Second-Generation Implants for Load Introduction into Thin-Walled CFRP-Reinforced UHPC Beams: Implant Optimisation and Investigations of Production Technologies

Intravertebral insertion of interbody fusion cage via transpedicular approach for the treatment of stage III Kümmell disease: a technical note and case presentation

BACKGROUND

Kümmell disease usually occurs in the elderly osteoporosis population and develops gradually into symptomatic, progressive kyphosis of the spine. However, current surgical methods to deal with stage III Kümmell disease are less satisfying. The objective of this study was to describe a less invasive technique for treating stage III Kümmell disease.

TECHNIQUE

A less invasive technique of intravertebral insertion of interbody fusion cage via transpedicular approach with posterior spine stabilization was applied to treat stage III Kümmell disease.

RESULTS

This study details a modified technique applied in a patient with stage III Kümmell disease, showing significant improvement in pain relief, anterior column height recovery, and kyphotic angle correction. And no complications were reported during our follow-up.

CONCLUSIONS

Intravertebral insertion of interbody fusion cage via transpedicular approach provides advantages of acceptable correction of kyphosis, bony fusion, minimal invasion. Thus, our method was a good alternative choice for stage III Kümmell disease.

Experimental and Numerical Investigation of Plastic–Concrete Waterproof Walls of an Underground Granary Subject to Combined Bending Moment and Water Pressure

To investigate the mechanical properties of plastic–concrete silo walls in practice, the mechanical properties and failure mechanism under the combined bending moment and water pressure were analyzed through the uniform loading test, water pressure test, and numerical analysis. The influence of the connecting plate spacing, radius, and the waterproof plate thickness on the water pressure-bearing capacity were analyzed. The test results show that the chemical adhesive force exists between the waterproof plate and concrete and can resist 20 kPa. The displacement and strain of the waterproof plate increases significantly with the increment in water pressure. When the water pressure reached 85 kPa, the specimen was damaged due to shear failure. The established numerical model was validated by the test results. The numerical analysis results show that the specimen failure mainly depends on the bolt strength when the thickness of the waterproof plate is greater than 14 mm or the radius of the connecting plate is greater than 60 mm. The relation between the design parameters and the water pressure-bearing capacity was proposed. Compared with the waterproof plate thickness, the connecting plate spacing and radius have greater influence on the water pressure-bearing capacity.

Second-Generation Implants for Load Introduction into Thin-Walled CFRP-Reinforced UHPC Beams: Implant Optimisation and Investigations of Production Technologies

Combining two high-performance materials—ultra-high-performance concrete (UHPC) as the matrix and carbon-fibre-reinforced composites (CFRP) as the reinforcement—opens up new possibilities for achieving very lightweight thin-walled concrete elements. This strategy, however, leads to a higher degree of material utilisation, resulting in the generation of higher forces around load introduction points and supports. The authors present a solution for increasing the performance of supports of very slender CFRP-reinforced UHPC beams by using metal implants. Implants are used in place of concrete in regions of stress concentrations and significant deviation forces. These are able to transfer high stresses and forces efficiently due to their ability to sustain both tension and compression in equal measure. A key issue in their development is the interface between the reinforced concrete and metal implant. Building on previous research, this paper deals with the conceptual design of three types of implants manufactured from different metals and with three different types of automated production technologies (water-jet cutting, metal casting with a 3D-printed plastic formwork and binder jetting of steel components). For this paper, tests were carried out to determine the load-bearing behaviour of beams with the three different types of support implants used for load introduction at the supports. A carbon rod served as bending reinforcement and a pre-formed textile reinforcement cage served as shear and constructive reinforcement.