We provide specialist consultancy related to wind-induced vibrations of building, bridges and other slender structures. We can assist with the creation of a dynamic design basis, determination of modal properties (frequencies, mode shapes and damping), determine the sensitivity to wind-induced vibrations, assist with wind-tunnel testing and numerical calculations of dynamic response and fatigue from vortex shedding. Our experts can assist with design of vibration mitigation devices such as Tuned Mass Dampers (TMD), Tuned Liquid Dampers (TLD) and viscous dampers.

Machine-induced vibrations are characterized by continuous (steady-state) vibrations at one or many frequencies. For larger machines such as steam turbines, diesel turbines and electrical generators, large dynamic loads. At the same time, the allowable vibrations magnitudes at the machine bearing points are small to ensure smooth operation. At KI, we provide dynamic calculations and design of new foundations and structures which are subject to machine-induced vibrations, including verification of the allowable vibration amplitudes and design of bearings, dampers and base isolation. Our experts assist with the assessment of existing structures – both in the form of calculations, simulations and field measurements.

Human-induced loads occur from rythmic movement of people such as walking, joggin, running, dansing, bouncing and jumping. The loads are periodic with a fundamental frequency equal to the frequency of the activity. Structures which are designed for human occupancy must be secured against human-induced vibrations, either to ensure adequate comfort (ref. DK NA to EN 1990), to ensure safe operation of sensitive equipment and machinery or to avoid preamature failur, fatigue or collaps of e.g. granstands and balconies. We have leading experts within footfall-induced vibrations of buildings and bridges and we are ready to assist in all aspect of the design and to ensure that your structures fulfils all regulatory requirements and it is fit for purpose.

Read more about human-induced vibrations her (Danish)

KI has leading experts within all aspects of human-induced vibrations of footbridges. We offer analyses of the natural frequencies, mode shapes and damping of footbridges (new or existing), we provide the dynamic design basis, response calculations and design and verifications in accordance with the most recent codes and guidelines.

All response calculations are based on KI’s in-house Monte Carlo simulation program for modelling of walking and running individuals and crowds. In addition, KI offers the design of Tuned Mass Dampers (TMD) where deemed applicable.

Tuned mass dampers (TMD) are frequently used to supress vibrations of slender structures such as footbridges, chimneys, grandstands, long-span floors etc. TMDs can be implemented in the design of new structures or used as a retrofit on existing structures that suffer from vibration problems. At KI, we provide the full-scope services related to design, fabrication, installation and commissioning of TMDs.

Often vibration measurements are used to calibrate and verify calculation models or to determine the naturla frequencies and mode shapes of a structure. In other cases, the measurements are used directly to verify the vibrations against codified requirements.

At KI, we can assist through the entire measurement proces, from initial diagnostics to analyses, field measurements and post-processing and interpretation of the measured data. Additionally, KI offers complete structural health monitoring systems (SHMS) – read more here [SHMS].

Read more about our monitoring services.

Throughout the years, KI has worked with many different systems for vibration measurements and data analysis. We have gathered our best experiences and developed our own hardware series consisting of accelerometers (KI-Tau), Inclinometers and data loggers (KI-Pion), which are directly connected to our own cloud-based monitoring platform, Senmos. With this system, we have successfully created a complete monitoring system, which is tailor-made for civil- structural applications, both in terms of frequency range, sensitivity, noise and weather resistance. The system is suited for short-term measurements as well as long-term monitoring of structures.