Measurement and Monitoring of Building Vibrations from External and Internal Sources
Ground-borne vibrations can have detrimental effects on building components and finishes, building contents, and cause annoyance to occupants. Vibrations could originate from external sources such as nearby construction, highway traffic, train induced vibrations, and ground motions; or internal sources due to occupants activities on flexible floors, fitness centers, exercise spaces, or internal construction. Several national and international standards are available with recommended thresholds to limit vibration induced damage to buildings (e.g., USBM RI-8507 and the German DIN 4150). Special vibration limits are also available for buildings with special uses, such as laboratory spaces, hospitals, or museums and artwork. This presentation provides case studies on how to measure, analyze, and monitor vibrations in buildings with the purpose of limiting vibration induced damage to the building(s) or its contents.
Speakers: Nathaniel Rende and Mohamed ElBatanouny, WJE
- Potential damaging effects of ground-borne vibrations on existing buildings and its components.
- Vibration limits and thresholds for different types of buildings and uses
- Monitoring and data analysis techniques for vibrations in existing buildings
Vibration Considerations for Building Design
This seminar provides an overview of the basics of vibration, and how it causes a structure to react. Vibration criteria for human comfort and ever‐improving, sensitive equipment are discussed. The means by which vibration sources are identified in the field are presented, and whether a site can be made suitable for its intended use is discussed. Methods of isolating mechanical equipment are summarized, with several examples illustrated. Basic and advanced methods of predicting footfall‐induced vibrations are shown, highlighting the advantages and limitations of each. Tuned mass dampers are discussed, highlighting their value as an alternative to traditional methods of floor‐stiffening to control vibration.
Speaker: Melissa Wong, Thornton Tomasetti
- Develop an understanding of how vibration caused by external and internal sources affects a building
- Learn which classifications of vibration criteria are appropriate for given occupancies, and how they alone can drive the architectural and structural design of a building in certain cases
- Become aware of evolving tools that are used to predict footfall‐induced vibrations in a building, and the mitigation options available to control them.
Wind-induced Vibrations in Structures: Mechanisms and Design Considerations
Lateral loads due to wind can often control the design of structures. For more rigid structures, the dominant wind load is often in the direction of the wind (generally referred to as a drag-based response). However, for more flexible or unique structures, fluctuations of the wind load perpendicular to the direction of the wind can often control and be greater than code-based estimates for the drag-based response. This mechanism of wind loading may exist at design level or below and can often be unforeseen at the design stage. This presentation reviews the underlying mechanisms which can result in vibration of structures, develops these in the context of aerodynamics and structural dynamics, and discusses approaches for consideration of wind-induced vibration in design. Various structure types are used to illustrate these concepts throughout the presentation, each with differing criteria and industry guidance for recommended limits of vibration.
Speaker: Tom Mara, CPP Wind Engineering Consultants, Inc.
- Develop an understanding of vibration from the context of wind-structure interaction
- Understand the interaction between design loads and service loads from a wind loading perspective
- Learn about approaches to identify susceptibility of structures to wind-induced vibration and strategies for mitigation should they be expected