Recent Developments in Structural Engineering, Volume 3

Inhaltsverzeichnis

1. Numerical Study and Behaviors of Nylon-66 Under Quasi and Dynamic Strain Rate

   Kailash Kumar, M. A. Iqbal, P. K. Gupta

   Abstract

   Nylon 66 polymers and their composite materials are widely utilized across various engineering sectors, including the aerospace and automobile industries, primarily due to their exceptional lubrication capabilities. Therefore, it is important to study the stress flow in Nylon 66 under different strain rates. In this study, the behaviors of Nylon 66 under low to high strain rates have been presented. The sensitivity of nylon 66 for different strain rates are measured by the compression-testing machine (CTM) and Split-Hopkinson Pressure Bar (SHPB). A 3-dimensional Finite element (FE) model has been made in Ls-dyna. Calibration of the numerical result has been done with the experimental result by using the Johnson–Cook (JC) material model and plastic kinematic material model for rods of SHPB and Nylon-66, respectively. The calibrated model is used to study the effect of strain rate and shape of Nylon-66, and simulated results are presented in this paper. The quasi-static strength of Nylon-66 measures 60 MPa, under a strain rate ranging from 0.0006 s-1 to 0.001 s⁻¹. In dynamic tests, the strain rate varies considerably, ranging from 400 s⁻¹ to 3380 s⁻¹. Accomplished by adjusting the striker velocity from 2 to 16 m/s. Notably, for circular sections, the dynamic strength of Nylon-66 exhibits a remarkable increase, rising from 82.42 MPa at a strain rate of 400 s⁻¹ to 316.59 MPa at a strain rate of 3380 s⁻¹. Similarly, in equivalent square sections, the strength varies from 70.92 MPa to 301.45 MPa.

2. Comparative Study and Review of IS 803:1976 with API 650 and NZSEE Guidelines

   Zalakkumar R. Chhaya, Vipul Prakash

   Abstract

   IS 803:1976 is the Indian standard code of practice for design, fabrication and erection of vertical mild steel cylindrical welded oil storage tanks, firstly published in 1962 and then first revision in 1976. After that no further revisions were observed till the date except a small amendment published in 1984. At present, API standard 650 on welded tanks for oil storage is widely accepted and used in many countries including India. The standard comprises detailed provisions on design, fabrication of the tanks along with explanatory examples. Similarly, New Zealand is following NZSEE guidelines, which has been prepared based on the Priestley and other researcher’s work. These guidelines have nicely focused on the design part of the tank aided with the design charts and design examples. In this paper, a brief review is carried out mainly focused to design part of IS 803 in comparison with API 650 and NZSEE guidelines. Generalised discussions/commentary are made on design provisions including seismic design criteria. The purpose of the study is to compare the IS 803:1976 provisions with the other widely popular standards in view of identifying the current state of provisions of the code.

3. Pushover Analysis of a RC Building Resting on Different Sloping Angles

   Nitin Jain, Goutam Ghosh, Aman Kumar

   Abstract

   Several previous earthquake studies have shown that earthquakes have significant impact on power grids and have major catastrophic effects on human life, buildings, bridges and the economy. Hilly buildings are more susceptible to severe damage from lateral forces (earthquake ground motion) in comparison to buildings in plains because they are irregular and asymmetrical in the horizontal and vertical planes and torsionally coupled. In this paper, the seismic response of a G + 4 Reinforced Concrete (RC) buildings is being compared by varying the angles of the sloping ground. Buildings with sloping angles of 0°, 10° and 20° are being considered for analysis. The seismic design of the buildings is being done as per the IS 1893(Part I):2016 while for the ductile detailing provisions IS 13920:2016 has been considered. ETABS software has been used for modelling and analysis purposes of the buildings considered. To incorporate the nonlinear behaviour in the structure’s plastic hinges have been assigned to the frame elements. Nonlinear pushover analysis has been performed and the capacity curves and ductility demands have been determined. This study helps in determining the effect of varying the angles of the sloping ground on different dynamic characteristics along with the variations in ductility demands of the buildings resting on slope ground. The results obtained from the present study will help in evaluating the seismic performance and risk of failure of the buildings resting on slope.

