Structure Selection And Parameter Analysis On Truss-type Pipe Rack

Large span truss-type pipe rack is the most common structural form in oil, natural gas pipeline crossing project. With the oil transportation industry's prosperity, more and more scholars have put forward the theories and design methods of the research on large span truss-type pipe rack. The research on the optimization and design of pipeline crossing structure, however, is not systematic.These days, most of this kind of structure's design methods are based on the “Code for design of steel structures”(GB 50017-2003), “Technical specification for space frame structures”(JGJ7-2010).In the basis of design experience and codes of the existing bridge and large-span truss, because of the different functional requirements, there are some differences in the large span and bridge on the rigidity, bearing load and so on.It leads to the carrying capacity of structures far more than the actual demand. This situation doesn't meet the requirement of “low carbon environmental protection, conservation oriented society”in China.The sorce of research project is Northeast Branch of PetroChina Natural Gas & Pipeline Company(CNPC). CNPC plan to construct oil pipeline transportation engineering in Northeast China, analysized the related performance of the large span truss structure in this research and based data are observed from CNPC. After concluding summary and analysis, the factors that affect the steel quantity of truss-type pipe rack are as follows : the shape of cross section, height-span ratio, aspect ratio, arrangement of abdominal bar, section shape, load(action), pitch, span, stress ratio, deflection, etc. This research mainly studies the cross section shape, the arrangement of the abdominal pole, the height-span ratio and aspect ratio of truss type pipe rack in different spans, other factors being in full agreement. Under the condition of ensuring the absolute safety of these designed structure,the comparison will be made about the steel consumption in the calculation model in order to find out the influence from difference factors.By using sap2000, the finite element model of the cross section shapes which are the inverted triangle, obtrapezoid and rectangle is analyzed. Optimization designs of the structure in each sapn(60m,80 m,100m) will be made based on the results. Compared with steel quantity,the type of these structures with the least amount of steel were found out. The cross section shape of inverted triangle is more suitable for large span truss structure. Arrangement of abdominal bar which cross section shape are inverted triangle have been analyzed. Then determined the most reasonable structure type.Next the cross sections' size parameter in the structural model which the cross section is the inverted triangle with the most reasonable arrangement of abdominal in different spans are analyzed. Parameter range of optimum value of steel quantity has been determined.Having analylised structural stability from these structures, the structural parameters in cross sections are distinguished by the structural stability control or the strength control in ANSYS.Having created the key node modal, height-span ratio being 1/15 and aspect ratio being 1/2, which the cross section is the inverted triangle with the most reasonable arrangement of abdominal in 100 m span by using workbench.