The evaluation of thermal bridges in buildings, following the UNI TS 11300-1:2014 standard, must be carried out with finite element analysis or through the use of atlases compliant with the UNI EN ISO 14683:2018. The paper illustrates the development of an analytical tool to determine the internal linear thermal transmission coefficient (ψi) for the thermal bridge between concrete wall and inter-floor slab, neglected in the main existing catalogs or atlases. This type of thermal bridge is relevant in multi-story buildings, and is typical of public housing districts built between the 1960s and 1970s throughout Europe by means of industrialized systems. Considering energy requalification, due to their low energy efficiency, these buildings require adaptation to the standards imposed by law, and this thermal bridge, which has a high percentage incidence on the total heat losses, cannot be overlooked. From the survey of a representative number of such buildings in Italy, three different technological solutions were examined, with dimensional variations in the individual technical elements and the related functional layers. The combination of these variables resulted in 216 different case studies. The analysis of the existing atlases and catalogues has demonstrated their inapplicability for the selected case studies. For each one of these, ψi was calculated, using off-the-shelf software. The correlation of the data made it possible to determine an analytical mathematical modeling process to assess heat losses due to the analyzed thermal bridge. The validity of this mathematical formula was verified by recalculating the typologies investigated, reaching an error evaluated by means of the mean square deviation equal to ±4%.

中文翻译：

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钢筋混凝土墙与层间板间热桥的解析数学建模

按照 UNI TS 11300-1:2014 标准对建筑物中的热桥进行评估，必须通过有限元分析或使用符合 UNI EN ISO 14683:2018 的地图集来进行。本文说明了一种分析工具的开发，以确定混凝土墙和楼板间热桥的内部线性热传导系数 (ψi)，在现有的主要目录或地图集中被忽略。这种类型的热桥与多层建筑相关，是 1960 年代至 1970 年代通过工业化系统在整个欧洲建造的公共住宅区的典型代表。考虑到能源再认证，由于能源效率低，这些建筑需要适应法律规定的标准，而这种热桥，它在总热损失中的发生率很高，不容忽视。通过对意大利代表性数量的此类建筑的调查，研究了三种不同的技术解决方案，其中各个技术元素和相关功能层的尺寸变化。这些变量的组合产生了 216 个不同的案例研究。对现有地图集和目录的分析表明，它们不适用于选定的案例研究。对于这些中的每一个，ψi 是使用现成的软件计算的。数据的相关性使得确定分析数学建模过程以评估由于分析的热桥引起的热损失成为可能。通过重新计算所研究的类型，验证了该数学公式的有效性，