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Showing papers on "Shear wall published in 1971"


Journal ArticleDOI
TL;DR: The behavior of short and relatively deep reinforced concrete beams, which occur in shear walls of multistory structures, and the damage or failure of which has been observed in recent earthquakes, is examined in this paper.
Abstract: The behavior of short and relatively deep reinforced concrete beams, which occur in shear walls of multistory structures, and the damage or failure of which has been observed in recent earthquakes, is examined. Experimental and analytical studies indicate that their ultimate flexural capacity is reduced by large shearing forces, even if a diagonal tension failure is prevented by adequate web reinforcement. After diagonal cracking, the distribution of internal forces radically differs from that observed in beams of normal proportions. The flexural reinforcement is found to be in tension in areas where compression is expected, and this affects the beam's ductility. Shear deformations of diagonally cracked coupling beams greatly overshadow those causd by flexure. With the aid of a model of the cracked beam its stiffness can be approximated. This satisfactorily agrees with observations which indicate that the stiffness after cracking is less than 20% of the stiffness of uncracked coupling beams.

161 citations


Journal ArticleDOI
TL;DR: In this paper, the performance of relatively deep spandrel beams, subjected to seismic type of alternating static loading, is analyzed and the principal modes of failure are identified and the stiffness degradations are evaluated from rotational measurements.
Abstract: The most critical components of coupled shear wall structures are the short and often relatively deep spandrel beams, formed between door or window openings. These may be subject to high intensity alternating flexure in the presence of large shear forces when the structure is exposed to seismic disturbances. The behavior of these beams, when subjected to monotonic one way loading, was previously reported by the writer. In this paper the more interesting features of the performance of relatively deep spandrel beams, subjected to seismic type of alternating static loading, are presented. In the experiments the performance of the flexural reinforcement, the deterioration of the stirrups with high intensity alternating loading was observed. The principal modes of failure were identified and the stiffness degradations were evaluated from rotational measurements. Some evidence is presented with respect to the available ductilities for two types of steel arrangement and the effectiveness of beam repair.

37 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed two formulae for the calculation of bearing capacity of shear-key joints and verified them on the basis of experimental data obtained from tests by Hansen and Oleson, Pommeret and the author.

33 citations


Journal ArticleDOI
TL;DR: In this article, the free vibration of planar coupled shear walls, a common lateral load-resisting configuration in building construction where two walls are coupled together by a system of discrete spandrel beams, is investigated.
Abstract: A study is made of the free vibration of planar coupled shear walls, a common lateral load-resisting configuration in building construction where two walls are coupled together by a system of discrete spandrel beams. The differential equations and boundary conditions are obtained by the variational method, and by assuming that the spandrels can be replaced by a continuous system of laminae, or small beams. Natural frequencies and mode shapes are determined, and the results are presented in a number of figures from which the natural frequencies of any coupled shear wall can be extracted. The importance of including vertical displacement in the analysis is discussed, and a study of the effect of neglecting the vertical inertia term is given. These cases are illustrated with graphs and with one specific example. Investigations are also made of the asymptotic behavior of the system as the spandrels become weak, as they become stiff, and as the frequencies become large. Finally, the theory of sandwich beams is presented and compared to that for coupled shear walls. It is observed that for most cases of constant properties, the differential equations (and boundary conditions) reduce to the same mathematical form for both theories.

28 citations


Journal ArticleDOI
TL;DR: In this article, the continuous method of analysis of coupled shear walls is reformulated in terms of deflection variables and used to study the dynamic behavior of plane coupled Shear walls.
Abstract: The continuous method of analysis of coupled shear walls is reformulated in terms of deflection variables and used to study the dynamic behavior of plane coupled shear walls. The assumption that mid-points of the connecting beams are points of contraflexure is relaxed so that the resulting theory is applicable to the general case where the lateral loading on the piers can be arbitrarily distributed. The equations of motion with appropriate boundary conditions are given. The free vibration of coupled shear walls is studied and the fundamental frequency determined. Theoretical results are verified by dynamic testing on two models to show the theory is sufficiently accurate to provide information for dynamic analysis in seismic design.

24 citations


Journal ArticleDOI
TL;DR: In this article, the stiffness matrices for the connecting beams are given a geometrical transformation so that their ends can be considered connected to the pier axes, i.e., their shear centers.
Abstract: A method of analysis is devised for asymmetrical coupled shear wall structures. The individual shear wall piers, one story in height, are considered to be single elements in a stiffness matrix assembly for the complete structure. The stiffness matrices for such shear wall elements are developed on the assumption that such walls act as thin walled beams, and include the torsional warping effect and its corresponding force parameter, the bimoment. The stiffness matrices for the connecting beams are given a geometrical transformation so that their ends can be considered connected to the pier axes, i.e., their shear centers. When the entire floor slab can be considered as rigid in its plane, a modification is developed which results in considerable reduction in computer time and storage. Displacements and torsional stiffness are computed for a 23-story building consisting of two channel shaped piers connected at the flanges. Results compare favorably with previous experimental work.

