It is one of the defects that cracks occur in the bottom slab of an extra-long prestressed concrete continuous rigid frame bridge. There are many influence factors.

大跨度预应力混凝土连续刚构桥底板出现开裂是该类桥梁出现的问题之一，其影响因素较多。

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In reconstruction and extension engineerings, the important point of bridge design is widening and reconstructing its bottom.

改扩建工程中桥梁设计的重点是其下部加宽改建方案。

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This thesis put forward Intelligent-video Bridge-detection Vehicle (IVBDV), using video scout and image processing technology detect the bottom of bridge where is hard to reach by manual.

本文提出开发小型无载人智能视频桥梁检测车，配以视频跟踪和图像检测手段对人员不易到达的桥梁底部进行自动检测。

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He also makes a hand-printed sign with the passenger's name and then drives to the gate of the inbound flight, parking at the bottom of the jet-bridge stairs.

WSJ: The Tarmac Express: A Porsche to the Plane

In essence, Apple cops to the fact there are reception issues with the new iPhone namely, that if you cover the bottom-left corner of the phone and bridge the gap between the notch there with your naked flesh, you could see some signal degradation.

FORBES: Please Remember To Hold Your New iPhone Correctly