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This paper presents the results of tests on 24, rectangular, reinforced concrete panels which were simply supported along all edges and subjected to uniaxial compression. The panels were constructed of normal weight concrete with design strengths of 2500 and 3000 psi (17.2 MN/m- and 20.7 MN/m²) and were reinforced with two-way, steel wire mesh placed in one and two layers. The panels were all loaded to failure. Failure was preceded in each case by plate buckling (biaxial curvature). In all cases the panels failed in a collapse mechanism sim-ilar to that for simply-supported plates which are subjected to uniform, transverse loads. The final load-carrying capacities of the panels were greater than their initial buckling capacities by from I to 24 percent. Formulas for the prediction of the loads at which buckling in such plates will occur are pre-sented and comparisons made with the experi-mental results. The formulas are in closed form and are suitable for design applications. [ABSTRACT FROM AUTHOR]

A series of apparel fabrics were bonded both to a cotton base cloth and to a worsted base cloth. The fabrics were then wrinkled by the AKU tester under wet and standard atmospheric conditions, and their wrinkle severity was determined by means of the Sivim Wrinklemeter. Buckling and cantilever tests were also made, and the wrinkling behaviour and bending performance were compared. [ABSTRACT FROM AUTHOR]

The problems involved in making a mechanical analysis of bending deformations in textile fabrics are discussed. It is suggested that progress can be made by making simplifying assumptions concerning the geometry of fabric structure and deformation and using energy considerations to calculate forces and moments. Certain simple examples are given of the usefulness of this approach. A foundation is laid for the construction of a computer model that will, it is hoped, simulate the viscoelastic bending and creasing behaviour of textile fabrics from a knowledge of the bending and torsional viscoelastic properties of the constituent fibre(s) and their relative geometrical arrangement. [ABSTRACT FROM AUTHOR]

In this paper the theories of fiber migration have been reviewed. Modification of an analysis of migration in a 7-ply structure has been carried out. The frequency of migration is predicted for two models, and it suggests that slack forma tion is the mechanism for outward migration in an open structure, while forced buckling of the central fiber is the corre sponding mechanism for a packed structure, such as occurs in practical spinning.The slack needed to initiate outward migration was analyzed and found to be dependent on the geometry and fiber arrangement in the zone hetween the roller nip and the point of yarn formation. On the other hand, the buckling strain in practical spinning theoretically depends on the surrounding fiber matrix, the twisting tension, and the mechanical properties of the fiber. [ABSTRACT FROM PUBLISHER]

Recent studies of potato and canna starch offer some additional evidence to support both a "stacked" layering found previously and a membrane encasing the granules. A scanning electron microscope was used to obtain a clearer interpre tation of the surface and internal detail of the granules obtained as a result of the swelling treatment. A mechanism for the cavitation during gelation of potato starch is suggested which implies the presence of a hilum canal. [ABSTRACT FROM PUBLISHER]

A full sized precast post-tensioned lightweight concrete folded plate unit was load tested. The folded plate had a V section with 4.24 in. (10.8 cm) thick and 101.5 in. (2.58 m) wide inclined plates. The span was 101 ft (30.78 m). The unit failed at a superimposed load equiva-lent to 34 psf (166 kgf/m2) or 62 percent of the allowable test load by buckling of one of the in-clined plates. A rough analysis of the critical stress of the inclined plate is presented. The strength of the corners and the safety factor against buckling are also reviewed. [ABSTRACT FROM AUTHOR]

This report recommends and suggests design procedures to be used for precast concrete wall panels not indicated or given in ACI 318-63. The report covers the design of solid, ribbed, hollow core, and sandwich panels used as bearing and nonbearing panels loaded in the plane of the panel. Precast concrete wall panels used as deep beams and loaded in the plane of the panel as well as wall panels used as beams and slabs and loaded normal to the face of the panel are also included. Design conditions that must be considered for the connections and connection assemblies including materials are also recom-mended. This Is the fourth and last installment of the series developed by ACI Committee 533 on precast concrete wall panels. [ABSTRACT FROM AUTHOR]

An extensive computer study of long column action in frames is summarized for both unbraced and braced building frames. This summary paper (I) indicates the weakness of the /-method in car-ing for column buckling in certain frames subject to sidesway, (2) compares the accuracy of the moment magnifier and /{-methods in this and other situations, and (3) gives the background for the modified R equations mentioned as alternates in the explanation of changes of the Building Code. [ABSTRACT FROM AUTHOR]

An experimental Investigation into the structural behavior of concrete-filled spiral welded steel tubes under axial load is described. The experimental results are compared with the ACI-NBC (1967) requirements, with a previously proposed new ACI-NBC requirement and with the tangent moduli method. Results on the manufacturing stresses in the steel tubes are also given. [ABSTRACT FROM AUTHOR]

Covered footbridge consists of two identical, symmetrical double cantilevers built one after the other. Structure is 8 in. (20 cm) thick folded slab system made up of roof slab and triangular side walls with post-tensioning tendons in the roof slab. Walkway panels are precast and suspended from superstructure. [ABSTRACT FROM AUTHOR]

Describes a theoretical and experimental investigation into the behavior of concrete filled steel tubes as axially loaded compression members. The experimental results are also compared to the loads allowed by the NBC and ACI and recommendations made. [ABSTRACT FROM AUTHOR]

The lateral stability conditions for a single span slender reinforced concrete beam under uniform bending moment are examined. A method for pre-dicting the critical bending moment is suggested, based on the lateral bending and torsional rigidities and, in the case of doubly reinforced beams, on the warping rigidity. It is shown that these rigidities depend not only on the overall dimensions of the cross section but also on the percentage of steel, the number, type and siie of stirrups, and the state of stress. Experimental results are described which support the proposed theory. These results are then compared with standard design recommendations. [ABSTRACT FROM AUTHOR]

Elastic and inelastic behavior of mortar filled tubes in compression was investigated. The work was restricted to seamless steel tubes ranging from 1 to 3 in diameter. Experimental values of the ultimate axial load capacities are compared to the theoretical values obtained from the tangent modulus formula. [ABSTRACT FROM AUTHOR]

A report on the practical aspects of shell design including recommendations and a commentary for designers of thin concrete shells. General guidance based on current practice is given on analysis, proportioning, reinforcing and construction. A selected bibliography on analytical methods featuring design tables and aids is included to assist the engineer. [ABSTRACT FROM AUTHOR]

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A review of the existing knowledge of buckling of shells. Note is taken of the lack of information concerned with concrete shells as against that available for plastic and metal shells. Reported work in metal and flastic shells in the areas of elastic, inelastic, and large deflection theory o buckling is applied to concrete shells. Cylindrical shells are discussed under conditions of axial load, radial pressure load, torsional load, and bending. Spherical shells under radial pressure and curved plates under bending are also covered. [ABSTRACT FROM AUTHOR]