Based on this point, the steel structure has been greatly optimized.
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The canopy overhanging 10m is suspended by the large inclined columns on both sides.
The communication opinions are as follows: the internal space of the sentry box should be cut flat, and the column position should be coplanar if possible (the right molding wall can be solved after being widened a little).
In the design, the truss height-span ratio is not applicable to the existing span, and the book reference is given, and the solid web beam crossing method is proposed.
The main difference is the method of inclined column.
Through the design of several small pieces, we can see that there is no agreement on the value standard of the load.
The small rain shed with a overhang of 8m is relatively simple and the design is relatively aggressive, so the main opinions are to control the safety and keep the surplus.
The main problems are the value of dead load and wind load, especially the shape factor of wind load.
The plane dimensions are inconsistent with the drawings; 2.
What has No3 done? The design institute has implemented a version of the canopy drawing according to the preliminary communication opinions.
The cantilever root should be reinforced by the structure.
The span is indeed larger, but it is only a light steel roof, which can be realized in any form.
From the current section size, the box section of 600×300 is basically adopted, which is too strict; The section thickness of the main steel beam should be optimized, especially the web should be thinned to reduce the dead weight; The beam section is welded anyway.
How to do rigid connection to reduce the uplift force at the bottom of the column, or add diagonal web members to form a lattice to enhance the integrity.
The steel beam section shall be further optimized in combination with the above opinions.
Deformation control standard The deformation under constant+live load can be controlled by 1/250L, but the code does not give the control standard of deflection under wind load control combination.
The span of the gate has also been improved when the design is deepened, from the original 40m to about 30m, so the span-to-height ratio of the structure crossing the gate is close to 40.
At present, the 400×2000 embedded parts are too cumbersome and the structure is too complex.
A few large overhangs (hard overhangs) of about 10 meters, a 40 meters wide span gate, and two 17 meters large signboards were still a little challenges! The design department is always more anxious than the design department! What does No1 do? 1.
Bearing structure problem, because the embedded parts on the large inclined column are optimized to be connected by two bearings, the steel structure side raised the problem of leveling, and it is suggested to add a short steel column in the middle for transition leveling.
The canopy overhang of 10m is also good because the load itself is not large, and the building also leaves space for the thickness of the canopy, and there is no objection to making the beam height of 500-600.
For the torsion resistance of box girder and I-beam, it is recommended to use box section for steel girder with large torque and unavoidable; For other cantilevered main beams, the main beam torque can be released through secondary beam hinge, so it can be optimized as I-beam section.
Through communication and verification, the vertical displacement and lateral deformation are relatively large, so that the structural stiffness can be strengthened.
In addition to subdividing the section plate thickness, the component can also be subdivided to control the cost; Whether variable section is considered for the main beam section, which needs to be communicated with the curtain wall for feasibility; The practice of the embedded parts at the top of the column should be optimized.
For the wind load value of the canopy, refer to the value of the grandstand for conservative; The negative wind pressure is considered to be – 2.0 in the later design, which is not negative pressure control anyway, so there is no problem, but the design is required to consider the shape factor of 1.0 in the positive pressure value.
(Click here to view) Brother H called one weekend and said that there was a matter that needed my help to review together.
The dead load is mainly the dead weight of the aluminum clad plate.
How to make the canopy for the gate with a span of 40m is feasible.
In fact, my initial idea was that the inclined column shape just has the conditions to make lattice columns, so that the steel structure can be realized easily and has relatively large stiffness.
In addition, the code allows the constant+0.5 live deformation to be treated by pre-arching, so the nominal deformation control is not a big problem in fact.
At this time, should we pay attention to economy or duration? If the construction period is the priority, it should be solved directly by solid belly, and it is better to roll the finished I-beam; If it is cost priority, it is estimated that the truss cost is better.
However, the method of column base is relatively troublesome, so it is strongly recommended to do it according to the concrete inclined column.
If the steel structure is to be built, the embedded column base must be built.
For the wind load value of the gate, refer to the shape coefficient value of the cross-air corridor in the industrial load code.
Double-row steel columns shall be considered for inclined columns, and the method of column base shall be simplified; 5.
For the shape coefficient, both positive and negative wind pressures should be considered.
The dead live load is considered too large and the wind suction effect is not considered; 4.
Add the layout of anchor bolts at the bottom of the column and the elevation layout of the steel frame.
The support conditions provided by the large inclined column for the roof canopy are incorrect; 3.
2.
Looking at the plan that had been finalized, it was also interesting.
Review opinions and communication details of steel structure: how to control the deflection deformation limit standard? At present, the overhang of 10m may mainly be the rigidity control.
However, after communicating with the designers on both sides, it is found that both sides have different ideas.
The practice of the inclined column has also been communicated to the site.
The overhang of the other canopy project is only 8m, so the other designer’s approach is also more radical.
According to the calculation results of the first round of canopy, the following suggestions are put forward: 1.
The shape of the inclined column is considered as double steel column (mouth 200x200x10).
ZhongXX thinks that the inclined column has an angle.
Both projects involved the need to add steel structure pieces (sentry box awning, cross-road gate and spiritual fortress).
Generally, it is necessary to consider the method from top to bottom, so the load value is considered as 0.3 * 2=0.6.
There is no comment on the construction, and it is no longer entangled.
