What problems should be paid attention to in the construction of tower crane foundation

Tower crane is a powerful lifting and transportation equipment, widely used in construction, transportation and other industries. 
Because of its huge steel structure, the stability of the tower crane foundation is crucial. However, tower crane collapse accounts 
for a large proportion in tower crane accidents, which is caused by unqualified tower crane foundation. So, in order to avoid the
occurrence of tower crane accidents, what problems should be paid attention to in tower crane foundation construction?

According to the following analysis of tower crane production and use experience, there are three types of causes of tower

crane foundation accidents:

First, some construction sites in order to rush time, in the case of insufficient concrete strength and hasty installation, so that the tower 

crane load beyond the ground stress limit, thus collapse, tipping unfortunate events.

Secondly, some construction units carry out excavation work near the foundation of tower crane, which leads to landslide or even 

displacement and causes tower crane accidents.

Third, in recent years, many cities in China have suffered from excessive groundwater extraction, resulting in groundwater funnel 

and uneven settlement, which affects the operation and construction of tower cranes.

Therefore, to prevent the collapse of tower crane accident, the construction unit in the tower crane foundation, must ensure that 

the endurance meets the design requirements, the strength of reinforced concrete at least 80% of the design value.

In addition, special treatment measures should be taken for the tower crane foundation with basement works, such as piling under

the foundation and firmly welding the steel bar at the pile end with the foundation anchor bolts. The bottom of the concrete
foundation should be flat and rammed. The bottom of the foundation should not be shaped like a pot. The size error of the foundation
bolt must be constructed in strict accordance with the requirements of the foundation drawing. The foundation bolt should maintain
sufficient length of exposure to the ground, and each foundation bolt should be pretightened with double nuts. Before installation, 
the surface of the foundation shall be treated to ensure that the level of the foundation shall not exceed 1/1000. Meanwhile, tower 
crane foundation shall not accumulate water, which will cause uneven settlement of tower crane foundation. No excavation or ditch
shall be made in the vicinity of the tower crane foundation.