by Catalog 1, design 2, construction process 3, material preparation 4, construction site layout 5, construction process 6, quality control 7, key and difficult points control 8, existing problems and solutions 9.
Comparative analysis of assembly and traditional methods.
With the progress of the times, housing industrialization has gradually begun to be popularized in China, learning from foreign advanced technology With the development of software, China has begun to make great strides.
Next, I will talk about some difficulties and key points from the overall assembly structure design and construction of the project.
First, design: 1.
First, we distinguish the design of traditional structure from that of assembly structure.
In most cases, the traditional structure is designed by the design unit entrusted by the construction unit, and then entrusted to the construction enterprise to construct according to the drawing, which has been relatively mature.
At present, most design units in China fail to involve the overall cast structure, which is relatively backward.
Only a few qualified and experienced design units can be appointed, and the construction unit can only adopt the integration of design and construction for bidding, which brings the importance of design time to the total construction period of the whole project.
2.
The current precast architectural design looks like only a few decades, but actually the whole process extends to the end of the structure, because the whole process is divided into preliminary design – function decomposition – process decomposition – expert verification – design correction – drawing evaluation – final drawing.
Among them, the functional design and process split diagram are particularly important.
① the functional design often needs to be completed at one time, involving local specifications, water, electricity, gas, solar energy and other aspects! After the factory is formed, it cannot be changed.
It cannot be as flexible as the traditional structure.
② the process split diagram.
The factory produces in full accordance with this diagram.
Only the factory technicians know most nodes.
After the factory is mass produced and formed, it will be pulled into the site for hoisting, and start one by one according to the site sequence diagram.
This shows the importance of function decomposition and process split diagram.
3.
Another difficulty in design is how to truly integrate design and construction.
Previously, design and construction integration can only be used in the bidding stage, but in practice, it is found that design and construction can not achieve real integration.
Although there is contact between the design director and the construction director, the actual tracking of the construction process is not achieved.
In the actual process of model house, there are many nodes, Such as column and beam joint; Joints between wallboard and concealed column; There are problems in the joints of the back sill of the toilet.
It often takes 2 to 3 people to bind the stirrup in a concealed column, which takes half a day.
The efficiency is extremely low.
The designer can not meet the operability of the actual construction.
In the process, it is found that the heavy correction, or even local change to cast-in-situ and reinforcement replacement, brings many difficulties to the project construction.
On the other hand, the design process and construction process are too complex, Often a node is discussed for a month.
In terms of final implementation, the design can not decide to implement in writing at the first time, which has a great impact on the whole total construction period.
In addition, there are still some details that will not be described.
How to truly achieve the integration of design and construction remains to be studied.
II.
Construction process: key points: sleeve grouting, grouting, floor flatness, slab joint control and outer frame protection.
(1) Sleeve grouting: floors 1 to 3 of phase II of XXX public rental house are cast-in-situ structures, and floors 4 to 25 are integral cast structures.
The most important and difficult is the 4-storey transfer floor, which is an important layer connecting the upper part.
The most important is the 18 sleeve connected load-bearing walls.
The accuracy of the reserved reinforcement and the precast wallboard shall reach 100%, otherwise it cannot be installed, To this end, all units have also made considerable efforts.
After installation, the sleeve grouting shall be carried out for a period of time.
The grouting machine shall be used for high-pressure grouting, and the key control shall be whether the sleeve is full or missing, and the tracking inspection shall be carried out.
(2) Floor flatness and setting mortar: the two complement each other.
Flatness is the basis of setting mortar.
If flatness cannot be effectively controlled, setting mortar will not effectively meet the specification and quality requirements.
Secondly, increase the loss of materials.
Therefore, it is necessary to increase the control of floor flatness in the process, which plays a very good role in later setting mortar.
(3) Control of slab joints: since the precast structure is spliced by plates independently of each other, there are bound to be multiple vertical and horizontal joints, so the splicing quality of plates should be strengthened in the construction process.
In most cases, the size of the seam is not fully controlled and can only be reduced as much as possible.
Reasons, plate to plate extrusion during assembly, avoidance of concealed columns, hoisting level and other reasons.
Therefore, the selection of materials, elastic modulus and professional team must be controlled in order to meet the quality requirements.
(4) Outer frame protection: safety is always the top priority.
The selection of outer frame of phase II of XXX public rental house is far from reaching the original assumption.
The biggest problem is that ① it can not be synchronized with the construction, ② corner hanging components can not be used effectively, and ③ excessive turnover and deformation.
Therefore, the above points should be fully considered in the later selection, otherwise the safety can not be effectively eliminated.
From many investigations, the traditional frame is the most effective, but there are too many holes in the outer wall and many treatment points.
Secondly, the triangular frame two-layer synchronous protection can also be considered, but the deficiency is that the external wall is manually perforated and fixed with bolts, which is easy to break the reinforcement and difficult to control the waterproof in the later stage; Most importantly, due to the large number of bolts, it is necessary to check whether each fixed point is tightened in place, otherwise the consequences are unimaginable.
In short, the outer shelf protection needs to be studied and gradually improved by all parties and experts..
