Abstract

Structural pounding may occur between two structures or at different parts of the same building during ground motions. Among all the structural damages, structural pounding has been commonly observed during several earthquakes in the past, which have lead to minor damage till complete collapse of the structure. The main focus of this paper is to study pounding responses and impact effects on structures subjected to ground motions. It is observed from the study that the response of stiff structure is more than flexible structure at dominant period of ground motion, irrespective of equal and unequal heights. If the structures vibrate at a non-dominant period of ground motion, then the response of flexible structure is observed more than the stiff structure.

Abstract

In this paper, Local Absorbing Boundary Conditions are presented for wave propagation through the viscoelastic media. This method is an extension of Local Absorbing Boundary Condition (ABC) proposed by Lysmer and Kuhlemeyer (1969). The proposed method does not converge for Kelvin type of viscoelastic materials but converges for Maxwell type of viscoelastic material model. This method is verified with 1D and 2D finite element models using explicit solver and the accuracy is compared with standard solutions. This study concluded that better responses can be obtained for the viscoelastic wave propagation using present approach when compared with traditional Local Absorbing Boundary Conditions. This study also concluded that the proposed method is suitable for low to medium viscous damping materials. For high viscous materials, the proposed method can be applied to transient wave propagation problems.

Abstract

In building construction, RC frame structure are frequently used due to ease of construction and rapid progress of work. Generally these frames are filled by masonry in fill panel. However, during past earthquakes it was found that the performance of of such type of structures significantly depends on out-of-plane behavior of infill panel wall. In this study two type of infills are used i.e, unreinforced masonry infill and semi-interlocked masonry infill. For analysis purpose of infill, double strut nonlinear cyclic model is used. The main objective of the study is to investigate the importance interlocked brick infill in RC frame structure. For R factor components such as ductility reduction factor and over strength factors were computed from nonlinear static pushover analysis and finally response reduction factor is calculated for all models. In this work, primary focus is given to numerical modeling and nonlinear behavior of brick masonry building subjected to lateral loads and calculation of response reduction factor of RC infilled frame

Abstract

In the present situation of building construction around the world, Flat slab is becoming widely popular in the multi-storied buildings due to its advantage and ease of construction over the slabs. However, during past earthquakes, many building with flats have performed poorly. This is mainly due to inadequate resistance for punching shear under the earthquake loading. Many codes that are available for the design are for the analysis of flat slab under gravity loading. Some provisions exist for punching shear resistance, however, they are inadequate. To understand the behavior of building with flat slab subjected lateral loads, a numerical study is performed. A three-dimensional finite element method is used to perform the analysis. A flat slab along with the columns is modelled. Nonlinear constitute equations are used to model material, ie, concrete. Parametric study is performed for understanding the nonlinear behavior of flat slab subjected to lateral loads.

Abstract

Lighthouses are the road signs of the ocean. They guide sailors through dangerous waters. Each lighthouse design is based on the land it is built on, its purpose, and the technology available. The Geometry of the lighthouses is round, square, octagonal, or conical in shape. These lighthouses need to be in operation 24 × 7 guiding the ships coming towards the coast. However, these lighthouses got affected during past earthquakes. The main objective of this work is to perform the nonlinear time history analysis of Navadra, Kachchigadh and Dwaraka point lighthouses subjected to eight ground motions. Since most of the Gujarat state is under Zone-III, IV and V, the analysis is carried out by normalizing them to respective zone factors as suggested by Bureau of Indian Standards IS 1893 (part-1): 2002. Using energy dissipation approach, damage is quantified at every displacement level. A fragility curve has …

Abstract

Methods capable of assessing the vulnerability of houses for future earthquakes are of fundamental importance for the safety and development of an area. As the detailed assessment is limited to number of houses and cost, one of the appraising methods currently used for seismic vulnerability assessment is rapid visual screening (RVS). This methodology has led to determination of risk of an area subjected to an earthquake event. Many codes have limited rapid visual screening to housing typologies like reinforced concrete and Brick masonry structures. This paper delivers an approach on how to perform RVS for five varieties of buildings in Himachal Pradesh state. The RVS scores have been calculated for 9099 buildings and normal distribution curves are plotted for each typology of building to understand the distribution of buildings in Himachal Pradesh. Finally, a new modified format for performing rapid …

