ASPS Conference Proceedings

Dynamic Response Reduction of Reinforced Concrete Structure using Tuned Mass Damper and Tuned Liquid Damper

K.P. Shiyam Sundar — 2022-12-19

Damping devices are used to reduce the dynamic response of a structure by energy dissipation. Common types of damping devices are fluid viscous dampers, tuned mass dampers, and tuned liquid dampers. This project aims to study the effectiveness of TMD and TLD in controlling the response of the structure when it is subjected to acceleration records of different earthquakes. A 20-storey reinforced concrete bare frame structure has been subjected to two earthquake acceleration records with and without dampers in SAP 2000. The dampers are modelled using link elements. The structure is attached with TMD and TLD having a mass of 0.5%, 2%, 4%, 6%, 8% and 10% of the modal mass. The analysis procedure used is nonlinear modal time history analysis (FNA). The variation in base shear and top storey displacement has been obtained and plotted.

Retrofitting Solutions for Existing Open Ground Storey RC Buildings

K. Bharadwaj — 2022-12-19

In the last few decades with the increase in population and decrease in usable land, there has been an enormous rise in the construction of residential buildings with open ground storey (OGS) to facilitate vehicle parking. Such OGS are created by removing the infill walls in the first storey. However, during the past earthquakes many of such OGS buildings have suffered severe damage and sometimes complete collapse of the structure. This is because OGS buildings, in general, exhibit soft story irregularity. Although the design codes have recommended provisions to enhance the seismic capacity of the OGS buildings, such provisions are barely implemented during construction. In order to avoid casualties and economic losses, it is necessary to retrofit the existing OGS structures. In this work, an attempt is made to strengthen the OGS buildings using masonry infill walls and braces as the retrofitting solutions. The models are developed in Seismostruct and analysed using suitable analytical methods. The behaviour of OGS buildings with masonry and braces at selected locations is evaluated. Retrofitting solutions that provide enhanced seismic performance and maximum parking space are proposed.open ground storey

Numerical Analysis of Chevron Braced Frames retrofitted using Vertical and Diagonal Brace Members

Narayan — 2022-12-19

This article discusses about the retrofitting of the existing chevron braced frames, constructed before the induction of the concept of thespecial concentrically braced frames (SCBF) braced frames. Two arrangements of upgraded bracing were developed; one configuration was inspired by X-brace and Y brace while the other was inspired by Zipper brace and Y-brace. Both arrangements resulted into unique dual half Y-brace (DHYB). The numerical analysis was done by using Abaqus software. The outcomes of the analysis for studying the behaviour of the braced frame after retrofitting were the hysteretic behaviour, plastic energy dissipation and the beam deflection. In most of the cases, retrofitting using the above mentioned technique provided a more stable and balanced hysteretic behaviour, improved energy dissipation, reduced beam deflection. This method of retrofitting would cause minimal structural intervention and least disruption to the occupants.

Performance Evaluation of RC Frame - Wall Structures Using Incremental Dynamic Analysis

K.Y. Desai — 2022-12-19

A structure whose resistance to lateral loading is provided by a combination of shear walls and rigid frames, may be categorized as a frame-wall structure. The behaviour of RC structures under the effect of earthquake loading has always been a subject of investigation. Structural seismic design has been undergoing a major revaluation in recent time, with importance shifting from strength to performance. Nonlinear Time-History Analysis (NLTHA) constitutes the accurate way for simulating response of structures subjected to seismic excitation. Incremental Dynamic Analysis (IDA), involves performing nonlinear dynamic analysis of the structure under a set of ground motion records, each scaled monotonically to several intensity levels. In the present paper, RC moment resisting frame-wall structure with 18, 22 and 26 storeys are analysed for seismic zone IV, resting on hard soil and designed as per IS code provisions. Geometrical configuration of the buildings are considered as per IS 16700:2017. Analysis and design of frames are carried out using ETABS-2016. The performance evaluation of above frames is done using NLTHA and IDA using SeismoStruct software for set of 11 recorded ground motions of past Indian earthquake varying in range of magnitude from 5.6 to 7.8. For this parametric study, the performance criteria as per FEMA 356 for the limit states of Immediate Occupancy (IO), Life Safety (LS) and Collapse Prevention (CP) are considered. Results obtained from NLTHA are shown in terms of Interstorey Drift Ratio (IDR) profile. The results of NLTHA showed satisfactory performance when evaluated by a set of recorded ground motions of past Indian earthquakes. Individual and summarized IDA curves for 16%, 50% and 84% IDA of IDR | Sa illustrates that RC Frame-walls crosses the IO performance level and are well below the CP level for all cases which shows acceptable performance.