4. Rail Structure Interaction on PSC Box Girder by Using MIDAS Civil

   Mayur M. Chopade, Keshav K. Sharma, Akileshwar Shahi

   Abstract

   Continuous welded rail (CWR), considerable longitudinal forces may develop due to temperature variation, train loadings like braking, traction, and deck end rotation due to vertical bending. Rail structure interaction (RSI) analysis is an integral part of bridge design to evaluate the longitudinal stresses in CWR, longitudinal forces on the substructure, and deflection/displacement of the structure. The stress developed in CWR significantly depends on the girder and substructure's stiffness. In this present study, RSI is done by using Midas Civil software. RSI analysis performed by two methods are Simplified Separate Analysis and Complete Staged Analysis. Here, considering three cases for analysis are 3 Span of 20 m, 3 Span of 30 m and 3 Span of 40 m bridge length. Results have been checked as per Union Internationale des Chemins de fer internationaler Eisenbahnerband International Union of Railways (UIC 774-3R) and Indian Railway Standards Bridge Rules (IRS Bridge Rules) codes. It is observe that the most favorable bed is a concrete bed that satisfies all the limits as per the codes given on Prestressed Concrete PSC Box Girder, and a complete staged analysis gives the exact result.

5. Strain Hardening Behaviour and Multiple Cracking Characteristics of Natural Fiber Based Engineered Cementitious Composite Specimens Under Tension Loads

   N. Prem Kumar, J. Maheswaran, M. Chellapandian

   Abstract

   Engineered cementitious composites (ECC) belong to the class of high-performance concrete possessing a large tensile strain capacity of up to 6%. In this study, an attempt is made to produce a novel strain hardening ECC with different types of plant based natural fibers such as flax, hemp, kenaf, and pineapple. Standard coupon specimens of size 330 mm × 60 mm × 13 mm complying with the ASTM E8-13a standards were fabricated and tested under direct tension loads. A minimum of three coupons were tested for each sample to understand the overall behavior of ECC with different fiber combinations. Test results revealed that the use of natural fibers produced excellent strain levels up to 3.0%. In specific, the use of flax and kenaf fibers showed a large tensile strain level of more than 5% without comprising the ultimate tensile stress of 12.0 N/mm² and 8.9 N/mm² respectively. Moreover, the microstructural examination of tested specimens revealed a strong interfacial bond between the natural fibers and ECC matrix leading to better stress redistribution and crack bridging mechanism like that of conventional artificial fiber-based ECC.

6. Efficacy of Different Retarders on Engineering Properties of Calcium Sulfoaluminate (CSA) Cement Based Paste, Mortar and Concrete—A Review

   Sathishraj Mani, Gowram Iswarya, Baranidharan Sundaram

   Abstract

   Calcium sulfoaluminate (CSA) cement is gaining popularity for both its distinctive technical properties and its eco-friendly benefits, such as lower carbon emissions and increased energy efficiency. One of its most notable qualities is how quickly it sets and hardens, which makes it especially appropriate for last-minute fixes and uses like stabilizing soil and ceilings. The process by which CSA cement hydrates in the presence of retarders is still not well understood, although there are circumstances in which a prolonged setting time is necessary. A major barrier to the widespread use of CSA cement is the lack of understanding of how changes in retarder dosage affect the short- and long-term characteristics of concrete. To address this, a comprehensive review of the impact of various retarders and their dosages on calcium sulfoaluminate cement-based materials, including paste, mortar, and concrete, is imperative. Such a state-of-the-art review can pave the way for the construction industry to harness the full potential of CSA cement in terms of fresh and mechanical behavior. This review underscores the importance of identifying the most effective retarder and its optimal dosage for calcium sulfoaluminate cement. Finding the right balance among various retarders and dosage levels is the key to resolving challenges associated with the fresh and hardened properties of the CSA cement system. Ultimately, this knowledge can promote the broader utilization of CSA cement in the construction sector.

