bluuebunny/crossref_metadata_2025 huggingface dataset:
Economical Robust Mix Proportioning of Self-Compacting Concrete Mixes - A Comparative Study
Authors: Kumar V.K.Pradeep , Kumar A.Sai , Venkat P. , Rama J.S.Kalyana
Published: December 2022

Concrete being the second largest consumed material after water needs attention towards sustainable construction with an increase in infrastructure. The world is moving towards innovative techniques and methodologies for sustainable and durable construction of concrete structures. The selection of suitable ingredients for making concrete and determining the relative amounts with an objective of producing a concrete of required strength and durability is the need of the hour. Standard mix proportioning of concrete should satisfy the workability requirements and also meet the requirement for mechanical properties, durability, economy, and even ecology of engineering applications. The study would focus on quality control aspects in mix proportioning the concrete as per the requirements of the industry. It includes mix proportioning of self-compacting concrete as per the standards prescribed in national construction community and Indian standards, plastic viscosity, and EFNARC based mix proportioning of self-compacting concrete. The mix proportioning would focus on utilizing various industrial and agro wastes as a suitable cement replacement material, locally available fine and coarse aggregate materials along with their alternates, appropriate dosage of admixtures, etc. The outcomes of the study include the formulation of handouts and readymade mix proportions of self-compacting concrete used in the construction of buildings and pavements along with their cost estimation. The study also provides information on some of the key points to be considered in making concrete using optimization concepts which would further reduce the cost of construction. The optimized mix proportions will be handy for the ready-mix plants especially in dealing with multiple large-scale construction activities. Mix proportioning using plastic viscosity approach was proven to be economical compared to other mix design methods.
Experimental studies on fiber cement boards under compression loading
Authors: Bhanushali J.D. , Nithyadharan M.
Published: December 2022

Fibre cement boards are widely used as external cladding in cold-formed steel (CFS) building systems, due to their superior durability and weather-resistant characteristics. These boards are made of cement and reinforced with short, randomly oriented, non-hazardous cellulose fibres. Characterizing the observed stress-strain behaviour of the board under compression loading is a challenging task due to: a) loading eccentricity which induces bending, b) global buckling caused by high slenderness of the specimen, and c) stress concentrations at the loading end resulting in bearing failure. The above failures are usually handled at the specimen preparation stage by gluing additional numbers of boards to reduce slenderness, and by the inclusion of end tabs to avoid bearing failure. However, the introduction of glue in the board specimen may alter the strength characteristics and modify the load transfer path. Preliminary studies on the board specimens following the standard testing procedure (ASTM D3501) for wood-based panels fail to simulate the real material behaviour of the boards under compression loading. It is clear that the existing test methods have several shortcomings and hence cannot be adopted for fibre cement boards. In this paper, the fibre cement boards were tested under compression loading using combined loading compression (CLC) test fixture. This paper presents the details of the experimental study and the results for board of thicknesses 8, 10, and 12 mm, respectively. The test matrix includes specimens tested in both longitudinal and transverse directions. Under compression loading, the board exhibited nonlinear behaviour up to failure. The structural parameters like ultimate stress, ultimate strain, Young's modulus, and Poisson ratio in both longitudinal and transverse directions were obtained. This study proposes a nonlinear constitutive model for the board material.
An experimental study on micro-structure and hardened properties of ultra-high strength self-compacting concrete by incorporating Graphene Oxide
Authors: Kumar BoppanaNarendra , Somasri M.
Published: December 2022

The modern material in the rapidly expanding building sector is ultra high strength self-compacting concrete (UHSSC). There are several ways to make UHSSC, but one of the best ways is by employing graphene oxide to improve the microstructure of cement (GO). GO is a cutting-edge nanomaterial that excelled in a number of disciplines. This study examines the microstructure and toughened characteristics of UHSSC with GO incorporation. Improved GO dispersion in the concrete is achieved by using silica fume (10% cement weight), while better pore structure and resistance to chloride penetration are achieved by using GGBS (30% cement weight). To achieve UHSSC, GO is added to cement at concentrations of 0.25, 0.5, 0.75, 1.0, and 1.25% by weight of cement. EDS (Energy dispersive x-ray spectroscopy) technique is used to determine the crystalline properties of GO nanomaterial and SEM (Scanning electron microscope) is used to determine the microstructure of the GO incorporated UHSSC.
Behaviour of Hybrid Fiber Reinforced Geopolymer Concrete Beams under Flexural Loading
Authors: Kashyap AddepalliMallinadh , Rao TanimkiChandraSekhar , Rao NaraparajuVenkataRamana
Published: December 2022

