More Than a Facade

A need for a design and testing standard for partially composite precast concrete insulated wall panels

Overview

Authors

Photo of Edward Losch, PhD, PE, SE, RA

Edward Losch, PhD, PE, SE, RA

Structural Engineer

Losch Engineering

edlosch@gmail.com

Photo of Marc Maguire, PhD

Marc Maguire, PhD

Assistant Professor

University of Nebraska-Lincoln

marc.maguire@unl.edu


Keywords


Abstract

In 2014, the American National Standards Institute (ANSI) approved the Precast/Prestressed Concrete Institute (PCI) as an accredited ANSI Standards Developer. Since then, PCI has partnered with the American Concrete Institute (ACI) to develop and maintain a standard specification for the design, fabrication, and handling of precast and precast/prestressed concrete insulated wall panels. This panel type has been supplanting traditional hard-wall construction for many building types.

A variety of proprietary partially composite wall systems have been developed by industry. These systems use thermally efficient wythe connectors to produce lighter, thinner walls with higher R values and minimal thermal bridging between wythes. The ACI 318 Building Code does not yet specifically cover structural analysis and design procedures for these partially composite concrete members (ACI Committee 318 2014).

To remedy this situation, PCI has funded research to determine the strength characteristics of the various commercially available wythe connector systems. Double-shear push-off tests have been and are being conducted to determine ultimate shear strength, deformation and ductility for each manufacturer's connector type. The resultant values will then be used as input for multiple proposed design and analysis procedures for this product category. If approved, these procedures will be recognized by ANSI and be included in the upcoming PCI/ACI Precast Insulated Wall Panel Design Standard.

Introduction

Precast concrete insulated sandwich wall panels have gained in popularity over the years. Typical applications include schools, gymnasiums, food processing plants, justice facilities and commercial/warehouse buildings. They provide a hard

Members Only

Background

Traditionally, composite wall panels have been fabricated using continuous steel wire trusses for the wythe connectors (Figure 2). Often, solid zones of concrete are also used at the top and

Members Only

Method

Before a standard design method can be implemented, a standard model for the wythe connector properties needs to be developed. While different connector systems may use specialized techniques that may

Members Only

Data

Example connector properties are presented in Figure 13. Clearly, the behaviors of different systems provide different properties. For engineering purposes in the elastic range, the engineer requires elastic stiffness, elastic

Members Only

Explanation

The Beam-Spring Model is intended to be a general-purpose model that can be used for any type of connector, whether truss, bar or plate. While not adopted into any design

Members Only

Conclusion and future work

Partially composite concrete sandwich wall panels are a rapidly growing segment of the market. These panels can be used for cladding or load bearing conditions and create a highly efficient

Members Only

Acknowledgements

Thank you to Fray Pozo-Lora for helping with compiling details for this paper. Special thanks for Taylor Sorensen for the thermal image picture.

Rights and Permissions

ACI Committee 318. 2014. “Building Code Requirements for Structural Concrete (ACI 318M-14), an ACI Standard, and Commentary on Building Code Requirements for Structural Concrete (ACI 318RM-14), an ACI Report.” In , 519. American Concrete Institute.

Al-Rubaye, Salam, Taylor Sorensen, and Marc Maguire. 2017a. “Full Scale Testing of Concrete Sandwich Wall Panels.” In Proceedings of the PCI National Bridge Conference,. Cleveland, OH.

———. 2017b. “Investigating Composite Action at Ultimate for Commercial Sandwich Panel Composite Connectors.” Civil and Environmental Engineering Faculty Publications. Paper 3532. https://digitalcommons.usu.edu/cee_facpub/3532.

Al-Rubaye, Salam, Taylor Sorensen, Jaiden Olsen, and Marc Maguire. 2018. “Evaluating Elastic Behavior for Partially Composite Precast Concrete Sandwich Wall Panels.” PCI Journal 63 (5): 71–88.

Einea, Amin, David C Salmon, Gyula J Fogarasi, Todd D Culp, and Mäher K Tadros. 1991. “State-of the-Art of Precast Concrete Sandwich Panels.” PCI JOURNAL 36 (6): 78–98.

Einea, Amin, David C Salmon, Maher K Tadros, and Todd Culp. 1994. “A New Structurally and Thermally Efficient Precast Sandwich Panel System.” PCI Journal 39 (4).