7. Confinement Studies on Concrete Filled Steel Tube Composite Columns: Numerical and Experimental Investigations

   Pratik Patel, Arth J. Patel, Sharadkumar P. Purohit

   Abstract

   Concrete Filled Steel Tube (CFST) columns are preferred as compared to conventional Reinforced Concrete (RC), steel columns owing to their higher axial-flexural capacity, ductility, higher usable floor area and faster construction. In the present study, confinement effect of outer steel tube on infilled concrete core for circular and square CFST columns with identical sectional area of steel tube are investigated through nonlinear Finite Element (FE) computational models under pure axial loading. Limited nos. of experiments investigations are carried out on circular and square CFST along with Hollow Steel Tube (HST) columns to validate of FE analysis of these models. Influence of parameters like; geometric shape and slenderness \(\left( \frac{L}{i} \right)\) ratio on confinement effect is studied by developing 24 nos. of FE models. Strength and deformation capacity of CFST and HST columns are obtained in terms of load–displacement and load-strain relationships for both, FE models and experimental test specimens. Though circular CFST column provides better confinement to core concrete vis-à-vis square CFST column, the later yields confinement of the order ~10% higher despite confinement effect is not considered in deriving strength capacity as per Eurocode design stipulations. It has been observed that, confinement effect found to reduce with increase in the slenderness ratio.

8. Blast Analysis of FPSO Topside Module Using Pushover Method

   Kiran Patil

   Abstract

   Floating Production Storage and Offloading (FPSOs) are ship-shaped oil and gas processing units capable of operating in various water depths and conditions. As FPSOs collect unprocessed fluids from subsea wells, extract and process oil, water and gas, the risk of explosion due to the handling of these hydrocarbon liquids is very high. To address this, explosion risk analysis is performed to define design accidental loads (blast overpressures) and topside modules shall be checked against blast effect considering these overpressures. The blast analysis can be performed by using linear static analysis and/or nonlinear dynamic analysis. Linear static analysis is very conservative and nonlinear dynamic analysis requires finite element modeling and is time consuming. This paper presents a non-linear pushover analysis method using SACS collapse module to perform the blast analysis in a simplified way. In the proposed method, unit pressure is applied to the structure as uniformly distributed member loads (UDL) in the corresponding directions to represent explosion scenarios. These UDL values are gradually increased until the structure reaches progressive collapse failure to determine the ultimate pressure resistance. The target overpressure is obtained by calculating the dynamic load factor by comparing the natural period of the structure with the pulse duration according to FABIG TN-4 requirements. Finally, the ultimate pressure from pushover analysis is compared with the target overpressure to demonstrate structural integrity of the primary structure of topside module against blast loads. The proposed modeling techniques and analysis method will be very useful and practical in evaluating the explosion risk assessment of FPSO topside modules.

9. A Study on Mainshock-Aftershock Seismic Sequence and Its Effect on Structural Response

   Aakash Varma, Debarati Datta

   Abstract

   Usually, after an earthquake of large magnitude (mainshock), a series of earthquakes known as aftershocks take place on a fault. Aftershocks happen nearby the fault zone where the main shock ruptures as part of the fault’s “readjustment process” after the main slip. Many times, these aftershocks cause additional damage to structures that were already affected by the main shock. Recently, in the Turkey earthquake of 2023, many aftershocks with high magnitude struck the country after a main-shock of magnitude 7.8, causing a huge number of structural collapses and loss of life. Earlier in the 2015 Nepal earthquake, similar things happened. So, the effect of aftershocks on structures is an essential subject for research. Therefore, many researchers studied the mainshock-aftershock (MS-AS) seismic sequences and developed some empirical equations for simulating the aftershock in relation to the main- shock and generating the artificial ground motion data. Based on this recorded and generated ground motion data, the structural response is studied and remedial guidelines are proposed. In this paper, a review is done on both topics. The recent studies on the performance assessment of steel frames, concrete frames and masonry structures under MS-AS are drafted in this paper. Finally, based on the study, the need for an MS-AS study is assessed.

