and the transition from glacial to interglacial conditions around 2.4 Ma as deduced from the deposits of the Kap København Formation, North Greenland. Our experiments show that no coherent ice sheet is likely to have existed in Greenland during the Mid-Pliocene Warmth and that only local ice caps may have been present in the coastal mountains of East Greenland. Our results illustrate the variability of the GIS during the Pliocene to early Pleistocene and underline the importance of including independent estimates of the GIS in studies of climate during this period. We conclude that the GIS did not exist throughout the Pliocene to early Pleistocene, and that it melted during interglacials even during the late Pliocene climate deterioration.
A surge of North Gasherbrum Glacier, Karakoram, China
Authors: Mayer Christoph , Fowler Andrew C. , Lambrecht Astrid , Scharrer Kilian
Published: October 2011

Between 2003 and 2007, North Gasherbrum Glacier on the northeastern slope of the Karakoram mountains in Asia underwent a dramatic acceleration, during which a velocity wave propagated down the glacier. There was a significant transfer of ice from up-glacier downstream, which resulted in a strong surface elevation increase over the lower tongue, but only a moderate advance of the glacier snout. We interpret this behaviour as that of a glacier surge, and we explain the observations by means of a simple version of the Kamb drainage-switching theory.
Transmission of solar radiation through the snow cover on floating ice
Authors: Järvinen Onni , Leppäranta Matti
Published: October 2011

Spectral measurements of solar radiation in the band 400–900 nm were performed above and inside the snowpack in two locations in Finland, using a spectroradiometer. The transmittance and extinction coefficient were estimated for different snow layers. Four small candle-shaped photosynthetically active radiation (PAR) sensors were also used to measure the transfer of PAR inside the snowpack. In addition to the light measurements, physical characterization of snow stratigraphy was done, including the thickness, density, hardness (hand test), salinity, and grain size and shape (photographs of crystals). The transmittance varied from <1% (0–12 cm layer) to 80% (0–4 cm layer), and the extinction coefficient was between 0.03 cm−1(4–8 cm layer) and 0.8 cm−1(0–4 cm layer). The physical properties of the snow varied considerably between locations and days. The density of the snow varied between 140 and 480 kg m−3.
Seasonal evolution of water contributions to discharge from a Greenland outlet glacier: insight from a new isotope-mixing model
Authors: Bhatia Maya P. , Das Sarah B. , Kujawinski Elizabeth B. , Henderson Paul , Burke Andrea , Charette Matthew A.
Published: October 2011

The Greenland ice sheet (GrIS) subglacial hydrological system may undergo a seasonal evolution, with significant geophysical and biogeochemical implications. We present results from a new isotope-mixing model to quantify the relative contributions of surface snow, glacial ice and delayed flow to the bulk meltwater discharge from a small (∼5 km2) land-terminating GrIS outlet glacier during melt onset (May) and at peak melt (July). We use radioactive (222Rn) and stable isotopes (18O, deuterium) to differentiate the water source contributions. Atmospherically derived 7Be further constrains meltwater transit time from the glacier surface to the ice margin. We show that (1) 222Rn is a promising tracer for glacial waters stored at the bed and (2) a quantitative chemical mixing model can be constructed by combining 222Rn and the stable water isotopes. Applying this model to the bulk subglacial outflow from our study area, we find a constant delayed-flow (stored) component from melt onset through peak melt. This component is diluted first by snowmelt and then by increasing glacial ice melt as the season progresses. Results from this pilot study are consistent with the hypothesis that subglacial drainage beneath land-terminating sections of the GrIS undergoes a seasonal evolution from a distributed to a channelized system.
Dispersive pressure and density variations in snow avalanches
Authors: Buser Othmar , Bartelt Perry
Published: October 2011

Snow avalanches possess two types of kinetic energy: the kinetic energy associated with the mean velocity in the downhill direction and the kinetic energy associated with individual particle velocities that vary from the mean. The mean kinetic energy is directional; the kinetic energy associated with the velocity fluctuations is non-directional in the sense that it is connected to random particle movements. However, the rigid, basal boundary directs the random fluctuation energy into the avalanche. Thus, the random energy flux is converted to free mechanical energy which lifts and dilates the avalanche flow mass, changing the flow density and increasing the normal (dispersive) pressure and, as a consequence, changing the flow resistance. In this paper we derive macroscopic relations that link the production of the random kinetic energy to the perpendicular acceleration of the avalanche’s center of mass. We show that a single burst of fluctuation energy will produce pressures that oscillate around the hydrostatic pressure. Because we do not include a damping process, the oscillations of the center of mass remain, even if the production of random kinetic energy stops. We formulate relationships that can be used within the framework of depth-averaged mass and momentum equations that are often used to simulate snow avalanches in realistic terrain.
Editorial Vol.1(1)
Authors: Kalam Abul
Published: October 2011

