See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/348558245 Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure Article in INTERNATIONAL JOURNAL OF ADVANCED ENGINEERING AND MANAGEMENT · January 2021 CITATIONS READS 11 2,967 2 authors: Bikram Bhusal Satish Paudel Tribhuvan University University of Nevada, Reno 18 PUBLICATIONS 100 CITATIONS 52 PUBLICATIONS 291 CITATIONS SEE PROFILE All content following this page was uploaded by Bikram Bhusal on 17 January 2021. The user has requested enhancement of the downloaded file. SEE PROFILE International Journal of Advanced Engineering and Management ISSN: 2456-8066 Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure Bikram Bhusal1, Satish Paudel2 [1] Lecturer, National College of Engineering, Tribhuvan University, Nepal, Email: bikramrijal103@gmail.com [2] PhD Student, School of Civil Engineering and Technology, Sirindhorn International Institute of Technology, Thammasat University, Pathum Thani, 12120, Thailand, Email: d6122300145@g.siit.tu.ac.th AbstractThe study focusses on the comparision of practicing seismic design codes, Nepal building code (NBC) and Indian standard (IS) both revised and existing in analysis and design aspect for the reinforced concrete building structures. With consideration of several design compliances a study is performed in evaluation of a G+6 building located in Kathmandu, Nepal. Various response parameters were compared for the studied prototype building using linear static and dynamic approaches. From the study all of the response parameters were observed to be predicted greater from the revised NBC 105:2019 as compared to other studied codal provisions. Longitudinal rebar percent in column was observed to be almost similar for NBC 105:2019 and IS 1893:2016. The period of vibration predicted by the revised code is higher than the existing ones since the reduced stiffness (considering crack section) is adopted in both revised IS 1893:2016 and NBC 105:2019. Keywords Nepal Building Code; Indian Standard Code; response spectrum, seismicity 1. INTRODUCTION Due to the movement of tectonic plates along the Himalayan belt, several faults have been formed resulting in making the entire territory of Nepal in high seismic hazard zone. With the longest seismic belt (app 800 km-long) which is formed by movement of Indian plate beneath the Eurasian plate at the rate of 30 - 40 mm/year [1]. As a result 17 percent of largest earthquakes in the world [2] have occurred in the region and placed as the 11th most earthquake-prone country in terms of seismic vulnerability [3]. From the study of Gupta and Das [4] due to the tectonic movement, accumulation of strain energy is occurred with potential of generating greater than ππ€ 8+ earthquakes. Also, a total of 92 active faults have been mapped throughout the country by the Seismic Hazard Mapping and Risk Assessment for Nepal carried out as part of the Building Code Development Project – 1992-1994 [5]. The tectonic environment of Nepal is distinct and complicated with variance in geology making it decorated with major seismic activities including most imperative in 1255, 1810, 1866, 1934, 1980, 1988 and most recent of 2015 A.D. [6]. After major seismic event of 1988 A.D., Nepal National Building Code (NBC) in 1994 AD was formulated by Department of Urban Development and Building Construction (DUDBC). In 25 April, 2015 having Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 moment magnitude of 7.8, with epicenter in Barpak Gorkha occurred major shaking was felt with recorded peak ground acceleration of PGA1=0.158g, PGAv=0.186g and PGA2=0.164g respectively at east-west, up-down and north-south direction as per Acceleration Histories from USGS Station in Kantipath (15 Km from Fault) [7]. The damage of about 800,000 houses were observed with most destroyed and 250,000 were partially damaged causing 8790 deaths and 22,300 injuries and 31 out of total 75 districts were deemed as most affected with 14 severely affected [8]. The damage was observed to be more in residential structure located in rural areas in mountainous terrain with more than 96% comprising of the load bearing structures [9]. Although, before this major seismic event the country was still encouraging the use of the NBC 105 :1994 [10] the dynamism of the code was still questionable since it was not revised for a long time. Even though, introduction of NBC, with no restriction on any policy level Indian Standards was and even is widely adopted, if not more. This can also be justified with the boundary of Nepal and India is along three directions with similar soil profile and tectonic environment. Even as of now, the provided compliance of both codes sufficiently ratifies seismic resistant design philosophy and hence the choice depends on the designer’s expertise. With revision of both standard i.e., IS 1893 2016 [11] and NBC 105 2019 [12] major changes have been incorporated which should be well understood by practicing Engineers. Moreover, NBC was functional without revision since 1994 with its first revision in 2019 so we aim to identify the placement of revised NBC 2019 with the notable code IS 1893 2016 with a prototype RC building in current study. So, an attempt will be done to study the updated compliances and compare with the existing ones. Hence, the study is performed to compare the codal provisions with a numerical model created in ETABS Vs 2019. 