A Literature Review on Seismic Response of Floating Column Building

Floating column building is a new fascination for engineers. As floating column buildings provides more space and good aesthetics to the building. But have high structural challenges, when a floating column is provided in a multi-story building in a high seismic zone. This paper reviews several studies conducted on the floating column building and its behavior under seismic loads. This paper studies that floating column building are vulnerable to the high seismic zones. The risk of damage also depends on the shape and size of the buildings.The ductile detailing of the joints is the promising solution for immediate failure of such buildings. Keywords: Floating Column, Response spectrum analysis. Vulnerable, damage, multi-story

Dynamic Behaviour Comparison of an Irregular Edifice with Different Locations of Floating Column and Shear Wall

Architects nowadays develop attractive edifices, and floating columns are widely employed in this process. Floating columns are used not only to provide a magnificent perspective but also when a vast open area is necessary. Edifices with irregular configurations are more vulnerable to earthquakes and hence, suitable shear wall placement is required to ensure the edifice's stability. Many multi-storey edifices collapsed in seconds after the Bhuj Earthquake (Jan 26, 2001), due to the presence of soft stories, floating columns, and mass anomalies. As a result, knowing the seismic reactions of these buildings are vital for constructing earthquake-resistant assemblies. The relevance of a Floating Column and the existence of a shear wall in an irregular multistorey building is highlighted in this study. Dynamic seismic behaviour of a G+18 irregular edifice with different locations of the floating column and different positions of the shear wall is explored in this research. The edifice is analysed and compared with the model without shear walls and floating columns to examine the alterations. The dynamic analysis is carried out using Response Spectrum Analysis and storey drift, storey displacement and base shear are calculated and finally, software compression is computed for different zones. The analysis is carried out by Indian standardized codes IS 1893:2016 and IS 456:2000 which are the codes specified by the Bureau of Indian Standards for earthquake resistance edifice design and plain and reinforcement concrete design respectively. Keywords: Floating Column, Shear Wall, Irregular Edifice, Seismic behaviour, Response Spectrum Analysis, storey drift, storey displacement, base shear.

Comparison of eigenanalysis and Ritz vector approaches for response spectrum analysis of soil-pile-bridge systems

Frequency-based analysis techniques such as response spectrum analysis (RSA) are widely used for designing bridges in seismically active regions. Two well-known analysis procedures that underlie RSA are the solution of the eigenproblem and the approximation of the solution to the eigenproblem (i.e., approximation of eigenvectors and eigenvalues) through use of force-dependent Ritz vectors. While frequency-based methods have achieved widespread adoption in practice, certain simplifications remain common, such as neglecting soil-structure interaction (SSI) due to a fixed-base assumption. In the present study, frequency-based techniques packaged within a research version of a design-oriented computational tool are employed to analyze, assess, and compare results obtained from RSA with use of the eigenanalysis, and separately, Ritz vector approaches. Importantly, for the bridge configurations analyzed, SSI is taken into account. As outcomes, the potential benefits of the Ritz vector approach (as well as modeling strategies) are demonstrated. The study outcomes are intended to aid practicing engineers when the need to account for SSI is recognized as pertinent to a given bridge seismic design application.

Comparison of Invasive and Non-Invasive Methods in Site Response, Case Study: Soil Deposits of La Estrella

A great part of the Colombian territory is under medium to high seismic hazard due to the complex tectonic condition, which in turn affects, particularly, areas where the population density is highest. A response spectrum analysis of the ground is currently required by seismic design codes for site response analysis. For this, the shear wave velocity (Vs) profile must be established. The use of seismic invasive methods such as Down Hole or Cross Hole for the determination of the shear wave velocity (Vs), has been typically recommended. In recent years, significant progress has been made in non-invasive seismic methods such as MasW (Multichannel Analysis of Surface Waves) and ReMi (Refraction Microtremor), in order to estimate the Vs profile from surface waves analysis. Due to the accessibility and low cost, these methods represent a viable alternative to determine the profile of Vs. In this project, the seismic response of soil deposits was evaluated in the La Estrella municipality located in the south of The Aburrá Valley. One-dimensional (1D) models were simulated by characterizing the soil profile through the shear wave velocity with MasW and ReMi seismic tests. The results were compared with models based on shear wave characterization through Down Hole methods. The 1D response spectrums were determined with an equivalent linear model in DEEPSOIL and GTS NX software. The resulting spectra were compared through relative difference and correlation coefficient. Final results demonstrated that the spectra present low relative differences for long periods, moderate relative differences for moderate periods, and low to moderate relative differences for short periods. The general correlation coefficients were 0.6. This was evidence that non-invasive seismic methods allow an appropriate response spectrum analysis.

