Showing papers on "Portal frame published in 1990"

Thermal gradient effects in reinforced concrete frame structures

Abstract: Three large-scale reinforced concrete portal frame models were subjected to combinations of thermal and mechanical loads. Test conditions included unrestrained thermal deformation, restrained deformation under shock thermal loads, and loading to ultimate capacity. Aspects of response were monitored in terms of resulting restraint forces, deflection, strains, cracking, and leakage. Test results indicated that thermal loads can result in significant stressing of a structure and can lead to concentrated damage in local regions. A proposed theoretical analysis procedure was found to give reasonably accurate predictions of response.

An Experiment to Identify the Structural Dynamics of a Portal Frame

Abstract: This paper describes the application of sequential frequency domain techniques to the estimation of mass, stiffness, and damping parameters using measured frequency response functions from a portal frame rig. The theory of the method has been described in the authors’ previous publications. A portal frame is representative of many engineering structures. It is lightly damped and may be thought of as an element of several larger structures such as bridges, transmission towers, and the steel foundations of modern power generating plant. The results offered in this paper are thus of interest to a broad range of engineering problems where it is required to obtain mathematical models in terms of physical parameters.

Apparatus for loading large containers

Abstract: Apparatus for loading large containers, having a portal frame which can be moved across the large containers and is essentially rectangular in cross-section, characterised in that the portal frame carries at least one jib projecting beyond one side of its cross-section, and in that the height of the portal frame can be set at least on its side facing the jib.

Response of Low-Rise Frame Structure to Dynamic Soil Motions

Abstract: : The major objective of this study was to develop a simplified model to simulate the response of low-rise structures subjected to dynamic loads. This model incorporates the influence of soil and floor flexibility and is based upon underlying assumptions of static portal frame analysis. This study was extended to incorporate mono-symmetric structures (with and without setback) subject to self-induced torsion, as well as asymmetric frames. This model provides estimates of any force or displacement which might be determined in a corresponding space frame model. For selected design parameters, including maximum base shear and torque, maximum horizontal roof deflection, and maximum beam forces (shear, moment, and torque), the average errors for all comparisons to space frame calculations were less than ten percent. Preliminary studies assessed the impact of linear soil-structure interaction effects upon the response of space frames with flexible mat foundations and composite beam/slab floor systems. Within the limits of linear analysis of uniformly applied horizontal soil loads, mat flexibility was found significant only to the response of the mat foundation of the structure. Dynamic loads and dynamic response above the mat are only slightly affected by soil and mat flexibility.

Machine tool for reducing round timber into logs

Abstract: The invention relates to a machine tool for reducing round timber into logs According to the invention, it consists of a framework 10 on which are arranged: - on the one hand, a portable frame 20 supporting a mechanical tool 30 for splitting the wood, - and, on the other hand, a turnstile 40 on which round timber to be split is arranged, so that the said turnstile 40 revolves below the said portal frame 20 by successive advancements, separated from one another by time intervals during which the said turnstile 40 is immobilised in order to allow the said mechanical tool 30 to split the said round timber

Seismic response of elevated steel water pipe

Abstract: Elevated steel water pipelines may be subjected to transverse and vertical seismic forces, and should be designed to withstand these forces safely. A specific elevated steel water pipeline is studied using a linear computer program that incorporates the response spectrum approach for seismic analysis. Two means of pipeline support are studied and compared: a steel moment-resisting frame system and a steel vertical truss system. Preliminary design of the individual supports is completed using an approximate lateral-force procedure. The bending moment in the pipeline is then investigated, as well as the lateral forces imparted to the support structures, using the response spectrum approach, with modifications for damping and ductility. Results indicate that the equivalent lateral-force procedure does not prove satisfactory for this particular pipeline. In addition, the vertical truss method of support results in a consistently lower bending moment in the pipeline than does the moment-resisting frame method of support.