2. due to variation of seismicity, distinct or localized nature of earthquake, characteristics of ground motion, available construction technology and skilled manpower, safety level usually varies from place to place. Moreover, to address the safety and serviceabity of the occupants within and the structure it is better if we consider national seismic codes. Hence, a study is proposed for placement of the revised NBC 105 :2019 with the most used Indian standard 2.1. NEPAL BUILDING CODE FOR SEISMIC DESIGN Following the Udayapur earthquake of 1988 A.D, Nepal National Building Code (NBC) in 1994 AD was formulated by Department of Urban Development and Building Construction (DUDBC). The formulation process was supported by United Nations Center for Huma settlements (UNCHS), the Ministry of Housing and Physical Planning (MHPP) with the support of consultants and was released in 1994. Although, NBC got its shape with several provisions related to seismic design in 1994, it seemed to enact around 9 years in 2003. With the use of NBC since 2003 for almost 15 years around 30% of the existing building stock is believed to be constructed following the provision of NBC 105 1994. The major concern previously was about the dynamism of NBC was since it was not revised even after the Nepal-Sikkim (MW 6.9) border earthquake of 2011 and the Gorkha earthquake (MW 7.8) of 2015. Now, as NBC 105:1994 was revised in 2019, the dynamism in seismic provisions within the code is still to be researched. The revision process was formally initiated after the major seismic event of Gorkha Earthquake. The project was initiated from the Central level project Implementation Unit (CLPIU) of the Earthquake emergency assistance project (EEAP) funded by ADB and the whole process is under Ministry of Urban development (MoUD) and later is transferred to the National Reconstruction Authority (NRA), Government of Nepal. OVERVIEW OF COMPLIANCES OF STUDIED CODAL PROVISIONS With no argument it can be mentioned that the primary objective of all the building code is to save life and property of the owners with providing several analysis and design provisions. However, Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 In NBC 105:1994 three soil types including Subsoil type -I, II and III were adopted in construction of basic response spectrum and seismic coefficient. These soil types were further classified as per standard penetration resistance (SPT) for the labeled depth and undrained shear strength for cohesive soils. However, for the revised code NBC 105:2019 four soil types including Soil type -A, B, C and D is considered with type D being very soft soil type with location inside Kathmandu valley. In NBC 105 1994 and NBC 105:2019 both for the design of the structural members both working and limit state design method is allowed however, limit state is encouraged in case of design of RC structures. Linear static approach is used for the structures with overall height limited to 40m, otherwise response spectrum method should be used. Provisions can’t be found for non-linear static and dynamic analysis, however since international practices are endorsed in the standard making open space for all the analysis options available to be used. At least 90% of the total mass should be participated for response spectrum analysis of the structures. However, torsional effects occurred due to structural irregularity is not made mandatory while a clause is outlined saying “an analysis of torsion may be conducted by static method.”