yes / This paper presents a relatively simple column strengthening procedure using unbonded wire rope and T-shaped steel plate units. Twelve strengthened columns and an unstrengthened control column were tested to failure under concentric axial load to explore the significance and shortcomings of the proposed strengthening technique. The main variables investigated were the volume ratio of wire ropes as well as geometrical size and configuration of T-shaped steel plates. Axial load capacity and ductility ratio of columns tested were compared with predictions obtained from the equation specified in ACI 318-05 and models developed for conventionally tied columns, respectively. The measured axial load capacities of all strengthened columns were higher than predictions obtained from ACI 318-05, indicating that the ratio of the measured and predicted values increased with the increase of volume ratio of wire ropes and flange width of T-shaped steel plates. In addition, at the same lateral reinforcement index, a much higher ductility ratio was exhibited by strengthened columns having a volume ratio of wire ropes above 0·0039 than tied columns. The ductility ratio of strengthened columns tested increased with the increase of flange width, thickness, and web height of T-shaped steel plates. A mathematical model for the prediction of stress–strain characteristics of confined concrete using the proposed strengthening technique is developed, that was in good agreement with test results.

[pt] Pilares mistos são pilares compostos de perfis metálicos, concreto e vergalhões. Um tipo destes pilares é aquele em que um perfil metálico fechado é preenchido com concreto armado, que é o tipo de pilar adotado neste trabalho. Uma de suas vantagens é a facilidade de execução. O objetivo deste trabalho é estudar experimentalmente o comportamento dos pilares mistos quando sujeitos à flexão-compressão. Inicialmente foi realizada uma série de ensaios em corpos de prova mistos com a finalidade de se obter a curva tensão- deformação do concreto confinado. Em seguida foram realizados 15 ensaios de pilares mistos onde as variáveis estudadas foram o comprimento de flambagem do pilar, a excentricidade da carga e a taxa de armadura. Os resultados experimentais foram comparados com as resistências calculadas de acordo com os métodos propostos nas normas técnicas NBR 14323 e no EuroCode 4. De uma forma geral, todos os métodos de cálculo forneceram bons resultados. / [en] Composite columns are a structural members subjected to compression and bending, made of concrete and structural steel. One particular type of composite column consists of rectangular steel hollow sections completely filled with concrete and reinforcing bars, which is the type of column considered in this work. One of the advantages of this column is the construction facility. The objective of this work is to study experimentally the behaviour of composite columns when subjected to combined compression and bending. Initially a series of tests of composite specimens was carried out in order to obtain the stress-strain curve for the concrete confined by the steel section. Following that, 15 composite columns were tested with the purpose of studying the effect of the buckling length, load eccentricity and reinforcement ratio on the column strength. The experimental results were compared to theoretical resistances calculated by the NBR 14323 and EuroCode 4 Code Requirements. In general, a good agreement was found between the experimental and theoretical results.

This thesis investigates the behaviour of hollow and concrete filled steel columns fabricated from thin steel plates. The columns are investigated under axial, uniaxial and biaxial loading. The currently available international standards for composite structures are limited to the design of concrete filled steel columns with compact sections and yield stress of steel up to 460 N/mm2. This thesis consists of both experimental and analytical studies and design recommendations for future use. Three comprehensive series of experimental tests are conducted on hollow and concrete filled steel columns. The principal parameters that have been considered in the test programmes are the slenderness of the component plates, the yield stress of the steel and the loading conditions. In the first test series, three slender hollow steel columns and three slender composite columns are tested under uniaxial loading. The steel utilised is mild steel. High strength steel is utilised in the second test programme. In this test series four stub columns, eight short columns and eight slender columns are tested, each set consists of four hollow and four composite columns. Short columns are tested under axial loading to investigate the confinement effect provided by the steel casing. Slender columns are tested under uniaxial loading to investigate the coupled instability of local and global buckling. The third test programme is quite novel and considers the behaviour of hollow and concrete filled steel columns fabricated with high strength structural steel plate and subjected to biaxial bending. In this test eight short columns and ten slender columns each of them consisting of hollow and composite columns are investigated under biaxial loading. Analytical models are developed herein to elucidate the behaviour of the hollow and composite columns considering cross section slenderness, yield stress and loading conditions. An iterative model considering the coupled global and local buckling in the elastic and plastic range incorporating material nonlinearities is developed to investigate the behaviour of slender columns fabricated from mild steel. An improved deformation control model is developed to investigate the behaviour of slender high strength steel columns considering the confinement effect and local and post-local buckling in the elastic and plastic range. Then a numerical model for biaxial bending is developed to study the behaviour of short and slender concrete filled high strength steel columns under biaxial loading incorporating interaction buckling considering material and geometric nonlinearities. The scope of the thesis presents a wide range of experimental and theoretical studies of an extremely novel nature. It demonstrates the benefit of confinement and the consideration of local and post-local buckling in the elastic and plastic range. It is hoped that this research will contribute to the area of composite steel-concrete structural applications.