DOI: http://dx.doi.org/10.3329/bdjps.v1i1.6484
Management of recurrent phyllodes with full thickness chest wall resection
Authors: Awwal R , Shashi SA , Khondokar MS , Khundkar SH
Published: October 2011

Phyllodes tumours are biphasic fibroepithelial neoplasms of the breast and each case represents a unique challenge. Even after apparent wide local excision of benign lesions, they recur and recurrences can occur even for 5-6 times. The ultimate end result is chest wall invasion and reconstruction then becomes an essential part of the curative surgical procedure. For a locally advanced breast malignancy, treatment is always palliative with simple coverage and oncologic support. But as Phyllodes tumour is of low aggressiveness, wide excision of even locally advanced malignant phyllodes can result in a good prognosis. Wide and extensive resection always invites the need of reconstruction, and surely it is a challenge when it is for a post-mastectomy recurrent lesion, where the role of plastic surgeons becomes essential. Two such cases are presented where disease control was only possible after full thickness chest wall resection.DOI: http://dx.doi.org/10.3329/bdjps.v1i1.6486Bangladesh Journal of Plastic Surgery (2010) Vol. 1 (1) pp.9-13
Earlobe Keloid Management- A RCT of Intra-Lesional Excision With Intra- & Post-Operative Steroids Versus Intra-Lesional Excision With Post-Operative Steroids
Authors: Dash PC , Islam MMT , Khondoker MS , Khundkar SH
Published: October 2011

A prospective, randomized controlled trial was designed to compare the outcome of earlobe keloid management by intra-lesional excision with intraoperative and two dose post-operative steroid injections versus intra-lesional excision with two doses post-operative steroid injections. Total 87 patients having 100 earlobe keloids were enrolled in the study with 50 keloids in each group allocated by lottery, but only 69 completed two years follow up. The age of the patients ranged from 15 to 40 years and all were female. Trauma from piercing ear lobule for earring was the main cause of keloid initiation. Both the groups were homogeneous preoperatively regarding age of patients, pre-operative volume of keloids, pattern of previous treatment received, patient's skin complexion and patient’s family history of keloid.Intra-lesional excision keeping 1mm margin followed by intra-operative steroid injection was given in one group and without steroid injection in other group. Residual keloid volume (length, Breath, and height) was measured intra-operatively and post-operatively during follow up period by blindfolded observers. Any symptomatic relief as well as local and systemic side effects of steroids were also recorded.Main observation of this study after two years was 8.3% recurrence in intra-lesional excision with intra-and two dose post-operative steroid injections and 21.2% recurrence in intra-lesional excision with two dose postoperative steroid injections. This difference was not statistically significant (p = 0.177). But, the former protocol reduced recurrence significantly during 1st one year follow up. Residual keloid volume reduction was faster in former protocol in early post-operative period, but not in later period. Symptomatic improvement was also faster in the former protocol, in early post-operative period, but no difference in later period. Local side effects and systemic side effects of steroid were more or less equal in both protocols.The study demonstrates that additional intra-operative steroid injection has better effect in early post-operative period in managing earlobe keloid, but has no significant effect in long term follow up.DOI: http://dx.doi.org/10.3329/bdjps.v1i1.6489Bangladesh Journal of Plastic Surgery (2010) Vol. 1 (1) pp.24-28
A young woman with multiple soft tissue tumors in various parts of the body, (Extra Abdominal Fibromatosis and Lymphangioma in both Axillas)
Authors: Kalam MD A , Ahmad F , Hassan M , Nasiruddin Md , Rahman SA , Rahman M , Islam Farhana
Published: October 2011

The term fibromatosis refers to a group of benign soft tissue tumors (fibromas), which have certain characteristics in common, including absence of cytologic and clinical malignant features, a histology consistent with proliferation of well-differentiated fibroblasts, an infiltrative growth pattern, and aggressive clinical behavior with frequent local recurrence. Lymphangiomas are malformations of the lymphatic system, which is the network of vessels responsible for returning to the venous system of excess fluid from tissues. Here we report a case of 30 years old lady with history of multiple soft tissue tumours in thigh, axilla and abdomen. On physical examination the swelling of the thigh and abdomen were firm and those of axilla were soft. All the tumours were excised surgically and diagnosis of thigh swelling was fibromatosis and that of axilla was lymphangioma, on histopathology.DOI: http://dx.doi.org/10.3329/bdjps.v1i1.6490Bangladesh Journal of Plastic Surgery (2010) Vol. 1 (1) pp.29-32