. Vertical component of ground motion is suggested for secondary structural elements in revised NBC 105:2019. The inter-story drift (ratio of top displacement to height) is limited to 0.01 with permitted maximum of 60 mm Fig 1. Seismic hazard map of NBC 105:2019 [12] The revised NBC 105:2019 divides the whole country into several seismic zones with uniform hazard within the zone. The zone factor can be obtained in tabular form for 475 years return period for selected municipalities and as a whole can be estimated from the seismic hazard map of the country as seen in Fig 1. NBC 105:2019 more specifically discusses the ultimate limit state and serviceability limit state for calculations of the performance characteristics of the structures i e., in estimation of horizontal base shear coefficients, ductility factors etc. Apart from the old one revised NBC 105:2019 incorporates vertical acceleration on load combination, changes in drift requirements and calculation of seismic forces with more as provided in Table 2. The revised NBC 105 2019 have incorporated the design ductile detailing for all the structural elements. For fulfilling strong column weak beam philosophy, the beam column capacity ratio is considered to be greater than 1.2 which will finally avoid the formation of plastic hinge in the Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 column. The Standard further explains the conditions where the vertical seismic shaking shall be considered as structures having structural members with any or more complaint including span more than 20m, cantilever projection more than 5m, pre-stressed component and in base isolated structures 2.2. INDIAN STANDARD CODE FOR SEISMIC DESIGN For the seismic resistant design of structures Bureau of Indian Standard formulated the criteria namely (ISC) [IS 1893-2002 (part I)] [13] which is widely practiced in India and South Asia. The revised version of the standard after Bhuj earthquake in 2002 includes dedicated design criteria and is adopted in designing structures. Since till date sixth revision is also performed in 2016 so this study was performed to explore the parameters updated in the new revision. The standard divides the entire country into four seismic zones from II to V with active seismic zone (severe shaking) as zone V. Moreover, IS 1893: 2016 standard have suggested recommendations on adoption of vertical shaking for design of building structures. Sa(g) IS 1893:2016 0.18 IS 1893:2002 0.16 NBC 105:1994 0.14 NBC 105:2019 ultimate limit state 0.12 NBC 105:2019 serviceabality limit state 0.1 0.08 0.06 0.04 0.02 0 0 1 2 3 Period (sec) 4 5 6 Fig 2. Comparision of the Response spectrum curve for studied codal provisions The Standard further explains the conditions where be located in Kathmandu, Nepal. For NBC 105: 2019 the vertical seismic shaking shall be considered as the distinction is provided among ultimate limit state structures having large overhangs in horizontal and serviceability limit state so the response spectrum direction or long spans, located in severe seismic is drawn for both states. zones (IV or V), resting on soft soil, Bridges, with The comparision of provisions in the studied code is plan or vertical irregularities (CL 6.3.3.1 IS shown in Table 1. 1893:2016). The response spectrum coefficient for the existing and revised codal provisions are presented in Fig 2. The soil type is adopted as soft soil for NBC 105:1994, IS 1893:2002, IS 1893:2016 while very soft for NBC 105:2019 for plotting the response spectrum since the building is assumed to Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 Table 1. Codal Provisions for various Parameters Codal Provision NBC 105:1994 Method ππ = 0.06π»0.75 ππ = ππ‘ π»0.75 ππ‘ frame Time Period Steel frames IS 1893:2002 IS 1893:2016 ∑ππ=1 ππ ππ 2 T1 =2 π √ π ∑ππ=1 πΉπ ππ 2 Rayleigh Concrete NBC 105:2019 0.075 ππ = 0.085π» 0.75 0.085 RC ππ Bare Same as IS frame = 0.075π»0.75 infill 1893: 2002 Steel ππ MRF concrete MRF steel frames Rc = 0.085π»0.75 structural Ta = 0.075 π»0.75 √π΄π€ walls Eccentrically With brick Ta = 0.09 π» 0.075 √π braced steel frame infill With brick Ta = 0.09 π» others √π Ta = 0.09 π» √π infill 0.05 All others V = π΄β ππ‘ , V = πΆπ ππ‘ , V = πΆπ (π1 )ππ‘ , π Base Shear and Horizontal Seismic coefficient πΆπ = πΆππΌπΎ πΆ (π) = πΆβ (π)ππΌ π΄β = π ( ) ( π) 2 π π ( ) πΌ Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 πΆπ (π1 ) = πΆ (π1 ) π π Ωπ’ (ultimate) πΆπ (π1 ) = πΆπ (π1 ) Ωπ’ (serviceability) πΆπ (π1 ) = 0.2 πΆ (π) 2 πΆπ£ (ππ£ ) = π 3 Vertical shaking π΄π£ = 2 π 3 2 ( π₯ ) (2.5) π ( ) πΌ πβπ Fi = V π π π ∑π=1 ππ βπ π Lateral Force distribution πβ2 πβ Fi = V∑ π π ππ βπ Fi = V∑π π π π=1 ππ βπ K depends on 2 structural period 1.2DL + 1.5LL DL + πLL ± (ELx EL can be elaborated as 1.5DL + 1.5LL Load Combination DL + 1.3LL + 1.25EL ±0.3 ELy ) 0.9DL + 1.25EL DL + πLL ± (0.3ELx DL + 1.3SL + 1.25EL ± ELy ) 1.5DL ± 1.5EL 0.9DL ± 1.5EL 1.2DL + 1.2LL ± 1.4πΈπΏ ± ELx ± 0.3 ELy ± 0.3 ELz ± ELy ± 0.3 ELz ± 0.3 ELx ± ELz ± 0.3 ELx ± 0.3 ELy π = 0.6 for storage facilities Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 =0.3 for other usage Flexure πΈπ πΌπ 0.35 πΈπ πΌπ πΈπ πΌπ 0.35 πΈπ πΌπ Shear πΈπ π΄π€ 0.4 πΈπ π΄π€ πΈπ π΄π€ πΈπ π΄π€ Flexure πΈπ πΌπ 0.7 πΈπ πΌπ πΈπ πΌπ 0.7 πΈπ πΌπ Shear πΈπ π΄π€ 0.4πΈπ π΄π€ πΈπ π΄π€ πΈπ π΄π€ Beams Effective Stiffness (RC) Columns Effective Beams With no reduction gross-stiffness value shall be used i.e., for flexure πΈπ πΌπ and for shear πΈπ π΄π€ Stiffness Columns (Steel) a) 25% of design live load up 60% reduction for to 3 kPa b) 50% of design storage, 30% reduction a) 25% of design live load up to 3 kPa b) 50% of design live load above 3 kPa c) not for otherwise with no live load above 3 kPa c) not considered for roofs. considered for roofs. reduction for roof Seismic Weight Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 The revised NBC 105:2019 and IS 1893 :2016 both have highlighted use of vertical acceleration as already discussed in previous sections. Ghobarah A and Elnashai A.S. 1998 [14] have studied contribution of vertical shaking to damage of buildings. The seismic response of non-ductile low and medium rise building structure was evaluated with and without vertical seismic excitation. It was observed that the performance of the studied structure was affected after incorporation of vertical shaking and was concluded on encouraging the vertical motion in the analysis especially in the buildings located in the vicinity of active faults. It is usually thought of ratio of vertical to horizontal pga less than one. The average value of V/H was proposed originally by Newmark et al., 1973[15] as 2/3 and with study of Collier and Elnashai 2001 [16] the ratio was confirmed as greater than 1 and greater than 2/3 for the source located within 5 km and 25 km radius and also was observed to be influenced by magnitude of event 3. METHODOLOGY AND GEOMETRIC DATA For the numerical study a prototype building model of seven-storey (G + 6, 21-m height above plinth level) was considered. The prototype building is assumed to incorporate the typical construction practice in Kathmandu, Nepal. The plan is rectangular with dimension of 12 m × 12m in x and y-direction with 4 and 4 nos. of bays respectively and is depicted in Fig 4. The structure is modelled in ETABs Vs 19 modelling tool [17] with the available modelling opportunity. The characteristic compressive strength of concrete was considered as 25MPa and yield strength of reinforcement as 500MPa for analysis of the structure. Since Nepal lies in the highly seismic zone so the building is assumed to be located at zone V as per IS code. Moreover, the building is assumed to be located in the capital Kathmandu. The soil beneath the valley consists of young soft fluvio-lacustrine sediments with silty-clayey in southern part and sand and fluvial gravel in northern part i.e., Bagmati river with a possibility of amplification of the ground motion in seismic events. Fig 3. A representation of geologic cross section for the Kathmandu basin, depicting distribution of sediment in N-S direction, [18] Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 As depicted in Fig 3 due to the presence of unsettled clay soil (Kalimati clay) and also as the valley where the lake once stood is highly vulnerable 3000 mm 3000 mm 3000 mm 3000 mm 3000 mm 3000 mm 3000 mm 3000 mm to significant both nearby and even distant earthquakes due to liquefaction and amplification of waves. Hence, the structure was considered to be the resting on soft soil located in Kathmandu valley. 21000 mm Z Y 3000 mm (each) Fig 4. Plan and elevation of the studied building The typical floor plan and elevation of the prototype studied buildings are shown in Fi.4. Also, a concise summary of the considered properties of prototype building adopted for the analysis is presented in Table 2. Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 Table 2. Summary of the considered properties of prototype building Parameter Description Type of the structure Multistory special moment resisting frame RC Seismic zone Zone V (IS Standard) Number of stories G+6 Floor height 3m Infill wall 230 mm thick for outer periphery walls and 130mm for interior (partition) walls with consideration of 40% wall opening Imposed load 3 KN/m2 for floor and 1.5 KN/m2 for roof Structural materials M25 concrete and Fe500 rebar Size of beams 300×450 mm [12×18”] Size of tie beams 300×300 mm [12×12”] Size of columns 400×400 mm [16×16”] Overall depth of slab 125 mm [5”] Specific weight of RC 25 KN/m3 Specific weight of infill 20 KN/m3 Type of subsoil Soft soil, (very soft as per NBC 105:2019) Location Kathmandu Occupancy Commercial Importance factor 1 - NBC 105:1994 and IS 1893:2002, 1.2 IS 1893:2016 and 1.25 - NBC 105:2019 Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 The studied prototype building is regular with no presence of abrupt strength or stiffness variation along the floor level so the modelling of infill wall is not performed during the analysis. The design of the prototype building is performed according to IS 456:2000 [20] for all the models. 