Seismic Risk Assessment of Asymmetric Buildings using Fragility Curves

Upasana R. Rana — 2022-12-19

It is very important and necessary to assess the seismic risk for the buildings subjected to uncertain and highly unpredictable dynamic forces produced from earthquakes. Fragility curves are the best tools for the representation of seismic risk assessment. In the present study, risk assessment of structure subjected to seismic loading is evaluated. Further, the effects of different eccentricities are also studied for seismic risk assessment. The fragility curves are developed for G+5 storied RCC bare frame building as well as G+5 storied RCC building with shear wall. The considered buildings are subjected to ground motions of past recorded earthquakes. Buildings with different eccentricities and various structural configurations are studied for various failure criteria. The responses of the considered buildings subjected to earthquake excitations are evaluated by Incremental Dynamic Analyses. Fragility curves are developed using Monte Carlo method considering various performance levels as per ATC-40. It is observed that for immediate occupancy failure criteria, the probability of failure is increased constantly with increasing the percentage of structural eccentricity. Further, it is observed that very less variation is observed in the probability of failure under life safety and collapse prevention failure stages.

Comparative study on response of jacket platforms under regular waves using Airy’s and Stokes’ fifth-order wave theories

Nilarghya Sarkar — 2022-12-19

Despite the random nature of ocean waves, to provide engineering solutions, regular wave theories are commonly used to estimate wave forces from the Morison equation in offshore structural analysis. These wave theories can be defined by three basic parameters, namely water depth, wave height and wave period. The applicability of a particular wave theory to a given set of wave characteristics and water depth is governed chiefly by the ratios of water depth and wave height to the wavelength. Airy’s linear wave theory, on account of its simplicity, is a popular choice, especially for preliminary calculations and for providing insight into the basic characteristics of wave-induced water motion. It is, however, applicable to small wave heights and in many conditions the linear theory is incapable of providing a satisfactory assessment of the water particle kinematics. A nonlinear theory is then required, and Stokes’ fifth order wave theory, based on the expansion of the wave solution in series form, provides a more accurate representation of the free-surface and is generally used for high waves in deep water. In this paper, a comparative study is conducted between the wave forces obtained from Morison equation utilising Airy’s wave theory and Stokes’ fifth order wave theory, acting at different levels of a jacket platform. Two sets of water depth, wave height and wave period are selected so that they satisfy the region of applicability of Airy’s wave theory and Stokes’ fifth order wave theory respectively. Two example four-legged jacket platforms are considered. It is found that for design purposes, in most cases the wave forces and structural responses from Airy’s wave theory are more conservative as compared to those from Stokes’ fifth order wave theory, though the converse is obtained in case of deep water conditions near the seabed. Overall, in deep water, high wave conditions, apart from Stokes’ fifth order wave theory, Airy’s wave theory may be used for preliminary estimations of wave forces and deck displacements, but in shallow water conditions, Stokes’ fifth order wave theory is entirely invalid.

Dynamic Analysis of Offshore Wind Turbine Supported by Jacket Substructure under Wind and Wave Loading

Seeram Madhuri — 2022-12-19

Burning of fossil fuel for the production of energy causes severe global warming effects. Renewable energy sources like solar, wind and tidal etc. are the alternative renewable energy sources which contribute in the reduction of adverse global warming effects. Wind turbines are being used for extracting wind energy from several years. Wind blow is continuous with limited disturbance in the offshore region when compared with main land. Offshore wind energy extraction is in research stage at many locations and implemented in European countries. Prediction of response of wind turbine supporting systems is essential in the design to withstand the environmental loads such as wind, wave, current and seismic etc. In the present study, a horizontal axis offshore wind turbine (HAWT) supported on an offshore jacket structure is considered and the response studies are performed. The jacket is considered at a water depth of 51m, thus total height of the jacket is 61m with a free board of 10m.

