Regular Building Research Articles

Seismic Analysis of Flat Slab Buildings on Hilly Ground

In India, hilly region especially northern part is more seismically active region. Flat Slab systems are widely popular in multi-storey buildings. Flat slab building has more advantages than a regular building like fast construction, free design space, reduced floor to floor height and economical. Flat slab buildings are also being built in high seismicity region. Buildings on hilly ground are vulnerable due to their vertical and horizontal irregularity and they undergo high shear and torsion during the earthquake. Further due to short column and soft storey on uphill side has higher lateral forces that are cause to failure of buildings. In this paper, an attempt has been made to assess the seismic behavior of flat slab resting on hilly slope with soft storey and set back configuration. The methodologies have been adopted are linear dynamic analysis i.e. response spectrum analysis. Building is analyzed and designed by Etabs software. Maximum displacement, maximum inter-storey drift and storey shear are determined as response quantities. It is observed from the study that for flat slab buildings on hill slopes the storey shear is very high in the bottom columns at higher ground level, therefore extra care should be taken to design these columns for earthquake load.

Vulnerability of Multistory RCC Framed Building with Shear Wall During Fire

Fire in a building is a casual phenomenon but cannot be completely ruled out in spite of the facts that buildings are provided with mandatory fire safety measures. A symmetrical in plan with 5 bays with 20 stories regular RCC building has been considered with fire at three different level that is at the bottom, middle and top. The building has been designed for gravity loads and lateral loads having three different configuration of shear walls and columns. Fire temperature of 700 0C was considered. The minimum value of maximum fire temperature for failure of vertical members has been found out by iterations. The worst verticals members due to fire has been identified and their displacement calculated. Best location of shear walls using commercial software etabs is used for the analysis and design.

Seismic Evaluation of RC Building with Vertical Setbacks as per IS1893 (Part 1):2016

Earthquake forces are the least predictable and most devastating form of forces. These forces are not only responsible for loss of economy, property and material but possess a huge threat to lives of people as well. In past several years, severe damages to buildings and causalities have been witnessed due to these disastrous forces there by challenging the designing and construction authorities. Many buildings are designed with vertical setbacks due to architectural, functional or economic reasons wherein fewer stories in a building are wider than rest of the building. Such setbacks in buildings cause sudden jump in seismic forces at the level of discontinuity due to change in stiffness, mass and strength distribution along height. This might lead to torsion in the building under seismic forces. Structures incorporating vertical irregularities need to be studied for their behavioural aspects, identifying the weak links which might trigger the collapse. In the present study, effect of vertical geometric irregularities in a building is studied with respect to a regular building using equivalent static method and response spectrum method as per IS1893 (Part 1): 2016. The results obtained are compared in terms of displacements, storey drift, base shear, forces, modal time period, modal mass participation factor and % increase in structural members along with concrete quantity.

Recent And Past Development In The Investigation Of Regular And Irregular Shaped Structures

This paper highlights the detail discussion of past researcher by categorizing the review on seismic analysis based on regular and irregular shape building. The review concludes that after careful observation there are lot of experimental and numerical investigation may be done on different shape of building and many researchers has already been done work on regular building but not given remedies hence there is need of application of retrofitting such as shear wall, bracing in structure as building material by the structural engineers.

Analysis of irregular multistorey buildings with and without floating columns under seismic loading

Floating column is a vertical structural member that rests on the beam. Floating column is advantageous to provide large open space in a building, but it is disadvantageous in earthquake conditions. On the other hand, by the advancements in civil engineering knowledge, architects try to adopt irregular shapes of buildings. Providing floating columns in irregular buildings is a challenging issue for civil engineers they should deal with. That’s why study of application of floating column in irregular buildings is one of the important topics in modern civil engineering. This study focuses on analysing the seismic behaviour of G + 10 irregular buildings considering floating columns and without floating columns to compare with a regular building. The building models are analysed in ETABS V19 software, then analytical findings are explained in terms of (maximum storey drift, maximum storey displacement, and torsional irregularity). From the study it is found that providing floating columns in irregular buildings increase storey drift and storey displacement significantly. Similarly, the torsion increases in buildings when the floating columns are not provided symmetrically.

How building layout properties influence pedestrian route choice and route recall

How pedestrians find and choose routes in buildings is a fundamental research topic that is immediately relevant to building design and safety. However, few studies have explored the relationship between pedestrian route choice and building layout in a systematic way. Here, we introduce a method based on spatial network theory for generating buildings with various layout properties. We conduct a virtual experiment with over 200 participants and many generated buildings to investigate how layout properties influence different aspects of pedestrian route choice. Our findings suggest route recall is worse in buildings that have more connections and possible routes, even when the overall size of buildings and length of routes is kept constant. Pedestrians also prefer more regular building layouts and are more likely to adopt the heuristic of walking along the outer edges of buildings the less regular they are and the more connections they have.

