Predicting Human Induced Vibration with GSA Footfall
Today’s Team Peter Debney Application Specialist Nigel Rees Sales Manager
Today’s Team Peter Debney Application Specialist Rhys Lewis Consultant
1. Viewer Window 2. Control Panel Oasys Software : GSA Footfall If you cannot hear, please check this setting GoToWebinar Attendee Interface
Agenda Product Demonstration GSA Questions and Answers NB: this webinar is designed as an introduction to GSA and footfall and is designed to provide an overview.
Who is Oasys? Wholly owned by Arup Formed in 1976 to develop software for in-house and external use Most developers are engineers who have moved to programming In recent years have added marketing and sales staff Since 2003 have expanded the development team worldwide Wide network of resellers and channel partners
Oasys Customers
Structural Geotechnical CAD Document Management Sustainability Crowd simulation
The Problem Vibration
The effects of vibration Structural Damage Inelastic response – overload Fatigue Discomfort Bouncy floors and stairs Wind-induced sway of buildings Ride comfort Noise Machine operation Machine operability High precision manufacturing facilities Medical facilities Laboratories
The effects of vibration Structural Damage Inelastic response – overload Fatigue Discomfort Bouncy floors and stairs Wind-induced sway of buildings Ride comfort Noise Machine operation Machine operability High precision manufacturing facilities Medical facilities Laboratories
What is Footfall? Human induced vibration
What is Footfall?
What is Footfall? Vibration (a)A bridge as a simply supported beam (b) The first mode of vibration (c) The displacement of mid-span after someone jumps once at mid-span
What is Footfall? Vibration
What is Footfall? Vibration
Results Velocities and Accelerations f = 1 / T ω = 2 π f x = X sin ωt v = Xω cos ωt a = -Xω 2 sin ωt
Results What is R? BS 6472 base curve for human perception
Modal mass F = ma a = F/m
Resonance 1 st harmonic
Resonance 2 nd harmonic
Resonance 3 rd harmonic
Resonance 4 th harmonic
Walking speeds – floors
Walking speeds – Stairs
Damping
Resonance and Damping Dynamic amplification under harmonic (single frequency) loading 1 - static excitation too fast for any significant response resonance
Resonance and Damping Dynamic amplification with multiple harmonics
Resonance and Damping Dynamic amplification with multiple harmonics
Transient Response – Impulse loading
Footfall Design Guides
Footfall - Simple Method f 0 = 18 / √δ
Footfall - FEA Method
Footfall - FEA Method
The Solution
Any Questions?
Contact Details Peter Debney – Nigel Rees – Next Webinars August 15 th : Raft and Soil-Structure Interaction September 19 th : Concrete Design Webinar has now Ended