This paper presents the behaviour of GPC beams with and without fiber under flexural loading. The work is presented in two parts. In the first part tests were conducted for mechanical properties of plain and hybrid fiber reinforced Geopolymer concrete to determine maximum strength characteristics of concrete. In the second part of the program two types of under-reinforced beams were cast with plain GPC and hybrid fiber reinforced GPC (HFRGPC) and tested under two points loading. The percentage of tensile rebar ratio is kept constant for two types of beams. The hybrid fiber reinforced GPC is prepared with 1.5%(1%Steel+0.5% Polypropylene) of fibers and used to cast the under reinforced beams .The cast specimens are tested after a specified curing period to determine first crack load, ultimate load, load-deflection behaviour and crack patterns. The results are compared with the theoretical values. From the test results, the fiber volume fraction has a compelling effect on the cracking load, ultimate load, crack pattern and failure mode. The flexural behaviour of the beams including the induced cracks, failure pattern, load deflection capacity and ductility index were compared. The ductility index of hybrid fiber reinforced beams is greater than that of GPC beams. The HFRGPC beams showed superior performance than that of GPC beams for parameters considered in this experimental study.
Use of recycled aggregate and fly ash in the development of concrete composite
Authors: Jatoliya A. , Mishra M. , Saravanan T.J.
Published: December 2022

Continuous economic growth poses severe problems of waste disposal for civil engineering construction and demolition works. In this research work, recycled aggregate (RCA) and fly ash in concrete composites for pavements are presented. The approach adopted here is to replace a large amount of normal aggregates (NA) with recycled aggregate, obtained from various crushed concrete and partial substitution of Portland cement by fly ash to develop rigid pavement concrete. A preliminary test is conducted on the materials which are used in the development of concrete pavement. Results have satisfactory results as per Indian standard guidelines. The compressive strength is determined at a proportion of fly ash varying from 0 to 40%, which gives a wide range of adding fly ash and recycled aggregate to achieve the aggregate's better mechanical property. It also determines the concrete's long-term flexural strength by partially replacing the RCA and fly ash, an important parameter in rigid pavement design. At 28 days and 56 days, the compressive strength is determined for different fly ash and recycled aggregate proportions, and concrete having more fly ash shows better results at 56 days’ compressive strength.
Effect of Shear Wall Shape on Seismic Response of RC Building Frames
Authors: Ningthoucha Y.S. , Ningthoukhongjam S.S.
Published: December 2022

This paper presents the effect of shape of shear wall on seismic response of a nine-storey moment resisting RC frames using non-linear static (pushover) analysis. The moment resisting RC frame is rectangular in plan and shear walls are provided along the least lateral dimension of the building plan. Different shapes of the shear wall (e.g., S, B, C, H and E) have been used in the analysis. The building frame along with shear walls has been modelled using FEM software SAP2000 and seismic responses of the building frames with different shapes of shear wall has been measured in terms of pushover curve (performance point, storey drift, top displacement and base shear). It has been observed that maximum performance level of building frame occurred when the shear walls are provided with S-shape.
On Flexure-Shear Interaction in Fibre Model for the Analysis of RC Section
Authors: Sahu S.K. , Singh A.K.
Published: December 2022

This paper investigates the effects of flexure-shear interaction on the force-deformation response of RC section. The analysis is performed using an improved version of fibre section model to consider the interaction of shear force. The model uses a supplementary shear strain field, in addition to the ‘plane-section’ hypothesis, for section kinematics. The concrete is modelled using a bi-axial stress-strain model based on a rotating, smeared-crack model with equivalent uniaxial stress-strain relation in principal directions. The confining effect of stirrups is considered by using Mander model. The reinforcing bars are modelled using a uniaxial stress-strain relation. The use of bi-axial model allow the flexure-shear interaction to reflect at the material point. The fibre section model is used to analyse an RC section to study the moment-curvature and shear force-shear strain response for increasing levels of shear forces and bending moments. The results shows that the moment-curvature and shear force-shear strain diagrams are significantly influenced by the presence of large shear force and bending moment respectively.
Behavioural Study of Truss Bridge using Isogrid Members
Authors: Jadhav P.V. , Joshi R.R. , Roy S.
Published: December 2022

The search for lightweight and highly efficient structural components is a continuing process. Reducing the structural weight and improving the load carrying capabilities of these structures will allow designers to append additional capabilities while reducing cost. Isogrid is a lattice of stiffened ribs forming an array of contiguous equilateral triangles. This rib pattern forms triangular trusses by maintaining isotropic property. Ribs when arranged in 60? pattern are known as Isogrid. The highly redundant nature of Isogrid stiffening concept provides high efficiency distributing loads and is less susceptible to impact damage, delamination, and crack propagation. Isogrid structure is typically found in stiffness critical components that resist buckling. The behavior and performance of Isogrid deck slab in a Bridge supported by the truss girders is studied. Isogrid is modeled, analyzed and designed using commercial Finite Element (FE) software. In the present work, a truss bridge is designed for a span of 10.305 m. The bridge is designed using three different kinds of deck configuration, rectangular section without skin, inverted T section with skin, and I section with skin. Commercial FE software is used for computing deflections and stresses. It is found that the deck profile of I section with skin is more preferable than other configurations for Truss Bridge.
Performance of solid steel beam under fire for different beam slenderness
Authors: Kotapati V.K.R. , Khatri A.P.
Published: December 2022

