Search

Paperboard tubes have been used in building construction as formwork for concrete columns for over 60 years. Paperboard tubes, typically produced for the sheet or fiber material converting industries, have been used in a number of unique and often prototype architectural and structural engineering application since the late 1980s. This chapter reviews recent developments in paperboard tubes for the construction industry and provides guidance on the analysis and design of paperboard tubes for use in load-bearing architectural and structural engineering applications. Structural system selection, the analysis and design procedures for column, beam, truss, and arch members and connection elements are provided. To provide background, an overview of typical dimensions and uses of paperboard tubes in industrial, construction, and structural applications is provided. The manufacturing technology used to produce tubes is described, and the nonlinear viscoelastic mechanics of paperboard and paperboard tubes are discussed. Special attention is paid to the effect of moisture and temperature on the short- and long-term properties of the paperboard and the tubes.

A novel method for the analysis of frames constructed of thin-walled members of anisotropic composite materials is presented in this paper. The method accounts for non-isotropic coupling effects that exist in composite material beams due to the anisotropy of the composite material laminates that form the thin-walled cross-section. The method also accounts for warping effects known to be significant in thin-walled members. The analysis is performed by the direct stiffness matrix method utilizing a new approach that divides each thin-walled member of the frame into one-dimensional warping-beam superelements and non-warping conventional beam elements. The element stiffness matrices for these two one-dimensional beam elements are obtained by a numerical procedure that is based on the classical force method of analysis. The stiffness matrices of both beam elements are 12 × 12 matrices corresponding to the six degrees of freedom per node required for conventional space frame analysis. The remarkable feature of this representation is that warping is accounted for without introducing additional degrees of freedom to account for the bimoment and warping twist in the members. This is accomplished by use of the warping-beam superelement that linearizes the regions of non-uniform torsion in the thin-walled beam. Examples of space frame structures constructed of thin-walled composite material I-beams are presented to demonstrate the method. Results of analyses using the proposed method are compared with those obtained from two-dimensional finite element models.

The physical and mechanical properties of polymer matrix composite materials, often referred to as fiber-reinforced plastic or fiber-reinforced polymer (FRP) materials, are discussed in this chapter. These properties are discussed with an emphasis on the potential uses of composite materials as reinforcements for concrete. The term FRP reinforcements is used to describe the composite material products developed for this purpose. Properties of composite materials that are likely to be significant for FRP reinforcements are identified. The influence of the properties of the constituents, viz , the fibers, resins, fillers and additives, on the properties of FRP reinforcements is discussed. Emphasis is placed on issues of heterogeneity and anisotropy of composite materials and how they can be expected to affect the properties FRP reinforcements.