Experimental and Analytical Investigation of Deformations and Stress Distribution in Steel Bands of a Two-Span Stress-Ribbon Pedestrian Bridge

The article is dedicated to the analysis of problems related to design of pedestrian bridges with flexible ribbon bands made of steel. The study is based on test results of a bridge model that has two spans (each with a length of five meters). A simplified analytical technique has been proposed for predicting vertical deformations of the bridge structure subjected to symmetrical or asymmetrical loading patterns. The technique also allows assessing the tension forces in the ribbons, which are very important for design of such structures. The analysis reveals the importance of the flexural rigidity of the ribbons that might cause significant redistribution of stresses within the steel bands

Non‐linear analysis of suspension bridges with flexible and rigid cables

One of the main problems related to the design of suspension bridges is stabilisation of their initial form. The tendency of suspension bridges to deform is generally determined by the kinematical displacements of the suspension cable caused by asymmetrical loads rather than by the elastic deformations. There are some suspension bridges when the so‐called rigid (stiff in bending) cables instead of usual flexible cables are suggested for stabilisation of their initial form. The analysis methods of such suspension bridges with rigid cables are underdeveloped. For the analysis of classical suspension bridges analytical models can be applied. However, in case of concentrated forces, the numerical techniques are preferred. The article presents analytical expressions for the calculation of internal forces and displacements of suspension bridges with a rigid cable. The article also discusses the discrete calculation model for classical suspension bridges. Santrauka Viena iš pagrindiniu kabamuju tiltu projektavimo problemu yra pradinus ju formos stabilizavimas. Kabamuju tiltu deformatyvuma lemia iš esmes ne tiek tampriosios deformacijos, kiek asimetriniu apkrovu sukelti kinematiniai kabamojo lyno poslinkiai. Yra žinomi kabamieji tiltai, kuriu pradinei formai stabilizuoti siūloma vietoje iprastiniu lanksčiuju lynu taikyti vadinamuosius standžius lynus. Tokiu kabamuju tiltu su standžiaislynais skaičiavimo metodai nera iki galo parengti. Klasikiniams tiltams su lanksčiu lynu skaičiuoti taikomi daugiausia kontinualūs modeliai, kurie esant tam tikrai tilto sandarai ar veikiant sutelktoms apkrovoms nera pakankamai tikslūs. Straipsnyje pateikiamos analizines išraiškos kabamuju tiltu su standžiu lynu iražoms ir poslinkiams apskaičiuoti, aptariamas diskretusis klasikiniu kabamuju tiltu skaičiavimo modelis. Published Published Online: 24 Jun 2011 Reikšminiai žodžiai: kabamasis tiltas, lankstus lynas, standus lynas, netiesine analize, kontinualus ir diskretinis modeliai, iražos ir poslinkiai

Entry of the bat influenza H17N10 virus into mammalian cells is enabled by the MHC class II HLA-DR receptor

Haemagglutinin and neuraminidase surface glycoproteins of the bat influenza H17N10 virus neither bind to nor cleave sialic acid receptors, indicating that this virus employs cell entry mechanisms distinct from those of classical influenza A viruses. We observed that certain human haematopoietic cancer cell lines and canine MDCK II cells are susceptible to H17-pseudotyped viruses. We identified the human HLA-DR receptor as an entry mediator for H17 pseudotypes, suggesting that H17N10 possesses zoonotic potential

LAND 22-97. Metodiniai nurodymai gamtosauginiam vandens debitui nustatyti : Lietuvos Respublikos aplinkos apsaugos normatyvinis dokumentas

Vytauto Didžiojo universitetasŽemės ūkio akademij

Arranging Parameters of Self-anchored Stressed Ribbon Supported on Arch Pedestrian Bridges

Stressed ribbon pedestrian bridges are most graceful, efficient and economical strains of suspension bridges. However, these structures have a major disadvantage – very large horizontal support reactions, which result mainly to the construction cost. In order to discover new forms and to extend the limits of stressed ribbon bridges, in the end of twentieth century these constructions were started to combine with other bearing elements in cable­stayed, under­deck cable­stayed bridges and other structures. At the beginning of the twenty­first century stressed ribbon supported on arch structure was discovered. The paper presents reviews of suspension supported on arch footbridges and classification. Considered the main geometrical design parameters and their interdependence. The paper presents a method of how to balance self­anchored suspension supported on arch bridge design computational scheme. Santrauka Straipsnyje pateikiama kombinuotųjų kabamųjų vienajuosčių pėsčiųjų tiltų, paremtų arka, apžvalga ir klasifikavimas. Aptariami kombinuotos pusiausvirosios konstrukcijos pagrindiniai komponuojamieji parametrai, jų tarpusavio ryšys. Straipsnyje pateikta metodika, kaip subalansuoti pusiausvirojo kabamojo arkinio tilto konstrukciją. Reikšminiai žodžiai: vienajuostis kabamasis tiltas; atraminė arka; pusiausviroji konstrukcija; racionalūs komponuojamieji parametrai; simetrinė apkrova; netiesinė analizė