The present work is intended to study the behaviour of solid steel beam (SSB) under the ISO834 fire curve for different beam slenderness when it is subjected to three-sided exposure and four-sided exposure condition. The properly validated finite element based thermo-mechanical analysis is carried out to predict the performance of SSB under elevated temperature. The present study takes into account the transient temperature effect and the geometrical and material non-linearity. The section selected for this study is a universal beam section UB356×127×39. The considered beam slenderness (span to depth ratio) for this study is varied between 15 to 35, as these slenderness are generally preferred in practice. The eccentric hinge-hinge boundary conditions at the bottom flange are applied to the beam and beam is assumed to be laterally supported at top flange all along its length, and the bottom flange is not restrained laterally along its length. The various parameters considered for the present study include: beam slenderness, load ratios, and exposure condition of the beam under uniformly distributed loading. The performance of SSB under fire is compared using mid-span deflection, lateral displacement, limiting deflection, limiting temperature, and fire resistance time of the SSBs. This study depicts that there is a significant effect of beam slenderness on the behavioural aspect of SSB under elevated temperature.
Numerical Study On Response Of Exterior Beam-Column Joint Under Cyclic Loading
Authors: Krishnan Alok , Ramtekkar G.D.
Published: December 2022

In Present scenario, recent earthquakes have illustrated the severity of existing reinforced concrete (RC) beam-column joints to lateral loading. The sub-assemblage of Beam-Column are severe portion in reinforced concrete moment resisting frame as the high shear forces and larger moments getting attracted towards the joint. The Philosophy of Exterior beam-column joint are to observe its behaviour and has a significant role on the response of the reinforced concrete structure. This study includes numerical study on Exterior reinforced beam column joint with adequate shear reinforcement at joint as per IS: 13920-2016 and without shear reinforcement at joint as per IS: 456-2000. The seismic performance of G+5 RC Building of Zone III analyzed using SAP2000 and output of maximum shear force and bending moments are obtained, and one of the exterior beam-column joints at an intermediate storey is designed and satisfied for strong column and weak beam concept. The earthquake analysis of RC building of Zone III are carried out by incorporating all the modifications as per IS 1893:2002(Part-I) for Seismic loading, the loading is followed as per IS: 875 for dead and live loads and design as per code IS 13920:2016 and IS456:2000. Full scaled specimens were Numerically modelled in ANSYS 19.0 for constant axial load on column top and cyclic loading on beam end of each specimen, detailed as per IS 456:2000 and the other as per IS 13920:2016, were tested and response are obtained. This study outlined that model of IS13920:2016 performs more effective in controlling the seismic responses compared with model of IS456:2000. Further, there is significant reduction in Shear stress and observed improved ductility by providing adequate shear reinforcement in joint core of beam-column sub-assemblage.
Selection of Appropriate Roof Truss Configuration for an Industrial Shed
Authors: Sahoo Debarshi , De Soham , Saha Purnachandra
Published: December 2022

With the industrial development in recent years, the need of huge industrial sheds has increased where structural optimization and cost are the two major aspects of design. Trusses are triangular formations of steel sections in which the members are generally, subjected to axial forces due to external load. For industrial sheds, the truss configurations commonly used are Pratt, Howe, Warren and Fink truss. All of these truss configurations have their own structural advantages depending upon shapes and member arrangements. The aim of this study is to compare these trusses to select the optimal truss configuration for a particular span of 30m. The length of the bottom chord members of trusses are varied keeping the overall truss height, inclination angle, span, structure length, spacing and external load same, for all configurations. The analysis has been conducted using Tekla software. It is observed that Howe truss configuration with 12 divisions of bottom chord provide best selection based on weight of truss and connections. This paper helps the designer to select an appropriate truss of span 30m, considering the safety, self-weight, truss configuration and economical point of view.
Comparison of Section Classification Procedure of Different Codes
Authors: Shankar S. , Kumar R. , Khatri A.P. , Gupta L.M.
Published: December 2022

The cross-section classification is essential to identify local buckling in steel sections. Local buckling restricts the section from attaining its maximum moment capacity. Cross section classification is based on the behavior of the element under direct and bending compressive stresses. Limit on width to thickness ratio of elements in a cross section is the governing criterion for the section classification in different national codes. In the case of seismic design, the post yield ductility is an important parameter; therefore, it is particularly essential to prevent local buckling. Design codes of different countries provide different limiting values for the section classification. The present study discusses the approach of various national codes towards cross section classification. The approach of Eurocode 3, AISC 341, AISC 360, BS 5950 and IS 800 on issues like section classification of members subjected to axial and flexural compression, sections with elements of different classes are explained and their salient features are compared with each other. It is observed from the study that, amongst the codes considered, AISC provides the most stringent limits for seismically compact section, whereas, for other class of sections Eurocode 3 limits are more stringent.
A Review on phase-field modeling of fracture
Authors: Sidharth P.C. , Rao B.N.
Published: December 2022

