Structural use of timber. Recommendations for the calculation basis for span tables. Joists for flat roofsdoi:BS 5268-7.2:1989对于平屋顶和坡度高达10°的屋顶,最大间距为610 mm的托梁允许净跨距.交叉引用:BS 648BS 4471:第1BS 4978BS 5268:第2BS 5268:第3BS 5268:第7.1BS 5268:第7.4BS 5268:第7.5...