A series of tests was performed to consider the behaviour of short composite columns under axial compressive loading, covering a range of S275 and S355 grade steel square hollow section filled with normal and high strength concrete. The interaction between the steel and the concrete component is considered and the results show that concrete shrinkage has an effect on the axial strength of the column. Comparisons between Eurocode 4, ACI-318 and the Australian Standards with the findings of this research were made. Result showed the equation used by the ACI-318 and the proposed Australian Standards gave better predication for the axial capacity of concrete filled SHS columns than the Eurocode 4.

<p> Trusses and Vierendeel girders are usually built from a single chord HSS "Hollow Structural Sections", but the largest HSS size as produced in Canada may limit its use for longer span applications. Therefore, the possibility of using double chord sections to enable the use of HSS for longer span trusses without the need for manufacturing new larger sections, presented itself. </p> <p> A new concept utilizing double chord square hollow sections in welded K-joints of Warren trusses is described. The experimental results of 29 tests are reported, including four connections types — standard, channel, bolted and back-to-back. The latter type comprised of gapped, overlapped and gapped with connecting stiffener plates. </p> <p> The results indicate that the standard type is an excellent joint in both strength and stiffness. The channel type is generally susceptible to twisting. It was found adequate only when a significant increase in chord thickness (≃ 50%) was employed. The bolted connection appears to hold promise when on-site assembly of large trusses is necessary. Its performance was further improved by connecting the chords with small tie bars. The back-to-back type needed to be reinforced or fully overlapped to develop full branch member strength. </p> <p> The double chord system of connection reveals itself to be much superior in strength to an equivalent single chord joint. </p> <p> The effects of eccentricity, branch member to chord angle, and chord preloading were investigated. Interaction formulae are presented for the standard and channel type joints which suffered from a chord failure at the connection. </p> <p> Results of four T-type connections using the double chord concept are also reported and were recently published in the ASCE (8). </p> / Thesis / Doctor of Philosophy (PhD)

Baigiamajame magistro darbe nagrinėjami santvarinių konstrukcijų iš kvadratinių vamzdžių tiesioginio jungimo mazgų skaičiavimo ir konstravimo ypatumai. Analizuojama konstrukcinių elementų elgsena mazge ir jos sąlygojamas jungties irties pobūdis. Nagrinėjamos takumo linijos teorijos taikymo galimybės sudarant analitinius modelius. Pateikiami analitiniai modeliai, taikomi mazgų ašinės laikomosios galios skaičiavimo algoritmams sudaryti, pateikiamiems projektavimo norminiuose dokumentuose. Aprašomas mazgą sudarančių konstrukcinių elementų projektavimas pagal STR 2.05.08:2005 ir EN 1993-1-1 reikalavimus, bei mazgų ašinės laikomosios galios nustatymas pagal STR 2.05.08:2005 8-tą priedą, bei EN 1993-1-8. Darbe atlikta skaitinė projektavimo normose pateikiamų santvarinių konstrukcijų tiesioginio jungimo mazgų ašinės laikomosios galios nustatymo lyginamoji analizė. Suprojektuota santvarinė konstrukcija, kurios skaičiuojamoji schema parinkta tokia, kad būtų išanalizuoti visi projektavimo normose pateikiami tiesioginio jungimo mazgų tipai. Įrąžoms konstrukciniuose elementuose nustatyti pasinaudota kompiuterine skaičiavimo programa Staad.pro. Konstrukcinių elementų elgsenos mazge analizei pasinaudota kompiuterine programa CosmosWorks. Ištirta pagrindinių skaičiavimo algoritmuose pateikiamų rodiklių įtaka mazgo laikomąjai galiai. Norint parinkti santvaros konstrukcinius elementus ir nustatyti mazgų skaičiuotinę ašinę laikomąją galią bei atlikti skaitinę analizę buvo pasinaudota... [toliau žr. visą tekstą] / This master thesis considers design and estimation of truss joints between square hollow sections. Behaviuor of joints and its failure modes analyzed. The posibility to apply the yield line theory for analytical models considered. Analytical models used for determining the design capacity of the joint formulae in design guids presented. Truss members design following STR 2.05.08:2005 and EN 1993-1-1 and joint design capacity calculation following STR 2.05.08:2008 8-th annex and EN 1993-1-8 presented. It was made numerical convergence analysis between diferent design guidilines for estimating design capacity of the joint in this study. Truss structure designed, including all most commonly known joint types. Truss member loiding estimated using structural design and analysis software Staad.Pro. The behaviuor of the joint designed using finite element analysis software Cosmos.Works. Also the influence of governing joint parameters for the design capacity equations analysed. For truss structure design, capacity of the joint calculations and numerical analysis the calculation program was made using Microsoft Office Exel software.