A wind turbine of 5MW capacity is considered to be on top of jacket structure. The height of the wind tower is assumed as 70m, and a transition structure of 4m height is positioned in between jacket and tower. A free vibration analysis is performed to estimate the natural frequencies and mode shapes of the jacket supported wind turbine. The modal analysis is carried out using ANSYS static structural module.

The response analysis under wind, wave, current and aerodynamic drag loads is performed using SACS 13.2 software. Wind force is estimated based on API 2005 provisions. The aerodynamic forces on the wind turbine blades are evaluated using Betz Theory. Wave loading is calculated using Morison equation and linear Airy’s wave theory. A parametric study is carried out by varying wave period from 6s to 20s. As the structure is symmetric about longitudinal and lateral directions, a wave directional analysis is also carried by considering 0^o and 45^o wave directions. The structural responses are studied for the combined wind, wave and current loads. Cut-in, rated, cut-out and storm conditions are simulated by modelling wind and aerodynamic loads on the tower, wind interacting area of the jacket and blades. Wave period and direction are varied to simulate different wave conditions. It is observed that the structural response is increasing as the wind velocity is increasing and wave period is decreasing.

A Parametric Study on Effect of Wave Height, Water Depth and Support Conditions on Behaviour of Offshore Jacket Structure

S.R. George — 2022-12-19

Fixed offshore jacket structures are constructed for facilitating oil/gas exploration and production. These structures and their foundations are designed to resist large vertical and lateral loads. Various factors including water depth, wave height and support conditions would affect the response of jacket structures. However, few studies have focused on understanding the response of offshore jacket structure due to variation in these factors. In this context, the present work evaluates response of typical X-braced, square base, 4-legged battered jacket structure using STAAD Pro. under combined vertical and lateral environmental loading. The variables included are water depth (60 m, 90 m and 120 m), wave height (5 m, 10 m and 15 m) and two foundation modelling approaches (viz., fixed at pile location and with defined pile stiffness). The connection between structure leg and pile location is modelled to simulate realistic connection. Deck loads, wind forces and current velocities are considered constant for this study. The wind and wave loads have been applied in parallel, perpendicular and diagonal directions with respect to jacket structure. The wave forces are calculated by Morrison’s equation. For obtaining pile stiffness, medium dense sand layer is considered as foundation soil. The increase in water depth and wave height results in corresponding linear increase in lateral deflection and support reactions, the effect of water depth being more prominent. Moreover, lateral and vertical deflection, shear force and bending moment in the legs, the axial forces in the lower tie beams and plan bracings, and support moments are observed to increase when pile locations are modelled with appropriate vertical, lateral and rotational stiffness instead of fixed support. The effect of water depth on member forces is higher as compared to wave height. The present work deliberates on the mechanisms/reasons to explain the observed results and contributes in direction of framing decision matrix for design optimization of jacket structures.Jacket Structure

Semi-active Groundhook Control of Offshore Tension Leg Platforms Using TMD with Optimized Parameters and MR Damper Under Regular waves

Suryasish Patra — 2022-12-19

The motivation and objective of the present study are to propose a semi-active control system for offshore tension leg platforms (TLPs) to mitigate the vibrations induced by regular wave loads. State-of-the-art indicates that not much work is reported on semi-active control of offshore TLPs considering potential nonlinearities for multiple hazards using a control algorithm, which is robust against uncertainties. A displacement based groundhook (DB-GH) control algorithm using tuned mass damper (TMD) and magneto-rheological (MR) damper is employed for the semi-active controller because of its robustness against parametric uncertainties and reliability. Optimized parameters of the semi-active TMD (SATMD) are obtained using constrained nonlinear optimization to achieve the best control performance. The flexibility of the groundhook control lies in its simplicity of implementation, computational efficiency and its demand for only two sensors in order to achieve the calculations of control forces. The scope of the present study is to demonstrate the efficiency of the proposed controller and investigate the effects of different influencing parameters. A TLP, reported in literature, is taken as an illustrative example. The non-linearly coupled dynamic responses of the structure-damper system is analysed and solved in time domain using MATLAB SIMULINK. The results show the SATMD performs quite satisfactorily in reducing the responses of the TLP in different critical conditions.

