Horizontal Irregularities Research Articles

Pushover Analysis of G+20 RCC Structure with Horizontal Irregularity

Pushover Analysis of G+20 RCC Structure with Horizontal Irregularity

Analysis of Diaphragm Force on Reinforced Concrete Building Structures with Horizontal Irregularities of Diaphragm Discontinuity

The diaphragm plays a crucial role in distributing seismic forces within buildings during earthquakes, affecting both regular and irregular structures differently. This study investigates the seismic behavior of diaphragms in various building geometries resembling the letters I, T, L, and O, focusing on their influence on structural performance and reinforcement requirements. Using analytical methods, diaphragm seismic forces, slab shear stresses, and internal forces were calculated for a sample of buildings with different geometrical irregularities. The study reveals significant differences in diaphragm earthquake forces between regular and irregular buildings, with irregular geometries exhibiting distinct patterns of shear stress distribution. Particularly, the building with an L-shaped plan and concentrated stress points showed the highest maximum shear stresses in both orthogonal directions. Analysis of internal forces—axial, shear, and moment—highlighted varying reinforcement needs among the studied buildings. While axial and shear forces necessitated minimal additional reinforcement across all structures, moment forces indicated substantial reinforcement requirements, particularly in the L-shaped building. These findings underscore the importance of tailored diaphragm design strategies for buildings with irregular geometries to mitigate potential structural vulnerabilities during seismic events. The study contributes insights into optimizing diaphragm design practices and emphasizes the need for further research in this critical area of structural engineering.

Analysis of Non-Linear Static Procedure Based on Fema 356 to Evaluate Structural Performance in the Alton Apartment Building

Alton Apartment is a high-rise residential building. The city of Semarang, within a radius of 500 km, has a fault range with a strength of up to 8.3 magnitude. The purpose of this study is to calculate the performance level of the structure, find out the nonlinear static procedure conditions and whether the analysis results can be used, calculate the value of ductility R, check the boundaries between levels, check the influence of P-delta, adjust horizontal irregularities, and check the vertical irregularity conditions. This study uses the FEMA 356 method. New regulations are used in the analysis, such as peak acceleration maps and response spectra from PuSGeN in 2021, deaggregation maps of Indonesian earthquake hazards for planning and evaluation of earthquake-resistant infrastructure from the Director General of Cipta Karya in 2022, and earthquake resilience planning procedures for building and non-building structures from SNI 1726-2019. The result of the structure performance of the drift value is below 1% for the life safety (LS) performance level on the 250-year earthquake map, and the result of the drift value is below 2% for the collapse prevention (CP) performance level on the 100-year earthquake map. The results of the FEMA 356 condition one analysis show that the strength ratio (μstrength) value of less than μmax has been met for 250-year and 1000-year earthquake maps with a review of the x and y directions of the earthquake. The value of the R ductility in 250-year and 1000-year earthquakes is above seven according to the earthquake force holding system of special reinforced concrete sliding walls.

Analysis Seismic Behavior of Structures with Planar Imperfections: A Comprehensive Numerical Analysis

This paper presents a comprehensive approach to the seismic analysis and design of a tall hospital building, accounting for horizontal irregularities and employing equivalent static analysis (ESA) methodology. The study initiates with the collection of relevant site data and building specifications, including the identification and characterization of horizontal irregularities such as setbacks, mass distribution variations, and irregular floor plans. Equivalent static lateral loads are calculated based on applicable building codes and standards, taking into account the effects of horizontal irregularities on seismic response. Structural modeling and analysis are then conducted using sophisticated software to evaluate the building's behavior under seismic forces, considering the influence of irregularities on structural performance. Design criteria, encompassing drift limits, strength requirements, and detailing considerations for mitigating irregularity effects, are rigorously adhered to ensure compliance with safety regulations and performance objectives. The iterative process of evaluation and adjustment ensures optimal seismic performance and adherence to design criteria despite the presence of horizontal irregularities. Documentation of the analysis and design process, coupled with meticulous construction oversight, guarantees the implementation of a robust seismic design strategy tailored to the unique characteristics of the tall hospital building. Post-construction evaluations are carried out to validate predicted seismic performance, accounting for the influence of horizontal irregularities. Through collaborative efforts and adherence to best practices, the seismic design of the tall hospital building prioritizes safety and resilience, even in the face of horizontal irregularities, aiming to safeguard occupants and critical healthcare infrastructure during seismic events.

