• International conference on construction engineering and project management
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• 2022.06a
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• pp.571-578
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• 2022

Modularization in a high-rise building is different from a small building, as it is exposed to more lateral forces like wind and earthquakes. The integrity, robustness, and overall stability of the modules and their performance is based on the joining techniques and strong structural systems. High lateral stiff construction structures like concrete shear walls and frames, braced steel frames, and steel moment frames are used for the stability of high-rise modular buildings. Similarly, high-rise stick-built buildings have concrete cores and perimeter frames for lateral load strength and stiffness. Methods for general steel-concrete connections are available in many works of literature. However, there are few modular-related papers describing this connection system in modular buildings. This paper aims to review the various research and practice adopted for steel-to-concrete connections in construction and compare the methods between stick-built buildings and modular buildings. The literature review shows that the practice of steel module-to-concrete core connection in high-rise modular buildings is like outrigger beams-to-concrete core connection in stick-built framed buildings. This paper concludes that further studies are needed in developing proper guidelines for a steel module-to-concrete core connection system in high-rise modular buildings.

• Journal of Korean Society of Steel Construction
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• v.12 no.5 s.48
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• pp.569-579
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• 2000

An improved multi-level (IML) optimization algorithm using automatic differentiation (AD) of framed structures is proposed in this paper. For the efficiency of the proposed algorithm, multi-level optimization techniques using a decomposition method that separates both system-level and element-level optimizations, that utilizes and an artificial constraint deletion technique, are incorporated in the algorithm. And also to save the numerical efforts, an efficient reanalysis technique through approximated structural responses such as moments and frequencies with respect to intermediate variables is proposed in the paper. Sensitivity analysis of dynamic structural response is executed by AD that is a powerful technique for computing complex or implicit derivatives accurately and efficiently with minimal human effort. The efficiency and robustness of the IML algorithm, compared with a plain multi-level (PML) algorithm, is successfully demonstrated in the numerical examples.

• Steel and Composite Structures
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• v.10 no.1
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• pp.23-43
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• 2010

In this paper, a nonlinear model is developed using the component method in order to represent the response of steel connections under various loading conditions and temperature variations. The model is capable of depicting the behaviour of a number of typical connection types including endplate forms (extended and flush) and angle configurations (double web, top and seat, and combined top-seat-web) in both steel and composite framed structures. The implementation is undertaken within the finite element program ADAPTIC, which accounts for material and geometric nonlinearities. Verification of the proposed connection model is carried out by comparing analytical simulations with available results of isolated joint tests for the ambient case, and isolated joint as well as sub-frame tests for elevated temperature conditions. The findings illustrate the reliability and efficiency of the proposed model in capturing the stiffness and strength properties of connections, hence highlighting the adequacy of the component approach in simulating the overall joint behaviour at elevated temperature.

• Steel and Composite Structures
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• v.26 no.3
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• pp.361-373
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• 2018

This paper presents the development of finite element (FE) models to simulate the behavior of diagonally stiffened steel plate shear wall systems (SPSWs) with differently shaped openings subjected to a cyclic load. This walling system has the potential to be used for shear elements that resist lateral loads in steel-framed buildings. A number of $\text\tiny{^1/_2}$-scale one-story buildings that were un-stiffened, stiffened and stiffened with opening SPSWs are modeled and simulated using the finite element method based on experimental data from previous research. After validating the finite element (FE) models, the effects of infill plate thickness on the cyclic behavior of steel shear walls are investigated. Furthermore, triple diagonal stiffeners are added to the steel infill plates of the SPSWs, and the effects are studied. Moreover, the effects of a number of differently shaped openings applied to the infill plate are studied. The results indicate that the bearing capacity and shear resistance are affected positively by increasing the infill plate thickness and by adding triple diagonal stiffeners. In addition, the cyclic behavior of SPSWs is improved, even with an opening in the SPSWs.

• Steel and Composite Structures
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• v.46 no.5
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• pp.591-609
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• 2023

In some buildings, the lateral structural response of steel framed buildings depends on the shear walls and it is very important to study the behavior of these elements under near-field seismic loads. The link beam in the opening of the shear wall between two wall plates is investigated numerically in terms of behavior and effects on frames. Based on the length of the beam and its bending and shear behavior, three types of models are constructed and analyzed, and the behavior of the frames is also compared. The results show that by reducing the length of the link beam, the base shear forces reduce about 20%. The changes in the length of the link beam have different effects on the degree of coupling. Increasing the length of the link beam increases the base shear about 15%. Also, it has both, a positive and a negative effect on the degree of coupling. The increasing strength of the coupling steel shear wall is linearly related to the yield stress of the beam materials, length, and flexural stiffness of the beam. The use of a shorter link beam will increase the additional strength and consequently improving the behavior of the coupling steel shear wall by reducing the stresses in this element. The link beam with large moment of inertia will also increase about 25% the additional strength and as a result the coefficient of behavior of the shear wall.

