How to reasonably save steel bars on construction sites?


Optimization method: start at 1 / 2 plate reinforcement spacing.

2.

There are 8 elevators in the project.

shear wall 1.

The starting bar of the vertical reinforcement of the wall is a vertical distance from the edge of the concealed column.

With the consent of the design, it is changed from hrb40022 to hrb40014 to reduce the use of large-diameter reinforcement.

The actual corner wall of the main building and garage on site shall be implemented according to the inner side of the horizontal reinforcement hook.

6.

The conventional method of the joint between the stirrup of the top plate beam and the beam and wall: both ends of the beam shall be densified.

A total of 11 tower cranes are set in the project.

The conventional method: take the larger value of 100mm and 5D.

The raft reinforcement in the 1.6m thick raft area is the same as that of the tower crane foundation HRB40025@200 Double layer and two-way, share the raft reinforcement with the tower crane foundation reinforcement on site to reduce the waste of tower crane foundation reinforcement.

The height of the column pier is greater than 1400mm, the dowel bars at the four corners of the column are inserted to the bottom and bent, and the other longitudinal bars are anchored Lae.

The horizontal reinforcement of the slope of the lower column pier belongs to the structural reinforcement, and the main reinforcement with the diameter of the garage raft is adopted.

In construction engineering, reinforcement accounts for the largest proportion of all disciplines and materials, up to about 30%.

Conventional practice: start at 50mm.

6.

So, how to optimize the reinforcement in construction engineering? Let’s take the project of China Construction Eighth Engineering Bureau as an example to see how to reasonably save reinforcement on construction sites? I.

(taking the diameter of reinforcement into account) 3.

2.

9.

The design institute will calculate and recheck according to the elevator parameters provided by us, strengthen the beam and slab reinforcement at the corresponding location of the elevator, issue the design change drawing, and use the main structure as the foundation of the elevator.

8.

The starting bar of the vertical reinforcement of the wall is one vertical distance from the edge of the concealed column.

The reason for the compression failure of large and small eccentricity is that the large eccentricity is far away from the axis of the member than the small eccentricity, and the bending moment generated by compression is relatively large, so the member is equivalent to bending failure..

4.

Optimization method: encrypt according to 100mm.

4.

The starting distance between upper and lower reinforcements of the floor slab is generally 50mm.

The project department will provide the design institute with the weight parameters and layout position of the elevator in advance.

In the 0.6m thick raft area, considering the increase of counterweight in the tower crane foundation, the project department communicated with the Design Institute, and the design institute calculated according to the tower crane foundation counterweight.

The raft reinforcement is designed to be arranged according to the column pier.

The vertical reinforcement of the wall starts at a spacing.

Swift Lift Anchors

According to the provisions on page 16g101-1p71 of atlas, the horizontal reinforcement of the wall shall be bent close to the inner side of the longitudinal reinforcement of the column.

The top end of the vertical reinforcement of the wall can be directly anchored.

After optimization, the descending plate area can meet the anchorage length.

Effect: there are 496 column piers in two pits a and C.

Optimization method: insert an anchor Lae under the corner bar except the corner bar to the bottom.

Optimize the root of the outer wall of the bottom plate on site.

The column pier reinforcement has larger specification and smaller spacing than the raft reinforcement.

Anchoring of non corner reinforcement of concealed column in raft conventional practice: all concealed column reinforcement shall be inserted into the bottom of raft.

The vertical reinforcement of the wall can be overlapped 100% on the floor.

The secondary utilization of short materials is realized by replacing the measure reinforcement with the anti floating anchor bar.

According to the provisions on page 16g101-1p73 of atlas, the vertical reinforcement of non bottom reinforcement part of shear wall with seismic grade I and II or shear wall with seismic grade III and IV can be overlapped 100% at the same part, and the overlapping length = 1,2lae.

On site, the vertical reinforcement of the main building wall is 100% overlapped (1.2lae effect drawing).

All tower crane foundations fall in the foundation raft.

11.

Tower crane foundation and elevator foundation are constructed by using the main structure.

5.

Therefore, reinforcement optimization is very important and directly related to the benefits of the project.

After the optimization of the original design node, the node is implemented on site.

According to the provisions of page 16g101-1p74, if the top end of the vertical reinforcement of the shear wall is a frame beam and the beam height meets the requirements of direct anchor, direct anchor can be used.

7.

10.

The erection reinforcement (supporting the upper reinforcement mesh) on the stirrup replaces the reinforcement on the raft in the same direction.

9.

Part II foundation 1.

However, the current reinforcement engineering is still extensive management, lack of unified planning, and do not consider the reinforcement measures, connection mode, anchor node and length combination in advance, resulting in a large amount of reinforcement blanking waste and low utilization rate.

Most of the column piers in the underground space are 5 * 5 * 1.2m, with reinforcement 25@120 , 42 on each side; Now @ 120 is optimized to @ 123, that is, 41 can be bound on each side (one longitudinal bar with a length of 7.14 meters and 25 can be bound on each side).

The fundamental difference between the anchorage of column longitudinal reinforcement in the foundation is whether the tensile reinforcement yields.

Conventional method of vertical bar and straight anchor of inner wall: all inserted into the bottom of raft.

Fig.

3.

The descending slab coincides with the lower column pier.

The stirrup at the lap joint of vertical reinforcement of concealed column shall be saved.

7.

5.

Optimization method: start according to the spacing s of one wall vertical bar.

The failure of large eccentric compression is tensile failure, and the failure of small eccentric compression is compression failure.

When the anti floating anchor rod replaces the stirrup, attention should be paid to the elevation control.

Optimization method: except along the wall, it shall be done as non encryption.

The same method is adopted for the reinforcement of wall and column of the main building.

Each tower crane foundation can reduce 5 anchor bolts, which reduces the construction period on site, It also saves the waste of reinforcement of tower crane foundation and creates benefits for the project department.

After optimization, the raft reinforcement and column pier reinforcement are reinforced respectively, and the original raft reinforcement is used for the reinforcement at the cross raft.

Optimization method: meet the length of straight anchor, and save the length of straight anchor and elbow.

Optimization method: start at 1 / 2 plate reinforcement spacing.

After the optimization of the original design node, the node is implemented on site.

The bottom reinforcement of the original design is directly connected to the edge of the raft.

The end of the horizontal reinforcement of the wall is bent and placed inside the longitudinal reinforcement of the column.

The vertical reinforcement of the wall column in the basement and garage reaches the top at one time to reduce the use of straight thread sleeve and save the binding and overlapping length of reinforcement.

According to the provisions on page 3-13 of 18g901-1, s = vertical spacing of one wall = vertical reinforcement of the wall, and the starting reinforcement shall be a vertical spacing from the column edge.

The raft thickness is divided into 1.6m and 0.6m.

The starting distance between the upper and lower bars of the garage roof is 50mm.

8.

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