Your search within this document for 'Building' resulted in 13 matching pages.
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“...International Journal of Civil Engineering https://doi.Org/10.1007/S409 99-018-0297-9 RESEARCH PAPER CrossMaik Seismic Assessment of a School Building in Nepal and Analysis of Retrofitting Solutions Hugo Rodrigues* 1 • Andre Furtado2 • Nelson Vila-Pouca2 • Humberto Varum2 • Andre R. Barbosa3 Received:25 September 2017 /Revised: 21 February 2018 / Accepted:27 February 2018 © Iran University of Science and Technology 2018 Abstract Recent earthquakes highlighted the vulnerability of some infilled reinforced concrete structures due to the presence and distribution of the infill masonry walls. Buildings such as school buildings and residential buildings are typically not designed considering the contribution of the infill panels to the structure strength and stiffness, when these are subjected to earthquakes. The lack of consideration of the infill panel results in observed poor performance and structural collapses. This manuscript presents a numerical study of a school in Nepal, representative...”
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“...terms of peak inter-storey drift, peak base shear and inter-storey drift profile. 2 Case Study 2.1 Architectural and Structural Description The school building under study belongs to the Tarun Ma Vi school, located in Balaju, Kathmandu, Nepal. The architecture of the school follows the typical standards for this type of infrastructure in Nepal. The structure is rectangular in plan and is composed of the ground floor (Storey 1) and three upper floors (Storeys 2, 3, and 4—Roof top), in which the last storey is set back, as shown in Fig. 1. At all upper floor level, in the front and back of the building, is developed an accessible cantilevered balcony along the building. There is also a plan extension on the 2nd floor level, which cantilevers off the right end of the building. The building plan is 5.5 m wide by 27.1 m long. The total building height is 12.4 m. The structure consists on ten transverse RC frames (frames A to J) and two longitudinal RC frames (frames 1 and 2). All transverse frames...”
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“...International Journal of Civil Engineering (a) (c) Fig. 1 Case study building dimensions: a general view; b ground floor building plan; and c front view (dimensions in mm) transverse reinforcement for all columns consists of 04.75 spaced at 150 mm on center. The beams have cross section of 400 x300mm2 with reinforcing steel consisting 3012 on top and 3012 on the bottom (Fig. 3). 2.2 Numerical Modeling and Calibration A three-dimensional (3D) numerical model was developed using the software SeismoStruct [15]. This software was developed with the goal of providing the expected behavior of different types of structures when subjected to ground shaking due to earthquake loading. SeismoStruct allows for Springer...”
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“...for: a concrete; b steel; c infill masonry wall (compression/tension struts); and d infill masonry wall (shear springs) the use of 3D models and for consideration of geometric and material nonlinearity. In addition, the software has an extensive library of different elements and material models that can be used to model reinforced concrete structures with masonry infills, such as the case study analyzed herein. The 3D model was developed considering the real configuration and geometry of the building as well as the location of the infill walls that were confirmed in situ [16]. The RC structure was simulated through non-linear lumped plasticity beam-column element models that are available in the SeismoStruct element library. A plastic hinge length equal to the largest dimension of the RC cross section was assumed, following recommendations in the literature [17, 18]. It was adopted 200 fibers for each cross section for a better representation of the seismic response of the RC elements. Two...”
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“...load equal to 0.5 kN/m2 corresponding to a Nepalese school building. The numerical model was calibrated based on the natural frequencies obtained by Bose et al. [16]. More details regarding the ambient vibration tests can be found in Bose et al. [16]. Figure 5 shows the first three vibration modes with the corresponding numerical and experimental frequencies. A good agreement was obtained with slight differences in the first and second mode that are transverse and longitudinal modes, respectively, with a maximum difference of 2% found in both vibration modes. The third mode is a torsional mode and presents experimentally and numerically obtained frequencies show a difference of approximately 2.5%. 3 Seismic Vulnerability Assessment of the Original Case Study School Building 3.1 Introduction The seismic vulnerability assessment of a school building is performed to predict the expected vulnerability and performance of the building when subjected to intense earthquake-induced ground shaking...”
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“...that retrofit strategies be implemented to improve the building’s seismic performance or, in some exceptional cases, a partial or total demolition and reconstruction of the structure may be warranted. Eurocode 8 [25] suggests four analysis methods, of which two are linear and the other two non-linear. In the present work, it was assumed that the material non-linearity and non-linear dynamic time history response analyses were the most appropriate tool to assess the seismic vulnerability of the building. Throughout the following sub-sections, the methodology adopted to assess the seismic vulnerability of the structure will be presented and the results will be presented and discussed in detail. 3.2 Methodology The seismic assessment methodology used is based on the analysis of the peak inter-storey drift ratios reached by the different floors of the structure during the non-linear time history response analysis. These peak inter-storey drift ratios are compared with global drift ratio limits...”
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“...distribution of the infill masonry walls. It must be mentioned that the irregular mass introduced by the balcony at this level of the structure amplified the torsion mechanism, which exacerbated the poor performance of the structure at this storey; • Globally, the structure is considered vulnerable to seismic actions and it is considered that urgent interventions are necessary at Storeys 1 and 3 for this building structure. While this is a single-case study, several schools in the country follow similar designs, and the findings here highlight the importance of the review of all school building designs, especially in the urban areas of the Kathmandu Valley as well as in other urban areas in the region. 3.3.3 Capacity Curve and Peak Base Shear Non-linear static pushover analyses, assuming uniform, triangular and adaptive load patterns, were carried out in two numerical models: (1) considering the RC frame only, and (2) considering both the RC frame and the infill masonry walls. Figure 10 shows...”
