scispace - formally typeset
Search or ask a question

Showing papers on "Portal frame published in 1985"


Journal ArticleDOI
TL;DR: In this paper, structural variation for rigidly jointed frames is extended to cover the nonlinear elastic-plastic analysis of frames to collapse, including strain hardening and other material changes.
Abstract: The theorems of structural variation for rigidly jointed frames are extended to cover the nonlinear elastic–plastic analysis of frames to collapse. Strain hardening and other material changes are included in the analysis. It is shown that the entire load–deflection history of a frame, following the successive formation of plastic hinges up to and including collapse, is obtained from a single initial elastic analysis. The manner in which these theorems are used to insert real (or plastic) hinges to a frame is presented and details of the manual calculations involved in the elastic–plastic analysis of a portal is given to demonstrate the simplicity of the method. This is followed by a comparison of the results with those obtained experimentaly by Baker and Charlton. The versatility of the method is then demonstrated by altering the shape of a frame before its elastic–plastic analysis.

26 citations


Journal ArticleDOI
01 Mar 1985
TL;DR: In this article, the effect of geometric imperfections due to right angle deviations is thoroughly discussed by using as model an unbraced rectangular frame, and it is found that the value of the angle between the center lines of the two members is of decisive importance for the response of the frame.
Abstract: By using as model an unbraced rectangular frame, the effect of geometric imperfections due to right angle deviations is thoroughly discussed. It is found that the value of the angle between the center lines of the two members is of decisive importance for the response of the frame. There is a critical angle for which the response of the frame changes from buckling to unbuckled states exhibiting a monotonically rising equilibrium path. It is shown that this critical angle depends on the column slenderness ratio as well as on the length and moment of inertia ratio of the two members. Moreover, formulas for direct evaluation of the critical angle as well as of the load-carrying capacity of the frame are established.

11 citations


Journal ArticleDOI

2 citations


Journal ArticleDOI
01 Jan 1985
TL;DR: In this paper, the problem of designing the structure for optimal swayless buckling is explored, and it is shown that the correct optimal solution is based on a double eigenvalue associated simultaneously with both a sidesway and a swayless mode.
Abstract: Portal frames subjected only to axial column forces usually fail by buckling into a sidesway mode. For a prescribed volume, the load parameter associated with this mode may be maximized. However, the optimal structure so obtained exhibits a hinge in each column and beam and can be demonstrated to buckle without sway, under a load parameter which is always smaller. Inverting the process by designing the structure for optimal swayless buckling is equally fruitless, in that it leads to sharply reduced resistance against sidesway buckling. These questions are explored, and it is shown that the correct optimal solution is based on a double eigenvalue associated simultaneously with both a sidesway and a swayless buckling mode. The relevant equations are developed and an analytical solution is obtained for the case of a symmetric portal frame under symmetric loading for various height-to-span ratios. As expected, and in conformity with the known solution to the fixed-fixed column problem, the c...

1 citations


Patent
16 Aug 1985
TL;DR: In this paper, a portal frame made of glued-laminated timber for constructing covered buildings is described, where a V-shaped coupled pole is assembled above the horizontal beam in line with the base pole via the tip of the V, and the branches of the coupled pole extend upwards in a plane which is perpendicular to the beam.
Abstract: The invention relates to a novel portal frame structure made of glued-laminated timber. The subject of the invention is a portal frame made of glued-laminated timber for constructing covered buildings characterised in that it comprises, on one side, at its base, a vertical pole 1 supporting a horizontal beam 2 resting on the various vertical base poles of the portal frames making up the building, a V-shaped coupled pole 3 made of glued-laminated timber which is assembled above the horizontal beam 2 in line with the base pole 1 via the tip of the V the branches of which coupled pole extend upwards in a plane which is perpendicular to the beam 2 and support one of the ends of the simple main load-bearing beam 4 made of glued-laminated timber the other end of which rests on a simple coupled pendular (pinned) pole 5 made of glued-laminated timber. Application in particular to the construction of covered buildings.

1 citations


Patent
14 Jun 1985
TL;DR: In this paper, the authors proposed a building framework component consisting of a portal frame having a height of one storey in which the portals 9 to 12 of the portal frame are essentially set back from the ends of the beam of the main portal.
Abstract: The invention relates to a building framework component, a building framework and the construction method The building framework component of the invention consists of a portal frame having a height of one storey in which the portals 9 to 12 of the portal frame are essentially set back from the ends of the beam of the portal frame Application to the construction of buildings

1 citations


Patent
24 Jun 1985
TL;DR: In this article, the authors mounted a telescopic brace adjustable with a force intensifying actuator between column and girder of a portal frame and tilting the whole portal frame to apply an accurate vertical force constantly on a test piece regardless of its change.
Abstract: PURPOSE:To apply an accurate vertical force constantly on a test piece regardless of its change, by mounting a telescopic brace adjustable with a telescopic actuator between column and girder of a portal frame and tilting the whole portal frame CONSTITUTION:Between girder 2 and column 1 on the lefthand side of a portal frame 3, and between girder 2 and column 1 on the righthand side, a brace 9 is mounted respectively The brace 9 is constructed partly by an oilhydraulic cylinder 10 for telescopic actions Between the girders 2 of front and aft portal frames 3, 2 beams 11 are mounted parallel and between these beams 11, a travelling bench 12 is mounted From the travelling bench 12, a force intensifying actuator 13, an example of oil hydraulic jacks provided with a servo-mechanism, etc is suspended with pin connection By telescopic actions of the braces, the whole portal frame 3 is avaivable for tilting with its entire structure, the force application axis of the actuator 13 can be turned out side of its plane, with the test piece 14 as kept under the vertical force

1 citations


Journal ArticleDOI
TL;DR: In this article, a program has been developed which aids the designer in this task and all of the fairly simple but very time-consuming calculations involved are done rapidly by the machine, while leaving complete control with the designer.