Four software in the same light frame structure analysis and comparison

Often heard the saying: "a certain software than XYZ software in steel", of course, for those who say such things in general is not our professional, at most is a have a superficial knowledge of, however, as a real professional design staff and understanding of component design of body in the process of how many?In the design of steel structure industry has a large number of just the software user, therefore, as in the design and software development, it is necessary to do such a thing: use different software on the same conditions of an engineering calculation results, have a look how big the difference.

The selected field is light steel structure, because it is the most widespread use, but also on the amount of steel is the most sensitive structure, and I just had one such software, so often hear most is about the light steel steel quantity problem.

The software is current popularity in the industry, they are: 3D3S, STS, PS2000 and Maggie_GJ.

One, project brief introduction

The selected works as follows:

Two new 27m, four slope, slope, elevation of 7.5m, 1/20, 9m column, Q235 material.Diagram as shown below, recorded Liang Zhu's Cross Section specification (beam marked only the left cross, right symmetrical with the circle), as member number, beam member segment size also made a mark,

Load:

Roof loads: 0.2 KN/m2

Roof live load: 0.3 KN/m2

Basic snow load: 0.45 KN/m2

Basic wind pressure: 0.45 KN/m2

Without regard to earthquake.

Two, the analysis results

In order to get an accurate conclusion, we do not use that software to optimize the function of the component, but only for a given component section checking, here only the software the calculated number component control stress.

Control stress comparison table units: Mpa

Member number

3D3S

STS

PS2000

Maggie_GJ

1

180.6 167.7.

189 176.

210.8

184.9 170.1.

2

189.2 167.7.

178 164.

191.9

163.6

3

165.5 150.5.

168 154.

167.9

153.6

4

139.8 139.8.

117 105.

167.9

153.6

5

124.7 111.8.

117 105.

139.6

118.4

6

193.5 178.45.

190 176.

191.9

176.2

7

189.2 167.7.

180 167.

212.9

181

8

135.45 90.3.

152 76.

129.5

144.3 85.9.

On the side column (1 members), lateral support length considering the factor of 0.6 (knee bracing effect), control stress for the in-plane stability stress, brackets for the out of plane stability stress value.

In the column (8 components), control stress for out-of-plane stability stress, in this case, due to live load is evenly distributed, and the structure is symmetrical, in the column for axial force, so the section according to the calculation is relatively small, but the actual situation should be properly considering non-uniform distribution of load, the calculation results it is not considered, brackets for the in-plane stability stress value.

The beam (2-7 component), portal frame of "technical specification for steel structure of light-weight" (CECS 102:2002) regulations, in plane bending press for calculating its strength, in the plane to calculate the stability, but 3D3S and STS were given in-plane stability stress, but also the control stress.The previous "portal frame of technical specification for steel structure of light-weight" (CECS 102:98) mentioned in the beam in the plane of the calculation length of vertical spacing, this later in the rules have been removed.If as beam-columns are in-plane stability calculation, then the beam is a bending member, while the axial pressure is along the rod in the axial direction, or as horizontal direction to take?And according to this calculation length calculation of stability coefficient is still have significance?So like a column so as to calculate the bending in-plane stability is a little far-fetched.While calculating the out of plane stability is actually of member in bending calculation of overall stability, but also takes into account the axial force only, but still is the beam characteristics.So Maggie did not calculate the so-called in-plane stability stress.

Three, question words

From the above control stress meter, basically are very close, but PS2000 slightly high, it may be I used earlier versions.Therefore, we can say, the so-called save steel consumption is not the key software, but the use of software, the software is only a tool only, just like the same calculator.The count against the component design process that do not understand people who can easily complete the structural design of the ideal software even exists, it is also a potential bomb.It generates the construction drawings, can deceive layman's owner, also can let the poor professional knowledge you steep give birth to unlimited expansion of self-confidence, so that steel structure design is just so so.

The real structural engineer possess first is the mechanical foundation, for a loading structure, with various boundary conditions are generally stress state has a certain feeling, especially planar structure system, for complex spatial structure system, need have the aid of structural analysis software to help understand the stress condition.The second requires component design theory, the steel structure, axial compression, bending and the problems needed to be considered should clearly know.Also need to grasp the common node connection mode and the calculation method, this involves some experience.Also need to understand the design, but the process of making and installation of the knowledge, because many of the issues that need to be considered in the design stage.Of course, the most important or as a structural engineer responsibility.