This webinar was co-sponsored by ASCE's Structural Engineering Institute and ASCE Continuing Education

Purpose and Background

Evaluation of floor vibration is an essential serviceability check of modern building structures, where imaginative architectural layouts, advances in structural analysis techniques, improvements in construction material, coupled with owners and users demands, lead to longer and thinner spans oftentimes with irregular support layouts. Common human activities, such as foot drop, can result in vibrations in large open space office areas, residential or shopping malls. Such vibrations, where perceived, can be unacceptable. Hospitals and certain laboratories are likely to be subject to more strict levels of vibration.

This webinar starts with a review of the causes of vibration from human activities, perception of vibration by the occupants, and the level of acceptance of vibration for different occupancies. The discussion is followed by methods for quantifying the source of vibration, the characteristics of a floor system for transmission of vibrational impulse, estimate of a floor’s response and the assessment of its acceptability. Different procedures for estimating the vibration response of concrete floors will be presented next. Starting from a simple and approximate method for a quick and rough assessment, the presentation progressively moves to the introduction of rigorous, yet practical procedures intended for design engineers in evaluation of vibration characteristics of concrete floors. The review extends to allowance for crack formation under service condition and its impact on vibration response. Numerical examples that follow each procedure introduced clarify the application and the level of approximation.

The presentation also covers the application software for the vibration assessment of concrete floors and to vibration of post-tensioned slabs, where applicable.

Learning Outcomes

Webinar Benefits

• Learn to quantify the source of vibration of concrete floors, the threshold for perception of vibration by occupants, and the level of its acceptability for residential buildings, offices and hospitals
• Find out about the available practical procedures and tools in estimating the vibration of a concrete floor system
• Through numerical examples offered, develop the skill of making a quick assessment of vulnerability of a concrete floor to vibrations, warranting a more detailed analysis
• Become familiar with the critical characteristics of a concrete floor that govern its vibrational response, and the means to control and dampen the effects
• Observe the application of a software specifically tailored for vibration assessment of concrete floor systems, and attain an overview of the spectrum of available means for vibration evaluation
• Understand the impact of cracks in conventionally reinforced concrete on their vibration response
• Discover the impact of post-tensioning on vibration of concrete floors

Assessment of Learning Outcomes

Students' achievement of the learning outcomes will be assessed via a short post-assessment (true-false, multiple choice and fill in the blank questions).

Intended Audience

Structural engineers, building officials, plan checkers, and students engaged in vibration evaluation of conventionally reinforced or post-tensioned floor systems, who are seeking to learn about practical procedures for estimating floor vibrations and its acceptance for specific applications will benefit from this webinar.

Webinar Outline

• Causes of vibration, with emphasis on foot drop and human activities
• Perception of vibration, threshold and limits of its acceptance
• Quantification of foot drop in different floor types and layout
• Floor system properties critical in intensity and transmission of vibration
• Methods of estimating the vibration response of given floors
• Current approximate and detailed tools and procedures for estimating the vibration response of a concrete floor
• Numerical examples for vibration evaluation of actual floor systems