Recent Developments in Structural Engineering, Volume 3

Inhaltsverzeichnis

1. Estimation of Prestress Loss of Pretensioned Concrete Beam with Different Tendon Profiles at Different Locations

   Lalatendu Mishra, Sher Bahadur Singh, P. R. Maiti, Supriya Mohanty

   Abstract

   From the point of load transfer, initial prestress introduced in concrete gradually decreases over time for a variety of reasons. This is generally referred as loss of prestress. This paper investigates the pattern of distribution of prestress losses along the length and cross-sectional dimension of prestressed beam. Emphasis has been made to investigate the effects of tendon profile on distribution of prestress loss along the beam's span. Prestressed concrete beams analyzed in present study includes four typical tendon profiles: (a) straight tendon, (b) triangular, (c) trapezoidal and (d) parabolic tendon. It is concluded from this study that the total prestress losses are not having uniform distribution along the length of a simply supported pretensioned concrete beam and are independent of tendon profiles. Prestress loss due to shrinkage in concrete and relaxation of tendons does not vary along the length instead shrinkage loss varies with cross-sectional dimension of the beam. It is observed that the loss of prestress due to creep of concrete is dominant along the length of beam as compared to elastic deformation and shrinkage losses.

2. Buckling Behaviour of Single Angle Subjected to Eccentricity

   Sangeeta H. Makade, Laxmikant M. Gupta

   Abstract

   This paper presents the study of behaviour of single equal and unequal angle compression member subjected to eccentric load with respect to major and minor principal axis. Non-linear finite element simulation was done. Study included imperfection factor with wide range of slenderness ratio. Study compared with other researchers. Numerical results suggested that load capacity of single angle was near to same when load eccentricity varied along the major principal axis of angle. Buckling curve for equal angle was drawn and compared with buckling curve of IS 800:2007. It was seen, buckling curve of IS 800:2007 was conservative.

3. Comparative Study of Plasticity-Based Steel–Concrete Bond Stress and Codal Development Length in RC Structures with Formulations Proposed in CEB-FIP 2009, IS456:2000 and ACI 408R-03

   Kankan Jyoti Deka, Arbind Kr. Singh

   Abstract

   The behaviour of steel–concrete bond is critical to the performance of reinforced concrete structures. Bond length is a key parameter that affects the load-carrying capacity of such structures. However, the linearized model commonly used to calculate bond length is not inclusive of the plasticity of concrete and steel. This oversimplification can lead to inaccurate results. In this paper, we compare the formulations for bond length as proposed by IS456:2000 (IS 456. Code of practice for plain and reinforced concrete. In: Bureau of Indian Standards (2000), ACI 408R-03 (ACI Committee 408. 408R-03: Bond and development of straight reinforcing bars in tension. In: Technical Documents (24)9) and transmission length by CEB-FIP 2009 (CEB-FIP model code 2009: design code. CEB Bulletin No.48, 2009(2009), with a more realistic simulation of the pull-out test. The simulation model incorporates plasticity in concrete using the concrete damage plasticity model (CDPM), classical metal plasticity in steel, and a linearized bond slip model. Our study highlights the significant differences between the bond length parameters obtained using the linearized model and the more realistic simulation. These findings emphasize the importance of considering the plasticity of both concrete and steel in the analysis of bond behaviour between these materials.

4. Longitudinal Behavior of Profiled Deck Composite Slab: A Probe

   Ritu Kesarsingh Chauhan, Sharda Phusnath Siddh

   Abstract

   Concrete is inherently weak in tensile strength, which necessitates the use of tensile reinforcement. Various forms are required to hold the concrete in place until it hardens sufficiently. With this as the main motive, profiled deck composite slabs has been widely used in current practice since decades. The deck serves not only as a lasting concrete form-work for proper settling but also establishes effective bond-slip properties. As the concrete gains strength, it combines with the deck material to function as a composite unit. Composite slab withstands three main types of failure, of which longitudinal failure is the dominating one. Though many researchers have worked to control longitudinal failure, the results have been scarce. Rigorous research has been carried out on profiled decking using experimental and analytical methods. According to Euro-code 4, “m–k” and “partial shear connection method” are effective in calculating the longitudinal shear capacity of profiled deck slabs. The objective of this study is to understand the role of the profiled deck composite slabs, its behavior and elements affecting the longitudinal failure in order to enhance their bond-slip characteristics. Moreover, this probe includes an exhaustive review of all the works that has been done to enhance the efficacy of profiled deck slabs to improvise bond- slip characteristics of composite slabs.

