短語詞組短語span -length 結(jié)構(gòu)跨度span fiber length 跨距長度zero span breaking length 零距裂斷長shear span length 剪跨長度sloping span length 斜檔距theoretic span length 理論跨徑allowable span length 臨界跨長maximum allowable span length 極限長度equivalent span length 當(dāng)量跨距 返回 span length