The Performance Assessment of the Structural Bracing Model for Multi-Story Building

Earthquakes are a severe issue for construction. The building collapsed due to the earthquake because it could not bear the earthquake load. Even more so, it was constructed using outdated and different building regulations that do not comply with modern building codes that account for seismic loads. As a result, disaster mitigation methods, such as retrofitting, must be implemented. Retrofitting procedures are commonly used in many developed countries. The bracing system is a typical retrofitting method used on building structures. In this study, a retrofitting program was carried out on The State Finance Building II Semarang, which was built in the 1980s, one of the old buildings in Semarang City, using a reinforced portal structure. This study's bracing system is a Concentrically Brace Frame (CBF) with Inverted V Brace and V Brace variations. The structural analysis software ETABS V.18.2.0 analyzes the building's structure. The structural review includes story drift, the P-Delta effect, and horizontal torsion irregularities. According to the results, steel bracing can minimize the period and displacement associated with story drift, making the structure more stable, with a maximum displacement reduction of 59.66% for inverted V-type steel bracing. Aside from that, steel bracing also can minimize the occurrence of torsion in the building. As a result, steel braces can be used to strengthen the structure.

Nonlinear Static Analysis of Tube in Tube structure with Horizontal Irregularity with constant plan area

Nonlinear Static Analysis of Tube in Tube structure with Horizontal Irregularity with constant plan area

Выбор и проверка метода схематизации случайного процесса нагружения пружин буксового подвешивания

The product life cycle contract also contains its cost for the preparation of the product, delivery to the supplier, subsequent maintenance, operation and repair of the product up to disposal. The article considers the development of a methodology for calculating the life cycle of axle box suspension springs (and later frames) of the Lastochka electric train trolley. The method of analysis is based on the assessment of the spring strength and the results of strength tests obtained during sea trials. These tests have been carried out on separate operating sections of railways, based on the results of data from the removed blocks of oscillograms recording forces from models of electric train bogies of virtual sea trials. Virtual sea trials have been conducted on certain created sections of the track, taking into account the horizontal and vertical irregularities of the track for different track conditions. The paper analyzes the tutorials on the methods for schematization of test results in the form of oscillograms recording the forces of random processes; the method of falling rain is used. The implementation in the software product of the methodology for analyzing the stress-strain state of box suspension springs and the results of sea trials, which have been proceed by the falling rain method, allows us to determine the actual service life of box suspension springs.

Real-time temperature field and thermal deformation of slab track on cable-stayed bridge

This study aimed to master the real-time temperature fields of slab tracks on cable-stayed bridges and analyze the thermal deformations. The pivotal heat conduction parameters of the geotextile and rubber pad were obtained through testing, and the governing equations for heat conduction considering temperature variations were improved. A thermal-fluid-solid coupling model for slab track on cable-stayed bridge was proposed. The results indicated that the high temperatures of the track were concentrated within 0.05 m depth of the slab. Under the resistance of the isolation layer, the temperature on both sides of the geotextile isolation layer appeared obvious abrupt change. The time of maximum and minimum temperatures of the truss beam were the same as those of the air. The effects of real-time temperature change on the irregularity of the rail were obvious. In summer, the maximum vertical rail deformation was 201.88 mm and the transverse deformation was 17.87 mm. The temperature change in just one day caused vertical deformation of rail with a range of more than 60%. On a single day in summer, the maximum horizontal irregularity was 1.74 mm, which was less than the 2.0 mm specified in the code.

Study on Horizontal and Vertical Irregularities in Structures Under Seismic Load – A Review

An increase in population has led more often towards vertical development rather than horizontal development, because of this the demand for multi-storied buildings has increased and they constitute about 60-70% of the urban infrastructure. In the present time, the analysis of civil structures is generally carried out by various design software. Now a day’s irregular structures contribute a large portion of urban infrastructure. Irregular structures have certain physical discontinuities either in plan or in elevation or both which affect the performance of the structure subjected to lateral loads. This work reviews the analysis done by various researchers in multi storey reinforced concrete structures subjected to seismic load. Key Words: ETABS, Seismic Load, Multi Storey buildings, vertical and horizontal Irregularity.