• Journal of Ocean Engineering and Technology
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• v.16 no.4
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• pp.25-31
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• 2002

This paper is to find optimum design of plane framed structures with discrete variables. Global search algorithms for this problem are Genetic Algorithms(GAs), Simulated Annealing(SA) and Shuffled Complex Evolution(SCE), and hybrid methods (GAs-SA, GAs-SCE). GAs and SA are heuristic search algorithms and effective tools which is finding global solution for discrete optimization. In particular, GAs is known as the search method to find global optimum or near global optimum. In this paper, reinforced concrete plane frames with rectangular section and steel plane frames with W-sections are used for the design of discrete optimization. These structures are designed for stress constraints. The robust and effectiveness of Genetic Algorithms are demonstrated through several examples.

• Structural Engineering and Mechanics
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• v.31 no.1
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• pp.93-112
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• 2009

In this study seismic analyses of steel structures were carried out to examine the effect of ground motion characteristics and structural properties on energy demands using 100 earthquake ground motions recorded in different soil conditions, and the results were compared with those of previous works. Analysis results show that ductility ratios and the site conditions have significant influence on input energy. The ratio of hysteretic to input energy is considerably influenced by the ductility ratio and the strong motion duration. It is also observed that as the predominant periods of the input energy spectra are significantly larger than those of acceleration response spectra used in the strength design, the strength demand on a structure designed based on energy should be checked especially in short period structures. For that reason framed structures with buckling-restrained-braces (BRBs) were designed in such a way that all the input energy was dissipated by the hysteretic energy of the BRBs, and the results were compared with those designed by conventional strength-based design procedure.

• Earthquakes and Structures
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• v.7 no.6
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• pp.1241-1258
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• 2014

This is paper presents the results of an analytical study aimed at evaluating the effect of narrow-banded mainshock/aftershock seismic sequences on the response of structures built on very soft soil sites. Due to the scarce availability of recorded seismic sequences in accelerographic stations located in the lake-bed of Mexico City, artificial narrow-banded sequences were employed. In the first part of this study, a parametric investigation was carried out to identify the mainshock/aftershock ground motion features that have detrimental effects in the seismic performance of equivalent single-degree-of-freedom systems representative of framed-buildings that house standard and essential facilities. In the second part of this work, the seismic response of two (8- and 18-story) steel-moment resisting frames that house essential facilities is examined. It is concluded that buildings with fundamental periods of vibration longer than the dominant period of the mainshock can experience a significant increment in their inter-story drift demands due to the occurrence of an aftershock.

• Steel and Composite Structures
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• v.6 no.2
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• pp.159-182
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• 2006

Current fire design codes for determining the temperature within the structural elements that form part of a complete building are based on isolated member tests subjected to the standard fire. However, the standard time-temperature response bears little relation to real fires and doesn't include the effects of differing ventilation conditions or the influence of the thermal properties of compartment linings. The degree to which temperature uniformity is present in real compartments is not addressed and direct flame impingement may also have an influence, which is not considered. It is clear that the complex thermal environmental that occurs within a real building subject to a natural fire can only be addressed using realistic full-scale tests. To study global structural and thermal behaviour, a research project was conducted on the eight storey steel frame building at the Building Research Establishment's Cardington laboratory. The fire compartment was 11 m long by 7 m wide. A fire load of $40kg/m^2$ was applied together with 100% of the permanent actions and variable permanent actions and 56% of live actions. This paper summarises the experimental programme and presents the time-temperature development in the fire compartment and in the main supporting structural elements. Comparisons are also made between the test results and the temperatures predicted by the structural fire Eurocodes.

• Fire Science and Engineering
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• v.26 no.1
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• pp.80-88
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• 2012

This study evaluates the fire resisting capacity of the beam of the legal fire resistance construction, which establishes the Article 3 of the Regulations on Escape and Fire Resistance of Buildings. There are a total of five structures that we consider as legal fire resistance constructions, however, this study has a primary target of the reinforced concrete beam, and tests the fire-resistant performance depend on the covering depth of reinforce concrete. The results showed that it meets the three hours, the maximum statutory fire resistance time, if it was a load ratio of 0.5 and covering depth of 40 cm. Steel framed mortar beam is legal fire resistance structure that it was possessed three hours fire resistance performance, if it was a load ratio of 0.4 and covering depth of 60 mm.