Strengthen foundation compaction
In the process of design and construction, it is necessary to strengthen the foundation compaction, ensure that the foundation and foundation of formwork, support and support are properly handled, and prevent settlement cracks.
One-time pouring concrete
For the underwater structure in bridge structure, concrete should be poured once as far as possible without leaving construction joints, and freeze-thaw cycle test and frost resistance strength calculation should be carried out on the components as needed to ensure the stability and durability of the structure.
Reduce cement consumption
The pier shaft is prone to irregular longitudinal cracks and reticular cracks. In order to prevent these problems, measures can be taken to reduce the dosage of cement, reduce the temperature of concrete entering the mold and the hydration heat temperature of cement, and accelerate the heat dissipation of pouring concrete.
Limit the length of continuous casting
Concrete bridge deck and wide abutment are prone to temperature cracks. This kind of crack changes with the change of environmental temperature and belongs to active crack. Therefore, the length of continuous casting is limited in design, and shrinkage-resistant steel bars are added; During construction, concrete should be poured in stages, and other measures should be taken to reduce the shrinkage of concrete.
Strictly control the drawing time.
In the prestressed construction, when the post-tensioning method is used to draw pipes to form holes, the drawing time should be strictly controlled to avoid the pipe wall cracking caused by premature drawing pipes and the occurrence of hole string during grouting. At the same time, in the process of pre-tensioned beam slab construction, it is necessary to prevent the pore-forming sac from floating up, weaken the upper end face too much, and avoid the surface cracks of the slab under the action of reverse arch.
Secondary pouring and tamping
Strengthening the vibrating and curing of concrete is the key to improve the strength and crack resistance of concrete. The secondary pouring and tamping before the initial setting of concrete can effectively eliminate the internal stratification caused by plastic settlement and improve the interface structure of aggregate. In addition, the "water storage method" can not only meet the needs of power growth, but also be very beneficial to temperature control.