PERFORMANCE ANALYSIS OF HORIZONTAL IRREGULAR BUILDINGS BASED ON RESPONS SPEKCTRUM AND TIME HISTORY METHODE

Indonesia is geographically located in the Pacific Ring of Fire, Especially on Java Island, which has the densest infrastructure and population and is located between the Indo-Australian plate and the Eurasian plate, causing this area to have many active volcanoes and has a high potential for earthquakes. Therefore, it is necessary to pay the planned earthquake load in planning the building structure design to minimize losses due to the earthquake. This study aims to determine the structure's performance against safeguards, deviations between levels, and structural stability limits against earthquake loads and to review horizontal structural irregularities based on SNI 1726: 2019 regulations in existing buildings at the Simpang Temu MRT Dukuh Atas Jakarta Building. The analysis process was carried out by 3D building modeling using the ETABS software program, analysis based on time history and spectrum response. Time History analysis uses recorded earthquakes of Kobe Japan, ChiChi Taiwan, and El Centro which match the earthquake response spectrum, the results of the analysis based on the program were carried out to compare the two methods used. Based on the results of the analysis, the building is classified into horizontal irregularities with excessive torque ratio > 1.4, average displacement value from the 2nd to 12th floor in the horizontal direction X exceeds the drift value limit. The results of the instability limit for structural stability against displacement based on the P-Delta effect still meet the structural stability limits so it can be stated that the structure is stable and safe.

Seismic control of vertically and horizontally irregular steel high-rise buildings by tuned mass dampers including SSI

The architectural requirements imposed on the structural design of buildings sometimes necessitate vertical and horizontal irregularities with their possibly dangerous effects when these structures are subjected to earthquakes. One of the greatest challenges in structural engineering is the design of a steel high-rise building (HRB) with vertical and horizontal irregularities. In this research, two irregular steel high-rise buildings (HRBs) were seismically analyzed as 3D models considering soil–structure interaction (SSI) and tuned mass damper (TMD) systems were used to mitigate their seismic response under different earthquakes. The two studied HRBs were a vertically irregular (step-pyramid-shaped) steel HRB, and a both vertically and horizontally irregular (L-shaped in-plan, stadium-shaped) steel HRB. The SSI provides the actual response of the tall buildings subjected to earthquake, and mitigation schemes using TMDs were suggested with arrangements of the TMDs on the top plan and along the elevation of the steel high-rise buildings to achieve seismic control of these structures. The present study has shown that the best efficiency in the mitigation of the effect of earthquakes on vertically and horizontally irregular steel high-rise buildings is obtained by implementing TMDs at the corners of the HRB plan on the top of the HRB and also at different floor levels along the upper half-height of the HRB.

State of art on seismic comparison of different types (V, diagonal and X) of bracings on different shapes of buildings (L, H, T and rectangular) with response spectrum method

Multi-storey buildings were particularly affected by the earthquake and tsunami. The real problem with the multi-storey building system is that the buildings are usually horizontal and resist lateral forces to control the floating sides of buildings. Structural analysis is a branch where it involves modelling a building, assigning sequential loading and analysing structural behaviour, and estimating the seismic responses of all building components. This project “Seismic comparison of different types (V, Diagonal, and X) of bracing on different shapes of buildings (L, H, T, and Rectangular) with response spectrum analysis” is an effort to perform analysis and design the commercial structure using the software ETABS. The steel bracing is quite economical and is easy to install, taking up little space and with design flexibility to reach the desired strength parameters and durability. For the thesis, it has been considered a building model with different types of binding systems based on the journals I have encountered, so the project focuses on other design features such as lateral displacement of story, Drift, and stiffness. During the earthquake, the behaviour of the building depends on the following factors, durability, and sufficient strength in the lateral direction, ductility, and normal configuration. The buildings with normal geometrical features and size with even distribution and durability and height have very little damage in comparison with conventional suspensions. But at present the need for the next generation and the Population density have made architects or engineers inevitable in planning unusual designs. Earthquake engineering had therefore developed significant effects while understanding the purpose of architectural planning. Irregularity is a variety of types such as vertical irregularity, and horizontal irregularity. Vertical irregularity refers to an immediate change in stiffness, strength, geometrical features, and the effect of mass on the abnormal transfer of energy or flexibility over the length of the structure.

