Antanas Kudzys

Probabilistic durability prediction of existing building elements

Abstract An effect of service and proof actions on probabilistic reliability (serviceability, safety and durability) of building elements (components and members) of existing enclosure and bearing structures is under consideration. Time‐dependent models for reliability assessment of elements under sustained variable and multicycle actions are presented. Revised reliability indices of existing elements exposed to service permanent and variable actions are discussed. It is recommended to assess the long‐term reliability index of elements taking into account the effect of latent defects. Truncated probability distributions of physical‐mechanical resistances of elements and an effect of their latent defects on reliability index assessment are taken into account. Methodological peculiarities of durability prediction of elements and avoiding unfounded premature repairs or replacements are analysed. The applied illustration of the presented method on the probabilistic reliability prediction of deteriorating conc...

The limit state design of spun concrete columns using load combinations recommended by EN 1990 and ASCE/SEI 7–05

Abstract The expediency of using precast spun concrete columns of annular cross‐sections reinforced by high‐strength steel bars is discussed. Test material properties, efficiency factors and resisting compressive stresses of plain and reinforced spun concretes are presented. Modelling a bearing capacity of eccentrically loaded members of annular cross‐sections is based on the concepts of compression with a bending moment and bending with a concentrical force. The comparison of test and modelling data of concentrically and eccentrically loaded members is analysed. The expediency to use in design practice the approaches of current methods of partial safety factors design (PSFD) legitimated in Europe and load and resistance factors design (LRFD) suggested in the USA and other countries is considered and illustrated by a numerical example.

ON DESIGN FEATURES OF PROPPED AND UNPROPPED HYPERSTATIC STRUCTURES

Abstract An effect of structural and technological features on the design methodology of hyperstatic precast reinforced concrete and composite steel‐concrete structures is discussed. Permanent and variable service, snow and wind loads of buildings and their extreme values are analysed. Two loading cases of precast reinforced concrete and composite steel‐concrete continuous and sway frame beams as propped and unpropped members are considered. A redistribution of bending moments for the ultimate limit state of beams is investigated. A limit state verification of hyperstatic beams by the partial factor and probability‐based methods is presented. It is recommended to calculate a long‐term survival probability of beams by the analytical method of transformed conditional probabilities.

Cargo piers in dredging harbour waters

Abstract Structural behaviour and reliability peculiarities of cargo piers in deepened harbour waters are discussed. Deterministic and probabilistic reliability assessment methods for permeable cargo piers exposed to lateral berthing actions and gravity permanent and variable loads are analysed. Some new methodological approaches to probabilistic reliability assessment of existing cargo piers are presented. The survival probability assessment of pier piles is based on their irreversible serviceability and safety margins. The numerical example illustrates the virtue of probability‐based approaches and methods of design practice of cargo piers.

Methodological Approaches on Structural Durability Assessment

Methods on durability assessment of structural components and auto-systems are discussed. Probabilistic safety and durability assessment is based on random performance process and sequence. Peculiarities of deteriorating structures, their actions and target safety indices are presented.