In cases with complicated crack topologies, the computational modeling of failure processes in materials owing to fracture based on sharp crack discontinuities fails. Diffusive crack modeling based on the insertion of a crack phase-field can overcome this. The phase-field model (PFM) portrays the fracture geometry in a diffusive manner, with no abrupt discontinuities. Unlike discrete fracture descriptions, phase-field descriptions do not need numerical monitoring of discontinuities in the displacement field. This considerably decreases the complexity of implementation. These qualities enable PFM to describe fracture propagation more successfully than numerical approaches based on the discrete crack model, especially for complicated crack patterns. These models have also demonstrated the ability to forecast fracture initiation and propagation in two and three dimensions without the need for any ad hoc criteria. The phase-field model, among numerous options, is promising in the computer modeling of fracture in solids due to its ability to cope with complicated crack patterns such as branching, merging, and even fragmentation. A brief history of the application of the phase-field model in predicting solid fracture has been attempted. An effort has been made to keep the conversation focused on recent research findings on the subject. Finally, some key findings and recommendations for future research areas in this field are discussed.
Performance of RC Frames with Mass and Stiffness Irregularity under Sequential Ground Motion
Authors: Tauheed Athar , Alam Mehtab , Datta T.K.
Published: December 2022

The seismic design codes consider only single earthquake events, ignoring the possibility of multiple earthquakes. In case a structure suffers damage during first event and prior to its repair more aftershocks occur the structure may collapse. An elaborative directive study on the inelastic seismic response of 11storey RC (2-D) moment-resisting frame having mass irregularity at sixth floor, and stiffness irregularity in sixth story has been done has been done. The frame has been examined under a sequence of a main shock followed by six aftershocks. Time history synthetically generated from the design response spectrum explained in IS-1893 Pt II: 2016 has been taken for non linear dynamic analysis with the help of SAP 2000 software. A comparison is done to understand the inelastic response of the frame taking into account the location of plastic hinges, maximum top displacement, residual top displacement, and storey drift. It is seen that the structure with the stiffness irregularity is the most vulnerable amongst all.
Effect of Curve Angle on Single Cell Box-Girder Bridge
Authors: Agarwal Preeti , Pal Priyaranjan , Mehta PradeepKumar
Published: December 2022

The behaviour of curved box-girder bridge is quite different from the straight one as it is experienced by the additional torsional moments. The analysis and design of such box-girder bridges are quite complicated when the curve angle is varied. The effect of curve angle on the forces and deflection in the girders, inner and outer, of a simply supported single cell reinforced concrete curved box-girder bridge is investigated in this study. A Finite element based software, CSiBridge v.20, was used for the analysis. A convergence study was performed on the proposed model to select the optimum mesh size and the results obtained are validated with the published literature. The variation of absolute values of forces and deflection along both the girders, under dead load (DL) and IRC (Indian Road Congress) live load (LL), is observed and the equations are proposed for their prediction in terms of non-dimensional parameters, using the statistical approach. The present results may be helpful to the designers in the analysis and design of curved single cell reinforced concrete box-girder bridges.
Seismic Response of an Isolated Curved Bridge with Lead Rubber Bearing by Considering Design Aspect
Authors: Gupta P.K. , Ghosh G.
Published: December 2022

Studies on the application of the lead rubber bearing (LRB) isolation system to various structures carried out as one of the measures to improve seismic performance. Curved bridges play noteworthy role in the modern transportation system. Due to complex interchange and the desire to conform to existing geometric confinements have made this type of structures more alluring. Horizontally curved bridges make up of a noteworthy portion of the bridge population in various countries. In the present study, Lead rubber bearings have been used in an Isolated Curved bridges. Seismic loadings have been considered for three recorded ground motions from PEER strong motion database (PEER 2014) without scaling viz. (1) Imperial Valley (1940) with two orthogonal horizontal ground motion components (PGA0.313g and PGA0.215g); (2) Kobe (1995) with two orthogonal horizontal ground motion components (PGA 0.83g and PGA 0.63g) and (3) Turkey (1992) with two orthogonal horizontal ground motion components (PGA 0.5g and PGA 0.39g). These three ground motions have been considered to represent conditions close to far-fault, near-fault and forward directivity of earthquakes, respectively. Unidirectional and Bi-directional loading have been considered in the present study. Design aspects of the Lead rubber bearings has been considered by deploying the interaction diagram of bearing displacement between the unidirectional and bi-directional responses. It has been found that the bidirectional loading should be considered while designing the isolators.
Mitigating Structural Vibrations due to Earthquake with Application of Slope Bottom Tuned Liquid Dampers
Authors: Patil G.R. , Singh K.D. , Nanda B.
Published: December 2022

