Plan Irregularity Research Articles

Seismic pounding of adjacent buildings considering torsional effects

This study aims to evaluate pounding effects in fixed-base models by considering torsional irregularity. For this purpose, 8 different adjacent building combinations were created by using 3-dimensional 5- and 9-story building models. In adjacent building models, the most critical situation was determined by evaluating the gap distance, different sequences of the same building models and regular or irregular plan view and if the structures are irregular, their eccentricity cases relative to each other. Nonlinear behavior of structural elements was taken into account for examine the change in the seismic behavior of structural elements due to pounding and torsion effects. The nonlinear time history analysis of the adjacent models was performed for 11 pairs of spectrum compatible ground motion recordings in the SAP2000 program. The results of 176 different analyzes show that the displacement demand, interstory drift ratio, damage ratio and torsional irregularity coefficient values tend to increase in general with the combined effects of pounding and torsion. The absolute maximum and most critical values of the relevant parameters were calculated in irregular structures with pounding where the eccentricity of buildings is in the same direction and same side. In addition, the large standard deviation of the result values according to the ground motion records indicates that care should be taken in choosing the number of ground motion records.

Response Reduction Factor for Structures Irregularities in Plan and Elevation Taking into Account Soil-Structure Interaction

The structure's ability to release energy through inelastic behaviour is reflected in the response reduction factor (R). It results from a combination of redundancy, ductility, and over strength. Thus, determining R with accurate values plays a critical function in the process of seismic design. This study aims to determine the response factor of structures of reinforced concrete (RC). With different structural irregularities, additionally, determine the impact of the interaction between soil and structure (SSI) using non-linear static pushover analysis was adopted in numerical simulation by using SAP2000. The selected irregularities included elevational and in-plan changes It was determined that, in comparison to regular buildings, buildings with irregular vertical geometries had poorer inelastic seismic capacities. Therefore, R is less than that which is stated in the ECP 2020, so it ought to be reduced by 15–40% before the design stage. The outcomes demonstrated that It isn't concluded that irregularity has a considerable effect on weak soil (C). The reduction in R, considering (SSI), reached 20.3% and 13.1% for fixed and isolated supports, respectively, in case of loose soil. Moreover, it became obvious that for the same structure the stiffer the base soil the greater the R's value.

Investigation of Seismic Response of Irregular Steel Buildings: A Case Study of U-Shaped Structures

Tills paper presents a dynamic analysis focusing on the influence of plan shape on tall steel structures. The study specifically investigates the seismic behavior of two 22-story buildings, one with a square plan and the other adopting a U-shaped configuration. Utilizing OpenSEES platform for nonlinear time history analysis, the research sheds light on the impact of plan irregularities on fundamental time periods, displacements, drift ratios, and base shear. Results reveal that the U-shaped building experiences liiglier dynamic response compared to the square shaped reference building, the U-shaped building experiences liiglier time periods across all modes due to increased mass and irregular stiffness distribution in the building's grid. Top story displacements reveal an increase in maximum displacement by 30% compared to the reference structure, showing a non-linear pattern. Inter-story drift ratios had peaks at the 8th and 18th floors showing increments of 43% and 117%. respectively. The time liistoiy response illustrates a liiglier response over time for the U-shaped building, indicating distinct behavioral differences. Base shear time liistoiy revealed liiglier values for the U-shaped building over time, including a 48% increase in maximum base shear compared to the reference building. These findings reveal the significant effect of plan regularity in tall steel building design on the seismic response and the importance of considering it in building design.

A Comparative Analysis of Seismic Behavior of Regular and Irregular Shaped Buildings with OMRF and SMRF Structural Systems: A Review

Abstract: These days, modern residential buildings are getting higher and higher. The way these structures perform is significantly impacted by the impact of lateral loads from wind and earthquakes. It is impossible to completely prevent irregularities when building. It is mandatory to investigate how these irregularly shaped structures behave during earthquakes. The behaviour of regular and irregular buildings is represented in this study. As a result of the irregular plan and elevation configurations of various buildings in the current situation, which could be subject to hazadous earthquakes in the future, it is necessary to assess how well the structures are performing in terms of their ability to withstand disasters, primarily earthquakes. This project aims to compare the seismic behaviour of regular-shaped buildings with OMRF and SMRF structural systems versus. The study will make use of STAAD-Pro software, and the buildings' performance will be evaluated according to several criteria. The results of the research will broaden our understanding of earthquake engineering and provide insight into the performance of OMRF and SMRF structural systems in both regularly shaped and irregularly shaped buildings.

