King post

Abstract: In design of steel trusses different types of geometries (A-type truss, Fink truss, Pratt truss, Howe truss, King post truss, Queen post truss etc) and sections (Angle section, Tube section, Square hollow section etc) are widely used. In present work, roof truss of span 16m has been analyzed for different geometries and sections to get the desired optimum truss design. The design is further optimized for varying slopes of truss. The support conditions (fixed/hinged) and type of connection (welded/bolted) between truss members also effect the forces in truss members. Although in the truss design, it is assumed that purlins are supported on truss joints, but due to specification of roof sheet, there may be a limitation of maximum purlin spacing which may cause the purlins resting on truss members instead of joints. The various truss analyses are performed by using structural analysis software i.e. STAAD Pro. The analysis results are compared to obtain optimum and accurate truss design. The results indicate that A-type truss has lesser weight compared to other truss geometries. The truss consists of tube/square hollow section is having much lesser weight compared to angle section. The optimum truss slope is found nearly 24⁰. The truss with rigid connection between members is found heavier than the truss with pin connection. Similarly truss supported on fixed base/purlins resting on truss members causes bending moment in top chord of the truss members which in turn modify the sectional requirement of the members. Hence case specific analysis is necessary for rational solution of truss design.

Abstract: A restoration project on the ancient Villa Rucellai in Quaracchi, Florence (XV century, project attributed to Leon Battista Alberti), kicked off the on-site inspection of the wooden structures, as basic way for the assessment of historical timber buildings. During the inspection of the two-trusses timber roof, some significant remains of pictorial decorations were found and, on many surfaces of the timber elements, some fragments of fabric were discovered. In front of these facts, by means of a multidisciplinary approach, the trusses were deeply investigated according to the following examinations: image analysis to recognise all the surfaces covered by textile materials; C dating on fabric and wood, in particular applying wiggle-matching for the latter material; microscopic analysis to identify the textile fibers and the wooden species. The results of the analyses, combined with the relevant information obtained by the on-site technological inspection, confirmed historical information on the Villa and proved the use of mercerised flax fibers, derived from pre-existing fabric artefacts, far older than decoration; in addition, it showed the widespread application of fabrics made of linen, to smooth the wood surfaces for painting, allowing us to establish the first case of \"marouflage\" (\"incamottatura\") applied on structural timber elements.

Abstract: This article presents an efficient design approach for the preliminary design of long-span king-post steel truss systems, First of all, the key parameters that govern effectiveness of the design of a truss system that has its own unique geometric configuration are identified. An optimization model based on the identified key design parameters and the proposed simplified analysis model is established next. A genetic algorithm is then applied to search for the optimal key design parameters. Finally, design examples based on the study of two arena projects in North America are presented. The results of the study suggest that the proposed design method provides an efficient and practical solution for the design of long-span king-post truss systems.

Abstract: As a result of investigating 16 architectural technical books and 72 buildings of modern architectural properties, this paper attempts to illustrate the various treatments of Western wooden roof trusses mixed with Korean roof elements in early 20th century Korea. During this time, new styles such as king post truss, queen post truss, wood-steel composite roof truss, and other roof structures were introduced; which resulted in a mixed style of wooden roofs that used braces, like a strut, in traditional Korean roof structures with a horizontal collar tie in the Western style for the purpose of increasing rigidity. Other changes also appeared in the various types of joint details such as rafter joint, principal rafter joint, and eave details. Korean carpenters tried to accommodate traditional elements and new western style systems in the structural aspect of roof construction. Through the extent to which the findings can be specified for some treatments in the historical and technical standpoint of Korean modern architecture, implications are briefly considered for a unique Korean roof shape in the process of modernization.