The upper and lower chords of the planar truss are in compression.The compression force is counteracted by the tension force provided by the perimeter beam at the top of columns.是什么意思_The upper and lower chords of the planar truss are in compression.The compression force is counteracted by the tension force provided by the perimeter beam at the top of columns.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句