Free Vibration Analysis of Stiffened Lock Gate Coupled with Reservoir Fluid considering Linearised Free Surface Condition

Deepak Kumar Singh — 2022-12-19

The effect of surrounding reservoir fluid on the stiffened lock gate structure is investigated using the finite element method. A single stiffener is used to stiffen the plate, which is placed edge to edge along the height on the plate's center nodal line. Mindlin’s plate bending and Euler’s beam theories are used to formulate plate and stiffener, respectively. The stiffened lock gate material is assumed to be isotropic, homogeneous, uniformly thick and elastic in nature. The fluid is assumed to be incompressible and inviscid, resulting in an irrotational flow field. The fluid domain's top free surface is assumed to be linear based on Airy’s linear wave theory. The far boundary of the fluid domain is truncated numerically close to the lock gate to control the size of computation without influencing the results, very much. It is truncated by solving the Laplace equation using Fourier half range cosine series expansion in the finite element formulation. Pressure and displacement are considered as nodal variables for the fluid domain and the lock gate, respectively. The interaction between the fluid domain and the lock gate is established by finite element formulation and transformed into a computer code, written in FORTRAN. The natural frequencies of clamped and simply supported stiffened lock gates are evaluated by the varying extent of the fluid. Both stiffened and unstiffened gates are compared. The results are beneficial to the engineers/designers when the gate structure is subjected to cataclysmic events.

Passive Control in Baffled Liquid storage Tank under Bi-directional Earthquakes

S. Vern — 2022-12-19

A comprehensive study of a 3D baffled concrete liquid storage tank (LST) is conducted to find out the maximum reduction in responses of the LSTs under a set of important parametric variations. They include (i) the type of earthquake; (ii) the optimum position and number of coupled baffles (top-mounted and bottom supported); and (iii) the angle of incidence earthquakes. Further, the percentage reductions of different responses of interest for the optimum baffled LST are investigated. The numerical study is performed in ABAQUS software for a square LST of 6m X 6m X 4.8m having a water height of 3.6m. The response quantities include the maximum mean values of base shear, overturning moment, top board displacement, hydrodynamic pressure, and sloshing height. The results of the study show that (i) with the optimum arrangement of baffles, significant reduction of in the sloshing height can be achieved; (ii) the type of earthquake does not have significant effect response reductions; and (iii) both PGA and angle of incidence of the earthquake have a moderate effect on response reductions.

Nonlinear Seismic Analysis of RC Elevated Liquid Storage Tanks

M. V. Waghmare — 2022-12-19

Liquid storage tanks are strategically important due to their essential requirement of service in the post-earthquake situation. Numerical modeling of the liquid storage tank needs special attention and cannot be done in the same manner as that of the conventional buildings. In the present paper, a numerical simulation of the RC elevated liquid storage tank is presented. The staging of the tank is modeled as a multi-degree freedom system, and the container with contained liquid is modeled as a two-mass system. Free vibration analysis of the tank is carried out, and mode shapes are extracted. Further, to study the seismic response of the tank, nonlinear time history analysis is carried out. The tank is subjected to time histories of real earthquake ground motions. The varying level of the liquid in the container is another characteristic feature of tanks. The filled condition of the tank is taken into account by considering the aspect ratio (S), defined as the ratio of height of the liquid to the radius of the container. The response of the tanks with two different aspect ratios viz. 0.5 (broad) and 2.0 (slender) is studied. The linear modal analysis also carried out to understand the significance of nonlinear analysis, particularly in liquid storage tanks. Displacement, velocity, and acceleration response at the bracing levels, as well as at container levels, are obtained. Additionally, the base shear response is also obtained. The effect of aspect ratio on the free vibration analysis and the seismic response of the tanks are presented. Liquid storage tanks are special structures that have typically low fundamental natural frequencies. The nonlinear time history response of the tank showed that the higher displacement and velocity response occurs at the convective level. It is found that the linear modal analysis significantly underestimates the response of the liquid storage tank.

