Creep and Shrinkage Analysis in Reinforced Concrete Structures during Construction of High-rise Buildings

Abstract

This thesis presents a simplified assessment of deformations of two reinforced-concrete high-rise buildings during construction, which are constructed at two different construction rates. The primary objective is the calculation of the difference in the vertical shortening of the two buildings, which should be connected thru an expansion joint so that the difference of the height at each floor level is unrecognizable to the user anytime during the service life of the two buildings. Step-bystep procedure, including construction schedule and assessment of structural stiffness, is performed in order to implement real situation and obtain adequate result. Therefore, characteristic values of most expected loads were used, such as self-weight of structure and heavy-weight equipment, in calculations of axial shortening. Time-dependent properties of concrete, such as Young's modulus of elasticity and compressive strength, as well as creep coefficient and shrinkage strain were evaluated by the Eurocode 2 model. All expected issues can be classified as loadbearing structure problems, problems related to detailing of non-load-bearing structures within one building and between buildings, separated by expansion joint.

This thesis presents a simplified assessment of deformations of two reinforced-concrete high-rise buildings during construction, which are constructed at two different construction rates. The primary objective is the calculation of the difference in the vertical shortening of the two buildings, which should be connected thru an expansion joint so that the difference of the height at each floor level is unrecognizable to the user anytime during the service life of the two buildings. Step-bystep procedure, including construction schedule and assessment of structural stiffness, is performed in order to implement real situation and obtain adequate result. Therefore, characteristic values of most expected loads were used, such as self-weight of structure and heavy-weight equipment, in calculations of axial shortening. Time-dependent properties of concrete, such as Young's modulus of elasticity and compressive strength, as well as creep coefficient and shrinkage strain were evaluated by the Eurocode 2 model. All expected issues can be classified as loadbearing structure problems, problems related to detailing of non-load-bearing structures within one building and between buildings, separated by expansion joint.