http://dspace.dtu.ac.in:8080/jspui/handle/123456789/126 2026-10-17T21:43:33Z 2026-10-17T21:43:33Z KUMAR, RAJEEV Goyal, Pradeep K. (SUPERVISOR) http://dspace.dtu.ac.in:8080/jspui/handle/repository/23361 2026-10-16T06:31:38Z 2026-05-01T00:00:00Z

Title: COMPARATIVE ANALYSIS OF PRECAST SEGMENTAL LINING FOR METRO TUNNELS Authors: KUMAR, RAJEEV; Goyal, Pradeep K. (SUPERVISOR) Abstract: This thesis covers the analysis of precast tunnel segments for the Metro tunnels. Maximum overburden cases have been considered for analysis in this study. Precast concrete segments are permanent structural lining of a circular tunnel ring formed by TBM. They resist permanent structural loads from the surrounding soil, rock, and groundwater pressure. The segments function as a reaction frame for advancing the TBM by pushing its hydraulic thrust jacks directly against the front face of the most recently installed segmental ring. There are various technical papers and literature available pertaining precast segmental lining of tunnels. Some of the most relevant literatures are reviewed during this project work. The principal objective is to verify one single precast segmental lining ring for circular tunnel. The segmental lining is verified for the maximum overburden height and with a uniformly distributed surcharge load of 50 kPa applied at the ground level. Tunnel case considered for this study is 5.8 m internal diameter circular tunnel and this is to be constructed using precast segmental lining. The results obtained in this analysis can only be used for the segment lining design. No conclusions can be drawn regarding the ground surface settlements. The model indicated can be used to obtain normal effective stresses around the tunnel lining to define ground loads acting on the segmental lining of tunnel. The bending moments obtained from FEM analysis are higher than those from Analytical calculations using Muir-Wood and Curtis approach, except for the Case-4 (i.e. without Surcharge). Shear forces in FEM analysis are generally on higher in all four cases. The axial forces in FEM analysis are also higher than those from Analytical calculations, except for Case-4 as presented in this thesis. It can be concluded that the values obtained from FEM analysis are generally on conservative side, however, it is recommended that these values should be verified through independent analytical calculations to arrive at maximum governing forces to be used for design. The higher one obtained from FEM analysis and Analytical calculations shall be used judiciously for the structural design of precast segmental lining to ensure safe and optimum design of Metro tunnels. Despite the recent advances in structural designs of tunnels, more research is necessary for analysis of precast segmental lining for metro tunnels due to its complex behavior.

2026-05-01T00:00:00Z DEOL, VIDIT http://dspace.dtu.ac.in:8080/jspui/handle/repository/18950 2022-02-21T08:50:21Z 2021-08-01T00:00:00Z

Title: SEISMIC ANALYSIS OF MASONRY STRUCTURE Authors: DEOL, VIDIT Abstract: From the beginning of construction history, masonry have been most widely used material Because of its light weight, great durability, fire resistance, thermal insulating characteristics, relatively simple method of construction and execution, and low cost, masonry has been the most extensively used material in construction history. Apart from possessing such features, masonry is thought to have several disadvantages, such as distinct directional (orthotropic) qualities. weak strength, mortar connections without proper thickness, low interface binding strength between brick and mortar, poor treatment and improper methods of installation, etc., Chourasia, A. et. al. (2017) [6] . Besides, having weak strength and weak seismic behaviour masonry is still used heavily in construction for structures all around the world notably for low rise buildings up to three floors, as well as antique and medieval structures. Masonry can be used in construction with or without reinforcement; however, providing reinforcement improves masonry's seismic performance. Confined masonry is a relatively new type of masonry that has been presented, where light-reinforced frame elements (tie beams and columns) are utilized to enclose a masonry wall, the system acts as a single unit under load, providing ductility and strong seismic properties. Confined masonry has been found to be superior to reinforced masonry in some cases. In this report a residentials G+3 building in, Delhi has been studied, building in its natural form is constructed of masonry single brick thick with 250 mm concrete slab. The building is further modelled in ETABS (2018) [12] software with masonry as thin shell element of 230 mm thick and concrete slab of 250 mm thickness and dead, live and seismic load is applied on this building. Building is further modified and modelled in software with a 1) lintel band and 2) with confining elements (confined masonry) and change is seismic behaviour and capacity is studied.