This thesis investigates the behaviour of hollow and concrete filled steel columns fabricated from thin steel plates. The columns are investigated under axial, uniaxial and biaxial loading. The currently available international standards for composite structures are limited to the design of concrete filled steel columns with compact sections and yield stress of steel up to 460 N/mm2. This thesis consists of both experimental and analytical studies and design recommendations for future use. Three comprehensive series of experimental tests are conducted on hollow and concrete filled steel columns. The principal parameters that have been considered in the test programmes are the slenderness of the component plates, the yield stress of the steel and the loading conditions. In the first test series, three slender hollow steel columns and three slender composite columns are tested under uniaxial loading. The steel utilised is mild steel. High strength steel is utilised in the second test programme. In this test series four stub columns, eight short columns and eight slender columns are tested, each set consists of four hollow and four composite columns. Short columns are tested under axial loading to investigate the confinement effect provided by the steel casing. Slender columns are tested under uniaxial loading to investigate the coupled instability of local and global buckling. The third test programme is quite novel and considers the behaviour of hollow and concrete filled steel columns fabricated with high strength structural steel plate and subjected to biaxial bending. In this test eight short columns and ten slender columns each of them consisting of hollow and composite columns are investigated under biaxial loading. Analytical models are developed herein to elucidate the behaviour of the hollow and composite columns considering cross section slenderness, yield stress and loading conditions. An iterative model considering the coupled global and local buckling in the elastic and plastic range incorporating material nonlinearities is developed to investigate the behaviour of slender columns fabricated from mild steel. An improved deformation control model is developed to investigate the behaviour of slender high strength steel columns considering the confinement effect and local and post-local buckling in the elastic and plastic range. Then a numerical model for biaxial bending is developed to study the behaviour of short and slender concrete filled high strength steel columns under biaxial loading incorporating interaction buckling considering material and geometric nonlinearities. The scope of the thesis presents a wide range of experimental and theoretical studies of an extremely novel nature. It demonstrates the benefit of confinement and the consideration of local and post-local buckling in the elastic and plastic range. It is hoped that this research will contribute to the area of composite steel-concrete structural applications.

Thesis (Ph. D.) -- University of Western Sydney, Hawkesbury, 2000. / Includes bibliographical references (leaves 225-241).

Thesis (M.S. in civil engineering)--Washington State University, May 2010. / Title from PDF title page (viewed on June 23, 2010). "Department of Civil and Environmental Engineering." Includes bibliographical references (p. 90-91).

The objective of this study was to numerically investigate the effects of slenderness ratios and end rotational restraints on the post-buckling behavior of non-sway columns. To study the effect of end restraints, numerical solutions were generated for three different support conditions, namely, hinged-hinged, fixed-hinged and fixed-fixed. Furthermore, for each of these support conditions, the effects of slenderness ratios on the post-buckling response were analyzed by considering the slenderness ratios of 50,125 and 200. Based on the numerical data presented in this thesis, the following conclusions can be made.  The unrestrained columns under mechanical loads do not exhibit any significant post-buckling strength.  Restrained Columns subjected to thermal loading undergo significantly smaller deformations in contrast to unrestrained columns, where deformations are relatively larger as the loads are increased only slightly above their critical levels.  The mechanical post-buckling response does not seem to depend on the slenderness ratios of the columns ;whereas the thermal post-buckling response depends on the slenderness ratios of the columns with the relative deformation decreasing with slenderness ratio at a given temperature ratio.  Post buckling behavior of columns subjected to mechanical loadings does not seem to change when the rotational restraints are added whereas in case of columns subjected to thermal loading, the post-buckling response depends on the rotational restraints at the ends of the column. o For a constant slenderness ratio, the deflection ratio was found out to be the smallest for the hinged-hinged column and largest for the fixed-fixed column subjected to thermal loads at a given temperature ratio.

