Effects of shear on the plastic behaviour of steel structures with foundation settlement

摘要

For structures susceptible to differential settlement, it may be appropriate to assess the integrity of structures on the basis of actual or predicted settlement data. The effects of foundation settlement can be included in an elastoplastic analysis, but provisions should be made to ensure that the serviceability requirements are not breached. In contrast to the conventional plastic analysis where the loads are increased proportionally, it is proposed that the behaviour of a structure subject to foundation settlement is analysed plastically using the concept of proportionally increasing settlements. In such analysis, the incremental loads, derived from the increasing settlements, are calculated from the elements where end movements occur. The forces derived in this way are, when taking into account the plasticity state of the element, termed Modified End Actions. The failure criteria are based on the serviceability requirements for which the inelastic rotation capacity is checked for each plastic hinge. The shear effect on the bending moment capacity of each element is also catered for through successive approximation.