4. RESULTS AND DISCUSSION The response of the building is analyzed for linear static and linear dynamic approaches for the four codal provisions. The response parameters under 1.4 comparision were period of vibration, top floor displacement, drift, storey response. Time period of the structure depends on stiffness and on the mass of the structure. With increase in height of structure the time period is higher depicting the flexibility of the structure. Usually several codal provisions provides the fundamental period of vibration (approximate) which depends upon the height of the structure [21]. The predicted time period doesn’t incorporate the irregularity if exists on the structure and hence the result might be over or under predicted. Approximate methods Natural period (FEM) Time Period(sec) 1.2 1 0.8 0.6 0.4 0.2 0 IS IS NBC 1893:2016 1893:2002 105:2019 NBC 105:1994 Fig. 5. Period of vibration of studied models The fundamental translation time period of the significantly different to the simulated results. analyzed structure was calculated using the Moreover, approximate by codal approximate period was amplified by 1.25 and was provision and was compared with the natural period compared with the Rayleigh method and the minimum from the FEM tool (ETABS Vs 19). As mentioned value was adopted relationship suggested as mentioned in NBC 2019, the earlier the approximate period seems to be Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 Height (m) 25 20 15 IS 1893:2016 IS 1893:2002 10 NBC 105:2019 5 NBC 105:1994 0 0 200 400 600 800 Storey Force (KN) Fig. 6. Storey shear force Storey shear was plotted for every floor along the height of the structure. Value of storey response was seen maximum for the revised code NBC 105:2019 while minimum in NBC 105:1994 as shown in Fig. 6 among the studied codes. The variation was obtained since the revised NBC 105:2019 and IS 1893:2016 modifies the importance factor for the commercial building structures as 1.25 and 1.2 respectively. Moreover, NBC105:2019 have distinguished the earthquake load for ultimate limit state and serviceability limit state. The summation of the storey shear provides the base shear of the structure which seemed to increase for the both revised codes as compared with respective previous versions. The plot of the NBC 105:1994 and IS 1893:2002 seems to be similar since the horizontal seismic coefficient was obtained to similar i,e., 0.08 and 0.082 respectively while considering soft soil for approximate fundamental time period. However, the slight variation is due to the distribution methodology of the obtained base shear i.e., linear and parabolic distribution respectively. The plots of displacement due to response spectrum loading along x direction (due to symmetric structure) with the height of building is shown Fig. 7. From Fig. 7 it can be observed that the value of displacement is significantly largest for the model with revised codal provision NBC 105:2019 as compared to other codes. The displacement as obtained is evident since the lateral load is maximum for the NBC 105:2019. Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 25 Height (m) 20 IS 1893:2016 15 IS 1893:2002 10 NBC 105:2019 5 NBC 105:1994 0 0 50 X-displacement (m) 100 (a) Displacement of models in X direction 25 Height(m) 20 15 IS 1893:2016 IS 1893:2002 10 NBC 105:2019 NBC 105:1994 5 0 0 20 40 60 80 X-displacement envelope(m) 100 (b) Displacement of models due to maximum load combination (envelope) Fig. 7. Displacement of numerical models Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 Height (m) Moreover, the plot of displacement due to maximum load combinations (envelope) along x-direction is plotted and shown in Fig. 7. As mentioned above the displacement was observed to be largest for NBC 105:2019 followed by IS 1893:2016. However, for envelope the displacement of the structure for IS 1893:2016 was observed to be increased since the revised IS code incorporates the all the three component of earthquake (mandatory for zone V) with load factor. However, as mentioned in NBC 105:2019 the vertical component was not considered since the studied structure is symmetrical (structural member spanning less than 20m without cantilever projection). Total drift and inter-storey drift ratio is simply total lateral displacement at the top of building and the ratio of the relative difference of the two consecutive floor displacement with the inter-storey height respectively. Drift is used exclusively as a measure of building damageability to limit the nonstructural damage with estimation of lateral stiffness of the structure. From Fig. 8 it can be observed that the value of drift is within permissible limit for IS 1893:2002, IS 1893:2016 and NBC 105 1994 with value of 0.004 times inter-storey height. However, the value of drift maximum for NBC 105:2019 as seen in Fig. 8 while it is still within the permissible value of 0.025 times inter-storey height for ultimate limit state. For serviceability limit state the permissible value is equal to 0.006 times interstorey height. 