Floating Floor.pdf
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Transcript of Floating Floor.pdf
Kinetics™
Fiberglass Isolators
Model KIP
Features
• Inorganic fiberglass media
• Flexible elastomeric coating
• Constant natural frequency in wide load range
• Permanent and predictable resiliency
• Predictable dynamic response
• High-energy dissipation
• Controlled viscous damping
• Load capacities 1 PSI to 500 PSI (0.07 to 35 kg per sq. cm.)
Application
Kinetics Model KIP fiberglass isolators can be applied in a wide range of noise, shock, and vibration
isolation uses, and are recommended whenever predictable dynamic response and permanent load
support characteristics are important.
Typical noise isolation applications include the use of Model KIP fiberglass isolators integrated into
Model RIM and Model FC to create high STC and IIC floating floors.
Typical shock isolation applications include the use of Model KIP fiberglass isolators as support
mounts for punch presses, metal shears, and similar industrial process machinery.
Typical vibration isolation applications include the use of Model KIP fiberglass isolators as support
mounts for high speed fans, pumps, and chillers, on grade, having operating speeds of 1750 RPM and
higher.
Model KIP fiberglass isolators are available in a wide range of standard and special mount
configurations for various load ranges, natural frequencies, and other support characteristics.
Description
Model KIP fiberglass noise, shock, and vibration isolators are superior to all pad-type isolation media
developed to date. Uniquely permanent and dynamically predictable, due to precise manufacturing
methods using inorganic materials, this isolation media provides freedom of design and use
unprecedented by any other material.
Model KIP isolator is a high-density matrix of compressed molded fiberglass; individually coated with
a flexible, moisture-impervious elastomeric membrane, designed to allow controlled air movement in
the fiber media. The pumping action of air between fibers provides viscous damping, reducing motion
caused by transient shock and vibration.
A range of densities and spring rates are available to provide load-bearing capacities from 1 to 500
PSI (0.07 to 35 kg per sq. cm). The annealed fiberglass of the isolation media is produced by a
multiple flame attenuation process which generates fibers having a modulus of elasticity of 10.5
million PSI (738,223 kg/sq. cm) and nominal fiber diameters of less than .00027 inches (6.8 microns).
The matrix of glass leaf springs is bonded at all fiber intersections with a water-resistant binder
during the molding process, under controlled heat and pressure. The material is then stabilized by ten
(10) precompression cycles to three (3) times the maximum published load capacity for the media.
Model KIP fiberglass isolators uniquely allow a wide range of loading on a given isolator while
maintaining a constant natural frequency. Natural frequency of Model KIP fiberglass media is
controlled by isolator thickness rather than static deflection as with linear steel springs. To determine
the natural frequency for other than 1" (25 mm) isolator thickness, the 1" (25 mm) thick isolator
natural frequency is divided by the square root of the actual thickness to be used, i.e. the natural
frequency of a 4" (102 mm) thick isolator is one-half the natural frequency of a 1" (25 mm) isolator at
the same load for the same density material.
Model KIP fiberglass is unique as a structural support in that applied loads are substantially below
precompression loads thus providing 300% or more overload safety factor. The result is permanent
resiliency with constant natural frequency.
Model KIP fiberglass is non-corrosive, non-combustible, non-absorbent, and resists rust, ozone,
mildew and fungus. It is vermin proof, will not shrink, swell, or decompose. Isolation characteristics of
the media are constant over a temperature range of -40°F to 250°F (40°C to 121°C).
Room-within-a-Room / Floating Floors
GERB Spring Elements for Low-Frequency Floating Floor and Room-in-Room Structures
Range of Application
Floating floor and room-in-room structures represent the state-of-the-art in efficiently reducing the
transmission of vibration and structure-borne noise within buildings. They are mainly used to
decouple sensitive performance centres like TV, broadcasting or recording studios, recital and
rehearsal rooms, theatres as well as gymnasia, but also discotheques and HVAC areas dynamically
and acoustically from the surrounding structure. Special applications of floating slabs can be, for
example, helicopter landing pads and seismic slabs for sensitive equipment in power stations.
For several decades GERB has been developing and supplying spring elements for floating floor and
room-in-room structures based on helical coil springs. They guarantee highest attenuation values by
extremely low system natural frequencies. Designed to achieve system eigenfrequencies of 2.5 to 7
Hz, GERB spring elements represent the most efficient solution to protect highly sensitive areas safely
and permanently from mechanical vibration as well as structure-borne noise. The low system
frequency as well as the ability of easy adjustments make them far superior to any elastic pad
material like rubber, cork or cellular foam.
