• Steel and Composite Structures
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• v.24 no.5
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• pp.561-568
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• 2017

Steel frames are widely used in steel structures. Exiting steel structures may be needed to strengthen for various reasons. Carbon Fiber Reinforced Polymers (CFRP) is one of the materials that are used to strengthen steel structures. Most studies on strengthening steel structures have been done on beams and steel columns. No independent study, to the researcher's knowledge, has studied the effect of CFRP strengthening on steel frames. This study explored the use of CFRP composite on retrofitting square hollow section (SHS) steel frames, using numerical investigations. Ten Finite Element (FE) models, which were strengthened with CFRP sheets, were analyzed under different coverage length, number of layers, and location of CFRP composite. One FE model without strengthening was analyzed as a control FE model to determine the increase of the ultimate load in the strengthened steel frames. ANSYS software was used to analyze the SHS steel frames. The results showed that the coverage length and the number of layers of CFRP composite have a significant effect on increasing the ultimate load of the SHS steel frames. The results also showed that the location of CFRP composite had no similar effect on increasing the ultimate load and the amount of mid span deflection of the SHS steel frames.

• Steel and Composite Structures
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• v.17 no.3
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• pp.215-236
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• 2014

The flexural behaviour of steel beams significantly affects the structural performance of the steel frame structures. In particular, the flexural overstrength (namely the ratio between the maximum bending moment and the plastic bending strength) that steel beams may experience is the key parameter affecting the seismic design of non-dissipative members in moment resisting frames. The aim of this study is to present a new formulation of flexural overstrength factor for steel beams by means of artificial neural network (NN). To achieve this purpose, a total of 141 experimental data samples from available literature have been collected in order to cover different cross-sectional typologies, namely I-H sections, rectangular and square hollow sections (RHS-SHS). Thus, two different data sets for I-H and RHS-SHS steel beams were formed. Nine critical prediction parameters were selected for the former while eight parameters were considered for the latter. These input variables used for the development of the prediction models are representative of the geometric properties of the sections, the mechanical properties of the material and the shear length of the steel beams. The prediction performance of the proposed NN model was also compared with the results obtained using an existing formulation derived from the gene expression modeling. The analysis of the results indicated that the proposed formulation provided a more reliable and accurate prediction capability of beam overstrength.

• Journal of Korean Society of Steel Construction
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• v.27 no.5
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• pp.471-481
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• 2015

Modular building is a prefabricated construction system for building where factory-produced pre-engineered modular units are delivered to site and assembled as substantial elements of a building. There are two basic kinds of modular structures. One is a load-bearing wall structure designed to transfer the load through longitudinal walls. The other is a frame structure composed of columns and beams. For frame structure, square hollow section is often used as a column member and channel as a beam member in modular unit. Lower and upper modules are fasten with bolts via a pre-installed access hole in the SHS column. However, the access holes can weaken the panel zone that would affect the behavior of beam to column connection. The 5 specimens of beam to column connections with parameters of access hole, column thickness and diaphragm were made and this paper describes the test results.