As the speed of construction of concrete frame structures has increased and the sophistication of design has improved, there has been an increased need for a more thorough understanding as to the way construction loads are disbursed into the structure. During the 60's and 70's, several designers and researchers proposed methods of analyzing the loads in multi-story structures during construction. A computer program employing one of these methods has been developed. In the 1982 PCA conference,the author used the results of this program to show how the number of levels of equipment, cycle time, and attained concrete strength affected the number of levels of reshores required. This paper describes in detail the process used to calculate the reshoring requirements for a 359-story flat plate structure built using a three-day construction cycle. The discussion includes the practical implications of providing reshoring for a mild steel structure. The hand calculation procedure presented parallels the computer program and is sufficiently detailed to provide the reader a practical procedure that can be used on the next project.

This text is the product of a collaborative effort by the concrete construction services staff of Ceco Industries, inc. Many staff members contributed their findings and recommendations, which were organized and integrated by William R. Anthony, PE, Manager, Market Development. Through its subsidiaries, Ceco Industries is a national formwork subcontractor, and provides the preconstruction services of value engineering, systems analysis and budget pricing. In a growing number of markets, Ceco also provides a total concrete building frame contracting service.

This paper deals with developments in caisson and high-capacity pile design and construction that have assumed importance during recent years and is heavily influenced by the writer's personal experiences which carry a decidedly U.S. perspective and in the case of caissons, a decidedly Chicago perspective. The developments covered include: In situ testing for better soil property information to use in design. Testing and instrumentation to facilitate caisson construction. 3 0 Use of large diameter, very high-bearing-pressure,belled caissons on both cohesive and non-cohesive soil.Developments in high-capacity piling and increased use of dynamic measurements during pile driving. Development of high-capacity friction caissons and design of rock sockets. 6 0 Construction of caissons under water or slurry. 7 0 Development of high-strength concrete for high-capacity caissons.

SP97 This publication is a collection of 12 papers detailing the new and definitive techniques that have made possible the construction of milestone buildings in high-rise construction. The "Chicago style" of construction and the concepts developed by the Chicago design and construction teams in the science of high-rises are covered in this publication. Topics covered include: high-rise system developments in concrete; prestressed concrete in high-rise construction; recent developments in deep foundations for high-rise buildings; and simplified design of slender unbraced columns. Analysis and Design of High-Rise Concrete Buildings offers a wealth of information on concrete technology such as high strength, lightweight, fiber reinforced, corrosion-resistant, and impermeable concretes that have been utilized to make possible some of the tallest buildings in the world.

When designing high-rise reinforced concrete buildings, length changes of vertical members caused by time-dependent effects must be considered. For design purposes, long-term deformations of columns, walls, and caissons may be considered to consist of instantaneous deformations, shrinkage deformations, and creep deformations. In most cases these are non-reversible deformations. Short-term time-dependent deformations are caused by temperature changes and lateral loads. These are generally reversible. Instantaneous deformations depend largely on vertical load, cross-sectional dimensions of member, and modulus of elasticity of steel and concrete at the age when the load is applied Creep deformations depend on concrete stress, size of member, amount of reinforcement, and creep properties of concrete at different ages. Shrinkage deformations generally depend on concrete materials, quantity of water in the mix, size of the member, and amount of vertical reinforcement. When the above factors are considered together with the actual stress histories and realistic material properties, it is possible to predict with reasonable accuracy the shortening of vertical members in high-rise buildings. Temperature changes occur on a daily and seasonal basis. The exposed portions of a building respond to these changes with induced forces or deformations that depend on degree of expo-sure and boundary conditions of the structural members.