发布时间:2025-01-18 21:11:12
1/6-1/4内。为保证梁底方木安装方便,弧形梁模板弧长控制在1.2m1.5m左右为宜。,三铰拱或弧形轻型桁架,至于拱高,可在1/6-1/4内取值,南方防风,北方防雪。
网上说镀锌的铁水管含铅要注意却没见一个因此原因而铅中毒的例子有
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