The issue of transmittance of thermal bridges in existing buildings has been addressed aiming to achieve correlations able to evaluate the ground-contact thermal bridges. A bi-dimensional steady state FEM model has been implemented to simulate wall-to-floor structural node and then validated in accordance with the EN ISO 10211:2017 standard. Different construction joints have been then simulated for the structural node foundations-vertical elements up to a total of 19 configurations, from which 1700 cases have been derived varying walls and floor stratigraphies and ground properties. Correlations for the linear thermal bridge transmittance have been calculated through regression technique for all the configurations, together with their validity ranges expressed in terms of 95% confidence interval values. Tests performed for more than 1000 practical cases confirmed the accuracy of the proposed correlations. Through those correlations ground contact thermal bridges in existing buildings can be hence analyzed in a simple and operative way, offering technicians in the sector a tool that covers most of the possible situations.

已经解决了现有建筑物中热桥的透射率问题，旨在实现能够评估接地热桥的相关性。已实施了二维稳态FEM模型来模拟墙到楼的结构节点，然后根据EN ISO 10211：2017标准进行了验证。然后，针对结构节点基础-垂直元素模拟了不同的施工缝，总共达到19种构型，从中得出了1700种不同的墙，地层和地面特性案例。线性热桥透射率的相关性已通过回归技术针对所有配置进行了计算，并且其有效范围以95％置信区间值表示。对1000多个实际案例进行的测试证实了所提出的相关性的准确性。通过这些相关性，可以以简单且可操作的方式分析现有建筑物中的地面接触热桥，从而为该领域的技术人员提供涵盖大多数可能情况的工具。