upper purlin tiebeam

例句：

1. 1. The upper purlin tiebeam is the main support for theroof.
   上桁梁是屋顶的主要支撑。
2. 2.The engineer carefully checked the upper purlintiebeam to ensure its strength.
   工程师仔细检查了上桁梁以确保其强度。
3. 3. The upper purlin tiebeamwas damaged during the storm, which causeda delay in the construction.
   暴风雨期间上桁梁受损，导致施工延误。