Experimental Investigation of Topology-Optimized Deep Reinforced Concrete Beams with Reduced Concrete Volume

Abstract

This paper presents an experimental investigation of digitally manufactured, reinforced concrete beams designed with topology optimization. The backbone of the current work is a hybrid mesh topology optimization algorithm that automatically generates strut-and-tie layouts. The resulting designs have tensile truss elements describing the reinforcing phase and compressive continuum force flow elements that illustrates how the concrete is carrying load. The aim of this work is to investigate the effect of removing a percentage of the non-load carrying concrete phase. A beam is designed with a standard, by-hand approach and the same steel amount is used in to generate a topology-optimized design. This work considers three beam designs; (i) the standard, (ii) a topology-optimized beam with a prismatic section (i.e. 100% concrete), and (iii) the topology-optimized steel layout in a beam with a reduced concrete volume (herein 75%). An alternative reinforcement method is used in which steel plates are cut by waterjet. To improve the bond quality between concrete and reinforcement, corrugations and anchors are added to the steel layouts. However, as opposed to previous experimental tests conducted by the authors, a poor bond quality is achieved, leading to premature failures of all test specimens. Due to the lack of proper bonding, comparison can only be made in the early elastic range. Here, a significant trend is that the by-hand and the topology-optimized specimens with 75% concrete exhibit near identical behaviors.

3D Printed Formwork for Concrete: State-of-the-Art, Opportunities, Challenges, and Applications

“…92 The opportunities and challenges of waterjet cut steel reinforcement have also been investigated in a series of small prototypes for topologyoptimized concrete elements. 93 Finally, metal 3D printing processes, such as wire arc additive manufacturing, can be used for the fabrication of steel structures. 94 This is the process that is most closely related to 3DPF and promises the highest geometric freedom.…”

“… 92 The opportunities and challenges of waterjet cut steel reinforcement have also been investigated in a series of small prototypes for topology-optimized concrete elements. 93 …”

Experimental investigation of ribbing pattern effect on the bonding qualities of water jet cut steel reinforcement

“…Figure 1 shows schematics of the three WC reinforcement types and gives examples of all used reinforcement configurations. The isosceles triangles pattern has previously been used by the authors [31], while both circular patterns were added to investigate potential benefits of curvature and concrete interlocking. All WC designs had the same crosssectional area of the standard rebar (Ø 19 mm) of 2.83 cm 2 .…”

“…Precision-cut steel plates have been explored in only limited capacities by engineers for applications in DFC. Recent examples include the use of laser-cut steel plates that are welded together and used as shaped form-works [28], and use by the authors and others of waterjet-cut (WC) steel plates as internal reinforcement in shaped reinforced concrete beams [29][30][31]. Cutting reinforcement from steel plates permits extraordinary design freedom for applications where non-uniform reinforcement may be desired.…”