5. Seismic Fragilities for Bidirectional Shaking Accounting Parameter Uncertainties

   Arijit Acharjya, Rana Roy

   Abstract

   In Performance-Based Earthquake Engineering, responses of structures are computed by nonlinear response history analysis under an appropriate set of ground motions. Based on the computed demand parameters, probabilities for exceeding certain limit states usually defined in terms of the peak deformation corresponding to appropriate intensity measures are estimated. This critical step in seismic design is known as fragility analysis. Seismic demand might be appreciably amplified under two orthogonal horizontal components relative to the unidirectional companion. Variability of record-to-record and the uncertainties of various parameters governing structural response may play an important role in this fragility analysis. Against this backdrop, the Bayesian linear regression model based seismic fragility has evolved for unidirectional seismic shaking. This is extended in the current study to account for bidirectional excitation for single degree of freedom systems. This also confirms the significance of bidirectional shaking.

6. Investigating the Influence of Surface Geometry, Embedment Length, Confinement, and Concrete Strength on Bond Behavior of GFRP-Reinforced Concrete Beams

   Amer Iliyas Rather, Sauvik Banerjee, Arghadeep Laskar

   Abstract

   Fiber-reinforced Polymers (FRP) composites have emerged as a viable solution to combat corrosion in reinforced concrete structures, drawing significant attention. The bond behaviour between FRP reinforcement and concrete significantly affects load-bearing capacity and serviceability of structural elements under flexural loading. Inconsistent experimental conditions and non-consideration of critical parameters in previous studies hinder accurate assessments. This research investigates the flexural bond performance of Glass FRP (GFRP)-reinforced concrete members, focusing on variables such as the previously un-explored bar surface characteristics, concrete grade, confinement, and embedment length. Twenty-four hinged type-beam specimens simulating practical field conditions, have been tested to investigate various combinations of the investigated test parameters. Influence of the test parameters on the failure modes and the post-peak behavior of the tested specimens under flexural loading also form part of the present study. The findings provide insights into bond behavior, which is essential for designing FRP-reinforced concrete structures. This research highlights the importance of revising design codes to include surface geometry properties and other previously non-considered factors, by enhancing the understanding of GFRP-concrete bond behavior.

7. Forecasting of Aerodynamic Coefficient on Two Identical Tall Building for Various Wind Incident Angle by CFD

   Himanshoo Verma, R. S. Sonparote

   Abstract

   The aim of the study is to utilize computational fluid dynamics (CFD) modeling to estimate the aerodynamic coefficient of a rectangular-shaped tall building aerodynamically modified for terrain type III at different angles of attack (AOA). The prototype is 180 m long, and the computational domain was scaled up at 1:300. The shape of the building was modified by chamfered corners and corner cuts. Calculation of pressure coefficient (C_P) and force coefficient (C_F) and moment coefficient (C_M) on each face of a high-building for wind incidence angles ranging from 0 to 90° with an interval of 30° using Reynolds-averaged Navier–Stokes method (RANS) k-epsilon turbulence model in CFD. Grid convergence research is performed to increase the accuracy of the results by using an extremely small meshing of the computational domain. Numerical analysis is also used to obtain the velocity and pressure variations at each face. The validation of the turbulence model is carried out by the Commonwealth Advisory Aeronautical Research Council (CAARC) building. However, in most instances, those modified corner faces draw more pressure than unmodified sharp-cornered structures. This emphasizes that cladding design must be approached with caution.

8. Flexibility Energy Quotient Difference Method for Structural Damage Detection in Beams

   V. Amruthavarshini, C. T. Monish Muthamma, Siddesha Hanumanthappa

   Abstract

   This paper presents the study between the two methods for the recognition and identification of various elements damaged cases in beams. Damage causes changes in the vibration characteristics, including the modal properties. This affects the stiffness, damping, and mass. FEQD- Flexibility Energy Quotient Difference method which basically utilizes the flexibility matrix difference of undamaged and damaged structures using first mode of vibration is employed in this research work. Different types of beams are evaluated to verify the efficacy of the method. For these beams, single and multiple elements are damaged by reducing the bending stiffness in the elements. The results specify that the recommended method is efficient in identifying single and multiple damaged elements in beams.