10. Determination of Hyperelastic and Viscoelastic Properties of Elastomer for Simulation of Force–Displacement Hysteretic Property of U-FREI

    Tori Basar, Sajal Kanti Deb

    Abstract

    Selection of appropriate hyperelastic and viscoelastic material models in Finite Element Analysis (FEA) is essential for accurate simulation of the lateral load–displacement behaviour of Fiber Reinforced Elastomeric Isolators (FREI). However, there are limited studies on the experimental determination of viscoelastic and hyperelastic properties of the elastomers used in FREI. The present study aims to experimentally determine the viscoelastic and hyperelastic properties of elastomers and use these parameters in FEA to accurately predict the mechanical behaviour of FREI. Uniaxial tension tests are conducted to obtain the hyperelastic constants, which describe the non-linear elastic response of the material. Additionally, Dynamic Mechanical Analyzer (DMA) tests are performed to determine the viscoelastic constants, which capture the time-dependent behaviour of the material. These experimentally determined material constants are then used to derive the coefficients for the three-term Ogden model and the two-term Prony shear model. These parameters are used for representing the viscoelastic and hyperelastic properties of elastomers in the FEA of Unbonded Fiber Reinforced Elastomeric Isolators (U-FREI). In order to validate the FEA results, a comparison is made between the force–displacement hysteretic response acquired from the simulations and those obtained from the experimental tests. The numerical force–displacement hysteresis loops of U-FREI are in close agreement with those obtained from the experimental study, which demonstrates the accuracy and reliability of the FEA model.

11. Comparative Study of Vertically Irregular RC Shear Wall Building Frames

    Snehal Kaushik

    Abstract

    Asymmetrical buildings with plan or vertical irregularity that are constructed in seismic prone areas are highly susceptible to damage during earthquake shaking. Architects often prefer to design buildings with vertical irregularity due to their aesthetics, but this can lead to serious safety concerns. Therefore, special attention must be given to the design of such irregular buildings, and various seismic codes may prohibit their construction in active seismic zones based on the degree of irregularity. The purpose of this study is to investigate the behavior of vertically irregular buildings with different types of irregularities, including mass, stiffness, and placement of shear walls. An ensemble of 19 building frames with various irregularities is considered and compared with a regular building frame. Static non-linear and time history analyses are carried out, and the results show that there is an increase in drift demand in the tower portion of set-back structures. The capacity of the structure decreases with the increase in irregularity.

12. An Approach for Utilization of Bamboo Reinforcement Technology in the Construction of Compound Wall Panel

    Shilpa Kewate

    Abstract

    In earlier eras’ bricks were considered to be the top choice for com- pound walls to easily work with them. Traditional compound walls are prepared from clay and their durability depends upon the superiority of plaster used while preparation. In relations of material, these walls are very expensive. Traditional compound wall construction implicates extensive installation and a hard labour process. To defeat this problem precast compound walls are gaining much attention for a better design. These Precast compound walls are cost-effective and provide long-lasting life. So there is a requirement to have an alternative and environmentally friendly material in construction that won’t harm the environment, similar to steel, which can add to sustainable development. Bamboo is natural, renewable, and its tensile strength to specific weight ratio is high. Also, it possesses both tensile and compressive strength. This research work recommends the use of bamboo as an alternative to steel reinforcement in the manufacturing process of Precast Reinforced cement concrete (RCC) compound walls. This Recently developed product will be eco friendly and sustainable as instead of steel Bamboo will be used as reinforcement. At the same time, it will have all the advantages of precast compound walls. This product will be cost-effective, reusable, lightweight, and durable, save the time of installation and it will have similar strength as that Precast RCC compound wall.

