Question

What is the reason that shallow bedrock condition adverse for open berth piers?

Answer

Most severe load on piers generally is horizontal load due to berthing of large vessels. Because widths of open berth piers are quite small thus they provides a short lever arm to counteract moment induced by berthing loads. Besides, dead load of open berth piers are normally quite light and therefore resisting moment provided by dead load of pier structures might not be sufficient to counteract the moment generated by berthing loads.

To aid in providing adequate confrontation to overturning moment by berthing load, soil resistance on top of bedrock contributes to stabilizing moment. Commonly adopted marine piling type such as driven steel tubular piles with reinforced concrete infill, driven piles be able to at mainly be founded on top of rockhead surface. In case rockhead level is shallow, then little soil cover might result in insufficient lateral resistance to berthing load.