Performance of RC frame structure with various beam to column flexural capacity ratio – a case study

The effectiveness of various Strong Column Weak Beam (SCWB) factors to enhance seismic performance is assessed for Reinforced Concrete (RC) frame building structures. In this study five RC frame buildings of different storey numbers have been analysed using different column overdesign factors. The results are compared as the influence of various SCWB factor over the expected performance of selected RC frame buildings in terms of enhancement in capacity and failure mechanism. With the lower value of SCWB factor insignificant change in capacity curve is observed while gradual improvement is observed with the higher factors. In terms of failure mechanism gradual change from column failure mechanism to beam failure is observed but the hinge formation at the base of bottom storey column is seen even with the higher value of SCWB factor. The effectiveness of alternative method of column flexural capacity enhancement by proposed modified SCWB (MSCWB) was also studied. MSCWB is found to be more effective in terms of enhancement in capacity curve and failure mechanism.

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Influence of structural irregularities on seismic performance of RC frame buildings

Journal of Engineering Issues and Solutions ◽

10.3126/joeis.v1i1.36820 ◽

2021 ◽

Vol 1 (1) ◽

pp. 70-87

Author(s):

Krishna Ghimire ◽

Hemchandra Chaulagain

Keyword(s):

Seismic Vulnerability ◽

Time History ◽

Frame Structure ◽

Rc Frame ◽

Building Structures ◽

Functional Requirements ◽

Finite Element Program ◽

Element Program ◽

Rc Frame Buildings ◽

Structural Irregularities

Irregular building structure is frequently constructed across the globe for fulfilling aesthetic as well as functional requirements. The structures with irregularities are the common building type in earthquake-prone country like Nepal. However, a post-earthquake reconnaissance survey reports revealed the high seismic vulnerability of the building with structural irregularities. In this context, the present study explores the influence of structural irregularities on performance of reinforced concrete (RC) frame structure. To this end, the structural irregularities are created in in the building structures. The geometrical irregularities are created by removing the bays in different floor levels. Likewise, the effect due to mass irregularities are studied by considering the swimming pool and game house at different floor levels. Furthermore, the stiffness irregularities are formulated by removing the building columns at different sections. All these irregularities are studied analytically in finite element program with 3-D structural models. The numerical analysis is done with non-linear static pushover and time history analysis. The results are analyzed in terms of fundamental time period, storey shear, storey displacement, drift and overturning moment. The results indicate that the level of irregularities significantly influenced the behavior of structures.

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Practitioner-friendly design method to improve the seismic performance of RC frame buildings

Earthquake Spectra ◽

10.1177/8755293020988019 ◽

2021 ◽

pp. 875529302098801

Author(s):

Orlando Arroyo ◽

Abbie Liel ◽

Sergio Gutiérrez

Keyword(s):

Seismic Performance ◽

Design Method ◽

Three Dimensional ◽

Rc Frame ◽

Structural System ◽

Standard Code ◽

Frame Buildings ◽

Rc Frame Buildings ◽

Mathematical Justification ◽

Story Building

Reinforced concrete (RC) frame buildings are a widely used structural system around the world. These buildings are customarily designed through standard code-based procedures, which are well-suited to the workflow of design offices. However, these procedures typically do not aim for or achieve seismic performance higher than code minimum objectives. This article proposes a practical design method that improves the seismic performance of bare RC frame buildings, using only information available from elastic structural analysis conducted in standard code-based design. Four buildings were designed using the proposed method and the prescriptive approach of design codes, and their seismic performance is evaluated using three-dimensional nonlinear (fiber) models. The findings show that the seismic performance is improved with the proposed method, with reductions in the collapse fragility, higher deformation capacity, and greater overstrength. Furthermore, an economic analysis for a six-story building shows that these improvements come with only a 2% increase in the material bill, suggesting that the proposed method is compatible with current project budgets as well as design workflow. The authors also provide mathematical justification of the method.

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