Abstract

In recent years, the introduction of Pre Engineered Building (PEB) concept in the design of structures has helped in optimizing design. The adoptability of PEB in the p lace of Conventional Steel Building (CSB) design concept re sulted in many advantages, including economy and easier fabricatio n. In this study, an industrial structure (Ware House) is analyzed an d designed according to the Indian standards, IS 800&1984, IS 800&2007 and also by referring MBMA&96 and AISC&89. In this study, a structure with length 187m,width 40m,with clear height 8m and havi ng R&Slope 1:10,isconsidered to carry out analysis& design for 2D frames (End frame, frame without crane and frame with 3 module cranes). The economy of the structure is discussed in terms of i ts weight comparison, between Indian codes (IS800&1984, IS800 &2007) & American code (MBMA&96), & between Indian codes (IS 800&1984, IS800&2007).

Abstract

Continental subduction and collision normally follows oceanic subduction leading to enormous crustal deformations. For understanding this mechanism oftectonic plates in collision area, which may propagate into the subductioncollision transition zone is of great interest. At the locations of high-pressure metamorphism, some places form huge crustal deformations like between Indian-Eurasian plates, and subduction at other places like Indian-Burmese plates. In either of the casesdeformation is a continuous, dynamic process. To understand the process, a study has been carried out using two dimensional finite element modeling. With the current availability of computing technology, advanced numerical techniques and material models it would be an easy task to know the parameters effecting the transition from collision to subduction process between different tectonic plates. In this paper, simpleinclined models are used to study subduction-collision transition zone. Elastic material rheology is considered for all the tectonic plates and contact analysis is used for the tectonic plate interfaces for the implementation of weak zones. Parameters consideredfor this study are geometry of plates, friction at the interface and length of the plates. This study concludes that vertical surface displacements are largely effected by the considered parameters.

Abstract

The pipeline systems are commonly used to transport water, sewage, oil, natural gas and other materials world over. These pipelines run over long distances and in some instances they cross high seismic areas including fault crossings. Many buried pipelines in India run through high seismic areas and are exposed to considerable seismic risk. These pipelines should be designed in such a way that they remain functional even when they are subjected to high intensity earthquake shaking. This paper illustrates the performance of one of the high pressure gas pipeline in the state of Gujarat, under the fault movement. Analysis shows that the burial depth of pipeline should be minimized in the fault zones in order to reduce soil restrain on the pipeline during fault movement.

Abstract

D uring past earthquakes many buildings suffered severe structural damage. Besides damage due to inadequate design and execution, buildings and building components suffered damage due to pounding also. Pounding is defined as collision between two buildings or different parts of the same building leading to severe damage or even sometimes complete collapse. In addition to simple lateral collision, buildings may also collide in torsion mode arising due to eccentricity of mass and stiffness, causing severe damage to adjacent building. In this paper two single storey reinforced concrete buildings are considered. To study the torsional effects due to pounding, buildings with different setbacks and unequal storey levels are analyzed using SAP 2000. The effect of collision is more when structures are kept at extreme levels of setback. At different elevation levels, the pounding response changes significantly than the structures at same elevation levels. More collision force is generated at mid height of column level than other height levels because of shear amplification.

Abstract

Pipeline generally extends over long distances traversing through wide variety of different soils, geological conditions and regions with different seismicity and ground motions. Vulnerability of the pipeline due to seismic hazards can be divided in to three categories i.e. hazard due to ground vibration, hazard due to faulting and hazard due to permanent ground deformation (PGD). Though there are no severe damage were observed due ground vibration in the modern buried pipeline though it may trigger to secondary effect of landsliding and ground motion due to liquefaction. Main stream researches in past especially analytical models are limited to strike slip fault motions with tension in pipe case only. As the large geometric changes incorporating in analytical study is a tricky task; however pipeline subjected to the large ground motion itself is a phenomenon of large geometric changes. Especially when pipeline subjected to compression, where in addition to material deformation it also undergoes general as well as local buckling with bending, contradictorily past work mostly assumed that pipeline is under tension. With day by day increasing capacity of computation and advancement in numerical modelling, one can find more facts for pipeline subjected to large motions including cases of pipe under compression as well. In this paper, past work is reviewed for pipeline subjected to large ground motion. A three dimensional FE based numerical model is suggested to carry out pipeline performance of buried pipeline subjected to large motion. A proposed model includes material nonlinearity, as well as considers the large geometric deformation. For this purpose, three dimensional FE program is developed using MATLAB. Displacement controlled Arc-length technique is implemented to solve the nonlinear behavior. To reduce the computation time of analysis here parallelization tool kit of MATLAB is utilized. Keywords: Buried continuous pipeline; Large ground motion; Nonlinear-large deformation FEM; Displacement controlled Arc-length technique.

