Résumé : Logical relations have now the maturity to deal with program equivalence for realistic programming languages with features likes recursive types, higher-order references and first-class continuations. However, such advanced logical relations---which are defined with technical developments like step-indexing or heap abstractions using recursively defined worlds---can make a proof tedious. A lot of work has been done to hide step-indexing in proofs, using Gödel-Löb logic. But to date, step-indexes have still to appear explicitely in particular constructions, for instance when building recursive worlds in a stratified way. In this paper, we go one step further, proposing an extension of Abadi-Plotkin logic with forcing construction which enables to encapsulate reasoning about step-indexing or heap in different layers. Moreover, it gives a uniform and abstract management of step-indexing for recursive terms or types and for higher-order references.