THE INFLUENCE OF CULTURAL AND ARTISTIC TRADITIONS OF CHINA ON THE IMAGE OF A RELIGIOUS BUILDING

The Buddhist temple complex of Dunhuang can be named as the oldest example of the transformation of architectural and artistic canons of foreign religions when they were transferred to the territory of China. The artistic canons of the sanctuaries, which originated in India, underwent more and more transformations as local architectural and artistic skills developed. The same can be said about the transformation of the image of an Islamic religious building in the case of mosques, for example, in Shaanxi province, which acquired the architectural and artistic image of a Chinese temple of the traditional beliefs of Taoism and Confucianism. The influence of local traditions even on the image of a Christian church, namely the German Protestant church in Qingdao, was studied. In particular, it is quite bright for the German northern national romanticism, the polychromy of the facades, which contrasts with the ascetic interior. 
 Unlike traditional Protestant churches, the Protestant church in Qingdao has an irregular plan and the entrance to it is located not from the west, as usually, but from the south (Fig. 1). The asymmetry of the church composition is emphasized by the dominant tower with a height of 39 m. 
 This object is traditionally mentioned in the same row as other objects of northern national romanticism – the Residence of the Governor of Qingdao and the Japanese Girl’s High School. First of all, let’s analyze what signs of northern national romanticism are present here: 
 – large scale;
 – an active silhouette with the presence of pseudo-Romanesque towers of different heights;
 – the presence of “torn” stone cladding;
 – lack of small details and decoration on the facades.
 Now let's define the features that are not inherent in the typical German northern national romanticism:
 – dominance of yellow tinted wall planes over planes faced with “torn” stone;
 – the introduction of bright polychromy (red tiled roofs – yellow plastered walls – planes faced with “torn” granite – green tower’s roof not in the outlines of northern national romanticism).
 An analysis of the appearance of the Protestant church in Qingdao led to the following conclusions.
 An analysis of the appearance of the Protestant church in Qingdao led to the following conclusions.
 The important role of this object in the planning structure of the settlement actually built on an empty site is evidenced by the following facts:
 – the location is close to the government district;
 – holding a competition in Berlin;
 – funding by the Qingdao Governor's Office;
 – the choice of the style of northern national romanticism. 
 However, despite the presence of some signs of northern national romanticism in its German version, the phenomenon of style transformation when transferred to Chinese soil should be noted. In particular, under the influence of the picturesque natural environment, other natural and climatic conditions and Chinese architectural and artistic traditions of bright colours, the Protestant church acquired features that are not characteristic of northern national romanticism.

The green divide and heat exposure: urban transformation projects in istanbul

Extreme heat events are happening more frequently and with greater severity, causing significant negative consequences, especially for vulnerable urban populations around the globe. Heat stress is even more common in cities with dense and irregular planning and lacking urban blue-green infrastructures. This study investigates the greening and cooling effects of five selected urban transformation projects and their surrounding areas (within a 10-min walking distance) in Istanbul from 2013 to 2021, with a focus on environmental justice and climate adaptation planning perspectives. By employing temporal analysis of Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) values derived from Landsat data sets to detect changes in these five selected urban transformation projects in the megacity of Türkiye, Istanbul, this study finds that the distribution of green infrastructures (e.g., tree canopy) is only limited to project sites of long-running and state-supported urban transformation projects in Istanbul. Consequently, the unequal distribution of green infrastructures creates cooling effects only for the locals residing in the new residential projects. However, the surrounding areas have less urban green infrastructure and are exposed more to the urban heat over time. Urban development policies and planning highly contribute to increasing the climate vulnerabilities among those who do not benefit from the recently developed residential units in Istanbul. Such a trend can affect adaptive capacity of vulnerable communities and redress environmental injustices in urban planning in the megacity of Istanbul.

Comparative Study on Seismic Response of Regular and Plan Irregular Base isolated structures

Earthquake is one of most destructing threat which cause severe damage to life and property. Recently, due to increasing demand and need for the present generations has made the designers and engineers to plan for structures having irregularities. It is impossible to avoid designing uneven buildings in reality. It is important to research how this irregular structure behaves in earthquake-prone areas, especially for structures with base isolation. When compared to regular structures with base isolation, structures with plan irregularity react differently. When a reinforced concrete building with varied plan configurations, such as an H, U, or L shape, is subjected to seismic loading, the impact of plan irregularity is explored. In the current study, a regular structure is also considered to compare the responses of the isolated irregular base structure. Building response spectrum analysis for seismic analysis was done in seismic zone III using IS 1893-2002 code [5]. The structural analysis software tool ETABS 18 was used to conduct the analysis. Among different types of isolators present, in the present study LRB isolator and friction isolators was used as a Nonlinear Support. The dynamic response of the structure such as base shear, time period and story displacement are used to compare the regular and irregular structures. The effectiveness of the base isolators in the structures in earthquake prone area is evaluated in the present study.