Experimental Study of the Wind Pressure Field on the Notre Dame Cathedral in Paris

ABSTRACT The paper concerns an experimental study on the wind pressures over the surface of a worldwide known Gothic Cathedral: Notre Dame of Paris. The experimental tests have been conducted in the CRIACIV wind tunnel, Prato (Italy), on a model of the Cathedral at the scale 1:200, reproducing the atmospheric boundary layer. Two types of tests have been conducted: with and without the surrounding modeling the part of the city of Paris near the Cathedral. This has been done, on the one hand, for evaluating the effect of the surrounding buildings onto the wind pressure distribution on the Cathedral, and, on the other hand, to have a wind pressure distribution plausible for any other Cathedral with a similar shape. The tests have been done for all the wind directions and the mean and peak pressures have been recorded. The results emphasize that the complex geometry of this type of structures is responsible for a peculiar aerodynamic behavior that does not allow estimating correctly the wind loads on the various parts of the Cathedral based on codes and standards, which are tailored for ordinary regular buildings.

Seismic vulnerability of reinforced concrete buildings with discontinuity in columns

AbstractIrregular reinforced concrete (RC) buildings constitute a significant portion of the existing housing stock. A common type of irregularity is in the form of discontinuity in the vertical framing elements, which can exacerbate their seismic vulnerability. The design guidelines available in seismic design codes essentially cater to only regular buildings, and the safety of such buildings, even when the other guidelines of the codes are followed, is doubtful. This article evaluates the vulnerability of RC frame buildings with discontinuity in columns designed for modern seismic codes, in the form of seismic collapse capacity, collapse resistance against maximum earthquake demand level, and failure mechanism. The adequacy and limitations of the provisions of the seismic design codes are evaluated for such buildings. Analysis results show that the sequential analysis of buildings considering the construction staged effects, considerably affects the design and hence the collapse failure mechanism of even low‐ and mid‐rise buildings. The results also underline the importance of strong column–weak beam design in the seismic performance of the floating column buildings. The vertical component of ground motion is also observed to be relatively more crucial in floating column buildings.

Performance Evaluation of Hillside Buildings under Blast and Blast-Induced Ground Motion

The present study evaluates the performance of two hillside building configurations, i.e., split foundation (SF) and step-back (SB), commonly observed in the seismically active Indian Himalayan region, under blast and blast-induced ground motion using an uncoupled approach. Force-controlled nonlinear static analyses are carried out to probabilistically assess the critical blast location for bare- and infill-framed buildings. It is observed that the blast on the downhill side is critical for the hillside buildings having a story ratio of 0.5; whereas, the blast on the uphill side is more damaging for the buildings with a story ratio of 1 and 2. The blast fragility curves, developed herein, show that the presence of infills significantly affects the blast response of RC hillside buildings and the location of the peak response. Further, critical scaled distances corresponding to various damage states for the hillside buildings are found to be more than that for the regular buildings. Furthermore, the response of hillside buildings was investigated under blast-induced ground motions to evaluate the key engineering demand parameters pertinent to structural and non-structural damages.

Research on Wind Load Characteristics on the Surface of a Towering Precast Television Tower with a Grid Structure Based on Large Eddy Simulation

Local wind pressures on tiny rods of complex grid structures are difficult to obtain through wind tunnel tests due to their small sizes after scaling down, resulting in a lack of data support in wind load calculations for similar structures. However, local wind pressures on tiny rods can be obtained through numerical wind tunnel simulation using full-sized models. In order to investigate the wind pressure distribution of a grid structure and the influence of grid structures on the wind load of core tubes, three different television tower models are established based on an engineering example for large eddy simulations. A turbulence inlet generator (NSRFG) is adopted in the simulations while reproducing a portion of the wind tunnel test section including the mean and fluctuating pressures for validation. The results indicate that the mean wind pressures on the intersection of rods in the windward zone of the grid structure are higher than those on adjacent rods. Distinct reductions in the mean and fluctuating wind pressure of the grid structure are found in different zones. Moreover, resultant wind load forces and bending moments in the X and Y direction of the grid structure generally exceed 70% of the total wind loads. Based on simulation results, extreme net wind pressures of the grid structure and shape coefficients of enclosed regular octagonal cross-section buildings with the grid structure are provided for reference.

