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Classic Steel Structure Design Q&a

Sep 07, 2017

1. When you look at the moment of bending moment, you can see the bending moment, but you don't know what is the relationship between the bending moment and the cross section.

Answer: the bending member is subjected to the bending bearing capacity Mx/(gamma x * Wx) + My/(gamma y * Wy) is less than or equal to f, where W is the resistance moment of the section and can be manually calculated by the cross section

2. What is the rule of h-beam?

Answer: how to answer, hehe. The main consideration is bending moment and/or the transmission of shear force. In addition, in the dynamic loading area, design welding joints should be especially careful to connect:

3. "flat top tight", do not need to be resoldered after tiding?

A: polishing the top is a kind of transmission method, which is used to bear the position of moving load.A kind of transmission method to avoid fatigue crack of welds.It is required that the polishing of the top shall not be soldered.See the specific drawing requirements.The contact surface requires that the finish is not less than 12.5, and the contact area should be checked with the plug gauge.Plane flat top tight purpose is to increase the contact area of the contact area, usually used in a horizontal displacement and simply supported node, and the node should have other way of connection (such as the top flange, it is possible to use web bolted).

Generally this node requirements of plane flat top tight parts do not need to welding, to welding plane flat top tight not conducive to the deepening of the melt fluid, when welding the weld quality is poor, welded parts even if they don't open groove will not ask too tight.Top tight and welding is contradictory, so the above said top tight position welding is not accurate, but there is also a likely top tight welding, is top tight node constraint of other degrees of freedom is not enough, and no other parts supply constraints, are likely to top position for the soldering to constrain the direction of the other degrees of freedom, this is a kind of installation of weld seam, it is impossible to full welding, more can't be used as the main force of weld.

4. When the steel structure is designed, the deflection exceeds the limit value, after the meeting what consequences?

Answer: affect the normal use or appearance of deformation;Local damage (including cracks) that affect normal use or durability.Affects the vibration of normal use;Other specific conditions that affect normal use.

5. What is the function of extruded plate?

Answer: extruded polystyrene (XPS) insulation board, polystyrene resin as the main raw material, through special process extrusion foam forming hard sheet.With a unique and perfect honeycomb structure, it has environmentally friendly materials, such as high pressure, moisture proof, air permeability, water absorption, corrosion resistance, low thermal conductivity, light quality, long service life, etc.The extruded polystyrene insulation board is widely used in the wall insulation, cryogenic storage facilities, parking platform, building concrete roof structure roof, etc.The extruded plate has a remarkable and enduring characteristic: it is stable and not easy to age.Available 30 -- 50 years, extremely excellent anti-humidity performance, under high water vapor pressure environment, can still maintain low thermal conductivity.The extruded plate has unparalleled thermal insulation performance: the extruded plate has a closed hole performance structure and its closed porosity is 99%, so it has good thermal insulation performance.Although the foaming polyurethane is the obturator structure, the closure rate is less than the extruded plate, only about 80 %.The extruded plate is superior to other insulating materials, such as heat insulation, water absorption and compressive strength, so it is not able to be used in thermal insulation.Extruded board has unexpected compressive strength: compressive strength of extruded board according to the thickness of the different models of 150 -- more than 500000 mpa, and other material compressive strength is only 150 - more than 300000 mpa, clear other material compressive strength, much lower than the compressive strength of extruded board.The extruded plate has a safe water absorbing property: it is used for road surface and roadbed, effective waterproof penetration.Especially in the north, it can reduce frost and frost affected soil freezing and so on, control the ground freezing, effectively obstruct the ground gas from moisture damage and so on.

6. What is length and detail?Radius of turn: the square root of (moment of inertia/area) length is equal to calculate length/radius of rotation

Answer: the length of the structure is greater than lambda = mu l/I, and I is the length of radius of rotation.The concept can be easily seen from the calculation formula: the ratio of length to length is the ratio of the calculation length of the component to its corresponding turning radius.From this formula, it can be seen that the concept of long fine ratio takes into account the constraints of the end of the component, the length of the component itself and the section characteristics of the component.The effect of long thin ratio is obvious to the stability calculation of the compression bar, because the larger the size of the member, the more likely it is to be unstable.Take a look at the calculation formula of axial pressure and pressure bending components, all of which have parameters related to the length of the ratio.For the tensile component specification, it also gives a long thin ratio requirement, which is to guarantee the stiffness of the component in the transport and installation condition.The higher the stability requirement, the lower the stability limit.

The buckling of the compression flange of the curved i-beam is the underdirection of the beam of the i-beam, or the axial buckling of the strong axis?

Answer: when the load is not big, beam in its biggest basically in-plane bending stiffness, but when the load to a certain value, the beam will produce larger lateral bending and torsion deformation at the same time, the last soon lose continue carrying capacity.At this moment, the overall instability of the beam must be bent and twisted.