Effect of Initial Geometry Defects and Crane Runway Partiality on Security of Single Layer Steel Structural Workshop

2011 ◽  
Vol 368-373 ◽  
pp. 2327-2332
Author(s):  
Yong Li Zhang ◽  
Xiao Peng Hu ◽  
Xin Zhang

External components loss injuries caused by various defects of steel material performance, design, production and construction, and adverse factors such as overloading, repeated load, high-temperature, corrosive media or mismanagement, direct impact on security of steel structure in the course of subsequent use. Based on the investigation of single layer steel structure industry workshop, from two aspects of nature and quantify, the effect of initial geometry defect on bear of axle pressure component and crane runway partiality on bear of crane beam system is analyzed, which is the basis of regularity uses、consolidating and monitors of the building. The result shows that through the computation of axle pressure component with initial geometry defect or crane runway partiality, the component's bearing capacity reduces many and the effect of security is big, and when the initial geometry defect or crane runway partiality surpasses the standard stipulation the certain proportion, bearing capacity will continue to reduce, the structure will be more unsafe. The effect of crane runway partiality on the crane beam web plate upper extreme edge's intensity and web plate horizontal stiffening rib's intensity is little.

2014 ◽  
Vol 926-930 ◽  
pp. 677-680
Author(s):  
Chao Nan Wang ◽  
Bo Zhang ◽  
Xiao Peng Hu

Based on the investigation of a single layer steel structure industry workshop in Baoshan Steel Incorporated Company, the effect of dust overload on the security of single layer steel structural workshop is analyzed, which is the basis of maintenance and monitor of the building. The results show that the dust-load overload 16%, the ratio of resistance-load of roof truss, bracket and framework column separately reduce 4%,4%,0.5%. If the dust-load overload 100%, the ratio of resistance-load of roof truss, bracket and framework column separately reduce 20%, 20%,1%.


Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.


Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 68
Author(s):  
Haidar Hosamo ◽  
Iyad Sliteen ◽  
Songxiong Ding

A ring footing is found to be of practical importance in supporting symmetrical constructions for example silos, oil storage container etc. In the present paper, numerical analysis was carried out with explicit code FLAC3D 7.0 to investigate bearing capacity of a ring footing on geogrid reinforced sand. Effects of the ratio n of its inner/outer diameter (Di/D) of a ring footing, an optimum depth to lay the geogrid layer were examined. It was found that an intersection zone was developed in soil under inner-side (aisle) of ring footing, contributing to its bearing capacity. Substantial increase of bearing capacities could be realized if ratio n of a ring footing was around 0.6. Numerical results also showed that, bearing capacity of a ring footing could increase significantly if a single-layer geogrid was laid at a proper depth under the footing. Similar contribution was found if a double-layer geogrid was implemented. However, such increases appeared to be rather limited if a triple-layer geogrid or a four-layer geogrid was used. A double-layer geogrid was recommended to increase the bearing capacity of a ring footing; the depth to lay this double-layer geogrid was also discussed.


2021 ◽  
Vol 8 (1) ◽  
pp. 119-129
Author(s):  
Fiammetta Venuti

Abstract Free-edge gridshells represent the majority of built gridshells. Indeed, the gridshell reference geometry usually needs to be trimmed in order to provide building access or to insert the gridshell within an existing building, giving rise to one or more elastic boundaries. Despite the current design practice, so far a very limited number of scientific studies has been devoted to investigate the influence of elastic boundaries on the overall structural behaviour of gridshells. This paper focuses on the effects of the orientation of the boundary structure with respect to the grid direction. This is done by studying the buckling behaviour of an ideal single-layer steel gridshell, for different grid layout (quadrangular, hybrid, triangular) and orientation. The results of the parametric study demonstrate that the sensitivity of free-edge single-layer gridshells to the free-edge orientation strongly depends on the grid pattern. In particular, isotropic gridshells have shown an almost negligible influence of the free-edge orientation in terms of buckling load, in opposition to orthotropic gridshells. Moreover, the change in free-edge orientation induces significant variations of the global structural stiffness for all the layouts, resulting in possibly unacceptable displacements in service conditions.


2013 ◽  
Vol 639-640 ◽  
pp. 807-811
Author(s):  
Yang Wang ◽  
Tian Li

To investigate the flexural bearing capacity in negative moment region of composite beams,we examined different ends constraint components. The modeling of the beam ends connected framework has been done by the finite element software ANSYS. The concrete thickness, slab reinforcement ratio and different component at the edge of the composite framework in the negative moment region are taken into account. The performance during the process of deformation and failure are got by nonlinear analysis. The flexural bearing capacity was reported, with the negative moment region of the composite frame beam, it revealed great differences when the beams are different component. Simulation results show that the concrete thickness take the biggest influence on bearing capacity. The results showed the behaviors of the composite frame beams are different with positive moment region, and calculation based on current code for design of steel structure (GB50017-2003) would be a big deviation.


2019 ◽  
Vol 10 (1) ◽  
pp. 5-16
Author(s):  
Maxim Stepanov ◽  
◽  
Karina Dzhabrailova ◽  
Gennadiy Rybak ◽  
Mikhail Stepanov

Author(s):  
B. Panigrahi ◽  
P. K. Pradhan

Abstract An experimental study has been carried out to improve the bearing capacity of soils by using geotextile. In the present study geojute (gunny bags) is used as geotextile, whereas sand is used as soil media. This research presents the results of laboratory load tests on model square footings supported on reinforced sand beds. A total of 32 load tests are conducted to evaluate the effects of single layer reinforcement placed below square model footings. Parameters of testing programme of the research are the depth of reinforcement, the plan area of reinforcement and the footing size. The test results indicated that the maximum gain in ultimate bearing capacity (UBC) of footings on reinforced soil (by using geojute) is found to be increased by a factor of 3.37 as compared to soil without geojute. Also, the optimum size of reinforcement is found to be 3.5B × 3.5B irrespective of the type of reinforcing materials used. The optimum placement position of geotextile is found to be 0.5B from the base of the footing. At low settlement rates, the study on the values of BCR reveals almost the same results with regard to optimum depth and size of reinforcement mentioned above. It is found that with increase in the settlement rate, BCR increases. Also, the improvement in bearing capacity is found to increase with increase in footing size.


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