Design Ultimate Load Research Articles

Ultimate Load Design and Testing of a Cylindrical Prestressed Concrete Vessel

The object of this research was to design, construct and test to failure a prestressed concrete pressure vessel model that could be used to investigate the behavior of a full scale structure underworking and ultimate load. The properties and the design of the model was based generally on full scale vessels already constructed to house the nuclear reactors used in atomic power stations. To design the model the ultimate load approach was adopted throughout. All load factors associated with the prestressing have been defined and kept to a minimum in order that the vessel's behavior may be predicted. The tests on the vessel were carried out first on the elastic range to observe its behavior at working load and then at the ultimate range to observe the modes of failure and compare the actual results in both cases with the predicted values. Although full agreement between observed results and predicted values was not obtained, the conclusions drawn from the study were useful for the design of full scale vessels.

Ultimate load design and testing of a cylindrical prestressed concrete vessel.

The object of this research was to design, construct and test to failure a prestressed concrete pressure vessel model that could be used to investigate the behavior of a full scale structure underworking and ultimate load. The properties and the design of the model was based generally on full scale vessels already constructed to house the nuclear reactors used in atomic power stations. To design the model the ultimate load approach was adopted throughout. All load factors associated with the prestressing have been defined and kept to a minimum in order that the vessel's behavior may be predicted. The tests on the vessel were carried out first on the elastic range to observe its behavior at working load and then at the ultimate range to observe the modes of failure and compare the actual results in both cases with the predicted values. Although full agreement between observed results and predicted values was not obtained, the conclusions drawn from the study were useful for the design of full scale vessels.

Reliability analysis for optimum design

With the widespread increase in industrialisation and the resulting increase in utilisation of World resources an increasing attention to optimum design is forecast. A reliability approach is presented which offers a means of enabling the influence of significant design parameters to be studied and the design to be optimised. It is illustrated by two applications—assessment of ultimate load design procedures for an offshore drilling unit and the derivation of a reliability based inspection procedure for a crop—dusting aircraft. The approach requires extensive data not normally available in design and is still in the development stage, but it is seen as an ideal approach to achieving an optimum design.

Reinforced Concrete Design for Strength and Deformability

A method of design is developed for reinforced concrete flexural frameworks wherein strength and deformability criteria are simultaneously satisfied at the specified service and ultimate design load levels. A limit design approach is adopted, and the required design moment capacities are found accounting for the same measure of plastic adaptability of reinforced concrete as that recognized by the ultimate strength design method for proportioning sections. The design solution comprises the set of cross-sectional dimensions and steel percentages for which the members have sufficient post-yielding moment and rotation capacities at the ultimate design load level while ensuring that deflections and stresses and strains are within acceptable limits at the service design load level. An example continuous beam is designed by the method to have minimum cost of concrete and steel.

Simplified computer approach to the ultimate load analysis and design of reinforced concrete frames: Amer. Concr. Inst. J., Vol 69, (1972) No 11, pp 690–698

Simplified computer approach to the ultimate load analysis and design of reinforced concrete frames: Amer. Concr. Inst. J., Vol 69, (1972) No 11, pp 690–698

Evaluation of a Boron-Epoxy Reinforced Titanium Truss

A of 24% weight is forecasted when comparing a boron/epoxy reinforced titanium tubular truss with an all-titanium design for application to the space shuttle booster thrust structure. This forecast is based on experimental results obtained by testing boron/epoxy composite cylindrical local buckling specimens, composite-to-metal bonded step joint specimens and a boron/epoxy reinforced titanium truss which failed at 118% of design ultimate load.

Simplified Computer Approach to the Ultimate Load Analysis and Design of Reinforced Concrete Frames

Simplified Computer Approach to the Ultimate Load Analysis and Design of Reinforced Concrete Frames

Ultimate load design of skew slabs by the strip method

The application of the strip method to the design of skew slabs is described, particular attention to skew reinforcement in uniform bands being given. An affinity theorem is derived which enables the design of a family of skew slabs to be obtained from the design of a rectangular slab.

Response of complex structures to turbulent boundary layers

where co = exp(— X). Equation (24) has been numerically evaluated for the ultimate design load factors UDU — 13, 11, 9, and 7 and the corresponding reliability functions have been constructed in accordance with Eq. (14) and are represented in Fig. 8 in terms of the number of load cycles and of hours of flight. The conversion is based on the assumption that roughly 10 load cycles are equivalent to 1 hr of flight at an average of 350-400 mph in accordance with the flight records.

Ultimate load design of simply-supported slab-beam systems

The application of the strip method of design to simply-supported slab-beam systems is discussed. Particular attention is given to the choice of load dispersions that are valid for the placing of reinforcement in uniform bands as is generally required in practice. Square slabs on beams are examined in relation to the minimization of the total amount of reinforcement required in the design.

Elastic and plastic behaviour of cased beams

Tests are described which were carried out by the author during a short stay in Cambridge University Engineering Department as a visitor and is part of a programme aimed at studying the behaviour of cased beams at ultimate load in order to develop ultimate load design methods for this type of beam. The work is restricted to simply supported beams consisting of mild steel joist encased in a concrete T-beam rib with the top flange projecting into the slab and stirrups provided to enable the slab to be connected to the encased steel rib up to failure, when interface bond would have broken down.

A note on a possible basis for a new method of ultimate load design of reinforced concrete slabs

Summary Because of tensile membrane action, reinforced concrete slabs can sustain loads far in excess of the ultimate load calculated by the yield-line theory. To take advantage of this, it is necessary to establish de flexion criteria for ultimate load conditions and to develop a method of calculating the corresponding load-carrying capacity. Such a method is proposed, and the possible advantages are indicated.

The rotation of reinforced concrete plastic hinges at ultimate load

Summary On the basis of the simplified ultimate load theory which assumes elastic members spanning between plastic hinges, the procedure for checking required rotations caused by moment redistribution and rotation capacities of plastic hinges is outlined, and the influences of strength of concrete, compression and tension reinforcement, and form of loading on hinge rotations are discussed. In particular, it is shown that compression steel, which significantly affects flexural rigidity in structural members, as well as concentrated rotations at plastic hinges, provides a convenient means of adjusting deformations in ultimate load design. From a study of test results from 54 beams and 13 struts, the paper shows that the methods and parameters that are recommended in the recently published report on “Ultimate load design of concrete structures” for the computing of plastic hinge rotations are safe and statistically acceptable.

Fundamental Concepts in Ultimate Load Design of Reinforced Concrete Members

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