• Journal of the Society of Naval Architects of Korea
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• v.40 no.2
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• pp.63-68
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• 2003

With the trend of large-sized ship in Korea, recently several hundreds of thousands of U-bolts for a year have been used as a pipe fastener In this paper, we have evaluated the strength for present U-bolt structure by pipe supporting conditions(deck, ceiling and wall mounting type) For this purpose, the equivalent and bending stresses have been calculated by linear elastic analysis using the finite element program ABAQUS. At the same time, a variety of load conditions such as design pressure, weight effect and acceleration are also considered.

• Steel and Composite Structures
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• v.28 no.6
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• pp.681-690
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• 2018

This paper highlights results of some experimental work that deals with strengthening of bolted shear joints in thin-walled ferrocement structure where steel wires, bent into U-shape are considered as simple inserts around the bolt hole. The parameters investigated include the number of layers of wire mesh, edge distance of bolt hole, size and location of the inserts. Test results have shown that for small edge distance, failure occurred either in cleavage or shearing mode, and the strength of the joint increased with an increase in the edge distance. This continued up to an upper limit set by either tension or bearing failure. The experimental study further revealed that for a given edge distance the strength of a joint can significantly be enhanced by using U-inserts. The equations developed for predicting joint strength in ferrocement composites can also be modified to include the effects of the inserts with a good level of accuracy.

• Smart Structures and Systems
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• v.32 no.2
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• pp.111-121
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• 2023

This study proposes an automated assembly performance evaluation method for prefabricated steel structures (PSSs) using machine learning methods. Assembly component images were segmented using a modified version of the receptive field pyramid. By factorizing channel modulation and the receptive field exploration layers of the convolution pyramid, highly accurate segmentation results were obtained. After completing segmentation, the positions of the bolt holes were calculated using various image processing techniques, such as fuzzy-based edge detection, Hough's line detection, and image perspective transformation. By calculating the distance ratio between bolt holes, the assembly performance of the PSS was estimated using the k-nearest neighbors (kNN) algorithm. The effectiveness of the proposed framework was validated using a 3D PSS printing model and a field test. The results indicated that this approach could recognize assembly components with an intersection over union (IoU) of 95% and evaluate assembly performance with an error of less than 5%.

• Steel and Composite Structures
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• v.1 no.1
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• pp.17-32
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• 2001

The Rosette-joining system is a completely new press-joining method for cold-formed steel structures. One Rosette-joint has a shear capacity equal to that of approximately four screws or rivets. The Rosette thin-walled steel truss system presents a new fully integrated prefabricated alternative to light-weight roof truss structures. The trusses are built up on special industrial production lines from modified top hat sections used as top and bottom chords and channel sections used as webs which are joined together with the Rosette press-joining technique to form a completed structure easy to transport and install. A single web section is used when sufficient but can be strengthened by double-nesting two separate sections or by using two lateral profiles where greater compressive axial forces are met. An individual joint in the truss can be strengthened by introducing a hollow bolt into the joint hole. The bolt gives the connection capacity a boost of approximately 20%. A series of laboratory tests have been carried out in order to verify the Rosette truss system in practice. In addition to compression tests on individual sections of different lengths, tests have also been done on small structural assemblies and on actual full-scale trusses of a span of 10 metres. Design calculations have been performed on selected roof truss geometries based on the test results, FE-analysis and on the Eurocode 3 and U.S.(AISI) design codes.