“Effect of floating columns on buildings subjected to seismic forces”

In Recent Trends, buildings are planned to fulfill their architectural and functional requirements but sometimes this creates complexity in its structural strength. One such element is the floating column. It is used to boost Floor Space Index. The Earthquake forces developed at different storey need to be carried down by the shortest path. Discontinuity in the load transfer path leads to poor seismic performance of the structure. Hence as per IS: CODE-1893:2016 clause no-7.1, the Construction of Floating Column is restricted. But there is no limit to research work. The purpose of this research is to analyze the structural irregularity occurring due to floating columns and also to find out the optimized solution to decrease the risk due to earthquake excitation. For Simplicity, the focus of this study is limited to symmetrical G+8 Structure. Finite element Based ETabs software has been used for the analysis. Response spectrum analysis was done in the software. Total ten models are considered with different conditions and their results were compared in terms of Storey displacement, Storey drifts, Base Shear and Overturning moments. All results are compared with the conventional building.

Seismic analysis of hybrid structures with and without shear walls

A hybrid structure is one that combines more than two different types of materials to compensate for weak places while also maximizing strength. Hybrid steel and concrete frameworks, as well as other modern materials, are unified at the member or framework unit. Hybrid structures are frequent in high-rise and super-high-rise building projects, and they provide the benefit of cost savings. Shear walls are built to withstand lateral loadings like earthquakes and winds loads. The response spectrum analysis approach is frequently used to measure design stresses for earthquake-prone structures. The modelling and analysis of the regular plan structures are done by CSI ETABS 2019 in IV seismic zones, on type II (medium soil) of India According to IS 1893 (Part-1) 2016. The aims of this study Response spectrum analysis of 41 storey RCC and hybrid structures with shear walls and without shear walls are compared. RCC and hybrid structures with shear walls showed lower storey displacement, storey drift, and story shear values than RCC and hybrid structures without shear walls, according to the results of this study. The research results will be helpful as a reference and a tool for seismic analysis of hybrid structures.

Response spectrum analysis of irregular shaped high rise buildings under combined effect of plan and vertical irregularity using csi etabs

In this research work several high rise buildings were analyzed using CSI ETABS under the influence of the response spectrum analysis over it. Several different shaped high rise buildings such as H shaped, O shaped and C shaped buildings were taken into consideration for carrying out the research work. All three shaped buildings were of different storey that is of 12 storey and of 16 storey. For proper seismic analysis of all the above discussed buildings, response spectrum method of seismic analysis were taken into consideration. The results of all the buildings for response spectrum analysis were quite different from one another and it was found that the H-shaped building showed better results as compared to the other shaped buildings. It was also seen that the 12 storey building results were quite impressive as compared to the results of the 16 storey building. With the transference of heavy mass, very little effect was seen in latera sway i.e. variation in maximum displacement was negligible. Again, for 16 storey building, maximum displacement was found in the case L-Shaped 16 storey building with the value of 87.804 mm. Again, the transference of heavy masses had a minimal effect on total quantity and cost of the 16 Storey building. In the gist, it was concluded that, bending moments and shear forces were increased from 1.17% to 1.84%. Maximum variation in B.M and S.F. can be seen in O-shaped Building. L-shaped Building produces maximum displacement from all the three irregular shapes i.e. H-shape, L-shaped and O-shaped.

Response Spectrum Analysis of Base Isolated Regular and Vertical Irregular Building in Different Types of Soil

These days earthquake is a major problem for development of high rise building in seismic zone areas. Researchers have developed devices to overcome these earthquake problems. So we need to design a structure which can withstand against the seismic loads. There for it became necessity to provide passive control device “base isolation” to resists large horizontal and vertical loads which lead the structure to collapse. In present workthe effectiveness of the fixed base and Base isolation (LRB) with different type of vertical irregularities in different type of soil (Hard, Medium, Soft soil) in plan are concerned the vibration of the structure. The present work G+10 story Building of different vertical irregularities ( Regular building, vertical irregular Type-I, vertical irregular Type-II, vertical irregular Type-III ) Situated in zone IV are analyzed under the various Loading such as dead load, live load and earthquake load. Free vibration analysis, response spectrum analysis have been carried out for these model of building with a fixed base and base Isolation Devices. It is observed that story displacement in response spectrum is significantly increases at top stories with the base isolated building. And this work shows that the response of building reduced by using base isolation (LRB) devices in all different typeof vertical irregularities building, but the same isolation device is more effectively work in Vertical irregular Type-II Building Keywords: Base isolation Techniques, LRB, Base Shear and Etabs etc.

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.

Comparative Study of Tube in Tube Flat Slab with Tube in Tube Waffle Slab, Structures Under the Sesmic Loads

The tube in tube structure is one of the type that is been broadly used as structural system for tall structures. Considering the lateral loads due to the seismic force it gives more stiffness and gives more strength to the high-rise structures. Lateral loads are shared between the inner and outer tubes our aim is to make the structure stiff by its connectivity and comparing them by providing drops to the waffle. By adding tube in tube to the flat slab and waffle slab, concept is they both does not have the beams such that to know the comparison of both the models. This both models have been designed using e-tabs software and the dimensions, limitations are been taken from the provision Indian standard code book. Keywords: High-rise building, tube in tube, Response spectrum analysis.