Presents a simple design aid for predicting long-term (up to 50 years) movements in reinforced concrete columns and bridge beams made of normal and lightweight aggregate concrete. The method is based on the principle of superposition using a creep factor chart, which takes into account varying sizes of members, age at loading, exposure conditions, and the percentage of reinforcement, and it requires only a knowledge of the concrete strength and the loading history of the member. The method is developed from the study of in situ movements in two reinforced concrete structures subjected to increment loading. The shrinkage strains in columns are predicted using a shrinkage chart, which requires only a knowledge of elastic modulus of concrete at 28 days. The predicted load-induced and basic strains show excellent agreement with measured strains in the two structures, and the method shows good agreement with literature. The paper demonstrates how the simple method of predicting long-term movements in buildings and bridges can be utilized by the structural engineer as a designer's tool.

In seismic zones, severe earthquakes occur within a certain period. However, the important functions of a concrete structure must be maintained after the earthquake. Hence, structures must be designed for safety during the earthquake and serviceability after the earthquake. The acceptable level of damage can be varied in accordance with the type and importance of the structure. When a reinforced concrete structure suffers significant plastic deformation, residual deformation and large crack opening in the structure are impaired. A new and rational seismic design method was proposed. The peculiarity of the concept of the design method is as follows: Seismic design should be performed to fulfill required serviceability after the design earthquake as well as required safety during the earthquake. High magnification factor due to dynamic response was introduced according to actual observation in the earthquakes. Reduction factor referred to the acceptable level of damages in the structure after the earthquake was introduced. The importance of design details was emphasized. Furthermore, the influence of axial compressive force on the ductility was pointed out.

Internal algorithms for creep and shrinkage when substituted by approximate algebraic equations lead to the adoption of a computational procedure substantially independent of linear equations adopted in the time-dependent prediction model. Presented herein are the numerical results of stresses and strains of reinforced and post-tensioned concrete bridge box-sections where creep and shrinkage are considered. Field measurements of deformations have been recorded and compared with the corresponding numerical results obtained by utilizing a computer program. Results are presented in a graphical form. It may be concluded that the computer method is a convenient tool for describing the behavior of structural concrete sections considering creep and shrinkage in connection with performance and service ability.

Deals primarily with statically indeterminate beams where settlement of the supports can produce stresses. A method of estimating the effects of support settlement is presented. The method accounts for the fact that soil consolidation and the corresponding support settlement often develop over an extended period of time. The method also demonstrates that creep of concrete can reduce the ultimate settlement-induced stresses in uncracked members by as much as 60 percent of the elastic values. Furthermore, flexural cracking of concrete results in reduction of the member stiffness. This corresponds to further relief of the settlement-induced stresses. Field studies on the effects of settlement in several bridges are presented. The relationship between the amount of settlement and its structural effects is illustrated.

Describes deterioration of concrete in the chambers and the culverts of Eisenhower Lock that were observed soon after the lock was completed in 1958. Investigators from the U.S. Army Engineer Waterways Experiment Station postulated that the most probable cause of deterioration was pressure created by freezing water in critically saturated concrete that was not mature enough to withstand the pressure. Slow strength gain of the concrete was believed due to the use of natural cement. The investigation conducted prior to repairs performed at Eisenhower Lock in the winter of 1985-86 suggested that poor durability of the in-place concrete may have been caused to a large extent by inadequate control over concrete operations during construction works. Therefore, all precautions have been taken to assure that the newly placed concrete will perform adequately under severe service conditions. The only operation that caused concern was adding hot water at the project site to the dry concrete mix containing portland cement.