Seismic Response of Large span slab in Horizontal Setback Building

The demand for multi-storey buildings is increasing day by day. Residential plus commercial building is mainly used for wide span needs. Wide span required for Flat slab, Waffle slab and ribbed slab stands An excellent option for architects when larger openings in a building need to be covered with as few columns as possible. The use of different types of plates is developing as a new trend and is becoming a major challenge for structural engineers. Therefore, it is necessary to study about its structural behavior. The project is carried out under earthquake zone III under the earthquake analysis of G+9 storey building. For this study, four different types of large span slab structure are modelled in C-shape (Horizontal Setback Building) having 10-stories i.e. G+9 storied buildings with 3.50 meters height for each story is modelled and analysed. The plan area of all four buildings is same i.e. 2859 square meters (49.50 m x 82.50 m) each. These buildings were designed in compliance with the Indian Code of Practices for earthquake resistant design of buildings. Base of the building were fixed. The square sections are used for structural elements. The height of the buildings is considered constant throughout the structure. The buildings are modelled using ETABSvr.2016. Keywords: large span slab, ETABSvr.2016, Horizontal Setback Building, Flat slab, Waffle slab and ribbed slab

Comparative seismic analysis study of G+ 20 story building with flat slab and conventional slab using ETABS

In the study, three dimensional analytical models of G+20 story buildings have been generated and analysed using CSI ETABS software version 2016. The earthquake zone III in India is considered for buildings during analysis. Here, the analysis and design is done of G+20 story building with flat slab(with drops) and conventional slab system. In earthquake zone the displacement and drift of the structures will be more so to have more stiffness to the structure shear wall is to be provided therefore a study is made by comparing between conventional slab & flat slab (with drops) building. Comparison of various parameters like story drift, story displacement, story stiffness and time period is done. The equivalent static method is used to design and analyze the structures, as categorized by Indian Standard Code for earthquake resistant structures. The study shows that story drift is 10% more in conventional slab as compared to flat slab; story displacements is observed linearly increasing with height of the building and is 11% more in conventional slab as compared to flat slab . Keywords: Equivalent Static Method, Flat Slab, ETABS 2016, story displacement, story stiffness, story drift, time period

Stability Analysis of High Rise Buildings by altering the Beam Members

A structure can be build with different building elements. These building elements are basic part to resist the various loads and stress acting on it. The Beam is on the basic and essential elements under it to resist the bending behaviour on the structure. The project deals with four different types of 17 storied structures are modelled by altering beam members having rectangular shape i.e. G+16 storied building with 3.50 meters height for each story is modelled and analysed. The plan dimension of all four buildings is kept same i.e. 15.15 m x 46.35 m each. These buildings are designed in accordance with the Indian Code of Practice for the design of earthquake resistant buildings. Base of the building were fixed. The height of the buildings is considered constant throughout the structure. The buildings are modelled using ETABSvr.2018. The model has been studied in the earthquake zone IV and soil type II. Keywords: ETABSvr.2018, Beam, zone IV, Soil Type II, altering beam members

Analytical Investigation of Composite Structure in Comparison of RCC Structure

High rise structures becoming very common everywhere due to scarcity of land and increasing population. Though we have RCC structure system as high-rise buildings, but in RCC buildings due to bulky size of the components of the structure self-weight will be more due to the heavy density of materials. By observing the difficulties and challenges in the field of high-rise structures engineers are using efficient structural system that is Steel Concrete Composite Structure. Composite structure consists composite deck slab, composite beam and composite column. Composite Structure complies of Concrete which is good in compression and structural steel which good in tension and composition of these material makes structure better in ductility which comparatively on higher side than RCC structure. Here G+7 high rise structure is considered for analysis by ETABS software. This paper involves Analysis of Commercial building by Equivalent static method on Composite structure and RCC structure with same plan of building and same design data. The structure is in earthquake zone III and wind speed 44m/s. Analytical comparisons of both Composite and RCC frame based on structural parameters are made with help of graphs and tables. By comparing the results, we found that Steel-Concrete Composite Structures are more desirable than RCC structures.

Seismicity map to analyze the depth and magnitude earthquake zone in Kwandang Area of North Gorontalo Regency

Kwandang is a district located in the northern part of Gorontalo. The purpose of this research is to analyze the depth and magnitude earthquake zone that occurred in the district of Kwandang, Gorontalo Utara regency based on seismicity map. The astronomical research location is located at 0° 49' 39" S, 122° 55' 8" E. The method used in this research is seismicity map analysis. The earthquake that dominates in Kwandang, based on the value of its depth, namely shallow earthquake (0-70 km) and medium earthquake (70-300 km). This is caused by subduction activity in the direction of the subduction of the north arm of Sulawesi towards south of Tomini Bay. Whereas based on the strength of the earthquake in Kwandang sub-district is dominated by small earthquakes (-) with a light, mild earthquake. Based on the depth zonation, earthquakes mostly occurred in the west. Based on the magnitude, the earthquakes mostly occurred in the southwest.

