Silva Welington V, Silva Ramon, Bezerra Luciano M, Freitas Cleirton A S, Bonilla Jorge
Department of Civil and Environmental Engineering, Darcy Ribeiro Campus, University of Brasília, SG12 Building, Brasilia 70910-900, Brazil.
Department of Civil Engineering, Federal University of Cariri - UFCA, Av. Tenente Raimundo Rocha S/N, Juazeiro do Norte, Ceará 63048-080, Brazil.
Materials (Basel). 2020 May 16;13(10):2305. doi: 10.3390/ma13102305.
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.
空间桁架是一种结构体系，通常由管材制成，因其在覆盖大跨度屋顶方面的优势而在全球范围内得到应用。除了成本低之外，桁架重量也相对减轻。这些结构的承载能力还取决于其节点连接的强度。由一个螺栓穿过扁平管端叠加而成的连接通常被称为典型节点。它们价格低廉，但存在偏心，会显著降低此类空间桁架的强度。为了提高桁架的承载能力，本研究展示了一个旨在减少典型节点偏心的试验项目的结果。这种减少是通过一种新型的由钢纤维或剑麻纤维包裹混凝土制成的垫片来实现的。试验测试表明，带有典型节点的桁架由于节点处的高变形而在局部破坏的情况下在较低荷载下倒塌。带有包裹混凝土垫片的桁架表现出良好的效果，其倒塌荷载增加了36%，并且是由于杆件屈曲而破坏。
