Experimental Analysis of Space Trusses Using Spacers of Concrete with Steel Fiber and Sisal Fiber.

Cleirton A S Freitas,Ramon Silva,Welington V Silva,Jorge Bonilla,Luciano M Bezerra

doi:10.3390/ma13102305

Cleirton A S Freitas, Ramon Silva + Show 3 more

Open Access

https://doi.org/10.3390/ma13102305

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Abstract

Space trusses are structural systems, generally made of tubes, used worldwide because of their advantages in covering long-span roofs. In addition to having a low cost, the truss weight is relatively reduced. The load capacity of these structures depends also on the strength of their node connection. Connections made with the superposition of flattened tube ends trespassed by one bolt are, generally, known as typical nodes. They are inexpensive but present eccentricities that reduce significantly the strength of such space trusses. To increase the truss load capacity, this research presents the results of an experimental program to reduce the eccentricities of the typical nodes. This reduction is done with a new type of spacer made of encapsulated concrete with steel fiber or sisal fiber. The experimental tests showed that the trusses with typical nodes collapsed under reduced load by local failure due to high distortions at the nodes. The trusses with encapsulated concrete spacer showed good results, with an increase in collapse load of 36% and failure by buckling bars.

Highlights

Space trusses are three-dimensional (3D) reticulate systems used worldwide because of their advantages in covering large, free spaces
The results showed that typical connection without spacers presented the largest local distortions and deformation, too
Connections made with the superposition of flattened tube ends trespassed by one bolt are known as typical connections or typical nodes

Summary

Introduction

Space trusses are three-dimensional (3D) reticulate systems used worldwide because of their advantages in covering large, free spaces. In addition to having low cost, the weight itself is relatively reduced. Space trusses are versatile in a range of applications, from small ornamental marquees, the cover of warehouses, gymnasiums, hangars, and shopping centers, to helipads, etc. The natural elements always seek to minimize stress and maximize strength in an efficient way, taking advantage of the load capacity of all members of the body [1,2]. The natural shapes have exceptional stiffness and use minimum materials to obtain the maximum structural advantage. The natural forms act in the direction of the least force [3]

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