Earthquakes are one of man’s most feared natural phenomena, producing almost instantaneous destruction of buildings and other constructed facilities. In order to mitigate damage of structures and save the life, various measures are adopted and use of structural control devices is one of them . Structural control devices can enhance the integrity of structures without increasing the dimensions of structural members. In this study, an attempt has been made to systematically investigate the performance of structural control device namely, tuned liquid damper (TLD) for controlling the dynamic response of reinforced concrete (RC) framed structure. Dynamic analysis of a 10 story RC framed structure with both flat and slope (W or central slope) bottom rectangular TLDs, subjected to five earthquake time histories have been performed. Key results have been presented in the form of tuning ratio, liquid mass reduction and displacement response reduction due to slope at bottom TLD. For the case of TLDs with central slope, the analyses have been performed for slope angle ranging from 5-14º. Based on the study, it has been observed that, tuning ratio of TLD decreases with increase of central slope at the bottom of TLD, the variation of liquid mass reduction with slope angle has been observed to be linear and reduction in displacement of structure increases with increase in central slope angle.
Seismic Performance of Irregular Building with different Variable sliding isolators and Semi active Dampers
Authors: Sharma Ajay , Soni Sudhir
Published: December 2022

The comparative performances of semiactive friction and stiffness dampers with different control laws in the base-isolated Irregular building subjected to bi-directionally acting strong earthquakes have been studied. The Irregular building is hybridly isolated with rubber bearings and friction pendulum system (FPS) or variable frequency pendulum isolator (VFPI) or variable curvature friction pendulum system (VCFPS). The shear type base-isolated Irregular building is modeled as three-dimensional linear elastic structure having three degrees-of-freedom at each floor level. Time domain dynamic analysis of the building has been carried out with the help of constant average acceleration Newmark-Beta method and non-linear isolation forces has been taken care by fourth-order Runge-Kutta method. The effects of variation of characteristic properties of semiactive dampers on their hysteresis loops and on the structural response of Irregular building is studied through parametric study. Comparative performances of different semiactive dampers with sliding isolation systems for seismic control of Irregular building have been observed through time history plots and peak response performance indices. It has been found that semiactive electromagnetic friction damper work efficiently with VFPI and VCFPS in comparison FPS for the Irregular building for near field earthquakes as it not only reduces base displacement at lower control force but also give lower base shear and story drift in base-isolated Irregular building. The control laws based on modulated homogeneous friction control semiactive friction dampers better than the predictive control law.
Energy Based Design of Rc Staging in Elevated Service Reservoir
Authors: Darwin G. , Kumar Ratnesh , Kumbhar Onkar , Khose VijayN.
Published: December 2022

Elevated service reservoirs (ESRs) are inverted pendulum structures and are often categorized under lifeline structures. They are expected to remain functional after the earthquake to provide essential drinking water and water for post-earthquake firefighting. The current code-based design procedure of ESR in India is similar to the design procedure of other structures and does not explicitly provide insight into its post-earthquake behavior. Energy-Based Design (EBD) can provide a better and more reliable alternative to overcome the deficiencies of code-based design. EBD considers a coherent approach to estimate the input energy, the elastic energy dissipation, and the plastic energy dissipation, taking into account the inelastic behavior of structural members. In the present research, various issues of the EBD for frame staging of the ESR have been identified and assessed using linear and nonlinear analysis. A comparison of the seismic behavior of the ESR according to the Indian code and the EBD has been made. Besides, the structural design procedure based on the column tree method (CTM) has been modified to suit the specific behavior of the ESR.
Disregarding the Effect of Openings in Infill Walls in Indian Seismic Code: A Scrutiny
Authors: Pathak K. , Dutta A.K.
Published: December 2022

This study attempts to scrutinize the provision of IS 1893(Part–I): 2016 in neglecting the effect of openings in infill walls in the context of earthquake performance of the same. It evaluates the effect of openings as per FEMA-273 and ATC-40 and compares the result with the provisions of Indian code. The comparative seismic performance, in terms of base shear and top displacement, using the response spectrum of IS 1893(Part–I): 2016, is done on an irregular block of the Jorhat Engineering College old building situated in Seismic Zone-V. Two models of the frame structure are made in SAP 2000®. Modelling of infill is done as Equivalent-Strut, pin-jointed to the RC frame, the width of the strut taking care of effect of openings as per FEMA-273 and ATC-40. The width of the infill wall with openings is found to be 61.465mm whereas, without opening it is 503.80mm. In contrast, as per IS provision the width of infill is 486.27mm. Nonlinear Static Pushover Analysis is performed in SAP 2000®. The building base shear capacity for pushover analysis according to FEMA-273andATC-40 with infill is 10626.107kN and Maximum displacement is 0.042m. In contrast, provisions of IS 1893(part-I):2016 yield the base shear capacity with infill as 20231.365kN and Maximum displacement was 0.063m. An increase in base shear in the latter case may be attributed to the bigger strut width as per IS provision. The formation of plastic hinges is also more in the latter case. It is concluded that IS codal provisions resulted in a doubly stiffer structure.
Effect of Openings in Shear wall on Seismic Behaviour of RC Buildings
Authors: Pawar G.D. , Dawari V.B.
Published: December 2022

