What are the reinforcing methods of steel structure building?
1 Change of steel structure calculation graphic reinforcement method
The method of strengthening the structure by changing load distribution, transmitting force, nodal property and boundary condition, adding additional rods and bracing, exerting prestress, considering the coordination of space and so on are adopted. The general method of changing the structure calculation graph is:
(1) Increase the support to form the spatial structure and check the spatial structure, add the support to increase the stiffness of the structure or adjust the vibration frequency of the structure, so as to improve the bearing capacity of the structure and improve the dynamic properties of the structure;
(2) Adding support or auxiliary rods to reduce the slenderness ratio of the structure to improve its stability;
(3) The stiffness of a column is strengthened in the rack structure to withstand most of the horizontal force, so as to reduce the load of other columns.
2 Additional Fulcrum Reinforcement method
After adding fulcrum in the span of beam and slab, the span is reduced, and the bearing capacity can be improved greatly, and the deflection of beam and slab can be reduced and restrained. It is suitable for the reinforcement of the horizontal structure such as beam, slab, truss and net frame in the large span structure with unrestricted housing clearance. The advantage is simple and reliable, the disadvantage is that the use of space will be affected.
3 Bonded External Steel reinforcement method
In general, the wet-type outsourcing method is adopted to reinforce reinforced concrete beams with external steel, that is, adopting the method of epoxy resin grouting to bond the steel and the reinforced member into one whole, and the reinforced member is greatly improved by the section area of tensile and compression steel, so the bearing capacity and the stiffness of cross-section are also
4 Bonding fiber Reinforced plastics reinforcement method
In addition to the advantages of bonding and external steel reinforcement, the reinforcement method of bonded fiber reinforced plastics also has the resistance to rot, moisture resistance, almost no increase in the structure of deadweight, durability, low maintenance costs and other advantages, but the need for special fire treatment, applicable to a variety of mechanical properties of concrete structural components and general structures.
After the reinforcement project is completed, the application of the small hammer lightly tapping and pasting the plate, judging the bonding effect from the sound or using ultrasonic method to detect the paste density.
If the anchoring area is less than 90% and the Anchorage area is less than 70%, the paste is not valid and should be peeled and pasted.
For the major projects, in order to test the reinforcement effect, the load test shall be carried out by sampling, generally only for the standard use load test, the unloading load will be completely added, and the deformation and crack of the structure should meet the requirements of the design.
5 prestressed reinforcement Steel structure technology
It is necessary to open a hole in the base material near the damaged part by using the bolt connection, weaken the section, and form a new stress concentration area; The common bolts are easy to loosen under dynamic load, and the high strength bolts are prone to stress relaxation, which reduces the repair effect of the structure. Bonding steel Reinforcement technology is on the surface of steel structure with a special building structure adhesive steel plate, relying on structural glue to make it bonded to the whole work together to improve the structure bearing capacity. The disadvantage is to increase the weight of the structure, the steel plate is not easy to make into a variety of complex shapes, transportation and installation is inconvenient, and steel plate corrosion, affect the bond strength, maintenance costs.