The phrase '连廊设计的公摊大' refers to a situation where the common area of a corridor design is relatively large. This could be a concern in architectural design as it may affect the usable space of the building. In terms of knowledge, the design of corridors in architecture should balance the need for common space with the efficient use of the building's floor area. Factors such as circulation, accessibility, and aesthetic considerations play a role in determining the size and layout of the corridor. If the corridor's public area is excessively large, it could be due to inefficient planning or design decisions.