Abstract

ndia and nearby countries in Asia witness major earthquake in recent days and in past. Although after witnessing many earthquakes in past, for aesthetic purpose big window openings in wall and even whole brick wall replaced by glass can be seen in metro cities and suburban areas in cities of India. Opening and aspect ratio in wall plays great role in strength and stiffness of wall and overall behavior of building. Without understanding effect of openings and aspect ratio on strength, stiffness and behavior of wall it can be dangerous to use such practices in construction of building. In this research study, effect of opening and aspect ratio on overall behavior of building has been studied. This numerical study has been done by considering a RC framed brick infill wall using Applied Element method. Applied element method is capable of showing crack initiation, crack propagation till total collapse of building. This research study will focus on importance of placement of opening and consideration of aspect ratio for RC infilled brick masonry building.

Abstract

It is well known that loss of life during an earthquake event is mainly due to collapse of buildings that are not designed, executed or maintained properly. Therefore there is an urge for pre-earthquake vulnerability assessment of buildings in moderate-to-severe earthquake prone areas world-wide. Vulnerability assessment of a building is a challenging task and it has to be dealt very carefully. However, for large number of buildings in a city or town, some simple methods have to be employed. Rapid Visual Survey (RVS) is one such method which is widely used all over the world. It uses many parameters like presence of soft storey, plan irregularities, stiffness irregularities, short-column effect, etc., for evaluating the score. This score has a limitation because the forms that are developed at one place cannot be used in different region, due to large variation in design guidelines and construction technology and hence it is important to develop forms which are specific to an area and also building technology used. In addition, it is also important to calibrate RVS scores to possible damage indicators. Hence it is important to know the effect of individual parameter (ie, vulnerability score modifier) on the overall score. This paper describes the numerical procedure for defining the value of vulnerability score modifiers for parameters that affect RVS score.

Abstract

This paper presents a parametric study on behavior of a shallow foundation resting on pond ash deposit with and without reinforcement. The behavior of foundation resting on the reinforced ash deposit is examined and studied by considering the parameters like effective depth of reinforcement; width of reinforcement; number of reinforcing layers. The parametric study has been performed using three dimensional finite element software, PLAXIS 3D. With the provision of reinforcement, the displacement is reduced as compared to unreinforced case. Also, with the increase in number of reinforcement layers, the bearing capacity of reinforced pond ash foundation is increased. Based on the results obtained, it is concluded that effective placement of reinforcement is observed at a depth of 2.67 B below the foundation for a width of 2B. Also, with the increase in number of layers, the bearing capacity is increased and the optimum provision of number of reinforcing layers is found to be two. Hence, it can be concluded that the performance of shallow foundation is better when pond ash underlying the shallow foundation is reinforced with geosynthetics material.

Abstract

Reinforced concrete structures with open ground storey have shown very poor earthquake performance during past events. Despite of considering the design recommendations provided in the various international codes of practices for structural elements of open ground storey, the damage in the building has not reduced significantly. Literature shows damage to structural members in the soft storey depends on their relative stiffness with respect to adjacent storeys and eventually affects the deformation characteristics. Hence the problem of soft storey cannot be addressed independently without considering the relative effects of adjacent storeys. In this paper, the seismic response of open ground storey structure with openings in the upper storeys is studied and amplification factor for designing and strengthening of open ground storey members is determined. Static Nonlinear pushover analysis is used to carry out the study. The main parameters investigated are stiffness, strength, inter-storey drift and fundamental period. It is found that the presence of wall opening in upper storey will decrease its stiffness and strength significantly compared to full infill, which directly leads to reduction in the deformation and decrease in amplification factors for design and strengthening of ground storey members.