Frankl, B, G Lucier, S Rizkalla, G Blaszak, and T Harmon. 2008. “Structural Behavior of Insulated Prestressed Concrete Sandwich Panels Reinforced with FRP Grid.” In Proceedings of the Fourth International Conference on FRP Composites in Civil Engineering (CICE2008), Zurich, Switzerland. Vol. 2224. http://www.iifc.org/proceedings/CICE_2008/papers/2.C.2.pdf.

Gombeda, Matthew J, Patrick Trasborg, Clay J Naito, and Spencer E Quiel. 2017. “Simplified Model for Partially-Composite Precast Concrete Insulated Wall Panels Subjected to Lateral Loading.” Engineering Structures 138: 367–80.

Granholm, H. 1949. Om Sammansatta Balkar Och Pelare Med Särskild Hänsyn till Spikade Träkonstruktioner: On Composite Beams and Columns with Particular Regard to Nailed Timber Structures. Chalmers Tekniska Högskola. Elanders boktryckeri aktiebolag.

Holmberg, Ake, and Erik Plem. 1965. Behaviour of Load-Bearing Sandwich-Type Structures. Byggforskningen.

ICC Evaluation Service. 2010. “AC422 Semicontinuous Fiber-Reinforced Grid Connectors Used in Combination with Rigid Insulation in Concrete Sandwich Panel Construction.” Los Angeles, CA. www.icc-es.org.

———. 2015. AC320 Fiber-Reinforced Polymer Composite or Unreinforced Polymer Connectors Anchored in Concrete. Los Angeles, CA: ICC. https://shop.iccsafe.org/es-acceptance-criteria/ac320-fiber-reinforced-polymer-composite-or-unreinforced-polymer-connectors-anchored-in-concrete-approved-oct-2015-editorially-revised-sept-2017-pdf-download.html.

Losch, Edward D, Patrick W Hynes, Ray Andrews Jr, Ryan Browning, Paul Cardone, Ravi Devalapura, Rex Donahey, Sidney Freedman, Harry A Gleich, and Gerald Goettsche. 2011. “State of the Art of Precast/Prestressed Concrete Sandwich Wall Panels.” PCI Journal 56 (2): 131–76.

Losch, Edward D. 2005. "Precast/Prestessed Concrete Sandwich Walls: Information for the Structural Engineer." Structure Magazine. April 2005: 16-20. https://www.structuremag.org/wp-content/uploads/2014/09/C-Building-Blocks-April-051.pdf.

Naito, Clay J, John M Hoemann, Jonathon S Shull, Aaron Saucier, Hani A Salim, Bryan T Bewick, and Michael I Hammons. 2011. “Precast/Prestressed Concrete Experiments Performance on Non-Load Bearing Sandwich Wall Panels.” BLACK AND VEATCH OVERLAND PARK KS.

Newmark, Nathan M. 1951. “Test and Analysis of Composite Beams with Incomplete Interaction.” Proceedings of Society for Experimental Stress Analysis 9 (1): 75–92.

Olsen, Jaiden, Salam Al-Rubaye, Taylor Sorensen, and Marc Maguire. 2017. “Developing a General Methodology for Evaluating Composite Action in Insulated Wall Panels.” Report to PCI. Chicago, IL: Precast/Prestressed Concrete Institute. https://digitalcommons.usu.edu/cee_facpub/3531.

Pessiki, Stephen, and Alexandar Mlynarczyk. 2003. “Experimental Evaluation of the Composite Behavior of Precast Concrete Sandwich Wall Panels.” PCI Journal 48 (2): 54–71.

Sorensen, T., S. Dorafshan, and M. Maguire. 2017. “Investigating Thermal Efficiency of In Service Concrete Sandwich Wall Panels.” In ASCE Congress on Technical Advancement. Duluth, MN.

Sorensen, Taylor, Sattar Dorafshan, and Marc Maguire. 2018. “Matrix Model Accuracy of Partially Composite Concrete Sandwich Panels.” In Proceedings of the PCI National Bridge Conference. Denver, CO.

Sorensen, Taylor, Sattar Dorafshan, Marc Maguire, and Robert J Thomas. 2019. “Thermal Bridging in Concrete Sandwich Walls.” Concrete International 40 (10).

Tomlinson, Douglas, and Amir Fam. 2015. “Flexural Behavior of Precast Concrete Sandwich Wall Panels with Basalt FRP and Steel Reinforcement.” PCI Journal. https://doi.org/10.15554/pcij.11012015.51.71.