Seismic fragility of low-rise piloti buildings based on 2017 Pohang earthquake damage

Due to the 2017 Pohang earthquake, many low-rise piloti buildings suffered minor to severe damage. Low-rise piloti buildings in Korea are generally both vertically and horizontally irregular systems. The first floor is a weak and soft story, and the core wall is located at the corner or edge of the plan creating a horizontal irregularity. Furthermore, the damage investigation indicates that the insufficient amount of column hoops and poor detailing of reinforcement. It was presumed that the combination of soft story, torsional behavior and poor detailing brought brittle failure at the columns located at the furthest distance from the core. Such a brittle and irregular nature makes it difficult to predict damage with a HAZUS-type approach, which uses seismic fragility functions defined in terms of the spectral displacement and the capacity spectrum method based on pushover analyses. Comparison of pushover analysis results of piloti buildings indicated that location of peak and overall deformation capacity differed with the intensity of the torsional behavior and failure mode of the column. Therefore, this study aimed to develop an improved seismic fragility function for piloti buildings. To reflect the observed damage, the use of damage criteria based on member performance, including stress and strain, and spectral acceleration was proposed. Fragility functions for the piloti buildings were constructed by using three-dimensional incremental dynamic analyses. Damage estimates for piloti buildings in the target area that were obtained by using obtained fragility functions showed good correlations with damage survey data.

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.

RESPON STRUKTUR AKIBAT PENEMPATAN DILATASI PADA BANGUNAN DENGAN KETIDAKBERATURAN HORIZONTAL

The placement of dilation in the building structure with horizontal irregularity causes a different response to the structure during an earthquake, because the structure is divided into several individual structures that stand alone so that they are different from the original structure. The proper placement of the dilation in a building will reduce the risk of collapse of the building during an earthquake as well potentially making structures simpler and more efficient. This study uses the design analysis method to compare the earthquake shear force, structural response, and internal forces in the structure due to the placement of the X-direction and Y-direction Dilatation. greater than the X direction dilatation, which is 42% in the X direction and 38% in the Y direction. The deviation that occurs in the Y direction dilation is greater than the X direction dilatation. X, but the internal force due to the Y direction of dilation on the beam is greater than the X direction dilation placement. So that the use of the Y direction dilation is slightly better than the use of the X direction dilatation in several things, such as the earthquake force and the inner force on the smaller column.

Performance of The Existing Building Under Earthquake Loads Based on Current Indonesian National Standard

This paper presents the results of an assessment of the existing 5-storey building built in 1980, which aims to determine the level of safety against the most recent standards. The method used is non-destructive testing, collecting planning data in the form of as built drawings and implementation data. The assessment of the existing structure consists of an evaluation of the condition of the material, structural system, and analysis of the structure using the latest load standards. The test results of the existing structural material show that the compressive strength of the concrete still meets the requirements based on SNI-2847-2019. The results of the evaluation of the structure against earthquake loads show that the performance of the structure has a mass participation of 100% and the dynamic base shear force (V) reaches 100% of Vstatic therefore it meets the requirements in SNI 1726-2019. The results of the evaluation of the performance of the structure show that the lateral drift and P-delta effects still meet the requirements of the most recent standards. Horizontal and vertical structural irregularities are found in the existing structural system. The structure's overall performance level (X and Y direction earthquakes) is Damage Control. These results are still permitted for structures with a priority factor (Ie) 1.50, with an earthquake return period of 2500 years.