22 citations


Journal ArticleDOI
TL;DR: In this paper, the coupled equations of motion for a thin-walled shear wall of monosymmetric cross section are presented based on thinwalled beam theory, and an exact coupled solution is obtained by simultaneously solving a coupled polynomial and set of homogeneous linear algebraic equations, in order to obtain the natural frequencies and mode shapes.
Abstract: The coupled equations of motion for a thin-walled shear wall of monosymmetric cross section are presented based on thin-walled beam theory. An exact coupled solution is obtained by simultaneously solving a coupled polynomial and set of homogeneous linear algebraic equations, in order to obtain the natural frequencies and mode shapes. An approximate solution is obtained by using the uncoupled flexural and torsional mode shapes in applying the virtual work principle in order to obtain the appropriate eigenvalues. A comparison of the exact and approximate solutions for a single shear wall of E-shaped cross section indicates extremely close agreement for both frequencies and mode shapes. The approximate solution requires considerably less computer time than the exact solution and consequently provides a valuable alternative.

13 citations


Journal ArticleDOI
01 Jun 1971

12 citations


Journal ArticleDOI
TL;DR: In this article, a computer program was developed to analyze steel frames with or without shear walls which are subjected either to blast loads or to earthquake motions Equivalent rotational springs are used at the ends of each member to account for the influence of axial load, the inelastic behavior (including the strain-hardening effect) of the member and joint distortion.
Abstract: A computer program has been developed to analyze steel frames with or without shear walls which are subjected either to blast loads or to earthquake motions Equivalent rotational springs are used at the ends of each member to account for the influence of axial load, the inelastic behavior (including the strain-hardening effect) of the member and joint distortion Estimating the axial load and the point of inflection for each member, the relationship between the moment, \iM, and the relaxation angle, \IΔΘ\N, of the rotational spring is calculated The \iM - \IΔΘ\N relationship may be modified to account for the presence of a semirigid joint or to include the shear distortion of the connection Slope deflection equations are developed for members attached with rotational springs and are combined to construct a stiffness matrix for the complete frame The dynamic equations are solved, changing the stiffness matrix so that it is compatible with the deteriorated structure at every instant of the motion Examples illustrate the procedure

10 citations


Journal ArticleDOI
TL;DR: In this article, the theory of bending and torsion in thin-walled members of open cross section is applied to shear cores included within the analytical model of the tier building.

7 citations




Journal ArticleDOI
TL;DR: In this paper, curves are presented for the rapid evaluation of the stresses and deflections in a system of coupled shear walls subjected to differential settlement. But these curves are not applicable to the case of a single wall.

Journal ArticleDOI
TL;DR: In this article, the authors used the Finite Element method to compute the stress distributions accumulated during the story-by-story erection of a typical precast concrete gable wall using the Shear Walls with Openings program SWALLO.
Abstract: Multistory buildings may be constructed economically by system building in precast concrete using large prefabricated wall panel and floor slab units with in situ horizontal and vertical joints. Like masonry and brick construction, the stability of such buildings is primarily dependent on the action of the gravity or self-weight forces and on the efficiency of the joints in transmitting shear and tension stresses between the panels. The stress distributions accumulated during the story by story erection of a typical precast concrete gable wall are computed by the Finite Element method using the Shear Walls with Openings program SWALLO. These are compared with the stresses calculated on the assumption that the total dead weight acts simultaneously on the completed wall. It is shown that there are considerable differences in the estimation of the loads acting on the foundation beam, especially for a wall with a small number of stories. Savings in the amount of reinforcement required within the precast wall panels and across the in situ joints can be made from the stress contours provided by the SWALLO program.

Journal ArticleDOI
TL;DR: In this paper, a series of tests on reinforced brick and concrete block walls subjected to cyclic static loading applied in the plane of the walls is described and the hysteresis loops from several cycles of load-deflection obtained by cycling at constant deformation are obtained and the walls loaded to failure.
Abstract: A series of tests on reinforced brick and concrete block walls subjected to cyclic static loading applied in the plane of the walls is described. The parameters varied were the magnitude of bearing loads, wall aspect ratios and reinforcing percentages and distribution. The hysteresis loops from several cycles of load-deflection obtained by cycling at constant deformation, normally a multiple of the deformation at maximum load, were obtained and the walls loaded to failure. In particular, the ductility capability, stiffness degradation, load deterioration and the ductility requirements as determined by dynamic analyses are discussed in relation to the aseismic design of load bearing masonry walls.





Journal ArticleDOI
TL;DR: In this paper, a load-carrying capacity analysis of coupled shear-wall frame structures is presented, taking into account the finite width of the shear wall and the migration of the plastic hinges in the steel members from the geometric center line of the joint.
Abstract: Tests of three, four-story, single-bay, coupled shear-wall, steel-frame specimens were performed as part of a general investigation of the behavior of multistory structures. Each test specimen consisted of a reinforced concrete shear wall and a steel column stack, connected at four levels by rigidly framed steel beams. The first two specimens were designed to exhibit behavior characteristic of the bottom stories of a tall structure and the third to simulate the behavior of the top stories. The experimental results are compared with the behavior predicted by a second-order elastic plastic analysis. The analysis takes into account the finite width of the shear wall and the migration of the plastic hinges in the steel members from the geometric center line of the joint. The results indicate that the load-carrying capacity of coupled shear-wall frame structures can be closely predicted by the analysis.