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“...analyses confirmed the occurrence of mechanisms such as soft-storey (longitudinal direction) due to the layout and distribution of the masonry infill walls. In the transverse direction, vulnerability of Storey 1 and Storey 3 are mainly due to the reduction of the cross section of the RC columns at the base of Storey 3, combined with the irregular distribution infill masonry walls along the height of the building and the eccentricity caused by the staircase and cantilevered balcony at the third floor level. The inadequate performance and undesired modes of damage for this case study building lead to the need for developing retrofit interventions that address the vulnerabilities, especially at the Storeys 1 and Fig. 9 Non-linear dynamic analysis results of peak inter-storey drift ratio in the longitudinal direction for a Storey 1, b Storey 2, and c Storey 3; and peak inter-storey drift in the transverse direction for d Storey 1, e Storey 2, and f Storey 3 (f) kb Springer .........Partial Co...”
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“...construction. In this solution, the materials and properties defined for infill masonry walls used in the original structure, as summarized in Table 3, are used. Thus, two infill panels are added in Storey 3, in the direction of grid lines F and H shown in Fig. lb. The main advantage of this solution is that it addresses the issue of the vertical irregularity of stiffness provided by the infill walls. However, the main disadvantage is on the impact of the functionality of the space. In the original building, the space where the walls are introduced corresponds to open space library for the students; 2. RC jacketing of all columns (RCJ): The RC jacketing of columns is a commonly used technique in Nepal as reported by Chaulagain et al. [31]. This retrofit solu-...”
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“...joints, and the possible need of strengthening the foundations [33]. Financially, it is considered to be an expensive solution since it requires high level of workmanship and sometimes requires that foundations also be strengthened. This can correspond to high direct construction costs as well as high indirect costs associated with the needed time for the retrofit and disruption of normal building functionality [34], Regarding the design of the new cross section for the columns and corresponding reinforcing steel detailing, as the main purpose of the retrofitting technique is to increase the building lateral stiffness, the minimum reinforcing steel requirements and section detailing designs according to Eurocode 8 [35], for example, can be adopted assuming a medium ductility class. In this case study, the new column section adopted is 500 x500mm2. The added longitudinal reinforcing steel is 16-mm-diameter steel bars, while the transverse reinforcement corresponds to 8-mm-diameter reinforcing...”
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“...International Journal of Civil Engineering Fig. 12 Distribution of the steel braces adopted for the retrofit: a Storey 1; b Storey 2; and c Storey 3 (dimensions in mm and location of steel braces shown in red) Table 6 Natural frequencies of the building with and without retrofit solutions (Units in Hz) Mode Original IIMW RCJ-GF RCJ-TOT SB Transv. 3.80 3.94 4.15 4.28 4.11 Long 4.09 4.05 4.70 4.89 4.76 Torsion 4.83 4.83 5.35 5.40 5.04 Table 6 presents results for the first three natural frequencies for each of the numerical models developed, with and without consideration of the seismic retrofitting. Figure 13 shows the 5% linear elastic acceleration response spectra corresponding to the average of 21 spectra of acceleration of accelerograms evaluated in this work, and the fundamental frequency values of numerical models with and without retrofit solutions. It can be observed that all the retrofit strategies did modify significantly the natural frequencies of the structure. The RCJ-TOT model...”
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“...school building in Nepal and study the efficacy of different strengthening solutions to be applied. The analyses for evaluating the building and the respective strengthening solutions were based on state-of-the-art numerical models that consider the non-linear behavior of the structures when subjected to earthquake-induced ground shaking. The assessment methodology consisted of performing both non-linear static and non-linear dynamic analyses. Results from the non-linear dynamic analyses indicated that the structure had large drift values in Storey 1 for the longitudinal direction, and in the Storeys 1 and 3 for the transverse direction. Additionally, using the data obtained from different analyses performed (pushover and dynamic), it was possible to compare the two methodologies and assess the adequacy of the pushover analysis, reinforcing findings existing in the literature. From the seismic vulnerability assessment of the original structure, it was concluded that the building proved...”
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“...Innovative Inf Solut 1 (1):1 14. Varum H, Furtado A, Rodrigues H, Dias-Oliveira J, Vila-Pouca N, Arede A (2017) Seismic performance of the infill masonry walls and ambient vibration tests after the Ghorka 2015, Nepal earthquake”. Bull Earthq Eng 15,3, 1185-1212 15. SeismoSoft (2004) SeismoStruc- A computer program for static and dynamic nonlinear analysis of framed structures [online],” ed: Available from URL: http://www.seismosoft.com 16. Bose S et al. (2016) Structural Assessment of a School Building in Sankhu, Nepal Damaged Due to Torsional Response During the 2015 Gorkha Earthquake. In: S. Pakzad and C. Juan (eds) Dynamics of civil structures, Volume 2: Proceedings of the 34th IMAC, A Conference and Exposition on Structural Dynamics 2016. Cham: Springer International Publishing,, pp. 31-41 17. Rodrigues H, Varum H, Arede A, Costa A (2012) A comparative efficiency analysis of different non-linear modelling strategies to simulate the biaxial response of RC columns. Earthq Eng Eng Vib 11:553-566...”