The interrelationship between electrical resistivity and VP/VS ratio: A novel approach to constrain the subsurface resistivity structure in data gap areas in a seismogenic zone

Large man-made water-reservoirs promote fluid diffusion and cause critically stressed fault zones underneath to trigger earthquakes. Electrical resistivity is a crucial property to investigate such fluid-filled fault zones. We, therefore, carry out magnetotelluric (MT) investigation to explore an intra-plate earthquake zone, which is related to artificial reservoir triggered seismicity. However, due to surface access restrictions, our dataset has a gap in coverage in the middle part of the study area. This data gap region coincides with the earthquake hypocenter distribution in that intra-plate earthquake zone. Therefore, it is vital to fill the data gap to get the electrical signature of the active seismic zone. To compensate for the data gap, we develop a relation that connects resistivity with the ratio of seismic P- to S-wave velocity ( VP/ VS). Utilizing this relation, we estimate a priori resistivity distribution in the data gap region from known vp/vs values during inversion to compensate for the data gap. A comparison study of the root mean square (RMS) misfits of inversion outputs (with and without data gap filled) proves the effectiveness of the established relation. The inversion outputs obtained using the established relation brings out fault signatures in the data gap region. To examine the reliability and accuracy of these fault signatures, we occupy a portion of the data gap with new MT sites. We compare the inversion output from this new setup with the inversion output obtained from the established relation and observe that the electrical signatures in both outputs are spatially correlated. Further, a synthetic test on a similar earth model establishes the credibility and robustness of the derived relation.

Comparative Study of RC Multistorey Building with Floating Column and Shear Wall Subjected To Seismic Load

: In modern multistorey building construction, irregularities like the soft storey, vertical and plan irregularities, floating columns etc are very common. Building with an open ground storey for parking is a common feature that results in floating columns. Floating columns provide column free space and a good aesthetic architectural view of the building. floating column means the end of any vertical element that rests on the beam which leads to discontinuity of columns such that the path of load distribution in multi-storey buildings is disturbed. The use of a floating column also tends to increase the moment in the column, storey shear etc which highly undesirable in seismically active areas. So, the study of the best location where the floating column needs to be provided to reduce the impact due to seismic loads is of primordial importance. Shear wall is a vertical member which is provided from foundation to top storey. In this study shear wall is used in the direction of orientation so that it provides additional strength and stiffness to the buildings. In the present analysis, 8 models are studied. The first model considers a multi-storeyed building without any shear wall and floating column. Other models analysed are with shear wall and by varying the location of floating columns. The analysis and design are done by STAAD.pro V8i SS6 version software and the method used is response spectrum analysis in earthquake zone 4. The effect of floating column location on parameters such as Base shear, Displacement, Maximum moment, storey shear and percentage of steel reinforcement are discussed. The comparison of results of different models is also carried out in detail using graphs and bar charts in this study. The suitable location for providing a floating column with the shear wall is also discussed. Keywords: Floating column, Shear wall, Seismic load, STAAD.pro.v8i, Response Spectrum Analysis.

Investigation of construction material quality and workmanship defects of RC buildings collapsed and severely damaged in the 6.8 Mw Sivrice, Elazığ, Turkey earthquake, January 2020

In the Sivrice, Elazığ, Turkey earthquake on January 24, 2020, 41 people lost their lives, more than 1600 people were injured, 672 buildings collapsed, and around 12600 buildings were severely damaged due to poor construction quality. After such devastating earthquakes, damage assessment and forensic investigations are normally carried out quickly for a judicial process, and material qualities are revealed. However, emotional sensitivity of the victims in the earthquake affected zone and disruptions in key lifeline services such as transportation, electricity supply often make these processes difficult. After the Elazığ earthquake, along with the conventional in-situ core sampling method, concrete pieces were collected from columns of collapsed and severely damaged buildings and transported out of the earthquake zone to overcome these adverse conditions. Unlike in the conventional method where the whole sampling process is carried out in the earthquake zone, the core extraction from the transported concrete pieces was carried out outside the earthquake-affected area. The extracted concrete samples were checked for compliance with the prevailing material standards. Moreover, multiple reinforcing bars of various diameters were also extracted and tested to check their compliance with the standards. Besides, the results of examination of the quality of materials and workmanship used in the construction are also discussed, along with the precautions required to minimize fatalities and damage from similar buildings.