Dosimetric impact of MLC positional errors on dose distribution in IMRT.

Optimizing the positional accuracy of multileaf collimators (MLC) for radiotherapy is important for dose accuracy and for reducing doses delivered to normal tissues. This study investigates dose sensitivity variations and complexity metrics of MLC positional error in volumetric modulated arc therapy and determines the acceptable ranges of MLC positional accuracy in several clinical situations. Treatment plans were generated for four treatment sites (prostate cancer, lung cancer, spinal, and brain metastases) using different treatment planning systems (TPSs) and fraction sizes. Each treatment plan introduced 0.25-2.0mm systematic or random MLC leaf bank errors. The generalized equivalent uniform dose (gEUD) sensitivity and complexity metrics (MU/Gy and plan irregularity) were calculated, and the correlation coefficients were assessed. Furthermore, the required tolerances for MLC positional accuracy control were calculated. The gEUD sensitivity showed the highest dependence of systematic positional error on the treatment site, followed by TPS and fraction size. The gEUD sensitivities were 6.7, 4.5, 2.5, and 1.7%/mm for Monaco and 8.9, 6.2, 3.4, and 2.3%/mm (spinal metastasis, lung cancer, prostate cancer, and brain metastasis, respectively) for RayStation. The gEUD sensitivity was strongly correlated with the complexity metrics (r=0.88-0.93). The minimum allowable positional error for MLC was 0.63, 0.34, 1.02, and 0.28mm (prostate, lung, brain, and spinal metastasis, respectively). The acceptable range of MLC positional accuracy depends on the treatment site, and an appropriate tolerance should be set for each treatment site with reference to the complexity metric. It is expected to enable easier and more detailed MLC positional accuracy control than before by reducing dose errors to patients at the treatment planning stage and by controlling MLC quality based on complexity metrics, such as MU/Gy.

Seismic control of T-shape in plan steel high-rise buildings with SSI effect using tuned mass dampers

A steel high-rise building (HRB) with plan irregularity is a major challenge in engineering design, especially under seismic loads. Soil–structure interaction (SSI) is one of the most important factors in designing steel high-rise structures. Herein, a T-shape in plan steel HRB subjected to four different earthquakes will mitigate the vibration and control the displacements and base straining actions resulting from earthquakes by using tuned mass dampers (TMDs) systems, and the most controlling arrangement of TMDs, in the fixed base HRB model and in the SSI HRB model, will be examined. Three-dimensional models of the steel high-rise building (HRB) with a T-shape in the plan subjected to four different earthquakes fixed or with the SSI effect were analyzed to investigate the seismic mitigation effect of six different plan arrangements of TMDs applied on the top plan of the fixed HRB model, while for the SSI HRB model, these TMDs distributions were applied on the top plan and additionally on two intermediate plans along the HRB height. The TMDs for the T-shape in plan steel HRB are more effective in the SSI model than in the fixed base model. In the SSI effect model, the distributions of the TMDs not only on the top plan of the model but also through the model (on two additional plan levels along the height) further reduced the HRB seismic response and this three-level TMDs distribution was required for the plan arrangement of 2 or 4 TMDs.

Probabilistic assessment of the rules used to combine peak floor responses of special concentrically braced frames under orthogonal seismic effects

AbstractEstimating seismic demands and the associated damage to nonstructural components (NSCs) is a critical step in the performance‐based earthquake engineering (PBEE) framework. To facilitate this type of assessment, NSCs are classified as being acceleration, velocity, or displacement sensitive. When two‐dimensional structural models and response history analyses are used in the PBEE framework, heuristics are used to combine the orthogonal responses. Although there has been significant research to develop and evaluate combination rules for structural component responses, comparatively much less attention has been placed on NSC demands. FEMA P‐58 does provide a combination rule specifically for NSC seismic demands; however, the basis and accuracy of these provisions have never been examined. In this paper, the effectiveness of three popular combination rules used to estimate peak floor acceleration (PFA) and peak floor velocity (PFV) is investigated. Incremental dynamics analyses under unidirectional and bidirectional record‐sets are performed on six special concentrically braced frame buildings with different heights and torsional irregularity. The associated floor responses are used to examine the efficacy of the combination rules. Subsequently, a probabilistic approach is proposed to enhance the accuracy of combination rules. The performance of the enhanced combination rules is compared to that of a surrogate model that estimates PFA and PFV under orthogonal seismic effects. The results show that the performance of existing combination rules is slightly affected by building height and plan irregularity. Also, the combination rule suggested by FEMA P58 is found to overestimate the PFA and PFV demands by 10–15% compared to the demands derived from bidirectional response history analysis.