Experimental Studies on Blast Performance of Unreinforced Masonry Walls: A state-of-the-art review

S.M. Anas — 2022-12-19

A large proportion of India’s residential buildings is of unreinforced masonry (URM) and falls under the category of non-engineered structures. URM walls in the residential buildings, customarily constructed from clay bricks or concrete blocks and cut stones, are found to be braced and therefore able to carry some out-of-plane loads produced by wind and earthquake, and survive. However, they are found to be more vulnerable to high air-pressure generated by explosive-induced detonations. Sufficient amount of investigations has been made by engineers to study the effect of brick strength, mortar strength, boundary conditions, wall thickness, and Young’s modulus of masonry on the blast performance of the URM walls. In this paper, available experimental studies on clay-brick and concrete block URM walls subjected to explosive-induced blast loading are briefly reviewed and summarized in tabular form. Studies conducted to improve the blast resistance of the walls using GFRP strips, GFRP rods, and Polyurea coating, and their effect on mid-span deflection, damage, and cracks have also been reviewed. It has been observed that the effect of brick strength and mortar strength on maximum mid-span deflection and damage resistance of the walls is insignificant under higher peak reflected blast pressures (> 2 MPa). Besides, the walls strengthened with the GFRP strips or Polyurea coating performed better with regards to mid-span deflection, damage, and cracking. The influence of Young’s modulus of masonry on the blast response of the walls is found to be more effective in reducing the maximum mid-span deflection. Also, the failure mechanism of the walls is found to be highly dependent upon the peak overpressure, duration of the blast, and support conditions.

Nonlinear Fe Model for Shear Strengthening of Simply Supported RC Beams with FRP DE Bars

Baisali Dutta — 2022-12-19

Deep embedment (DE) is emerging as a potential and effective shear strengthening approach for existing reinforced concrete (RC) structures. A two-dimensional nonlinear finite element (NLFE) model for simply supported RC T-beams strengthened in shear with embedded carbon fibre reinforced polymer (CFRP) and steel bars is presented in this study. VecTor2, version 4.2, was used to create a two-dimensional NLFE model. To validate the nonlinear FE models, three sets of six simply supported RC T-beams from Breveglieri et al. (2015) are employedEach set consists of two beams with vertical and inclined (45) DE bars. Set one strengthens the beams with steel DE bars without vertical steel stirrups in the shear span. In the shear span, the beams of Sets two and three are reinforced with CFRP DE bars with vertical steel stirrups @180 mm c/c and @300 mm c/c, respectively. The above-mentioned NLFE model is validated by comparing experimental and predicted results for failure load, deflection, and failure mode. For both experimental and simulated beams, the fracture pattern is diagonal, and the failure mode is shear failure. The overall mean predicted/experimental loads at failure and deflection at failure ratios are 1.09 and 1.00, respectively, with corresponding standard deviations of 0.03 and 0.04. Following the validation of the proposed NLFE model's correctness, numerical parametric tests are conducted to determine the influence of concrete compressive strength and effective depth of RC T-beams on shear capacity of simply supported RC T-beams. The parametric analysis findings reveal that enhancing the cylinder compressive strength increases the predicted failure load while increasing the effective beam depth decreases it.Fibre reinforced polymer (FRP) bars

Non-contact based photogrammetric technique for testing of rigid blocky masonry arch