Prediction Method of Heavy Load Wheel/Rail Wear Mechanical Properties Based on GA-BP Hybrid Algorithm

Due to its large axle load and high-density operation mode, heavy haul transportation has greatly improved the cargo transportation capacity, and is receiving unprecedented attention from all countries in the world. Since the development of heavy haul freight transport in China, wheel rail wear has been paid much attention, especially the use of heavy axle load locomotives on upgraded heavy haul lines, which makes reducing wheel rail wear and damage become a technical problem to be solved urgently. Considering that there are too many mechanical parameters involved in the prediction of heavy load wheel rail wear mechanical properties, the prediction accuracy is reduced. Therefore, this paper proposes a method based on GA-BP hybrid algorithm to predict the mechanical properties of heavy load wheel/rail wear. Hertz contact theory is used to simplify the wheel rail contact relationship, and the wheel rail contact model is established. According to the wheel/rail contact model, the expressions of heavy load wheel/rail in the case of vertical, horizontal, direction and gauge irregularity are analyzed, and based on this, a mechanical model of heavy load wheel/rail wear is established. In order to solve the problems of slow convergence speed and easy to fall into local optimum of BP neural network in the prediction of heavy load wheel/rail wear mechanical properties, the global convergence of genetic algorithm is used to optimize the BP network. According to the obtained mechanical parameters of heavy load wheel/rail wear, the mechanical parameters are input into the optimized model, and the relevant prediction results are output. So far, the research on the prediction method of heavy load wheel/rail wear mechanical properties based on GA-BP hybrid algorithm has been realized. The experiment is designed from three aspects of wear degree, hardness and tensile strength, and compared with the measured value, reference [4] method, reference [5] method and reference [6] method to verify the effectiveness of the proposed method. The experimental results show that the predicted results of wear degree, hardness and tensile strength by this method are closer to the measured results. It is proved that the proposed method has higher prediction accuracy and better practical application effect.

Analytical Modelling of T-Shaped Monolithic & Independent RCC Buildings

Abstract: During an earthquake the behaviour of the building depends on its overall shape, size & geometry. Now a day’s many buildings are asymmetric in plan and elevation because everyone wants to win the race of aesthetically beautiful and complex structures. Due to irregular distribution of mass, stiffness and strength, it may cause serious damage in structural system. There are various types of irregularities in the buildings depending upon their location and scope. Mainly two types of irregularities as per IS – 1893 (Part-1)-2002. are a) plan or horizontal irregularities b) vertical irregularities. Irregularity in structure makes analysis of the seismic behaviour very complicated. The objective of present study is to analyze and compare the behaviour of T shape monolithic and independent RCC structure under seismic loading. The comparison of both structures is studied by calculating, finding and tabulating comparative values of displacement, base moments and shear values. The study reflects that with change in structure i.e. the behaviour of structure towards earthquake changes, nodal displacement, moment, and base shear values shows drastic changes towards resistivity against seismic forces. The soft computing tool and commercial software STAAD-Pro is used for modelling and analysis also the study done over here thus helps to understand effect of earthquake on both structures for achieving stable and safe structure

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.

Response Spectrum Analysis with Regular and Irregular Structures with Diagrid Systems Using Etabs

Abstract: One of the most catastrophic natural disasters is an earthquake. that wreak havoc on buildings and the loss of life. The irregularities of a building or an asymmetrical system are often found in construction due to the need for architecture view in buildings. Today, the use of buildings and economic barriers requires that vertical and unusual structures be built in urban areas. Therefore proposing measures to reduce the damage to these buildings during an earthquake is important. Strict rules of design and analysis of unusual structures have been applied in view of their high risk of injury compared to conventional structures. There are different types of structural deficiencies depending on their location and width, but most importantly, they are divided into two groups - horizontal irregularities and vertical irregularities. In the study, both irregularities are considered. The current paper seeks to investigate the proportional distribution of lateral forces arising from earthquake action at each floor level due to changes in the strength of the frame in the irregular structure. In accordance with the provisions of the Bureau of Indian Standard (BIS) 1893: 2002 (part1), the unusual G + 14 vertical building is modeled as a model of the simplified lump mass to analyze the rigidity of the floors. To analyse parameters such as storey drift, storey displacement and story base shear under seismic force under dynamic analysis are studied