Complexity analysis of VMAT prostate plans: insights from dimensionality reduction and information theory techniques

Abstract Introduction: Volumetric Modulated Arc Therapy (VMAT) is a state-of-the-art prostate cancer treatment, defined by high dose gradients around targets. Its unique dose shaping incurs hidden complexity, impacting treatment deliverability, carcinogenesis, and machine strain. This study compares various aperture-based VMAT complexity indices in prostate cases using principal component and mutual information analyses. It suggests essential properties for an ideal complexity index from an information-theoretic viewpoint. Material and methods: The following ten complexity indices were calculated in 217 VMAT prostate plans: circumference over area (CoA), edge metric (EM), equivalent square field (ESF), leaf travel (LT), leaf travel modulation complexity score for VMAT (LTMCSV), mean-field area (MFA), modulation complexity score (standard MCS and VMAT variant MCSV), plan irregularity (PI), and small aperture score (SAS5mm). Principal component analysis (PCA) was applied to explore the correlations between the metrics. The differential entropy of all metrics was also calculated, along with the mutual information for all 45 metric pairs. Results: Whole-pelvis plans had greater complexity across all indices. The first three principal components explained 96.2% of the total variance. The complexity metrics formed three groups with similar conceptual characteristics, particularly ESF, LT, MFA, PI, and EM, SAS5mm. The differential entropy varied across the complexity metrics (PI having the smallest vs. EM the largest). Mutual information analysis (MIA) confirmed some metrics’ interdependence, although other pairs, such as LTMCSV/SAS5mm, LT/MCSV, and EM/SAS5mm, were found to share minimal MI. Conclusions: There are many complexity indices for VMAT described in the literature. PCA and MIA analyses can uncover significant overlap among them. However, this is not entirely reducible through dimensionality reduction techniques, suggesting that there also exists some reciprocity. When designing predictive models of quality assurance metrics, PCA and MIA may prove useful for feature engineering.

Probabilistic Evaluation of Seismic Performance of Steel Buildings with Torsional Irregularities in Plan and Soft Story under Mainshock-Aftershock Sequence

Due to the tectonic plate movement, numerous aftershocks may occur following an earthquake. There are several real mainshock-aftershock ground motion records in which the peak ground acceleration of aftershock is greater than that of the mainshock. Furthermore, irregularities such as soft story and torsional irregularity may change the structural behavior under the influence of earthquakes. This study investigates the fragility curves associated with the three-, five-, and eight-story models with steel moment-resisting frames under the main earthquake and mainshock-aftershock sequence to probabilistically evaluate the aftershock impacts on the steel structures with irregularities in the plan and height. The seismic fragility curves were calculated for four damage levels by selecting the relative displacement capacity at seismic performance levels of slight, moderate, extensive, and complete damage from the US HAZUS code. The analysis was done using structural reliability relationships and incremental dynamic analysis with the OpenSees software platform. The analytical results showed that the structures with soft-story and torsional irregularity were more vulnerable with an increasing number of stories. Also, aftershocks were found to have a more destructive effect on low-rise models. The probability of structural collapse in a given peak ground acceleration for a damaged state due to the mainshock-aftershock sequence is higher than that of the mainshock sequence.

Effect of P-delta on RC framed buildings with plan irregularities for wind

In recent times due to rapid population rise and the lack of open spaces, the demand for tall buildings especially in the urban areas ís increasing day by day. At the same point, the frequency and magnitude of extreme natural events are also trending up, due to which tall buildings are becoming vulnerable under lateral loading. So, while designing and analysing a high-rise, additional emphasis must be given on both the first and second-order loading effects on tall buildings which are essential to understand its response under lateral stochastic loading. P-Delta, a second-order effect that are mostly manifested in tall buildings when subjected under lateral sway. Besides, the shape of the plan also plays a significant role in it in terms of its regularity in shape. Structures with irregular plan are becoming widely visible and popular among urban and modern infrastructure for space management as well as aesthetics views. The current study is aimed to perform a comparative study of different RC framed buildings having geometric plan irregularities without P-Delta and with P-Delta using ETABS. The study is focussed to detect the effect that P-Delta has on the buildings with irregularity in terms of maximum displacement, storey drift etc. and draw the parametric deviation of the irregular buildings with the regular buildings having equal plan area subjected to wind as their lateral load. Additionally, the study is also enlightening the effect of bracing systems on buildings with irregularity with & without P-Delta.

