Role Of Infills Research Articles

Investigation of the seismic resilience of reinforced concrete special moment frames with infills

AbstractIn this paper, the role of infills in seismic resilience of reinforced concrete moment frames with special ductility is investigated. For this purpose, frames of 4, 8, and 12 stories are simulated in OpenSees software in three cases, namely, bare frame, frame with infills, and frame with infills having openings. Using incremental dynamic analysis, their capacity and demands are evaluated and fragility curves are plotted via statistical methods. Finally, resilience index is calculated by quantifying seismic damages under a selection of 15 earthquake records. Based on the results, infills decrease structural losses and increase resilience in different hazard levels. The effect of infills on resilience index grows in higher hazard levels and this is much more impressive in low rise frames. In the other hand, infill openings, less decrease the resilience index in tall buildings than shorter ones.

Effect of infills on seismic resilience of special steel moment resisting frames

This study evaluates the effects of infills on the seismic resilience of special steel moment resisting frames. For this purpose, three structures of 4, 8 and 12 story are selected and designed in three different modes namely without infills, with Infills and with infills having openings. Finite element models are developed in OpenSees software. Seismic capacity and demand of structures are calculated using incremental dynamic analysis (IDA). Then, using statistical methods and probabilistic functions based on inter story drifts of the structures, fragility curves are obtained according to the HAZUS instructions. Finally, by quantifying damages, changes in seismic resilience are assessed. This makes it possible to relate the probability functions, fragility and resilience curves in an integrated approach. The results of the analysis show that infills may significantly reduce structural damages and an increase its resilience at different risk levels. The role of infills in increasing the resilience index is highlighted by the increase in risk level. This increase has been far more significant in low rise frames. It is also observed that the decreasing effect of infill openings in resilience index of high-rise buildings is less than low-rise ones although insignificant in some cases which can be overlooked.

Seismic Loss Estimation in Pre-1970 Residential RC Buildings: The Role of Infills and Services in Low–Mid-Rise Case Studies

The lessons learned after recent earthquakes have highlighted the key role played by infills and services in damage and loss of Reinforced Concrete (RC) buildings. Their influence in seismic performance and loss estimation of selected RC building case studies is thoroughly analyzed here. The case study selection aims to be representative of existing buildings built in Italy before 1970, and covers a different number of stories and design typologies. The seismic responses of the case-study buildings are numerically analyzed by means of non-linear static pushover analysis (PO) considering a lumped plasticity approach with a quadri-linear flexural response for beam/column elements (properly calibrated for RC elements reinforced with plain bars) and a tri-linear compressive-only axial response with diagonal concentric struts for infill panels (empirically derived from experimental data on hollow clay masonry walls). Economic loss estimation is carried out via a component-based methodology that relies on the main repairing activities and resultant costs required for the refurbishment of infills and services for different damage levels. Accordingly, a damage analysis is performed herein, given the intensity measure, based on a comparison between Interstory drift demand from PO analysis and drift-based fragility functions specific for masonry infills. Loss curves, relating the total building repair cost to peak ground acceleration (PGA), are presented and compared for the analyzed case study buildings to show their trends and quantify the incidence of infills and services with respect to the reconstruction cost. A comparison between these outcomes and those recently found in the literature emphasizes the robustness of the considered approach and the reliability of the hypotheses about damage and loss assessment.

Infill as catalyst for vivid urban fabric formation – A study on increasing walk-ability in Hong Kong

By envisioning Hong Kong as a city formed by fractals, the pattern of old districts are examined, and the urban elements which moderate the problems of mega-development and high density living are identified. The study focuses on exploring the impact of infill to generate city form under the aspects of perforated and crinkled fractals, scale moderation, functional diversity and unfolded functions inside-out. A pattern measure is adopted to study the psychological responses of archetypal spaces in the urban fabric of one study district. Although the role of infill and lanes to enhance an ‘exciting’ urban fabric is not obvious, infill can be seen to work as a catalyst to create a vivid city fabric in many aspects – scale, diversity and walk-ability. The findings about the smallest fractal scale – infill, may trigger our exploration into new architecture which engages sustainable urban development and involves inclusion of multi-layer fractals instead of creating monochromatic mega structures of retail and residential projects. The focus of urban design should shift towards the creation of qualities that create vibrant neighbourhoods and contribute to a successful world city that evolves and maintains its attractiveness through time.