2021-08-01T00:00:00Z VERMA, SAURAV KUMAR http://dspace.dtu.ac.in:8080/jspui/handle/repository/18925 2022-02-21T08:46:23Z 2021-09-01T00:00:00Z

Title: SEISMIC RESPONSE OF REINFORCED CONCRETE FRAME RESTING ON HILL SLOPES Authors: VERMA, SAURAV KUMAR Abstract: The Constructions done in the hilly regions are more vulnerable seismically in contrast with the structures built in flat terrains. The structures constructed in hilly regions are usually irregular, these structures are irregular both in mass and stiffness. Constructions done on the sloping ground is different from usual structures since they're asymmetrical in both horizontal and vertical directions. Columns of the bottommost storey have a varying height because of inclining ground and are torsionally coupled, henceforth draw in a lot of shear forces, and without proper detailing building constructed on sloping ground is susceptible to moderate to heavy damage. In this analysis, the seismic response of three different building configurations i.e., Regular, Stepback, Stepback-Setback is evaluated. The structural analysis tool ETABS 2017 was used to perform seismic analysis utilising the linear static and dynamic methods. Buildings on a hill slope with various configurations are studied in two parts; first being: bare frame, soft storey, totally concrete blockwork infill, a soft storey with shear wall at corners, frame with composite columns at the bottommost storey and second part being: L-shear walls(LSW) at the corners, C shear-walls at core(CSW) and Reinforced concrete-filled steel tube column (RCFST) at corners and core in stepback, and stepback-setback configurations. The characteristic parameters such as base shear, forces in the columns at the ground floor, storey drift, maximum top storey displacement, time period, the bending moment in columns at every floor level and storey shear in structures will be determined and analysed for the different structures at the sloping ground. Finally, the reasonableness of various designs of slope structures would be proposed.

2021-09-01T00:00:00Z GAUR, NIKHIL http://dspace.dtu.ac.in:8080/jspui/handle/repository/18365 2021-07-19T08:31:11Z 2020-08-01T00:00:00Z

Title: RESPONCE VINDICATION OF EFFECTS OF CORNER CONFIGURATION AND INTERFERENCE ON TALL BUILDINGS UNDER WIND LOADS USING CFD MODELLING Authors: GAUR, NIKHIL Abstract: This study explores a recent application of the computational fluid dynamics technique “CFD” for wind analysis and its comparisons with the conventional wind tunnel experimentations. This study is centered on the wind response of square and corner cut-shaped building models and its optimization caused by the variation of the wind incidence angle. Extensive rigid model experiments of two building models of length scale 1:100 have been performed in the boundary layer wind tunnel. The numerical analysis has been carried out with the standard k-ε turbulence model to evaluate the force coefficients, base moments, power spectra, external surface pressure coefficients, and flow field characteristics of the models with variable wind angles of incidence. The comparisons between experimental results and CFD analysis suggest the computational approach’s viability in wind analysis of tall structures efficiently and accurately. A case study of aerodynamic mitigation by corner cut suggests minor modification techniques performance, efficiency, and limitations. Wind induced interference plays a vital role in the design of tall structures. However, the complex features of structure design and shape require a detailed wind tunnel/CFD (Computational Fluid Dynamics) study as codal provisions don’t suffice for such scattered parameters. iv The current study focuses on the effects of height ratio, orientation, and blockage configuration of interfering structure on interference effects. Interference factor (IF), transient pressure, and force spectra are used to account for the interference effects at major probe points to understand the dynamic wind response. To study these effects among complex arrangements, a numerical simulation for a CFD analysis on a corner configured principal building model and a single upstream interfering building model having identical geometry has been performed. The configuration included six kinds of heights ratio (Hr=Hprincipal/Hinterfering). Furthermore, force coefficients, base moments, and external surface pressure coefficients both in the along and across wind direction are determined and listed for wind incidence angle of attack of 0° to 90° at an interval of 15°. Interference effects among full, half, and no blockage conditions were investigated. The data is presented in terms of the interference factor relating wind load responses of the isolated principal building to interference configuration. The results indicate that in close proximity of structure, the shielding effect suppresses the interference effects on the principal building, but across wind responses have been investigated in close vicinity configurations too. This study also suggests the interfering model’s orientation contributes to great measures to the wind response under interference.

2020-08-01T00:00:00Z