Progress 12/01/00 to 05/15/04
Outputs
Molding and testing of small specimens (16 inx16 in panels) with 3/8 in thickness, 8 in wavelength and 1.125 in overall depth were completed on December 2002. A total of 48 panels were made for flexure and concentrated load tests. The results showed good flexural stiffness and strength for the 3/8 in thickness as sub-floor panels. Therefore the same corrugation profile was used to machine a set of full-size 58 in x 108 in aluminum dies, delivered in March 2003. After the dies were installed in the hot press, 3000 lbs of flakes were purchased from GFP Strandwood Corporation to make 52 full-size 4'x 8' corrugated panels between April and June of 2003. Eight types of three-point bending tests, with loading parallel to the strong axis, were performed with six specimens for each test setup. The specimens were tested on simply supported and two-span continuous supports, at 24 in and 32 in span, with and without 15/32 in OSB nail-glued to the corrugated panel as underlayment.
The underlayment was selected based on preliminary testing for punching shear resistance at seams crossing the cavities in the upper surface of the corrugated panels. The adhesive was a typical AFG-01 floor adhesive, used throughout the project. Bending tests were completed on August 2003. The test results indicate that stiffness, rather than strength, is the limiting performance factor for typical residential or light commercial construction. The bending stiffness in the strong direction meets the performance criteria for APA Rated Sturd-I-Floor with a 32 in on-center span rating. This means that the corrugated panel composite system is comparable to standard 7/8 in to 1 in APA Rated Sturd-I-Floor. Upon completion of three-point bending tests, four composite action tee beam specimens were made. These specimens had a 9.5 in I-joist spanning 10 ft with a 24 in wide flange made with the corrugated panel and 15/32 in OSB underlayment system. These composite action specimens were tested
in Oct 2003. The stiffness of the composite sections averaged 1.66 times that of the I-joist. A mock-up floor system was built in March of 2004. Four 9.5 in I-joists, 12 feet long and 32 in on center formed the base of the floor system. The joists were simply supported on concrete blocks set on a heavy concrete slab and had end lateral restraint from 1.25 in thick, parallel strand lumber rim boards. Three 4 ft by 8 ft corrugated panels were nailed and glued to the joists. A 15/32 in OSB underlayment was nailed and glued to the corrugated panels. Blocking, in the form of short pieces of 1x4 lumber was installed at one of the underlayment seams and at one of the floor edges to simulate construction for high concentrated loads and bearing walls. Construction was very easily accomplished. Subjective impressions from a variety of people indicate the floor has very good vibration and deflection characteristics. Finite element modeling of the panels and the partially composite floor system
showed good agreement with experimental results. It will be possible to do analytical investigations of other panel and joist configurations.
Impacts
Corrugated panels have potential advantages in structural and material efficiency in comparison to flat panels. This project has demonstrated that corrugated panels of moderate draw depth and wavelength can be produced with minimal modifications to the current commercial OSB manufacturing process. The panels produced in the study are less than half the weight of a flat panel with similar performance characteristics. Although the panels must have a second layer in the form of underlayment, hardwood flooring, or a light weight concrete topping, it appears that the lighter panels contribute to ease of construction. This is due to the wider joist spacings permitted by the corrugated panels as well as the lighter weight of the floor system components.
Publications
- Pang, W.C. and Sandberg, L.B. 2004 Corrugated composite panels for structural decking. paper presented in Session 7: Advances and Research in Wood Engineering at the 58th annual meeting of the Forest Products Society, Grand Rapids, MI, June 27-30.
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Progress 10/01/02 to 09/30/03
Outputs
Molding and testing of small specimens (16"x16" panels) with 3/8" thickness, 8" wavelength and 11/8" overall depth were completed on December 2002. A total of 48 panels were made for flexure and concentrated load tests. The results showed good flexural stiffness and strength for the 3/8" thickness as sub-floor panels. Therefore the same corrugation profile was used to machine a set of full-size 58"x108" aluminum dies, delivered in March 2003. After the dies were installed in the hot press, 3000 lbs of flakes were purchased from GFP Strandwood Corporation to make 52 full-size 4 ft x8 ft corrugated panels between April and June of 2003. Eight types of three-point bending tests, with stress applied parallel to strength axis, were performed with six specimens for each test setup. The specimens were tested on simply supported and two-span continuous supports both at 24" and 32" span, with and without 15/32" OSB nail-glued to the corrugated panel as underpayment. Bending
tests were completed on August 2003. The test results indicate that the bending stiffness in the strength direction meets APA Rated Sturd-I-Floor with 32" on-center span rating. This corrugated panel composite system is comparable to standard 7/8"and 1" APA Rated Sturd-I-Floor. Upon completion of three-point bending tests, four composite action specimens were made. These specimens consist of a 9.5" I-joist spanning 10 ft with a 24" wide flange consisting of the corrugated panel and 15/32" OSB underlayment system. These composite action specimens will be tested in Oct 2003. A mock-up floor system will be built and evaluated upon completion of the composite action specimen tests.
Impacts
Corrugated panels have potential advantages in structural and material efficiency in comparison to flat panels. In a properly design floor or roof system they can allow the use of fewer, more widely spaced joists or beams.
Publications
- No publications reported this period
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Progress 10/01/01 to 09/30/02
Outputs
Design studies - A look at how a corrugated panel floor system would be integrated into current light frame construction. It appears that this can be done with minimal changes in construction practice. The corrugated panel configuration we have developed has a 3/8 inch thickness, an 8 inch wave length and an overall depth of 1.125 inches. This section will work for typical residential and light commercial load requirements over a joist spacing of 24 inches. Any blocking requirements can be conveniently met with pieces cut from nominal 1 inch lumber. Blocking will be required where the panel is sandwiched between load bearing stud walls to prevent short term or creep induced crushing of the wave form of the panel. Where the underlayment spans the opening in the channel wave form, the punching shear resistance of the underlayment against concentrated loads will be a critical consideration. Blocking may be required at underlayment panel edges over the wave cavities in
the corrugated panel to achieve an efficient underlayment thickness. Blocking might be avoided by using so-called high quality oriented strand board, possibly tongue and grooved, as the underlayment. Analysis - A finite element model of the corrugated panel has been made using the SDRC-IDEAS software package. IDEAS will allow for the modeling of the joist-corrugated panel-underlayment system. Small test panels - A set of molding dies, 18 x 18 inches were machined to study mat molding response and to furnish specimens for preliminary mechanical property testing. When trimmed, the specimens have two full corrugation waves. Not problems were encountered in molding the specimens. Bending strength and stiffness, both parallel and perpendicular to the corrugations, along with shear and bearing strengths of the panels were tested. Stiffness and strength values are within the expected range and indicate good overall performance. Preparations for full size panels - The design of the molding
dies to produce full sized 4 foot x 8 foot panels is complete. We are currently in the process of readying the equipment necessary to produce the full sized panels.
Impacts
The findings should demonstrate the increased efficiency in material utilization of a corrugated panel in comparison to flat panels, leading to better utilization of available wood resources. It should also demonstrate the practicality of adapting current oriented strand board manufacturing equipment and processes to production of corrugated panels.
Publications
- No publications reported this period
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