25 IS 1893:2016 20 IS 1893:2002 15 NBC 105:2019 10 NBC 105:1994 5 NBC 105:2019 Serviceability limit 0 0 0.002 0.004 0.006 Drift(unitless) 0.008 Fig. 8. Comparison of Drift for studied models Also, from Fig. 8 it can be observed that the studied model even though fulfilled the drift requirement of ultimate limit state the structure failed to comply with the serviceability limit state depicting the need to increase the section of the structural member as per NBC 105 :2019. Further, a study of overturning moment was performed for the studied prototype based on four codal provisions. The overturning moment was observed to be largest for NBC 105:2019 followed by IS 1893:2016 and then it can be observed to be similar for both NBC 105:1994 and IS 1893:2002. Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 Height (m) 25 20 IS 1893:2016 15 IS 1893:2002 NBC 105:2019 10 NBC 105:1994 5 0 0 10000 20000 30000 Overturning Moment (KN-m) Fig. 9. Comparison of overturning moment As the column is the major structural component for usually plays important role while detailing and will the survivability of the structure during major affect the failure mode of the structure. Percent reinforcement (%) ground shaking. Also, the reinforcement percent 3 2.5 2 1.5 1 0.5 0 IS 1893:2016 IS 1893:2002 NBC 105:2019NBC 105:1994 Fig. 10. Comparison of longitudinal reinforcement (%) in column Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 So, the result was compared for longitudinal reinforcement (%) in column for the studied prototype based on four codal provisions. The reinforcement percentage was observed to be similar for NBC 105:2019 and IS 1893:2016 followed by IS 1893:2002 with least that of NBC 105:1994 5. CONCLUSION A study is performed in evaluation of a G+6 Building located in Kathmandu, Nepal with Nepalese (Nepal National Building Code, NBC) and Indian (Indian Standard Code, ISC) previously existing and revised standards with consideration of several design compliances. NBC was functional without revision since 1994 with its first revision in 2019 so we aim to identify the placement of revised NBC 2019 with the notable code IS 1893 2016 with a prototype RC building in current study. A study of fundamental period of vibration, inter story drift, base shear etc., is performed for the studied prototype building using linear static and dynamic approaches. The important conclusion as obtained can be enumerated as below: ο ο ο All of the response parameters were observed to be predicted greater from the revised NBC 105:2019 as compared to other studied codal provisions. The major reason behind this is the adoption of the latest seismic catalogue in estimation of the hazard. Although the response parameters were observed maximum in NBC 105:2019 the longitudinal rebar percent in column was observed to be almost similar for NBC 105:2019 and IS 1893:2016 followed by IS 1893:2002 with least that of NBC 105:1994. The reason might be due to load combination. The period of vibration predicted by the revised code is higher than the existing ones since the reduced stiffness (considering crack section) is adopted in both revised IS 1893:2016 and NBC 105:2019. It is recommended to adopt the revised code NBC 105:2019 in seismic analysis and design of structures located within the country since it incorporates the local seismicity and several design safety factors based on the construction practices within the country. 6. REFERENCES [1] Stevens VL, Avouac JP. Interseismic coupling on the main Himalayan thrust. Geophysical Research Letters. 2015 Jul 28;42(14):5828-37. [2] Ulak N. Nepal's Earthquake-2015: Its Impact on Various Sectors. 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Contribution of Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 International Journal of Advanced Engineering and Management ISSN: 2456-8066 Bikram Bhusal, and Satish Paudel, “Comparative study of existing and revised codal provisions adopted in Nepal for analysis and design of Reinforced concrete structure” International Journal of Advanced Engineering and Management. Vol 6, No. 1 Page 16-24, 2021 View publication stats
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