Embedded Spring Elements type PF
The PF type floating floor spring element system (European Patent No. 0610634 dated 13.01.1999)
offers the following features:
• A range of different springs is available to provide system natural frequencies as low as 2.5 to
7 Hz. The choice depends on the respective requirements in terms of vibration attenuation,
slab stability, and function.
• The springs are accessible from above making subsequent levelling of the floating slab as
well as the replacement of springs with springs of other load capacities possible.
• In order to achieve uniform spring deflections, elements of different type and loading
capacity can be combined in a system layout to allow for irregular slab loadings.
• Slab construction and the installation of the springs is very simple. Apart from a bond-
breaking plastic layer, there is usually no need for bottom formwork. The slab is lifted directly
from the substructure after the concrete has reached its design strength.
• The elements can be equipped with a damping system in order to stabilize the floating slab
and to further improve the attenuation capacity at higher frequencies.
• The jack-up and adjustment facilities are an integral part of every element.
• Low construction height, from just 125 mm slab thickness (plus air gap).
• In addition, acoustic pads arranged below the steel springs can provide a further
improvement in the audible range.
Fig. 1: Type PF spring element, cross section
The thickness of the floating slab is usually established based on the structural requirements, the load
conditions, and the intended use. However, a minimal slab thickness H given in the table below is
necessary. The air gap between the floating slab and the substructure should have a minimum depth
of 30 to 40 mm to ensure that the air spring effect will have no noticeable influence on the vertical
system natural frequency. In special cases, usually on demand of the acoustics consultant, a gap of
100 mm or more is also possible. In order to further improve the attenuation of structure-borne
noise, a suitable acoustic layer can additionally be arranged within the air gap.
Selecting elements
In order to meet the requirements of a wide range of applications, GERB has developed a series of
elements based on the standard types PF1 - PF4. The elements come with height-adjustment as
standard, and can be equipped with a damping system.
Fig. Table: Properties of each basic type of PF element equipped with the respective standard springs.
Elements with other properties are available on request.
Arrangement of Spring Elements
The slab thickness needs to be chosen to suit the dynamic and static requirements, according to the
intended use of the structure. In order to achieve the optimum spring element arrangement, all
permanent loads including wall and ceiling loads must be known at design stage. The expected actual
live loads need to be estimated as precisely as possible, areas of high load concentrations must be
known as well as those where no spring elements can be placed.
Fig. 2: Example of a spring arrangement plan
Larger slabs and especially slabs with a non-rectangular shape, e.g. as regularly used for recording
studios, usually require detailed calculations.
Fig. 3: Arrangement of type PF spring elements underneath a heavy wall of a room-in-room structure
The reinforcement of the concrete slab may be determined by the contractor or a structural engineer
on the basis of the spring element arrangement plan.
Elements Type K and F
Spring elements type K and F are simply arranged between the isolated and the non-isolated
structure. Their height usually determines the acoustic gap below the floating slab. These low-cost
elements have no provision for later adjustment, the final load distribution therefore has to be
precisely known at design stage already. They offer the following features:
• System natural frequencies as low as 2.5 to 7 Hz provided by a range of different
types of springs. The choice depends on the respective requirements in terms of
vibration attenuation and slab stability.
• The elements can be equipped with a damping system in order to stabilize the
floating slab and to improve the attenuation capacity at higher frequency levels.
Fig. 4: Type K elements
Fig. 5: Type K elements with metal deck floor
Fig. 6: Type F elements
Elements Type GP and GPNV
Spring elements type GP and GPNV are designed for high, concentrated loads. They are placed
underneath the isolated structure, and have to be accessible for initial adjustment after installation.
They feature:
• System natural frequencies between 3.5 and 7 Hz.
• The spring elements can be adjusted for precise levelling of the floating slab as
well as replaced with spring elements of other load capacities.
• The elements are equipped with the GERB Coil Resonance Damping System as
standard, ensuring improved attenuation capacity at higher frequency levels.
• High load bearing capacity makes them an ideal choice for heavy room-in-room
solutions, heliports, etc.
Fig. 7: GPNV elements supporting TV production studio (showing temporary struts during
construction)
Fig. 8: Spring elements in a helipad structure
Fig. 9: Arrangement of spring elements underneath TV studio
Scope of GERB Services
• Consultation with GERB expert engineers
• Vibration measurements and surveys
• Selection and arrangement of spring elements, in consultation with the architect and
structural engineer
• Preparation of layout drawings
• Design, manufacture and supply of spring elements and accessories
• (adjustment shims, adhesive pads, etc.)
• Complete installation or just supervision
• Inspections