Deix Karl, Huber Christian, Gogic Josip
Department of Building Material, Vienna University of Technology, 1040 Vienna, Austria.
Camillo Sitte Bautechnikum, 1030 Vienna, Austria.
Materials (Basel). 2025 Apr 29;18(9):2032. doi: 10.3390/ma18092032.
In the case of load increases and the refurbishment of existing buildings, it is often necessary to carry out strengthening measures on existing timber beams. When timber concrete composite (TCC) ceilings cannot be used, it is possible to reinforce the undersides of the beams with structural steel or fiber composites (aramid or carbon-fiber-reinforced polymer). This work investigates how significant effects on the load-bearing and deformation behavior can be achieved with these materials in terms of construction practice. The article is intended to show structural engineers which reinforcement measures lead to which forces, deformations, etc., and how these are utilized. This should form the basis for the planning of reinforcement measures, as it is not clear from the beginning whether AFRP, CFRP, or steel is the most suitable material. For this purpose, a comparative parameter study was carried out under practical conditions and with a variable degree of reinforcement using the corresponding formulas. The internal forces in the timber and reinforcement cross-sections, the deflection behavior, and the failure loads at the strength and design levels were calculated. It was demonstrated that, particularly for steel and carbon-fiber-reinforced polymer (CFRP) reinforcements, significant increases in the ultimate load can be achieved and the often-important deformation behavior can be significantly improved. Especially the steel variant leads to high improvements in deflection and breaking load behavior, with the base material (wood) also being utilized more economically as a result. A comparative ecological study in the form of the global warming potential showed that reinforcement methods are also advantageous from the point of view of sustainability compared to renovations with timber concrete composite slabs or new concrete slabs.
在负荷增加以及既有建筑翻新的情况下，通常有必要对现有的木梁采取加固措施。当无法采用木-混凝土组合（TCC）天花板时，可以用结构钢或纤维复合材料（芳纶或碳纤维增强聚合物）对梁的底面进行加固。这项工作研究了在建筑实践中，这些材料对承载和变形行为能产生多大的显著影响。本文旨在向结构工程师展示哪些加固措施会导致何种力、变形等情况，以及如何利用这些情况。这应该成为加固措施规划的基础，因为从一开始并不清楚芳纶纤维增强聚合物（AFRP）、碳纤维增强聚合物（CFRP）还是钢材是最合适的材料。为此，在实际条件下并采用相应公式进行了不同加固程度的对比参数研究。计算了木材和加固截面中的内力、挠曲行为以及强度和设计水平下的破坏荷载。结果表明，特别是对于钢材和碳纤维增强聚合物（CFRP）加固，极限荷载能显著提高，而且通常很重要的变形行为也能得到显著改善。尤其是钢材变体在挠曲和破坏荷载行为方面有很大改进，同时基础材料（木材）也因此得到更经济的利用。以全球变暖潜能值形式进行的对比生态研究表明，与采用木-混凝土组合板或新混凝土板进行翻新相比，从可持续性角度来看，加固方法也具有优势。