9. Performance Assessment of Superelastic Slit Damper (SSD) as the Seismic Retrofitting Device for Building

   Rahul Kumar, Vaibhav Singhal, Sourav Gur

   Abstract

   Seismic failure vulnerability of structures can be substantially reduced by retrofitting the structure using smart materials. Though metallic dampers are extensively used for this purpose, they leave a large residual deformation leading to a non-operative condition under post- earthquake scenario. This study deals with the seismic performance analysis of a superelastic slit damper (SSD), composed of shape memory alloy (SMA) bars diagonally connected to the web of steel slit damper. The SSD is analyzed for various fractions (25, 50 and 75 %) of SMA bars strength in terms of the energy dissipation capacity and residual deformation. It is observed from the cyclic loading of the dampers that, with increasing fraction of SMA, the energy dissipation capacity of SSD decreases by 20–45% and the recentering ability increases by 55–100% than slit damper. Further, the performance of these dampers is studied for 5, 10 and 15-storey frame structures. Displacement based pushover analysis is carried out in SAP2000. It is observed that, addition of SMA has no effect on structural performance, and the SSD follows similar pattern of slit damper. The hinge states of the slit damper and all SSD are compared at a 2% drift ratio. It is found that with increasing SMA percentage in SSD, the load carrying capacity of the frames increases by 5–20%, and also improves the damage stages (as per FEMA) from collapse prevention to immediate occupancy.

10. Behavior of Hinges in a Building with and Without Lateral Load Resisting System Provided at Ends—Pushover Analysis

    S. Deepa, S. V. Venkatesh

    Abstract

    The principle objective of this paper is to compare regular bare frame with fixed base and regular building with Lateral load resisting system (LLRS) analyzed by Nonlinear analysis. Considering fixed base and performing linear analysis is conventional method. But subjecting the same bare frame to nonlinear analysis and observing the response is very necessary to study the behavior of the building. Usually of the building behavior changes when subjected to any load which is generally nonlinear. A 3D model of ten storey building with fixed base is selected. The building dimension 25 × 25 m with base as fixed is analyzed by nonlinear pushover analysis. The 3D model is modeled using SAP 2000 V.19.2.1 software. The behavior of hinges in case of bare frame and bare frame with LLRS is studied and compared for nonlinear analysis. The LLRS adopted in this model is shear wall and the shear wall is modeled as shell element layered with nonlinear material behavior. The nonlinearity is incorporated by applying reinforcement to shear wall. The shear wall is provided at ends and the model is subjected to nonlinear analysis to study the behavior of hinges. The results obtained in case of both bare frame and bare frame with LLRS is tabulated. The results in case of displacement, base force, number of hinges and time period are compared and the behavior is studied. The results indicate that shear wall provided at ends shows better result.

11. Sustainable Self Compacting Concrete with Recycled Coarse Aggregate and Fly Ash

    Rakesh Kumar, Anjali Singh, P. K. Mehta

    Abstract

    In this study, the effect of partial substitutions of Natural Coarse Aggregates (NCA) with Recycled Coarse Aggregates (RCA) and Ordinary Portland Cement (OPC) with Fly Ash (FA) was investigated in Self Compacting Concrete (SCC), after exposure to sodium sulphate solutions (2.0 and 8.0 g/l) for 28, 120, 365 and 540 days, along with CO₂ emissions. A total binder content of 465 kg/m³ was used for three different SCC mixes with a water/binder ratio of 0.43. The Control Mix [OPC (100%)] is referred to as CM, while the other mixes are referred to as Mix-FA25 [OPC(75%) + FA(25%) + NCA(100%)] and Mix-FA25RCA25 [OPC(75%) + FA(25%) + NCA(75%) + RCA(25%)]. Micro-structural changes in SCC mixtures resulting from sulphate attack were investigated using analytical techniques such as X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The deterioration in compressive strength of CM, Mix-FA25 and Mix-FA25RCA25 exposed to 2.0 and 8.0 g/l sulphate solutions is in the range of 1.57–6.38% upto 540 days of exposure, in comparison to it’s corresponding strength in normal tap-water. Also, the decrease in CO₂ emissions is between 22.10 and 23.63%, when OPC and NCA are replaced by FA and RCA, respectively. The study revealed that SCC mixtures containing RCA and FA (Mix-FA25RCA25) exhibited a relatively smaller reduction in strength due to sulphate attack. This mixture not only offers enhanced strength and cost-effectiveness but also contributes to environmental protection, distinguishing it from other mixtures such as CM and Mix-FA25.

