scope:

The VDI 2038 series of guidelines is concerned with loads which are time-dependent and thus can lead to vibrations in structures and thereby cause problems in buildings, components, machines and equipment or result in annoyance to individuals, either directly or - in the case of individuals and items of equipment - indirectly via secondary airborne sound. However only those loads relevant to serviceability will be treated explicitly.

Section 5 of the present guideline first sets out a systematic exposition of the methods and procedures used in structural dynamics. Here there is also a detailed treatment of the question whether a structural dynamics engineer should be involved in a building construction project, during which phase of the project this should take place and which individual amongst those involved in the project should have the responsibility for this (Section 5.1 to Section 5.3). This aspect is of importance to architects, project managers and general contractors and where applicable also to other individuals with responsibilities in the project. This is because the structural dynamics engineer, in contrast to other specialist engineers (such as those involved in structural design, soil engineering architectural acoustics, thermal building physics), is often not yet firmly embedded as a planning team member in the consciousness of the other individuals involved. In many cases the need for this involvement becomes apparent when it is already too late and, due to vibration problems or secondary airborne sound, serviceability impairments of a greater or lesser severity have emerged which in some cases can only be corrected with considerable effort or even not at all. Timely involvement of the structural dynamics engineer is useful here in reducing or preventing technical problems. At the same time, taking structural dynamics criteria into consideration even at the contract formulation stage will ensure a greater degree of confidence regarding the legal situation.

In Section 6 an overview is given addressing all of the principle dynamic loads and identifying those to be dealt with in concrete terms later on. These are described individually in Section 7 and where possible presented both numerically and as formulae.

The guideline will not be concerned with questions relating to primary airborne sound or to footfall insulation in other words, architectural acoustics. Neither will the guideline deal with questions relating to industrial health and safety relevant to operating or working close to high-vibration machines. In this regard see guidelines VDI 2057 and ISO 2631.

The frequency range to be examined in the present guideline in the case of mechanical vibrations is restricted in most cases to the range up to 315Hz. The upper limit is as a rule considerably lower.

Basically the same shock and vibration topics are covered in ISO 10137. Here vibrations are evaluated exclusively on the basis of accelerations, in contrast to the evaluative approach usual in central Europe which uses weighted vibration velocities. There is also an overlap with DIN 4150-2, which, in a very detailed approach, makes it possible to evaluate the effect of vibrations on individuals in dwellings with the aid of weighted vibration velocities, the KB values. Since a decision in favour of velocities or accelerations as an evaluative criterion is not currently to be expected, the VDI 2038 series of guidelines will use both possibilities where this makes sense. The advantage of using vibration velocity is that not only human perception but also stress in structures is primarily proportional to vibration velocity and that the transition to vibration displacement or vibratory acceleration in each case only requires a single integration or differentiation.