13. Seismic Performance Assessment of RC Hill Buildings Considering Strong Column and Weak Beam Design

    D. Kushwaha, N. Kumar, S. Setia, P. Lohchab

    Abstract

    Seismic performance of hilly buildings is utmost essential study for the safety of structures in the Himalayan region, as major area lies in the Zone -V of seismic zone map of India. In this paper, the seismic performance of RC hill buildings is assessed by comparing the various parameters of hill building at different slopes with a building on plain having the same number of storeys with and without the consideration of strong column and weak beam design (SCWB). The short column effects and torsional effects are dominant in the building situated on the steep slopes in comparison to building on plain, reducing the overall seismic performance and base shear capacity. The result shows the improved performance of RC hill buildings with the use of strong column weak beam (SCWB) design concept as compared to the buildings designed without the use of SCWB. Further, improved performance of hill buildings considering the SCWB concept appeals to consider in the design and construction of buildings, especially during current times of expeditious industrialization in the Himalayan region.

14. Effect of Uniaxial Eccentric Loading on Strength of Steel Built-Up Beam-Column Section

    Mohit Pipariya, Mamta R. Sharma

    Abstract

    Steel construction has a prominent place in field of construction industry. For heavy loads, the single sections or rolled sections found to be insufficient in their strength. It is mandatory to use of built-up section for high stresses. Under uniaxial bending with axial force, the section strength and member strength for single rolled sections and welded I and H sections may be determined by the interaction equations as per the codal provisions. It is found that currently used linear interaction equations generally lead to conservative result for built-up section in biaxial loading. Therefore, built-up sections are required to some modification in estimation for their load resisting capacity under combined uniaxial and biaxial forces. In this study, nonlinear sectional strength equations are derived for the design of back-to-back connected built-up channel section with connected flange plate under eccentric forces on both minor and major axis. The change in neutral axis location under eccentric uniaxial forces incorporates in this study resulting physical nonlinearity in section behavior. In this Paper, the variations in strength along the minor axis with variation in eccentric force along the major axis and vice versa are interpreted by interaction diagrams. Interaction curves for load-bending moment are developed for uniaxial bending.

15. Seismic Behaviour of Steel Frame with Different Bracings Subjected to Mainshock and Aftershock Sequences

    Vasudeo Chaudhari, Oshu Solanki

    Abstract

    The recent 2023 Turkey earthquake and many past seismic events demonstrated that aftershocks could potentially collapse the structure, which may not collapse during the mainshock. However, design philosophies are based on the peak earthquake force. Hence understanding the performance of structures subjected to mainshock and aftershock earthquake sequences is crucial. The effect of the earthquake sequences is well-studied for reinforced concrete buildings, but more work is needed for steel structures. Hence, this study evaluates the behaviour of a 12-story frame with various bracing, including V, inverted-V (IV), K and inverted-K (IK). The duration of the rest time between the mainshock and aftershock is defined, and nonlinear dynamic analysis is performed using OpenSees. The performance of the frame with various bracing is compared by varying the seismic intensity and soil condition. The findings can contribute to the development of effective seismic design strategies.

16. Comparative Study of Seismic Analysis and Design of RC-SMRF by Force Based Design and Performance Based Seismic Analysis Method

    Rohit Vyas, R. C. Bush, B. Biradar Bapugouda, Anoop I. Shirkol

    Abstract

    The proportioning and detailing requirements of Reinforced Concrete Special Moment Resisting Frame (RC-SMRF) are intended to make the frames capable of resisting strong earthquake shaking without significant loss of stiffness or strength. But it has been observed in recent years that the current seismic design methods are not always able to provide the desired and satisfactory performance. It happens because of inelastic behaviour of frame elements during strong earthquakes. So Performance Based Seismic Analysis (PBSA) is proposed in this study to incorporate the inelastic behaviour. Out of 6 type of performance based method, performance based plastic design (PBPD) method is considered for the study which is suggested by Liao and Goel in 2012. A 6 storey RC-SMRF is considered for the study which is initially analyzed and designed by Force Based Design (FBD) method as per the IS 1893:2016 guidelines and later the same frame is analyzed by performance based plastic design (PBPD) method as per Liao and Goel (J Mar Sci Technol 20:304–310, 2012) guidelines. ETABS software is the tool used to create the mathematical model of the frame. To assess the seismic performance of the study frames, Non Linear Static Pushover Analysis (NLSPA) is performed on both the frames and a comparison is prepared in terms of displacements and drift ratios and it is found that at performance point performance based plastic design (PBPD) frame has 3.01 times higher strength than FBD frame from which it is found that PBSA method represents better seismic performance and strength in nonlinear region up-to predefined target drift for the current study frame.