12. Vibration-Based Structural Health Monitoring Using Bayesian Model Updating

    Nihal Khaimee, Sonal Djanvijay

    Abstract

    Model updating is an important aspect of Structural Health Monitoring (SHM) because it ensures the accuracy and reliability of the structural models used to assess structural health. The need for model updating arises as a result of errors in the process of developing a theoretical model of a structure. Model updating allows models to be calibrated and validated using actual measured data, thereby improving their predictive capabilities. This paper implements a general Bayesian statistical framework for model updating. The Bayesian approach to model parameter updating entails solving a high-dimensional integral. It has been addressed by a numerical method known as the ‘Markov Chain Monte Carlo’ (MCMC) technique along with the ‘Metropolis–Hastings’ (MH) algorithm. To validate the framework, experimental data has been generated by applying dynamic base excitation to building prototypes using the shake table. The effectiveness of the proposed framework has been demonstrated by comparing theoretical response before and after model updating with the experimental response.

13. Enhancing Seismic Performance of Buildings in Seismic-Prone Regions Through Base Isolation Techniques

    Arun Kumar, Arun Menon, A. Meher Prasad

    Abstract

    Base isolation is one of the popular and powerful earthquake-resistant design strategies adopted for the seismic performance enhancement of structures. The selection of an appropriate isolation device can significantly reduce the engineering demand parameters (e.g., base shear, story displacement, inter-story drift, story acceleration, etc.) and functional disruption caused by earthquakes. The present study investigates the seismic performance enhancement of a five-story reinforced concrete (RC) moment-resisting frame building supplemented with different base isolation strategies. Three types of isolation devices commonly adopted in practice, namely (i) Lead rubber bearing (LRB), (ii) Single friction pendulum bearing (SFPB), and (iii) Triple friction pendulum bearing (TFPB), are evaluated for their effectiveness in improving the seismic response of the isolated building model. The modeling and analysis of the base-isolated building is done using the commercial software SAP2000 with the Fast Nonlinear Analysis (FNA) solver. The isolation systems are modeled using a two-noded nonlinear link element. The influence of the effective isolation period on the dynamic response of the base-isolated building model is investigated under seismic conditions. The effective isolator damping ratio is kept constant throughout the study to facilitate comparative analysis. The study demonstrates that base isolation techniques can effectively enhance the performance of structures in seismic-prone regions. The analysis results highlight the importance of considering the appropriate isolator parameters for base isolation design based on the structure's performance requirement and seismic hazard level of the region.

14. Vibration Control of Light Weight Structural Panels Using Particle Dampers Following Bidirectional Data Coupling Between Python and LIGGGHTS

    Baharul Hussain, Aditya Zad, Atanu Sahu

    Abstract

    Particle damper (PD) is an effective and low-cost passive damping technique that can be used for vibration control of host structures for a wide range of ambient temperature and frequency variation. A particle damper usually consists of several small-sized particles inside a container attached to the host structure. When the host structure vibrates, the damper attenuates structural vibration by absorbing the kinetic energy of the host structure through friction and inelastic collisions between particles and particle to container walls. In the present work, a numerical model is proposed for investigating the particle damper behaviour in attenuating structural vibration. The discrete element method (DEM) is employed to model the particle damper using LIGGGHTS (an opensource software) and the host structure is modelled following the finite element method (FEM) in the Python platform. A coupling strategy is developed and implemented in the present research work for bidirectional data exchange between Python and LIGGGHTS to couple the DEM and FEM simulation. Numerical simulations are carried out to find the effectiveness of particle dampers in attenuating the dynamic response of an aluminium flat panel by varying the mass ratio of PD for different types of external excitations. It is concluded that the developed numerical model can be successfully applied to model any structure with complex geometry and boundary conditions, with PD attached to it.

