Design Provisions and Test Methods for Architectural Glass

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April 2011
Seismic Design Provisions
Seismic Test Methods
Conclusion
References
About Architectural Testing
Authors
Design Provisions and Test
Methods for Architectural Glass
Subjected to Seismic Induced
Building Movements
Other Links
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The reference standards of the current building codes require the
relative seismic displacement at glass fallout (∆fallout) of an
individual glass panel be greater than the actual relative seismic
displacement of the panel. Exceptions to this requirement are
granted for:
ATI Locations
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Glass with sufficient glass-to-frame clearances to
accommodate seismic displacement;
Fully tempered monolithic glass less than 10 feet above
walking surfaces and;
Single thickness laminated glass that is fully captured and
wet glazed.
Where the exceptions cannot be applied, the glass fallout shall be
determined in accordance with AAMA 501.6 or through
engineering analysis.
Photo No. 1 Horizontal Racking
Displacement using Hydraulic
Actuator.
Both test methods are routinely specified by architects. AAMA
501.4-09 is a static racking test method concerned with the
serviceability of curtain wall and storefront glazing systems
following a seismic event. This method requires companion air
infiltration, water penetration and static load tests which typically
require a chambered mockup. Thus, this testing is normally done
in conjunction with a full air/water/structural performance mockup.
AAMA 501.4 includes the following testing sequence:
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Photo No. 2 Dynamic Testing
Apparatus.
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Baseline air leakage (ASTM E 283-91, Standard Test
Method for Determining the Rate of Air Leakage Through
Exterior Windows, Curtain Walls, and Doors Under
Specified Pressure Differences Across the Specimen)
Static water resistance (ASTM E 331-00, Standard Test
Method for Water Penetration of Exterior Windows,
Skylights, Doors, and Curtain Walls by Uniform Static Air
Pressure Difference)
Structural performance at design wind pressure (ASTM E
330-02, Standard Test Method for Structural Performance
of Exterior Windows, Doors, Skylights and Curtain Walls by
Uniform Static Air Pressure Difference)
Static horizontal racking displacement of design-specific
value or default value of 0.01 x story height is applied with
hydraulic actuators (see Photo No. 1)
Repeat air leakage, static water resistance and structural
performance
Static horizontal racking displacement of 1.5x design
value.
AAMA 501.6-09, is a dynamic racking test method focusing on
the seismic safety of architectural glass components within
curtain wall and storefront wall systems. This test involves
mounting individual, fully glazed wall panel specimens on a
dynamic racking test apparatus (see Photo No. 2). The upper
anchorage points move back and forth in sinusoidal motions at
progressively higher racking amplitudes, as in a musical
crescendo (see Figure 1). The bottom anchorage points remain
fixed, thereby imparting a dynamic, in-plane story drift on the test
specimen.
Figure 1 Displacement History of
Dynamic Racking Test (From AAMA
501.6 with permission).
Dynamic racking frequencies are 0.8 Hz at lower racking
amplitudes (< ±75 mm [3 in.]) and 0.4 Hz at higher racking
amplitudes (> ±75 mm). The amplitude at which glass fallout is
first observed for a given specimen is designated as ∆fallout for
that test specimen. The lowest value of racking displacement
causing glass fallout for three replicate specimens tested in
accordance with AAMA 501.6 is the reported value of ∆fallout for
that particular wall system glazing configuration. This value of
∆fallout must be greater than the actual relative seismic
displacement of the panel for the specific project under
consideration.
Developed within the National Earthquake Hazards Reduction Program NEHRP, seismic design provisions for
architectural glass were adopted in ASCE 7 and are now constituents of all major building codes. These
provisions make reference to a specialized laboratory test method developed and published by AAMA.
Together, the design provisions and laboratory test methods are intended to improve the life-safety
performance of architectural glass components in earthquake-prone regions.
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AAMA 501.6-09, Recommended Dynamic Test Method for Determining the Seismic Drift Causing
Glass Fallout from a Wall System.
ASCE 7-05, Minimum Design Loads for Buildings and Other Structures.
2009 International Building Code.
Architectural Testing continues to search for new ways to diversify our business using our broad capabilities
and talented staff. Should you require any of our services or know of other unique opportunities where you can
utilize our expertise, please don't hesitate to contact us.
Travis Hoover
Program Manager of Structural
Systems Testing
Joseph Reed
PE Director of Engineering
Mr. Travis Hoover has continual engineering experience since joining Architectural Testing in 1997. He
oversees all AAMA 501.6 testing at Architectural Testing. He has Bachelor of Science in Mechanical
Engineering Technology from The Pennsylvania State University. thoover@archtest.com
Mr. Joseph Reed has continual engineering experience since 1988 and joined Architectural Testing in 2002.
He is a Professional Engineer licensed in seven states. He has Master of Science in Civil Engineering from
Lehigh University. jreed@archtest.com
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