Scania is undergoing a transformation from being a supplier of trucks, buses and engines to a supplier of complete and sustainable transport solutions. Scania Test Rig Development (NLR) group is responsible for developing technical solutions for component testing at Scania R&D and its subdivision Testing Systems (NLRI) is responsible for the development of the software. NLRI maintains the physical server storage including a test result database where results from all over R&D are stored. This database is based on a combination of a file server and a SQL server. The database structure is outdated and restricting to users. The technology for storing data has excelled in many areas since this system was developed. This thesis proposed a new database solution consisting of a new relational model and storage improvements. The varying attributes created by the testing rigs was to be handled with dynamic columns. Dynamic columns allow one to store different sets of columns for each row in a database table. This was tried out in a prototype database using the MariaDB database management system utilizing the JSON syntax for dynamic columns with sample data converted from the database currently in use. The prototype was successfully set up and could utilize the functionalities of dynamic columns. Performance tests, or benchmarks, comparing the current database, the dynamic column prototype and a reference regular SQL column prototype were done. The tests showed that temporarily parsing a dynamic column into regular columns when querying, something referred to as creating virtual columns, was very slow in comparison to a equivalent query on the current database. When fetching the whole or parts of the dynamic columns JSON content the query speeds were only insignificantly slower than a query fetching the same data from regular SQL columns: Both were much faster than the current database. The conclusion was that the new database model with dynamic columns, along with other improvements to the structure presented in this thesis, could be a more future-compatible replacement to the current solution, although it doesn't contribute on its own to new functionalities that for example a cloud platform or advanced analysis tools could give. The proposed database system could be a good complement to further innovations. / Scania genomgår just nu en transformation från att vara en leverantör av lastbilar, bussar och motorer till att vara en leverantör av helhetslösningar av hållbara transportsystem. Scania Test Rig Development (NLR) gruppen är ansvarig för att utveckla tekniska lösningar för komponenttester hos Scania R&D och underavdelningen Testing Systems (NLRI) är ansvarig för utvecklingen av mjukvaran. NLRI underhåller den fysiska lagringen av data, vilket inkluderar en testresultat-databas som lagrar resultat från hela R&D. Databasen består av en kombination av en filserver och en SQL-server. Databasstrukturen är föråldrad och begränsande för användare. Teknologin för att lagra data har fortskridit i många områden sedan denna databas utvecklades. Denna rapport föreslog en ny databaslösning bestående av en ny relationsmodell och förbättringar av datalagring. De varierande attributen som skapas av testbänkarna skulle hanteras med hjälp av dynamiska kolumner. Dynamiska kolumner tillåter att man lagrar olika uppsättningar av kolumner för varje rad i en databastabell. Detta prövades i en prototypdatabas som använde databashanteraren MariaDB och JSON-syntax för de dynamiska kolumnerna på en provdatamängd konverterad från den nuvarande databasen. Prototypen upprättades framgångsrikt och kunde utnyttja funktionerna hos de dynamiska kolumnerna. Prestandatester utfördes där den nuvarande databasen, prototypen med dynamiska kolumner och en referensprototyp med vanliga SQL-kolumner, jämfördes. Testerna visade att tillfälligt skapa vanliga kolumner ur den dynamiska kolumnen vid en sökning, något som kallas för virtuella kolumner, var väldigt långsamt jämförelse med en ekvivalent sökning i den nuvarande databasen. När man hämtade hela eller delar av den dynamiska kolumnens JSON-innehåll var sökningshastigheten obetydligt långsammare än att hämta samma datamängd från vanliga SQL-kolumner: Båda var betydligt mycket snabbare än den nuvarande databasen. Slutsatsen drogs att databasmodellen med dynamiska kolumner, tillsammans med andra förbättringar av databasstrukturen presenterade i denna rapport, kan vara en framtidskompatiblare ersättning till den nuvarande databasen, även om det föreslagna systemet inte på egen hand bidrar till nya funktionaliteter som en molnplatform eller avancerad analysverktyg kan ge. Det föreslagna databassystemet kunde därför vara ett gott komplement till vidare innovationer.

This paper summarises the data from 1819 tests on concrete-filled steel tube columns and compares their failure load with the prediction of Eurocode 4. The full data is given on the website http://web.ukonline.co.uk/asccs2 . The comparison with Eurocode 4 is discussed and shows that Eurocode 4 can be used with confidence and generally gives good agreement with test results, the average Test/EC4 ratio for all tests being 1.11. The Eurocode 4 limitations on concrete strength could be safely extended to concrete with a cylinder strength of 75 N/mm2 for circular sections and 60 N/mm2 for rectangular sections.

No / This paper presents the behaviour and design of axially loaded concrete filled stainless steel circular and square hollow sections. The experimental investigation was Conducted using different concrete cube strengths varied from 30 to 100 MPa. The column strengths and load-axial shortening curves were evaluated. The study is limited to cross-section capacity and has not been validated at member level. Comparisons of the tests results together with other available results from the literature have been made with existing design methods for composite carbon steel sections-Eurocode 4 and ACI. It was found that existing design guidance for carbon steel may generally be safely applied to concrete filled stainless steel tubes. though it tends to be over-conservative. A continuous strength method is proposed and it is found to provide the most accurate and consistent prediction of the axial capacity of the composite concrete filled stainless steel hollow sections due largely to the more precise assessment of the contribution of the stainless steel tube to the composite resistance.