Pratyusha Naik — 2022-12-19

In case of dry jointed stone structural systems, the stone blocks can be assumed to be rigid with relative predominant displacements occurring along the joints giving rise to geometric non-linearity in these systems. The testing of such discontinuous systems becomes challenging task with contact-based measuring instruments such as LVDTs as the blocks are free to displace and/or rotate with six degrees of freedom. This technique is more often used for surveying of large existing structures in the field of civil engineering and its applicability to testing of structural systems has not been explored to a larger extent yet. The photogrammetry with motion module has been observed to be the one of the most reliable and feasible methods of instrumentation for dry jointed stone structural systems. With few quality control measures adopted from taking photos to the processing stage, sufficient accuracy of measurements can be achieved. In the present study, non-contact-based technique, photogrammetry is used for testing of a typical dry-stone corbel vault taking a scaled down model of an existing vaulted gallery of Ta Prohm, Cambodia. The findings from the study have been in agreement with the observed distress in the existing corbel vaulted galleries. It has been proved to be efficient, low cost method that uses simple handheld digital cameras giving reliable results with an accuracy up to 0.4 millimetres. Thus, photogrammetry is a way forward for testing of discontinuous structural systems such as dry-stone masonry.

On Effects of Shear Deformation on the Static Pull-in Instability Behaviour of Narrow Rectangular Timoshenko Microbeams

Kedar S. Pakhare — 2022-12-19

MEMS devices utilize electrostatics as preferred actuation method. The accurate determination of pull-in instability parameters (i.e., pull-in voltage and pull-in displacement) of such devices is critical for their correct design. It should be noted that similar to parallel plate capacitors, the electrostatic force between the surface of the deformable microbeam and stationary ground is non-linear in nature. Hence the analysis associated with MEMS devices is always inherently non-linear. In the literature, these devices have been majorly analyzed as Bernoulli-Euler microbeams with cantilever or clamped-clamped beam end conditions. However, Dileesh et al. (doi: 10.1115/ESDA2012-82536) have studied the static and dynamic pull-in instability behavior of slender cantilever microbeams by developing a six-nodded spectral finite element based on the Timoshenko beam theory (TBT-SFE). They have demonstrated the accuracy of the TBT-SFE by comparing their results with corresponding results of COMSOL-based three-dimensional finite element simulations. In addition, effects of shear deformation also start to play significant role as the beam thickness-to-length ratio increases. In this paper, authors have developed the TBT-SFE based on the work by Dileesh et al. for the case of statics. However, unlike Dileesh et al. where they have developed a six-nodded TBT-SFE, authors have investigated the best combination of number of nodes per element and total number of elements to carry out the study. For this purpose, authors have first calculated results of the maximum beam transverse displacement, for a shear deformable propped-cantilever microbeam under the action of uniformly distributed transverse load, obtained by utilizing the developed TBT-SFE with different combinations of number of nodes per element and total number of elements. These results are then compared with corresponding analytical results available in the literature to arrive at the best combination of number of nodes per element and total number of elements for the electrostatic-elastic analysis. In the second step, the finalized TBT-SFE is utilized to determine static pull-in instability parameters of narrow microbeams with various fixity conditions and beam thickness-to-length ratios. This study highlights the importance of transverse shear effects on pull-in instability parameters of Timoshenko microbeams.MEMS

Seismic (effect on) time history analysis for cable-stayed suspension hybrid bridge considering different geometrical configuration for far field earthquakes

J. H. Gabra — 2022-12-19

To increase the maximum span of cable-stayed bridges, Uwe Starossek has developed a modified statical system. The basic idea of this new concept is the use of pairs of inclined pylon legs that spread out longitudinally from the foundation base or from the girder level. Spread-pylon cable-stayed bridge has distinct advantage like reduction of sag of cables and oscillation of cable during earthquake over traditional cable-stayed bridges. Spread-pylon also improves seismic performance of deck during strong ground motion. Here in this paper dynamic behaviour of cable stayed suspension Hybrid bridge with different structural configuration with seismic loading was studied.

