Deck Floor Research Articles

FAILURE OF DRY DOCK FLOOR IN SCARAMANGA, GREECE, RESULTING FROM STRESS CORROSION DAMAGE TO ANCHOR PILE TENDONS.

Keywords T E BURNS, POSFORD DUVIVIER DOCKS, FAILURES, DRY, FLOORS, STRESS, CORROSION, DAMAGE, ANCHORS, PILES, TENDONS, REINFORCED, CONCRETE, RAFTS, PRESTRESSED, UPLIFT, STRANDS, REPAIRS, METHODS, CONVERSION, SILLS, DESIGN, CONSTRUCTION, WORKS, INVESTIGATIONS, SHIPYARDS, MODIFICATION SCARAMANGA GREECE, EUROPE... Show All

A plate model for composite slab analysis

Composite floor decks constructed with profiled steel sheeting acting as formwork and reinforcement to a concrete slab are increasing in popularity. In this paper an elastic folded palte method of analysis has been applied to model their behaviour. The analytical model idealises both the steel sheeting and the concrete as a collection of thin-walled plates and separates the bending and shear action between horizontal and vertical elements. The effects of concrete in tension and slip between the concrete and steel have been included. The method has been used to analyse the results of 32-full-scale slab tests and is found to give good results.

Demonstration of Torsional Coupling Caused by Closely Spaced Periods—1984 Morgan Hill Earthquake Response of the Santa Clara County Building

The parameters of the dominant modes of vibration of the steel-framed Santa Clara County Office Building in San Jose, California, are determined using “the modal minimization method” for structural identification. The optimal estimates of the model parameters are determined by minimizing a selected measure-of-fit between the responses of the structure and the model. Two types of models are used: (1) A planar linear model with classical damping and (2) A three dimensional linear model consisting of rigid floor decks, where each floor is allowed three degrees of freedom - two orthogonal translations plus a rotation. The Santa Clara County Office Building continued vibrating in a free vibration manner with very low damping, long after the intense part of ground motion had ended. The records of its torsional motion exhibit a strong beating effect which is explained by the strong coupling of torsional and translational modes of vibration. Such a strong coupling of modes of vibration is attributed to the proximity of the value of torsional stiffness to that of translational stiffnesses.

Ponding of Concrete Deck Floors

Floor construction consisting of concrete over metal decking and supported by steel beams and girders is a frequently employed structural system. When temporary shoring is not used, the steel framing and decking deflects during placement of the concrete floor slab. If the concrete were placed to the specified uniform thickness, the result would be a floor surface defined by the deflected shape of the supporting members. The purpose of this paper is to present an interim report concerning studies toward an ultimate objective of predicting concrete volumes required to produce an acceptably level slab which is placed over a flexible substrate. As concrete is placed, the supporting system deflects. As more concrete is placed to compensate for the deflection, additional displacements occur. The situation may be considered analogous to the rainwater ponding phenomenon of roof systems. However, there are notable differences between the rainwater ponding phenomenon and the concrete placement operation. Concrete is plastic, not liquid, consequently it does not seek a constant level. Also, the concrete placement process is controlled by man and rainwater deposition is not.

Some Design Considerations for Composite-frame Structures

Over the past 25 years, numerous innovative structural systems have evolved in tall building design where structural steel and reinforced concrete have been combined to produce a building having the advantages of each material. The use of these so-called composite-frame structures has as its underlying principle the combination of these two distinctive and different building materials to benefit from the advantages of both—namely, the inherent stiffness and economy of reinforced concrete and the speed of construction, strength and light weight of structural steel. The term composite-frame structure has taken on numerous meanings in recent years in utilizing several different building materials. As used here, it is taken to mean a building employing a structural steel and composite metal deck floor system and concrete encased steel columns. The composite beams use headed studs (shear connectors) to achieve composite action between the steel and concrete. The bare steel columns carry the initial gravity, construction and lateral loads until such time as the concrete is cast around them to form composite columns capable of resisting the total gravity and lateral loads of the completed structure.

Point Loads on Precast Concrete Floors

A method of analysis is developed for determining the response of precast concrete floor decks to point loads. Torsion is accounted for, and the method can be applied to a variety of cross sections, including double tees and hollow-core units. A computer program is described which generates influence surfaces for internal member forces.

Design Recommendations for Steel Deck Floor Slabs

The recommendations are based on the steel deck serving as the structural load-carrying element during the construction phase and the composite steel-deck concrete floor slab serving as the load-carrying element for the service-load phases. The recommendations focus on application of strength principles based upon data obtained from performance tests for the shear-bond and flexural failure modes. The design equations for the shear-bond capacity are derived from data obtained by means of a performance test series. A plot of the parameters, is made and a linear regression is performed to determine the slope and intercept constants needed for design. A separate regression is necessary for each steel deck profile; and, in addition, a separate regression is suggested for each steel gage thickness, steel surface coating, and concrete type. Additional recommendations presented consider construction, shoring, deflections, and span-to-depth ratios. /Author/

等分布荷重を受けるSwaged Plateの曲げ

Bending problem of the swaged plate can be analyzed as a sort of orthotropic flat plates. In this paper, first we solved the problem of the rectangular swaged plates with clamped edges under uniform pressure by GALERKIN'S method. From this calculation it was shown that the deflection curve in the normal plane to the swages is flatbottomed type such as a bathtub section. According to this property, the deflections and stresses in the middle part can be approximately calculated by beam theory. In this manner, useful approximate results were obtained in many practical cases. In the last paragraph, we showed its application to the deck floor of an automobile, constructed from the swaged plate.

On the Calculation of the Transverse Strength of Ships by the Relaxation Method

The formulae of influence coefficients for the curved members which are connected stiffly to the structures were derived in this paper. By the aid of these formulae, influence coefficients of the members of the transverse structures of ships can be calculated, and these values are used to the calculation of the transverse strength of a ship, in which the calculations are preformed by the R. V. Southwell's Relaxation Method. By the Relaxation Method, we can get the bending moments acting on the transverse structures of ships, which have two or more decks, more easily than thecalculation by the orthodox method (i. e. the principle of the least work), and the deformations can be also obtained at the same time. Hence the strength and the rigidity of the transverse structure can be known at the same time, by this method.As an example of application, the cargo ship “Okinoyama Maru” was treated, and it was confirmed that the bending moments calculated by the above method consist with them by the orthodox method. By the way, the effects of the camber of the deck beam, bridge deck and skeleton floors on the strength and rigidity of the transverse structure were investigated on the same ship.