Showing papers on "Portal frame published in 1994"

Damage Detection in Steel Framed Structures by Vibration Measurement Approach

Abstract: This papa reports the application of a proposed method combiig Sensitivity .%I@ and MAUCOhfAC Analysis in damage detection for a steel portal frame. Experimental work has been carried out for the veritication of this method. Before and after the structure was damaged, altogether 6 sets of vibrational data were measured under 2 different joint conditions (Rigid and Pinned) and 2 different damage locations (Beam-Column and Column-Base connections). The results show that if the most sensitive correlated mode pairs selected from the sensitivity study are used in the MACICOMAC analysis, the COMAC values Vs. Node Number graph can give a more reliable indication of the location of damage. NOMENCLATURE

Top house for constructing operation of building

Abstract: PURPOSE:To facilitate the carry-in/out operation of materials and permit a simple lift-up device to be used by a method in which operating field can be all or partly opened or closed or freely moved. CONSTITUTION:Temporary scaffolds B are asembled to the surrounding of a building A under construction. A top house C is made up of portal frame structural frame 1 consisting of steel-frame truss column base 1a and a roof 1b and a film 2 set between the roofs 1b of the structural frame 1, having an accordion-type structure to be freely opened or closed. The film 2 may be set between the column bases 1a. The frames 1 on the central and both sides are integrally reinforced by bracings 1c to the opening and closing directions, and the film 2' can not be folded up. By increasing or reducing the number of the frames 1, the length in the opening and closing directions of the top house C is adjusted according to the length of beam direction of the building A. Also, by increasing or reducing the truss frames of the roof 1b of the frame 1, the span direction of the top house C is adjusted according to the length between the beams of the building A.

Bi-criteria optimization of structures liable to instability

Abstract: The paper deals with the optimization of the geometry of structures prone to bifurcation instability. The optimization problem is treated as a bi-criteria one, with the aims of minimizing the volume of the structure and maximizing the safety factor against buckling. Since the two aims are conflicting, the solutions to the problem are taken to be of Pareto type. Two numerical examples are presented; the first one refers to a simple pin-jointed truss and the second one to a portal frame.

A foldable tent frame

Abstract: A foldable tent frame has two upright foldable end portal frames interconnected at each side by horizontal foldable side frame members Each portal frame has two vertical foldable legs (4, 4a) which are interconnected by a roof member (5) via joints The ends of the roof member are offset so that a first folded leg can occupy a space defined between the roof member and a second folded leg Offset side frame members (2) connected to the roof member ends are foldable inwardly through offset planes to prevent collision of frame members when frame is collapsed The frame can be folded and collapsed with or without a fabric enclosure attached and provides for a compact package when folded