Shear walls along the exterior perimeter of buildings increase the efficiency of buildings to resist seismic forces. In some conditions, the locations of shear walls are very critical because of the demand of architectural openings like doors and windows in the exterior face of the buildings. The literature has revealed that stiffness and seismic response of the structure is affected by the size of openings and location of openings in shear walls. This paper demonstrates effect of static and dynamic actions on 15 storey RC building having shear walls with openings. 32 building models have been prepared in commercial software STAAD for various inline and staggered openings in shear walls. Seismic coefficient method and Response spectrum method are used for seismic analysis. The analysis is carried out for the seismic zones III and IV for hard and medium soil conditions. The paper compares the response of these building models having shear wall with and without openings on parameters of time period, base shear, storey displacement, storey drifts and surface stress distribution. Uniform stress distribution was observed in shear wall with staggered opening as compared to inline openings.
Seismic Fragility Analysis of an Existing Bridge Pier
Authors: Sonowal D.B. , Pathak J.
Published: December 2022

The main objective of this paper is to develop the fragility curves for an existing bridge having circular pier by static nonlinear analysis (Pushover Analysis). In this study, a cantilever circular bridge pier which is located in Assam, a highly seismic zone in India is considered for development of seismic fragility curve. Capacity of the bridge has been determined by Pushover analysis of bridge pier and demand parameter of the bridge were obtained by using ATC 40 Capacity Spectrum method and IS 1893:2016 (Part 1) along with IRC 6:2017. Civil Software SAP 2000 version 20 is used to analyze the bridge pier. The fragility curves of the pier have been constructed assuming a lognormal distribution. The evaluation results presented here describes the probabilistic seismic failure of the bridge pier and its capacity to meet the desired performance level.
Effect of Frequency Content of Earthquake Ground Motions on Structures with Varying Dimension
Authors: Bajad K.N. , Waghmare M.V.
Published: December 2022

An earthquake is a catastrophe which is always a topic of concern for structural designers and civil technocrats. Not only it causes physical damage to the structures but also successful to impart psychological disorder in human minds for long-run. In order to mitigate the devastating effects of earthquake on society, it is eminent to study the dynamic characteristics in detailed manner i.e. to examine how the structure responds owing to the seismic characteristics. The various ground motion characteristic includes time-duration and velocity, frequency content and amplitude, displacement, incremental velocity and incremental displacement, peak ground accelerations (PGAs), etc. Out of these, effect of frequency content and maximum amplitude value of earthquake ground motions on the seismic response of structures is often underestimated. This paper investigates the effect of frequency content and maximum amplitude value on the seismic response of structures which is dominant of all characteristics. The study proceeds with recording time-history of acceleration obtained from conventional unidirectional harmonic shake table. Further, FFT (Fast Fourier Transform) analysis of applied time-history is done and the effect of frequency content and the maximum amplitude value of applied time-history on the seismic responses of structures is investigated and studied. For this, structures with varying dimensions (height, length, and width) are modelled and time-history analysis of structural models has been carried out in SAP2000v19. Seismic responses of analysed structures are represented in the form of fundamental natural frequency, storey displacement, and base shear. It is reported that out of many earthquake indices, frequency content and amplitude of earthquake ground motions are the most dominating. It is reported that the resonance phenomena occurs for the less height structure and thus it shows maximum displacement and base shear responses. Also, as height, length, and width of structure increases; displacement, base shear, and fundamental time-period of structure increases.
Effect of Vertical and Mass Irregularity on RCC Structure Subjected to Seismic Loading
Authors: Kumar Nilesh , Parmar Jay , Dalal Maitri , Samal Abhishek , Patel Jenish , Patil Y.D.
Published: December 2022