The primary aim , here, is to present response to Seismic effect on Cable stayed Bridges with different cable system taking under consideration SSI.It is evidently clear that Soil Foundation Structure Interaction relies greatly on various factors such as soil and its properties, manner and type of structure and/or its foundation.. In this paper , the emphasis is on the simplified model and foundation on piles. For the modelling author has used SAP2000 software. The study includes the response of the bridge modelled towards variation in the cable system under consideration of SSI. A bridge similar to that of Bridge at Ling Ding Strait China is taken as a reference and 6 models are created with variation in cable system ( ranging from original cable stayed bridge to suspension type, composite bridge and cable stayed suspension hybrid bridge). Soil modeling is done using the spring and dashpots ( Kelvin element) for simulation of SSI effects.The results observed that effects of SSI has a substantial impact on selection of system of cables and the pylon leg inclination for any Cable- Stayed- Suspension Hybrid Bridge(CSSHB)

Effect of Seismic Analysis Approach and Provision of Shear Walls on Parameters for Raft Foundation Design

Sujay Teli — 2022-12-19

The present work attempts to understand the effect of different methods of seismic analysis on the design of building raft foundation. The study also evaluates the role of shear wall on the foundation response. A ten storey building with raft foundation has been analyzed in STAAD Pro using three different seismic analysis methods, viz., Linear static analysis, Linear dynamic analysis and Non-linear dynamic analysis. Furthermore, building with two different arrangements of shear walls (peripheral and core region) are studied by Non-linear dynamic analysis and compared with the model without shear wall. The raft is modeled with plate elements supported by soil springs using Winkler's approach. To consider the effect of different soil and raft stiffness, three different soil spring values and two raft thickness values have been considered. It has been concluded from the study that linear static analysis yields lower values of all foundation design parameters (viz., base pressure, settlement, foundation bending moment and shear stress) as compared to dynamic analysis. Dynamic analysis yields higher variation in base pressure and settlement distribution, which suggests adopting dynamic analysis approach for obtaining more realistic response, especially for settlement sensitive structures. Further the provision of shear wall has negligible influence on base pressure and settlement of foundation, while maximum bending moment and shear stress in foundation increases. Hence, provision of shear wall may increase cost of foundation, however, considering its role in improving structural integrity, shear walls are deemed important. Further, the increase in soil stiffness and reduction in raft thickness yields higher maximum base pressure and variation in base pressure, which confirms the importance of considering the effect of soil-foundation interaction for design of foundation. It is opined that the findings of the study would help in more realistic foundation design to achieve better performance during its life cycle.

Simulation and Soft Computation on Materials Prognostication Seismic Assessment

P.V. Ramana — 2022-12-19

The research paper ETABS is an integrated programming software providing mass distribution and rapid analysis of structures building where we can assign loadings per codal provision. Different methods are also available to elongate our research and analysis of the system. This software developed by CSI is also utilized in the designing of Burj khalifa. ETABS is coordinated programming giving mass dispersion and immediate investigation of building designs where one can allocate loadings according to any codal arrangement. Various strategies are additionally accessible to extend our examination and examination of construction. This paper depicts to determines the role of dampers in tall structures. To assess the stability of the system under seismic load considering dampers. To compare two distinct types of dampers to evaluate the seismic effect of different earthquakes. To provide cost analysis of form per SOR to assess the seismic impact on distant earthquakes.

Static Stress Analysis of Functionally Graded Cylindrical Stiffened Shells

S. M. Shiyekar — 2022-12-19

In this paper, a study on bending performance of functionally graded (FGM) cylindrical shells under transverse mechanical load is presented. Computational and analytical tools are used to study the behavior of FGM cylindrical shells under bending. Analytical modeling is based on first order shear deformation theory (FOST) and a finite element computational tool ABAQUS is used to model the FGM cylindrical shell. Material properties are estimated by power law index. Results from computational tools for isotropic and FGM cylindrical shells with various boundary and loading conditions are validated with literature and present FOST. Stiffened FG cylindrical shells with cutouts are analyzed. The FGM circular cylindrical shells subjected to an internal pressure with various arrangements of stiffeners are also analyzed and von – Mises stresses are also studied.