Assessment of the Seismic Vulnerability of a Multi-storey RC Structure with Plan Irregularity: A Case Study

A nine-story reinforced concrete dual system (wall-frame) building located in Bucharest, categorized as plan-asymmetric and designed according to the provisions of Romanian and European codes was studied. The criteria for regularity in plan were verified comparatively according to three codes (Eurocode 8, ASCE 7-16 and the Romanian seismic design code P100-1-2013). The seismic behaviour of the studied building was further investigated by detailed nonlinear static analyses (pushover) and nonlinear dynamic analyses performed on the 3-D building model, for various load patterns and spectrum-compatible ground motion records, respectively. The seismic vulnerability of the building was estimated based on the structural vulnerability index, determined from the nonlinear analyses. The study highlighted the significant effects of the overall torsion on the investigated parameters, in particular on interstory drifts and roof displacements, but also on the seismic vulnerability index.

Vulnerability assessment of RC buildings with irregularities using probabilistic analysis

Modern construction comprises of large number of reinforced concrete structures with geometric irregularities. Even though these types of structures have good serviceability and aesthetic appearance, such structures show high vulnerability during earthquakes. The present study investigates the performance of multistorey RC buildings, with different irregularities under seismic excitations, using Pushover analysis. Fragility curve, defined as the probability of reaching or exceeding of a specific damage state under a seismic excitation, provides an estimate of possible damage during occurrence of an earthquake. Four structural models of multi storey reinforced concrete buildings with different configurations consisting of bare frame with plan irregularity, setback frame, set back frame with shear wall without openings and set back frame with shear wall with openings are considered. Three-dimensional models of the structures with different geometric irregularity are generated and pushover analysis of each model is carried out using the software ETABS. The capacity curves generated using pushover analysis are transformed into bilinear curves and the roof displacement at the yield and ultimate levels are obtained. The procedure asper ATC-40 is followed to find the performance point from this nonlinear analysis. Later the damage probability is calculated based on the damage state levels, and curves of fragility are generated. To quantify the damage of the structure using fragility curve, damage state levels are fixed as Slight, Moderate, Extreme and Collapse Damage Level. The results of pushover analysis indicate the effect of enhancement of the stiffness of the setback frame by providing shear wall without openings, but no significant effect in terms of stiffness and ductility while including shear wall with openings. Based on the damage state level chosen and fragility analysis of the four structural models, the structural system with setback frame with shear wall without openings has shown better performance.

Automatic Minimization of the Drift Performance of RC 3D Irregular Buildings Using Genetic Algorithm

This study introduces the application of genetic algorithms for the optimal design of the seismic torsional drift performance of three-dimensional reinforced concrete buildings. Attempts have been made to achieve an optimal automatic design of the torsional drift of the storeys of reinforced concrete buildings with plan irregularities to build torsional balanced structures. The storey torsional drift response generated by static and dynamic loads can be clearly expressed in terms of vertical structure elements’ sizing design variables. Two examples are provided to demonstrate the efficiency and practicability of the proposed optimum design approach. The performance of the structures was assessed as per the procedure prescribed in modern seismic code languages. Mathematical and finite element modelling were used to perform seismic analysis on buildings. MATLAB® programming was used as a solution to the sizing optimization problem. The results confirmed the proposed genetic algorithm’s ability to find efficient optimum solutions to three-dimensional reinforced concrete structures through the problem of size optimization.