he greatest challenge for any structural engineer in today’s scenario is to design seismic-resistant structures. The presence of vertical geometrical irregularity in building is a matter of concern when it is subjected to devastating earthquakes. Irregular configuration either in plan or in elevation is recognize as one of major causes of failure during earthquakes. The performance of a high rise building during strong earthquake motions depends on the distribution of stiffness, strength and mass along both the vertical and horizontal directions. If there is discontinuity in stiffness, strength and mass between adjoining storeys of a building then such a building is known as irregular building which triggers structural collapse of building when subjected to seismic loading. In present study G+14 story building with mass and vertical geometrical irregularity is analysed using static method and dynamic method in ETABS v 18.0.2 as per IS-1893-2016 (part 1). Analysis is performed for zone III. Also, response spectra analysis is done for torsion check in building. For dynamic analysis linear time history data of Bhuj, Mexico, and Kobe (Medium, Low and High Intensity) is used. Comparison of behaviour of irregular building is done with G+14 regular building in form of max storey shear, story displacement, story drift. From the analysis results, it is found that the mass irregularity has maximum storey shear, story displacement, story drift compares to regular and vertical geometrical irregular building. Also, sudden change in story shear is observed at set back level.
Seismic Performance of Elastomeric and Sliding Friction Isolation System
Authors: Vibhute A.S. , Bharti S.D. , Shrimali M.K. , Vern S.
Published: December 2022

The base isolation technique is widely used in the isolation of structures for providing efficient protection to structures concerning different loadings. This study aims to evaluate comparative performance and inelastic responses of the base-isolated structure for two types of isolation systems under the Far-field and Near-field earthquake. For this purpose, seismic response quantities like base shear, peak ?oor displacement, absolute acceleration, and isolator displacement for ten-story reinforced concrete building frame base isolated by lead rubber bearings (LRBs) are evaluated and compared with the seismic response of the same structure base isolated by Friction Pendulum Bearing Isolator. Nonlinear time history analysis is carried out to investigate the inelastic behavior of the base-isolated structure. The building frame was designed according to IS1893:2016 seismic code and IS 456:2000. To represent a wide range of assessments, a 10 storey building frame taking identical isolation parameters for elastomeric and sliding isolation system was analyzed in SAP 2000. It was observed that the responses of both the isolation system are nearly the same for all the three earthquakes.
Comparison between Seismic Performance of Semi-Integrated Bridge and Conventional Bridge
Authors: Kumbhojkar K.R. , Sharma V.R. , Shrimali M.K. , Bharti S.D. , Datta T.K.
Published: December 2022

The performance of a three-span integrated bridge is evaluated and compared with a conventional bridge for unidirectional and bi-directional excitation. The conventional bridge deck is connected to abutment through elastomers and the pinned connection is assumed at pier location. The height of the piers is 9.5 m, and the central and end spans are 38.0 m and 15.5 m respectively. A nonlinear time history analysis of the bridge is performed by using CSI Bridge software, for unidirectional and bi-directional excitation. The responses of the integrated bridge are compared with those of the conventional bridge in which bearings are provided between the deck and the support. The parameters varied are the major direction of the application of earthquake time history and PGA. The response quantities of interest include the maximum base shear of piers, maximum stresses developed at the critical sections of the deck, maximum deck deflection at the mid-span, and at the pier supports. The results of the numerical study show that as compared to the conventional bridge the integrated bridge has less base shear but has more stresses in the deck near pier supports; however, the stresses developed at the mid-span of the deck are significantly reduced.
Seismic Response Analysis of Vertically Irregular RC Building with MR Dampers
Authors: Dumne ShivajiM. , Shrimali M.K.
Published: December 2022

Seismic hazard mitigation has become one of the emerging problems in structural engineering therefore; many researchers have been studied on seismic performance of reinforced concrete structures having vertically regular and irregular. It is noted that vertically irregular structures are more prone to hazards due to earthquake. The recent emerging trend is to use active, passive, semi-active controls that aid in keeping the responses of structures in permissible. The most dynamically varied semi-active damper is a Magneto-Rheological (MR) damper which is used in this study to control the seismic responses. In the present study, four different models with and without MR dampers of which three models are vertically irregular in height are subjected to four realistic ground motions. The governing equation of motion for various building models is solved numerically by Newmark’s step-by-step integration method. The dynamic behaviour of semiactive MR damper has been predicted by modified Bouc-Wen model. This study employed the Lyapunov direct approach as a control algorithm for stability analysis and design of MR controller. The responses of various building models are simulated through MATLABâcomputing software. The study observed that considerable reduction in seismic responses of models with MR dampers is obtained as compared to respective building models without control. It is also observed that responses of building models are influenced by the vertical irregularities in mass and stiffness of building models.
Seismic Analysis of Sagging Elasto-flexible Cable using Placement Model
Authors: Kumar Pankaj , Tiwari Sanjay , Jain S.K. , Raj Ritu
Published: December 2022

