为了保证箍筋在整个周长上都能充分发挥抗拉作用,必须将箍筋做成 () 形状,且箍筋的两个端头应相互搭接且搭接长度不小于30d(d为箍筋直径) 。
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
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