Abstract

Understanding earthquakes and its prediction is most challenging tasks. Even though the earthquakes have been understood clearly, the prediction of earthquakes would take more time to come into reality. For this, collection of earthquake data and its interpretation plays a vital role. Its importance continues for few more decades in understanding the various aspects of earth structure and tectonic plate interactions. India, the second largest populous country of the world has experienced and is continuing to experience both inter and intra plate earthquakes, claiming life loss as well as damage to built environment. Apart from earthquakes, India has also experienced Tsunamis in both the directions; eastern tsunamis from Sumatra and western tsunamis from Makran. In this paper using past earthquake data, Indian plate interactions with its neighboring major (Eurasia, Africa & Australia) and minor plates (Arabia, Burmese & Sunda plate) have been understood. Upon clearly observing seven interactions, it is clear that interaction types, their lengths and thickness of plate play a great role in the occurrence of major to great earthquakes.

Abstract

Most seismic design codes allow structure to be designed for lesser force than elastic force, thus allowing structure to damage at appropriate locations. Indian seismic code IS 1893-2002 divides seismic design of structures into three categories; Ordinary moment resisting frame, Intermediate moment resisting frame and Special moment resisting frame. The classification differs based on reinforcement detailing and response reduction factor. It is expected that the performance of ductile detailed building would be better than non ductile detailed building and the capacity shall be more and damage is less compared to non ductile detailed building. This paper compares the performance of structure designed considering non ductile detailing and ductile detailing, in terms of capacity, damage, response reduction factor and drift. As a case study, a 5 storey building designed for Gravity loads as well as lateral load as per IS: 1893-2002 for seismic zone III is considered. Static Non Linear (Pushover) analysis and fragility analysis are performed for estimation of post damage yielding behavior of structure. The change in non linear behaviour of structure based on assumed load patterns in pushover analysis is done. This paper also provides other important conclusions on seismic design provisions, response reduction factor and interstorey drift.

Abstract

The Chi-Chi earthquake (M7.6) was triggered on 20th September 1999 at 17:47:12 UTC in Chi-Chi, Taiwan. This was the largest inland earthquake occurred in Taiwan region. Chelungpu fault was the main cause for this earthquake and the fault was ruptured over 100 km. The ground motions were recorded at more than 600 stations. This study presents simulation of near field ground motions of 1999 Chi-Chi earthquake. For this purpose, 3 stations on foot wall side and 7 stations on hanging wall side are selected to generate ground motions using semi-empirical approach. The ground motion characteristics of the earthquake are calculated at 10 stations. It is found that the distribution of peak ground acceleration (PGA) obtained from semi-empirical approach, similar to real PGA distribution. Higher frequencies of simulated ground motions match with frequencies of real ground motions.

Abstract

Lifeline structures like dams should always be designed for highest safety, resisting worst forces of nature. However, events that took place across the world proved how devastating an earthquake could be, particularly in the near-field areas. Landers earthquake (1992 – Mw 7.3), Northridge earthquake (1994 – Mw 6.7), Hyogoken-Nanbu earthquake (1994 – Mw 6.8) and few more earthquake events caused damage due to near-field effects. Notable damage to Koyna dam due to Koyna earthquake (1967 – Mw 6.5), India and Shih-Kang DamdueChi-Chi earthquake (1999 – MW 7.6), Taiwan proved earthquakes and near-field effects can cause damage even to dams. In India there are several dams constructed near the active faults, which might suffer moderate to severe damage in an event of earthquake in near-field areas. In this concern, a proper study on behaviour of concrete gravity dam subjected to near-field ground motions should be performed. In the proposed study, a concrete gravity dam is selected from the National Importance Dams of India (NRLD-2009) and numerically modeled using Applied Element Method (AEM). Fault normal and fault parallel components of 5 near-field ground motion are considered as input. The behaviour of dam subjected to near-field ground motions is then studied by understanding the displacement response, and stress distribution on upstream and downstream side of the dam body.

Abstract

Understanding the mechanism behind the tectonic plates in collision area, which may propagate into the subduction-collision transition zone is of great interest. At the locations of high-pressure metamorphism, some places form huge crustal deformations like between Indian-Eurasian plates, and subduction at other places like Indian-Burmese plates. In either of the cases deformation is a continuous, dynamic process. To understand the process, a study has been carried out using two dimensional finite element modeling. With the availability of computing technology (Parallelization), advanced numerical models (FEM, XFEM) and material models (Elastic, Visco-elastic), it would be an easy task to know the parameters effecting the transition from collision to subduction process between different tectonic plates. In this paper, Arc-collision model is used to study subduction-collision transition zone. Visco-elastic material rheology is considered for all the tectonic plates. Effect of parameters such as geometry of plates, friction at the interface, length of the plates and type of loading are studied.