Component repair cost functions in Indian context for seismic loss estimation of reinforced concrete buildings

This study proposes component level repair cost functions for efficient estimation of financial losses expected to be incurred due to earthquake-induced damages to typical reinforced concrete (RC) buildings in the Indian context. The proposed repair cost functions account for the variability in the local construction practices and their associated financial implications. Repair cost functions for four drift sensitive building components, i.e., unreinforced masonry walls, reinforced concrete beams, reinforced concrete columns and reinforced concrete beam-column joints, are developed. A detailed case study is presented for three different building configurations commonly observed in the hilly region, i.e., 4-story stepback, 4-story split-foundation, and 4-story regular buildings. The variation in the floor-wise and component-wise repair cost ratio with varying levels of ground motion intensity is investigated. This study also proposes the expected repair cost ratio function for the considered building configurations corresponding to the four building components. It is observed that the expected repair cost ratio is least in 4-story regular building and maximum in 4-story split-foundation building.

Reliability-based assessment of progressive collapse in horizontally irregular multi-story concrete buildings

Structures’ resistance against progressive collapse varies depending on their design and taxonomy. However, despite numerous studies addressing the impact of geometric configuration, limited attention is given to the effect of irregularity. This study presents a reliability-based approach to evaluate the effect of horizontal irregularity on the progressive collapse potential of seismically designed concrete buildings. Incremental dynamic analysis is performed on three-dimensional nonlinear finite element models of six prototype buildings with different levels of horizontal irregularity subjected to four column removal scenarios. Probabilistic demand models are then derived to construct fragility curves based on the first-order reliability method. In addition, an analysis of covariance is performed to measure the sensitivity of demand models to column removal scenarios in terms of floor and location. The results show that the studied irregular buildings do not pose a greater risk of progressive collapse than the regular building. In addition, while the probability of collapse under sudden column removal is significantly low for the seismically designed concrete frames, all buildings are expected to experience significant damage under such abnormal loads.

Extension of the improved upper-bound pushover analysis for seismic assessment of steel moment resisting frames with setbacks

Pushover analysis technique is a key tool for the performance-based seismic design that has been largely adopted in the new generation of seismic codes. Therefore, more precise and reliable performance predictions are highly demanded. Improved upper-bound (IUB) pushover analysis is one of the advanced nonlinear static procedures (NSPs) that has been recently developed. This procedure adequately estimates the response of regular and tall buildings. In this study, IUB is extended to assess the seismic response of irregular buildings with setbacks. To this end, an adjustment of the IUB lateral load distribution is implemented by integrating a third mode of vibration to control the response of these complex buildings. Fifteen multi-storey steel frames with different types of setbacks including a reference structure are used to test the accuracy of the proposed procedure by comparing its results to those from other NSPs and the nonlinear time history analysis (NTHA). The findings show the superior capacity of the extended IUB in predicting the seismic response of buildings with different levels and types of setbacks.

Study of Structural Performance of Multi-Storey Regular and Irregular RC Buildings Located in Zone III Under Seismic Loads

Abstract: this analysis shows it is based on carrying the foundation of the shear and the level of performance of the building under the Indian severe zone. The result marks the conclusion that, in the case of a building with poorly constructed strength, it provides stability and attracts the storey shear. The soft computer software and commercial software CSI-ETABS is used for modeling and analysis

Torsional Improvements in a Multistoried Building with Plan Irregularities

Irregular buildings consist of large number of modern urban structures. Though some buildings look symmetrical in plan might have irregular distribution of mass, strength and stiffness along the plan and height of the buildings. In common sense, a building with a regular geometry is supposed to be regular building. While the building is designed to be used for different functions along the building area and along the building plan the presence of opening, staircase positioning and positioning of the shear/core wall for different purpose like lift and HVAC (Heating, Ventilation and Air Conditioning) leads to the irregularity in the plan. Ultimately, torsion irregularity occurs, which if remains not taken care properly may create substantial damage of the building structures. The purpose of this study is to determine the conditions for excessive torsional irregularity and solve them with the proper positioning of the shear wall to counter the torsional behavior of the building. A linear response analysis was conducted and the studied structures were both six- storey buildings. First building has opening left for different purpose like lift and HVAC systems. While the second building has shear wall for lift at the edge of the building. Though both buildings seem fine with their geometrical orientation after the analysis torsional irregularity was evident. The proper placement of the shear wall has been used to stiffen the building to counter for the torsional modal and make to regular in terms of the mass and stiffness distribution.