Seismic Analysis of Irregular Buildings With And Without Lead Plug Rubber Bearings (LPRB)

Base isolation has become an effective technique that aids in earthquake hazard mitigation and has been in use for the past decade. By properly separating the structure from the horizontal ground motion components, the base isolation system lowers the likelihood of resonance. Isolators are provided at the base of the structures, and decoupling is accomplished by modifying the system's flexibility and adding adequate damping. Structures with irregular plans are gaining popularity owing to their aesthetic appearance as well as architectural designs. The response of such structures to seismic action will be different from conventional structures. This paper aims to study the effect of base isolators on structures with irregular plans, while simultaneously observing the changes occurring when the height of the structures is increased. Three unique plans are chosen, namely plus, L and T shapes, whose responses are studied on 5, 10 and 15-storeyed structures. All the columns in the base-isolated structures are equipped with lead plug rubber-bearing base isolators which is the chosen isolator for this study. The base isolators are designed for each structure specifically so that the behavioural patterns observed are as accurate as possible. From the obtained results, it is discerned that base-isolated buildings exhibited better performances in comparison with fixed-base buildings, and as the height of the structure increases the effect of the base isolator tends to decrease.

Study The Effects Of Various Wind Loadings In High Rise Rc-Framed Structures In Zone –V

The construction of high-rise buildings, both residential and commercial, is increasing. Every structural designer must be aware of the forces such as earthquake and wind effects. Every engineer is challenged to provide stability and strength for loads such as lateral forces (wind and seismic loading). That is why wind loading has become one of the most important issues in high-rise buildings. Lateral loads are crucial for drift; therefore, drift must be considered for high-rise structures. This research work focuses on the effects of various wind loads on high-rise structures with the provision suggested in IS 875(part 3):2015 and for seismic load using IS code 1893(part1):2016. For the study, four irregular plan building is used with G+20 story in seismic zone V and terrain category II with a basic wind speed of 44, 47, 50, and 55 m/s that is analyzed and designed using the structural analysis software tool STAAD Pro. The bending moment, shear forces, story displacements, story shear, and story drift are analyzed on every level of height on the building, and the results are compared with them.

Seismic effects of bracing irregularity of light timber-framed buildings

Most residential buildings in New Zealand are low-rise light timber-framed (LTF) buildings, constructed according to a prescriptive standard – NZS 3604:2011 Timber-framed buildings. NZS 3604:2011 tabulates the seismic demand and also specifies the test procedure for evaluating the seismic resistance of proprietary LTF walls, which are often plasterboard walls. Designers need to ensure the provided total seismic bracing capacity is at least equal to the total seismic bracing demand, provided that bracing arrangements satisfy the specified irregularity limits. The irregularity limits of bracing arrangements in NZS3604:2011 were established based on engineering rules of thumb rather than rigorous scientific evidence. Earthquake damage observed in the 2010/11 Canterbury earthquake sequence demonstrated that simple regular LTF houses performed well while irregular houses often had significant damage that was uneconomical to repair. This suggested that the irregularity of LTF buildings was an important factor responsible for the exacerbated earthquake damage. To quantify seismic effects of permissible irregularities in NZS 3604:2011 and provide scientific evidence for elaborating irregularity limits in NZS 3604:2011, three single storey LTF buildings with varying degrees of permissible plan irregularities were designed and their seismic performance was studied by conducting three-dimensional non-linear push-over analyses. For the non-linear push-over analyses, the in-plane behaviour of LTF walls and ceiling diaphragms were modelled using the models, developed based on NZ practice, as reported in previous research. The study revealed that permissible irregular bracing arrangements in NZS 3604:2011 could amplify lateral deflections significantly, in comparison with the regular counterparts. As a result, irregular LTF buildings within the scope of NZS 3604:2011 could be susceptible to damage due to excessive deformations in earthquakes and this suggests that the irregularity limits in current NZS 3604:2011 be reviewed and tightened.

Seismic Behaviour of the Low-Rise RC Buildings in Nonlinear Static and Dynamic Analysis

This paper presents the behavior of three different types of irregular low-rise buildings, subjected to earthquake load. The study is performed by numerically modelling the buildings for the linear static analysis. Structural parameters displacements, drift, and storey shear are checked for various time periods of the building. The same models are also analyzed using nonlinear pushover analysis. The model is made nonlinear by introducing the hinges in the beam and column. The execution of nonlinear analysis is done by applying push in X and push in Y directions in controlled displacement mode. After the execution of nonlinear pushover analysis, different colours of hinges were formed, which were used as a basis for the study. The parameters like maximum displacement, max storey drift, and storey shear were computed in both in X and Y directions. Peak ground acceleration of Gorkha earthquake, EI Centro earthquake, and Kobe earthquakes was used for time history analysis. The results for max displacement, base shear, and max storey drift are presented and the comparison is made for the different building models. The study showed that a building behaves well in seismic loading even though they have an irregular plan with a larger structure size, compared to a building that has a regular plan and a smaller structural member size.