Weightless sagging elasto-flexible cables lack unique natural state. However, heavy cables are assumed their natural state under their self-weight for predicting their static and dynamic response. In most of the existing literatures the nodal coordinates or placements are generally defined in reference to the chosen Cartesian coordinate system for the discrete formulation called here Placement Model. In this paper, Placement Model is applied to predict the seismic response of weightless sagging cables. The cable is fixed at their both the ends and two masses are attached in its intermediate points leading to a 2-node 4-DOF system. The dynamic response of the cable node is investigated by applying two different seismic excitations in three different conditions as only horizontal excitation, only vertical excitation and both horizontal and vertical excitation act simultaneously. El-Centro and Loma Preta Seismic excitation is applied to predict the seismic response of the cables.
Evaluation of Regional Demand Parameters for Design of Mid-high-rise Building Using Past Earthquake Records
Authors: Raisinghani B.M.
Published: December 2022

Category of earthquake and distance from epicenter are the prime parameters that decide the demand on buildings for its engineering. As observed in past Bhuj earthquake of 2001 (7Mw), seventy buildings got severely damaged in Ahmedabad city which is located 250kms from the epicenter. Intensity index through observed damages fills the gap for the demand anticipations. Design of a building considering excitation frequency rather than just the zone factor is necessary to include effects of low frequency waves (e.g. Mexico-city). This paper shows the broad ways in which seismic demand can be obtained for performing PBD in Indian context. A mid-rise RC building is designed as per three standard code of practices (i.e. IS, ACI, EN) to provide seismic resistance. The anticipated demand levels are obtained using GMPEs (PEER), magnitude-intensity relations, micro-zonation study and NDMA hazard contours for 15 storey building in Ahmedabad. The highest capacity curve is for design using IS 1893 code and this building will survive earthquake having 0.22g PGA value. The magnitude-intensity-epicentral distance relation (Gutenberg et al, 1956) shows that the intensity of VII for Zone-III is not correct for Ahmedabad city and it shall be taken as VIII which is for Zone-IV (0.24g) as per zoning map of India. However, as per the micro-zonation study showing PGA of 0.18g for the city it can be said that building will survive the next earthquake of 7.0Mw in Bhuj. The damage to non-structural elements is evident from the NLTHA using matched response spectrum obtained using Uttarkashi and Chamoli earthquake records (COSMOS). It is suggested to use intensity-based response spectrum for design of mid-high-rise buildings in Ahmedabad city. Moreover, a local directive based on social and technology resilience shall be developed to provide design basis based on loss (%)-multiple hazard (PGA) matrix using the matching relations found in this paper. Design provisions and loss reduction strategy can only lead to sustainable infrastructure in cities planning for vertical development.
Earthquake Response of Arch Dams including Hydrodynamic effect using ABAQUS
Authors: Khandelwal Deepak , Shrimali M.K. , Bharti S.D.
Published: December 2022

A simple arch dam [1] is analyzed to find responses due to an earthquake, including the hydrodynamic effect of the reservoir water. The simple arch shape dam was modeled as a monolith structure, assuming the linear behavior of dam concrete. The arch dam is modeled with finite elements. The hydrodynamic effect is considered as an added mass of water adhered to the dam’s upstream surface [2]. Natural frequencies and mode shapes are computed for the dam without water and the dam with water. Time history analysis of the dam is performed for the Kern County earthquake (1952), Taft component 111 acceleration time history. The added mass of water is calculated according to the Kuo 1982 [2] research paper. Various results containing Cantilever stresses, arch stresses, and deflections are shown and plotted. Analyses are performed with the help of the Abaqus Software.
Seismic Analysis of RCC Building with Different Shape of Shear Wall and Without Shear Wall
Authors: Bush R.C. , Shirkol AnoopI , Sruthi J.S.
Published: December 2022

Shear walls are earthquake-resistant structural components used in structures at different locations to resist lateral loads. Shear walls possess large in-plane stiffness that aids in the resistance of lateral loads. In this study, dynamic analysis was carried out on a (B+G+26) storey building and the outcome is studied for varying locations of shear walls. The models considered have been analysed and modelled using FEM integrated software ETABS wherein the models are assumed to be present in the seismic zone IV of INDIA as per IS1893-2016. The models are regular in plan and are assumed to be on type -II (i.e., medium soil). The observations made post analysis through the response spectrum method conclude that a regular structure with uniformly placed shear walls at the centre performs better in comparison to structures without shear walls or structures with other positions of shear walls. The result parameters such as storey drift, storey displacement, storey stiffness, time period and base reactions of the models are compared.
Dynamic Analysis for High-Speed Locomotive in Distinct Depths
Authors: Ganesh Engammagari , Tiwari Naveen , Naharla Rohit , Ramana P.V.
Published: December 2022

The study uses coupled finite or boundary element models expressed in terms of the axial wavenumber. It is found to be important to include the track in the model as this determines how the load is distributed at the soil’s surface, which significantly affects the insertion loss of the barrier. Calculations are presented for a range of typical layered grounds in which the depth of the upper soil layer is varied. Variations in the width and depth of the trench or barrier are also considered. The results show that in all ground conditions considered, the notional rectangular open trench performs best.