Quality Of Lighting In Regular And Fullday Class Tsanawiyah Miftahul Huda Tayu Pati

An analysis of the quality of the lighting level in the classroom needs to be carried out to determine the existing lighting level. If the level of lighting is below the specified standard, it can cause eye damage. Meanwhile, if the level of lighting is above the standard, the classroom will be too bright. The purpose of this study was to determine the level of lighting in the Regular and Full Day classroom of MTs. Miftahul Huda Tayu. The tools and materials used in this experiment are lux meter, roller meter and thermohygro. The experiment was carried out in the Regular class school building and the Full Day classroom building with a sample of three rooms per building with each room representing each floor. The experiment was carried out during the day for three consecutive days. There are two types of the intensity measured in this experiment, namely natural intensity (lights off) and natural artificial intensity (lights on). In each room, 9 points were taken. The floor area and window area were measured using a roller meter. From the experiments that have been carried out, it can be concluded that the lighting in the Regular class (17-73 lux) and Full Day class (97-181 lux) buildings do not meet Indonesian National standards (Standar Nasional Indonesia, SNI).

COMPARISON OF MULTISTOREY BUILDING USING RESPONSE SPECTRUM ANALYSIS IN DIFFERENT SEISMIC ZONES BY USING STAAD.PRO SOFTWARE

A multi-storey building is just a building that has multiple storeys above the ground. A multi storied building is either residential or commercial. Migration of individuals from rural to urban centres where job opportunities are significant. The land available for building to accommodate this migration is becoming scarce which ends in rapid increase within the cost of land. And this leads to construction of multi-storeyed buildings as they supply an outsized floor area in an exceedingly relatively small area of land in urban cities. A comparison of highrise buildings by response spectrum analysis in different seismic zones of India. The main objective of this research paper is to compare regular and irregular buildings in seismic zone III & zone V by response spectrum analysis in STAAD. Pro. The soil type taken into consideration is medium soil type. The aim is to find base shear, storey drift and story displacement and eigen value and eigen vector by response spectrum analysis. Cost analysis has also been done. Analysis is done as per IS 456:2000 and IS 1893:2002. It focuses on dynamic analysis of buildings. Without increasing the area, we can extend only the building’s floor to design a multi-storied building as this will save overall building cost. Key Words: Seismic Analysis, Response Spectrum Analysis, Base Shear, Storey Drift, Story Displacement, STAAD.Pro

Determination of Mass Properties in Floor Slabs from the Dynamic Response Using Artificial Neural Networks

Most of the research on accidental eccentricity is directed at both the evaluation of accidental eccentricity design code recommendations and the study of building torsional response. In contrast, this paper addresses how the mass properties of each of the levels of a building could be determined from the dynamic response of a building. Using the dynamic response of buildings, this paper presents the application of multilayer feed forward artificial neural networks (ANNs) to determine the magnitude, the radial distance, and the polar moment of inertia of the mass for each level of reinforced concrete (RC) buildings. Analytical models were developed for three regular buildings. Live-load magnitude and mass position are considered as random variables. Seven load cases were generated for the 1, 2 and 4-story models using two excitations. As for the input parameters of the ANNs, three different choices of input data to the network were used. The developed ANN models are able to predict with adequate accuracy the radial position, magnitude, and polar moment of inertia of masses of each level. The implementation of this method based on ANNs would allow the monitoring, either permanently or temporarily, of changes in mass properties at each building floor slab. Doi: 10.28991/CEJ-2022-08-08-01 Full Text: PDF

Discussion on Recent and Past Development in the Field of Seismic Analysis on Symmetry and Asymmetry Shaped Building Frames

Abstract: This paper highlights the detail discussion of past researcher by categorizing the review on seismic analysis based on regular and irregular shape building. The review concludes that after careful observation there are lot of experimental and numerical investigation may be done on different shape of building and many researchers has already been done work on regular building but not given remedies hence there is need of application of retrofitting such as shear wall, bracing in structure as building material by the structural engineers

Kinerja Ketidakberaturan Kekakuan Struktur Menggunakan Metode DDBD dan CSM

The current earthquake-resistant building planning concept leads to a performance-based design concept. In this study, the direct displacement based design (DDBD) method was used to design the earthquake load and the capacity spectrum method (CSM) to determine the level of building performance using pushover analysis. The purpose of this study is to analyze and compare the performance of regular buildings with buildings that have irregular soft story stiffness. The building to be reviewed in this study consists of 3 variations of the building with a total of 8 floors. Variation A of regular buildings, Variation B of buildings with irregularity of soft story stiffness on the 1st floor, and Variation C of buildings with irregularity of soft story stiffness on the 5th floor. The maximum displacement value occurs in Variation C, the X direction is 0.281m and the Y direction is 0.304m. The mechanism for the occurrence of plastic joints in variations A, B, and C is in accordance with the strength column weak beam design concept. The earliest collapses occurred in Variation B buildings and the last occurred in Variation A buildings. Performance of variations A, B, and C structures using the CSM method was at the level of Damage Control.