17. Finite Element Modelling of Shivsagar ‘Shiva Dol’

    Monalisha Gautom, Nayanmoni Chetia, Baharul Hussain

    Abstract

    In this study, natural frequency of Shiva Dol which is the tallest Shiva temple tower (40 m) in India has been obtained. The dol has a massive dome on the top which is termed as Kosoloi and this part of the temple is made of pure gold. The structural stability and its seismic behaviour of the temple using Finite Element Based software have been done. The North-East India lies in the seismic zone ‘V’ which is the most vulnerable earthquake zone of India. This temple has been in existence for more than 280 years and has continued to stand without any reinforcement after being hit by Assam's most powerful earthquake “1897 Assam earthquake” and “1950 Assam—Tibet earthquake”. It was built using only traditionally available materials i.e. sticky rice, snail lime, stone lime, Mati maah (vigna mugno), hemp (a kind of plant fiber), molasses, duck eggs etc. without the use of any modern construction techniques, thus the temple's durability is quite high even under harsh climate. The Shiva Dol constructed during the Ahom dynasty (1744-1751AD) in Shivsagar district of Assam at 26°59′18″N and 94°37′59″E in the banks of the Sivasagar tank, India. This graceful temple of brick and stone masonry was built by Ambika Devi, one of the queens of Ahom King Siva Singha (1714–44 CE). The temple stands on the southern bank of sivasagar tank which is termed as Borpukhuri covering an area of 130 acres. It has fully developed axial plan comprising of garbhagriha, antarala and mandapa. After a detail topographic survey of the site, the plan and elevation of the temple was prepared using AUTOCAD®. A 3D model of Shiva Dol has also been prepared using SOLIDWORKS®. Numerical analysis of the temple using ABAQUS® has been carried out. The first fundamental frequency of the temple was found to be 23.845 cps which was quite high as compared to the frequencies of the past earthquakes.

18. Seismic Vulnerability Assessment of Building Stocks at Village Jant, Mahendergarh, Haryana

    S. A. M. Zaidi, N. Kumar, R. R. Nath

    Abstract

    Seismic vulnerability assessment of structures is a preliminary objective of any seismic microzonation process that aims for disaster risk reduction. Vulnerability assessment of the building stocks in potential earthquake hazard zone have high significance as a part of preparatory phase of disaster mitigation practices. The Mahendergarh-Dehradun fault (MDF), situated in western Ganga basin is an active fault and it has showed some recent low to mid intensity earthquake in last few years. Village Jant which is in vicinity of Central University of Haryana (CUH), Mahendergarh is considered for assessing the seismic vulnerability of building stocks adopting the Rapid Visual Screening (RVS) procedure proposed by the National Disaster Management Authority (NDMA). In this approach mapping of life threatening parameters (LTP) are taken as basis of primary assessment. The nuances associated with buildings like sitting issues, foundation, architectural aspects, material conditions and materials details are considered as LTP. In Village Jant, 104 buildings are investigated through RVS and it is observed building stocks comprises of mainly burnt clay brick masonry buildings (74%) and the left buildings are either confined masonry buildings (20%) or random rubble stone masonry (4%) etc. Most of the building built post 2015, are confined masonry buildings. Other common observations are like adjoining buildings with different storey heights (prone to ponding effects), large or heavy cantilever balconies, unanchored water tank, unanchored roof, cracks in load bearing walls, staircase at unsymmetrical location, buildings have walls made with mud mortar. Above mentioned results highlight the presence of non-engineered buildings which are vulnerable to low to moderate earthquake hence simplified vulnerability assessment is required in order to go forward in disaster risk reduction.