15. Identification of Microstructure from Macroscopic Measurement Using Inverse Multiscale Analysis

    Anjan Mukherjee, Biswanath Banerjee

    Abstract

    Most of the tailored materials are heterogeneous at the ingredient level. Analysis of those heterogeneous structures requires the knowledge of microstructure. With the knowledge of microstructure, multiscale analysis is carried out with homogenization at the micro level. Second-order homogenization is carried out whenever the ingredient size is comparable to the structure size. Therefore, knowledge of microstructure and its size is indispensable to analyzing those heterogeneous structures. Again, any structural response contains all the information of microstructure, like microstructure distribution, volume fraction, size of ingredients, etc. Here, inverse analysis is carried out to identify a heterogeneous microstructure from macroscopic measurement. Two-step inverse analysis is carried out in the identification process; in the first step, the macrostructure’s length scale and effective properties are identified from the macroscopic measurement using gradient-based optimization. In the second step, those effective properties and length scales are used to determine the microstructure in inverse second-order homogenization.

16. Development of Bacterial Based Self Healing Concrete

    Pratik Mule, Shruti Shingane, Gayatri Yadgire, Shrikant Harle, Milind V. Mohod, Swati S. Nibhorkar

    Abstract

    An overview of current achievements in research on the self-healing of cement-based materials is given. Bacteria such as Bacillus subtilis and Bacillus cohnii were used in this study. Depending on the concrete material, different percentages of bacteria are used. Various tests are done on the product before mixing design and casting. In this study, slump tests were performed to control the consistency of test fabricated new concrete to prevent water escaping from the concrete structure. Bacillus cohnii was found to provide good strength to cement concrete. In addition, the combination of Bacillus subtilis and Bacillus cohnii provides better compressive strength than concrete. It was found that 5% of Bacillus conigiens cured a 0.3 mm fracture in 30 days, while 4% of Bacillus conigiens cured a 0.1 mm fracture in 30 days. The combination of 4% and 5% Bacteria Concrete helps repair cracks up to 0.1 mm. Bacillus subtilis takes longer to heal cracks than other combinations.

17. Behaviour of Steel–Concrete Composite Beams Under Hogging Bending

    Meera, S. Arul Jayachandran

    Abstract

    The basic principle of composite beams is to take advantage of the strength of steel and concrete in tension and compression respectively, connected with shear connectors, resulting in high strength-to-weight ratios. These steel–concrete composite (SCC) beams are also used for the continuous span. When these beams are subjected to negative or hogging bending, cracks are developed in concrete due to tension and the majority of the bending is resisted by steel. The analysis and design of the same is still a complex phenomenon which mandates experimental work to evaluate the design capacity. The aim of this paper is to study the development of the procedures to design the beams under hogging bending and the influence of research in the development of the code provisions. Comparisons of the design methods for the SCC beams with different codes IS:11384, Eurocode-4, AISC:360-10 and Australian Standard: 2327 are presented in this paper.

18. Comparative Study on the Flexural Behavior of BTRC and CTRC Panels

    Sophia Immanuel, Baskar Kaliyamoorthy

    Abstract

    Sustainability has become a driving force in the construction industry to bring out novel technologies and low carbon innovative materials to use. Textile Reinforced Concrete (TRC) is a cement based composite material that uses textiles meshes as non-metallic reinforcement. In the present study, the flexural behavior of Carbon Textile Reinforced Concrete (CTRC) panels and Basalt Textile Reinforced Concrete (BTRC) panels are investigated and compared for their behavior. Four-point bending were experimentally performed for these panels. The main aim of the study was to correlate on the interface and matrix properties with the crack pattern, mode of failure and bending stiffness. The results show that for same mesh size of 25 mm and for same thickness of the panels as 30 mm with 4 layers of textiles equally spaced, the specimens showed a multiple flexural crack, and most cracks appeared in the pure bending zone. The BTRC panels exhibited excellent flexural bearing capacity, good ductility and higher toughness in comparison to CTRC. It was observed that with the increase in the textile layers within the panels had enhanced performance. The stiffer basalt textiles improved the flexural capacity by 15% more that carbon textiles. The performance of basalt textiles and carbon textiles used as reinforcement for the panels are quite comparable, both in terms of its flexural behavior highlighting the possibility of using basalt textiles to be a valid alternative to carbon, without significant loss of performance, and it provides less environmental impact and carbon footprint.