Evaluation of Seismic Performance Factors for Concrete Filled Steel Tube Diagrid Structural System

D.V. Mehtani — 2022-12-19

Seismic performance factors are used in current building codes and standards to estimate strength and deformation demands on seismic force resisting systems that are designed using linear methods of analysis, but are responding in the nonlinear range. Many recently evolved seismic force resisting systems have never been subjected to any signi?cant level of earthquake ground shaking. As a result, the seismic response characteristics of many systems, and their ability to meet seismic design performance objectives, are both untested and unknown. Therefore, it is necessary to determine the seismic performance factors of new seismic force resisting systems proposed for inclusion in building codes that will result in equivalent safety against collapse during an earthquake when properly implemented in the seismic design process. In this study, the response modification factor, overstrength factor and period based ductility for concrete filled steel tube (CFST) diagrid structural system are evaluated. To quantify these factors, the rational procedure introduced in Federal Emergency Management Agency (FEMA) P695, which is based on low probability of structural collapse and encompasses nonlinear static and dynamic analyses, is used. To this end, performance group consisting of 4, 8, 16 and 24 storey diagrid structures with 50° angle of external braces is considered. Nonlinear static analyses are performed to obtain overstrength factor and period?based ductility. Incremental dynamic analyses are then performed to assess collapse margin ratio of the archetypes. For modelling and numerical analysis, Open System for Earthquake Engineering Simulation (OpenSees), an open source software is used.

Finite Element Analysis of Bridge Deck Using MATLAB

Ahmad Farhan — 2022-12-19

Bridges are the most common types of structures generally adopted when there is a obstacle in the path such as water body, valley, road etc without closing the way underneath. Moving live load is one of the critical loading for which bridge superstructure need to be analysed by developing model as realistic as possible. Even though various conventional methods are present for the analysis of bridge superstructure but finite element analysis gives us more realistic behavior of structure. The objective of the thesis is to develop a finite element model of T-beam slab bridge ,bridge pier and pier footing and analyse to study behavior of bridge superstructure for moving live load as per Indian road congress standards given in IRC:6-2017 and IRC: 112-2011 and the dead load of the structure.

In my work, bridge deck is modelled as Mindlin-Reissner plate element which is two dimensional plate in which shear deformations effect is considered whereas longitudinal girders ,cross girders and diaphragms are modelled using Euler-Bernoulli’s grid element which are a one dimensional element . A MATLAB code is developed to model T-beam slab composite action in which beam elements is modelled in plane of plate element so that the nodes of beams are coincide to the nodes of the plate by doing such center of gravity of the beam coincides with the plate element ignoring offset present between them. Moving live load analysis is performed using step by step method in which load moves in longitudinal as well as transverse direction giving the worst case for maximum bending moments, shear forces and deflections. Then Moving live load analysis for 2 lane T-beam bridge is carried out for IRC Class 70R wheeled vehicle and compare the result by modeled in sap2000,2016 of same dimension and the effect of the number of cross girders in the deck span on bending moments, shear forces and deflections of longitudinal girders is presented.

Automated Construction of Structures using 3D Printing: A Review

Suraj Vairagade — 2022-12-19

The recent advances in 3D printing techniques from past one decade in terms of materials development, product evolvement methods, industry 4.0, technological up-gradations, manpower free constructions, customised production, waste minimization, freedom from designs at an affordable cost. 3D printing processes are extensively contributing in the field of structural industry. To meet the fast-growing demand of the humans there is a need to understand the concepts and in-depth knowhow of 3D printing processes. The technological developments of 3DP to infrastructure domain are still untouched zone worldwide. It is because of lesser projects successfully carried out since its inception. The article presents insights of additive manufacturing processes and its applicability to the construction industry. In the construction industry, 3D printing has not yet reached the point of commercial availability at global level. Fewer number of 3DP experiments for large-scale buildings can be discovered in the literature. A critical analysis of past and present literature studies is conducted worldwide and also investigated the potential benefits of additive manufacturing processes to construction industry. This article's unique contribution is its examination of the many uses for 3D printing in the construction industry, as well as the advances in technology that have made this possible.