Showing papers on "Shear wall published in 1972"

Free vibrations of coupled shear walls

Abstract: The continuous connection method of analysis is extended to deal with the free vibrations of a coupled shear wall structure. The natural modes and frequencies are determined from the Galerkin technique, and the dynamic response following an imposed lateral displacement is evaluated. A comparison is made between theoretical predictions of natural frequencies and the results from tests on model structures.

Dynamic properties of planar, coupled shear walls

Abstract: The paper is a study of the natural frequencies and mode shapes of planar, coupled shear walls, a common lateral resistive element in building construction. The equations of motion are derived for the general case, and the eigenvalue problem associated with free vibrations of equal, constant shear walls is solved, both with and without the inclusion of the inertia of vertical motion. Explicit solutions are presented for the characteristic equation and the mode shapes and the results are illustrated with figures, including an example calculation based on the shear walls of the Mt. McKinley Building, damaged by the Alaskan earthquake of 1964. The results affirm the necessity of including vertical displacement of the shear walls in the analysis of such systems, and suggest that the inertia of vertical motion also must be considered in the analysis for certain ranges of the parameters.

Some aspects of shear wall design

Abstract: The usefulness of certain walls in the structural planning of multistorey buildings in particular has long been recognised. When external or internal walls are situated in advantageous positions they can be very efficient in resisting lateral loads originating from wind or earthquakes. In addition to the potential strength, which shear walls possess, they offer considerable lateral stiffness and thus can protect a building against non-structural damage that arises when lateral displacement or sway becomes excessive during a moderate seismic disturbance. Only in the last few years did the subject receive more attention and many aspects of the behaviour of shear walls are still being studied and evaluated. Because of necessary space limitations relevant features, which have been treated in well known publications, will be mentioned very briefly here, but reference to the appropriate source will be made. Other aspects, which are now understood a little better because of more recent research efforts, are presented in more detail. Emphasis is placed on features of behaviour relevant to loading of seismic origin rather than on design recipes.

Model Investigations of Shear Wall Structures

Abstract: Results are presented from a series of tests on perspex models to illustrate the behavior of three-dimensional shear wall structures subjected to combined bending and torsion. Three 20-story models of varying complexity were employed, representing the cross-wall form of construction associated with apartment blocks. Deflection profiles are presented for all wall assemblies, together with the bending stress distribution at specific levels. The results are compared with those from an influence coefficient analysis based on the continuous connection technique. Good agreement is reached between theory and experiment, the discrepancies being least when torsional deformations are small compared to flexural deformations. The theoretical analysis indicates that a considerable redistribution of load between the different structural elements occurs throughout the height of the building.

Influence of Joints in Panelized Structural Systems

Abstract: Multistory residential structures are partially well suited to panelization and thus industrialization. Compared to the cast-in-place coupled shear wall, the panelized structure is less rigid and not necessarily monolithic. Moreover, joint performance is often critical with respect to both serviceability and safety. For a representative series of apartment buildings with similar floor plans a cast-in-place, a full panelized and a semipanelized (i.e., wall panels only) solution are compared. A finite element procedure (SHWALI) was used for the analysis. The significance of the floor-to-wall interconnection, the horizontal joint and the vertical joint between load-bearing panels are evaluated with reference to the various limiting design states. Relative to codified recommendations for the design and construction of large panel buildings the structural implications of using panelized construction are examined.

Behavior of Structures under Loads Causing Torsion

Abstract: The results of several analyses of a 24-story structure are presented. The structure is composed of two series of orthogonal bents; the bents consist either of steel rigid frames or of steel rigid frames coupled to reinforced concrete shear walls. The analysis used to predict the response of the structure is an approximate elastic-plastic technique which first lumps the members of each bent into an equivalent structural model. The results presented illustrate the change in behavior which accompanies an increase in the eccentricity of lateral load or an increase in asymmetry of structural arrangement. The effect of increasing the torsional resistance of the vertical element or shifting the positions of the stiffer bents, is illustrated. A reduction in ultimate strength is predicted (below that for the symmetrical case) whenever the secondary moments are effectively increased. This may be achieved by increasing the eccentricity of lateral or vertical loads or by changing the structural arrangement and ranges up to 66% in the extreme case.

Buckling of Lateral Restrained Thin-Walled Cantilevers of Open Cross Section

Abstract: Herein is a method for determining the buckling load of lateral and torsional restrained thin walled cantilever of open cross section under uniform distributed axial load. It is assumed that the restraining medias are distributed along an axis parallel to the axis of the bar. It is supposed that the shear forces in the restraining medias are proportional to the derivatives of the respective displacement. This kind of restraints appears in the analysis of multistory structures in which the lateral and vertical loads are resisted by common action of shear walls and frames. The analytical model of such structures is a vertical cantilever with a thin walled open cross section representing the shear wall, lateral and torsional restraint. The restraining media idealizes the frames, which may be assumed to have the previously mentioned properties. The solution of the problem leads to a system of three third order homogenous differential equations with variable coefficients. The solution selected is in the form of an infinite power series.

Approximate Inelastic Analysis of Shear Wall-Frame Structures

Abstract: Herein is presented an approximate method of analysis for structures composed of shear walls and frames. The structure is reduced to an equivalent frame and an equivalent wall with appropriate values of EI and appropriate plastic moment capacities. The plastic moment capacities of the beams are reduced to allow for gravity loads on the beams. Second-order Ρ-Δ moments are accounted for by equivalent lateral loads at each storey. These loads are calculated in an iterative procedure. The analysis is checked against a more rigorous analysis.

Analysis of multistory frames with light gauge steel panel infills

Abstract: Cladding and partitions are known to have a significant effect on the behavior of structures, yet that effect is generally ignored in design. The objective of this investigation is to study the use of light gauge steel cladding and/or partitions to control drift of multistory frames. The investigation deals only with the service load behavior of an infilled multistory frame assuming linear elastic behavior of all components. A computer program is written to analyze a general three dimensional structure including shear walls, infills and rigid or flexible floors. The equation solution routine makes use of a variation of Gaussian elimination known as wavefront processing. A documented program listing and flow charts are included. The requirements which the connections between frame and panels must meet are determined and details proposed. An "exact" idealization of the light gauge infill which models the proposed construction as nearly as possible is developed for use in studying suitability of the infill. The light gauge steel sheets making up the panel are idealized as assemblies of orthotropic, plane stress rectangular finite elements with two degrees of freedom at each corner. The connections of sheet to sheet and sheet to frame, which are assumed to be welded, are modelled as springs whose spring constants are found experimentally. Single story, single bay frames with different member sizes infilled with panels of different thicknesses are used to demonstrate that the reduction in drift obtained using infills is