Kent Gylltoft

Concrete in compression: a plasticity theory with a novel hardening law

This paper deals with the modelling of the behaviour of plain concrete in triaxial compression using the theory of plasticity. The aim is to model the load resistance and the deformation capacity in uniaxial, biaxial and triaxial compression by means of few parameters, which can be determined easily. A novel hardening law based on a non-associated flow rule and the volumetric plastic strain as hardening parameter is combined with a yield surface proposed by Menetrey and William (1995). The novel hardening and softening law differs from a classic strain-hardening law, as instead of the length of the plastic strain vector only the volumetric component of the latter is used as a hardening parameter. Thus, the non-linearity of the plastic potential is utilized to describe the influence of multiaxial compression on the deformation capacity and no additional ductility measure is required. The implementation and calibration of the novel hardening law are discussed. The prediction of the model is compared to results of uniaxial, biaxial and triaxial compression tests. It is shown that with one set of calibration parameters a good prediction of the load resistance and the deformation capacity for all three types of compression tests can be achieved.

CDPM2: A damage-plasticity approach to modelling the failure of concrete

A constitutive model based on the combination of damage mechanics and plasticity is developed to analyse the failure of concrete structures. The aim is to obtain a model, which describes the important characteristics of the failure process of concrete subjected to multiaxial loading. This is achieved by combining an effective stress based plasticity model with a damage model based on plastic and elastic strain measures. The model response in tension, uni-, bi- and triaxial compression is compared to experimental results. The model describes well the increase in strength and displacement capacity for increasing confinement levels. Furthermore, the model is applied to the structural analyses of tensile and compressive failure.

Load-Carrying Capacity of Scaffolds

An evaluation method for scaffold systems is presented. The method combines numerical modelling and laboratory tests. The results of a parametric study of a typical scaffold are also presented. A f...

Anchor Bolts Analysed with Fracture Mechanics

A fracture mechanics analysis is presented of anchor bolts embedded in concrete or grouted in concrete or rock. A discrete crack approach is used with a bi-linear softening material model.

HIGH PERFORMANCE JOINTS BETWEEN PREFABRICATED TRAFFIC SLAB ELEMENTS FOR INDUSTRIAL BRIDGE CONSTRUCTION

This paper describes a recently conducted study of an innovative new concept for joints between prefabricated concrete elements. The aim was to design a joint that is stronger than the surrounding elements, but remains a joint that is easy and fast to perform. A special steel fiber reinforced high performance concrete was used in the joint. Several lab tests were performed showing that the joint meets the demands place upon it and can be treated monolithicly in design.